Origin, evolution and sedimentary processes ...

1 downloads 0 Views 10MB Size Report
Sierro, F.J., Flores, J.A., Civis, J., González-Delgado, J.A., Francés, G., 1993. Late Miocene ... Sobiesiak, M.S., Kneller, B., Alsop, G.I., Milana, J.P., 2016.
SEDGEO-05229; No of Pages 16 Sedimentary Geology xxx (2017) xxx–xxx

Contents lists available at ScienceDirect

Sedimentary Geology journal homepage: www.elsevier.com/locate/sedgeo

Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain F. Sola a, Á. Puga-Bernabéu b,⁎, J. Aguirre b, J.C. Braga b a b

Departamento de Biología y Geología, Universidad de Almería, 04120 Almería, Spain Departamento de Estratigrafía y Paleontología, Universidad de Granada, Campus de Fuentenueva, 18002 Granada, Spain

a r t i c l e

i n f o

Article history: Received 18 May 2017 Received in revised form 28 August 2017 Accepted 12 September 2017 Available online xxxx Keywords: Mass-transport deposits Slope failure evolution Debrites and turbidites Late Miocene Sierra de Gádor Almería-Níjar Basin

a b s t r a c t A submarine landslide, the Alhama de Almería Slide, influenced late Tortonian and early Messinian (late Miocene) sedimentary processes in the vicinity of Alhama de Almería in southeast Spain. Its 220-m-high headscarp and deposits are now subaerially exposed. The landslide occurred at the northern slope of the antecedent relief of the present-day Sierra de Gádor mountain range. This is a large antiform trending east– west to east-northeast–west-southwest, which has been uplifting since the late Miocene due to convergence of the African and Eurasian plates. During the Tortonian, this relief was an island separated from the Iberian Peninsula mainland by the Alpujarra corridor, a small and narrow intermontane basin of the Betic Cordillera in the western Mediterranean Sea. The materials involved in the slope failure were Triassic dolostones and phyllites from the metamorphic Alpujárride Complex and Tortonian marine conglomerates, sandstones, and marls that formed an initial sedimentary cover on the basement rocks. Coherent large masses of metamorphic rocks and Miocene deposits at the base of the headscarp distally change to chaotic deposits of blocks of different lithologies embedded in upper Tortonian marine marls, and high-strength cohesive debrites. During downslope sliding, coherent carbonate blocks brecciated due to their greater strength. Phyllites disintegrated, forming a cohesive matrix that engulfed and/or sustained the carbonate blocks. Resedimented, channelized breccias were formed by continuing clast collision, bed fragmentation, and disaggregation of the failed mass. The conditions leading to rock/sediment failure were favoured by steep slopes and weak planes at the contact between the basement carbonates and phyllites. Displacement of collapsed rocks created a canyon-like depression at the southeast edge of the landslide. This depression funnelled sediment gravity flows that were generated upslope, promoting local thick accumulations of sediments during the latest Tortonian-earliest Messinian. The insights from this exposed outcrop have implications for understanding the mechanisms and products of mass-transport deposits on the modern seafloor and the recognition of past failures from subsurface records. © 2017 Elsevier B.V. All rights reserved.

1. Introduction Submarine mass-failures include the largest sedimentation events on Earth and are fundamental in the long-term evolution of continental margins worldwide (Gee et al., 2007; Micallef et al., 2009; Alves, 2010; Joanne et al., 2010). These processes considerably remould the submarine landscape by remobilizing up to 104 km3 of sediment covering seafloor areas on the order of 100,000 km2 (Moore et al., 1989; Haflidason et al., 2004; Calvès et al., 2015; Safranova et al., 2015; Leslie and Mann, 2016). The resulting mass-transport deposits also influence the characteristics of post-failure sedimentation, particularly turbidite deposition, as these deposits may create conduits favourable for channelling turbidity-current flows, obstacles that redirect turbidity currents, or local irregularities for sediment ponding ⁎ Corresponding author. E-mail address: [email protected] (Á. Puga-Bernabéu).

(Armitage et al., 2009; Algar et al., 2011; Tinterri and Magalhaes, 2011; Abdurrokhim and Ito, 2013). After release, submarine slope failures generate a variety of mass-transport deposits (Moscarderlli and Wood, 2007; Tripsanas et al., 2008) and may transform downslope into a flowing mixture of sediment and water that lead to the deposition of debrites and turbidites (Strachan, 2008; Talling, 2014). Subaerial outcrops provide detailed information on the internal structures and the architecture of the redeposited sediments, allowing a process-based analysis at the meso-scale (i.e., seismic and sub-seismic) of the mass-transport deposits (Drzewiecki and Simó, 2002; Strachan, 2002; Callot et al., 2008; Ogata et al., 2016). These insights complement the information on the overall gross anatomy of mass-transport deposits depicted with modern seafloor imagery and subsurface seismic data (Canals et al., 2004; Janson et al., 2010; Dalla Valle et al., 2013; Hogan et al., 2013) as well as relatively scarce scientific drilling (Friant et al., 2015).

https://doi.org/10.1016/j.sedgeo.2017.09.005 0037-0738/© 2017 Elsevier B.V. All rights reserved.

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

2

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

Large ancient landslides (102 to 103 km2) are often difficult to recognize in the exposed sedimentary record because of their size and relatively low preservation potential, especially in orogenic belts (Woodcock, 1979; Macdonald et al., 1993). By contrast, less extensive, submarine landslide deposits can be potentially preserved and sedimentary processes associated with the slope failure can be studied Almanzora Corridor

in detail. In this work, we present the Alhama de Almería Slide, an example of an emerged, well-preserved, Miocene submarine bedrock landslide, not of an accretionary slope, formed in an uplifting compressive tectonic setting in southeast Spain. The main aims of this paper are: 1) to describe the main sedimentary facies of the pre-, post- and landslide deposits; and 2) interpret the sedimentary processes involved

A

Huércal-Overa

C

IBERIA

Sª de Baza 100 km

External Zone

Vera

Internal Zone

Sª de los Filabres Sorbas Tabernas

Alpujarra Corridor

Sª Alhamilla Níjar

Fig. 1B,C

Sierra Cabrera

Unit 1 Sub-unit 2a

UB

Sub-unit 2b Carboneras

CM

Sª de Gádor Poniente Basin

BC-2

BM

Almería Cabo de Gata

Maláguide Complex Alpujárride Complex Nevado-Filábride Complex

BC-1

37°N

20 km

1000 m

Unit 3

2°W

Neogene sediments Neogene volcanics

2°37'W

undisturbed basement +Tortonian cover coherent land-slid bedrock blocks chaotic mélange

post-landslide marls post-landslide SGF younger deposits 2°33'W

2°35'W

B

400

700

Huéchar

Alhama de Almería 0

0 11

36°57'N

Cerro de la Cruz 700

UB BC-1 900

600

Collado Moradillo Loma de los Hinojos

CM

illo

BC-2

36°56'N

Cerro del Mortero

ch

u lC

o.

de

Bc 1100

BM

500 m 700

contour

Alpujárride phylites & quartzites - Triassic

redeposited heterozoan carbonates, bioclastic sandstones & conglomerates - late Tortonian/early Messinian

sandstones & conglomerates - Tortonian

marls - late Tortonian/early Messinian

track

sandy marls & sandstones - Tortonian

reef limestones - Messinian

stream

chaotic melange - late Tortonian

marine & continental deposits - Pliocene

logged sections

marl intervals in the chaotic mélange - late Tortonian

Quaternary deposits

base of headscarp

Alpujárride carbonates - Triassic

road

Fig. 1. Geological location of the Alhama de Almería Slide. (A) Neogene basins in south-eastern Spain and location of the study area (red inset) on the north-eastern slope of Sierra de Gádor. (B) Detailed geological map of the study area. Logged stratigraphic sections: UB: Undisturbed bedrock; CM: Collado Moradillo; BC: Barranco del Cuchillo; BM: Balate de Murillo. Contours in metres. (C) Simplified geological map showing the distribution of the recognized landslide units (see text). The landslide materials involve large coherent blocks of basement and Miocene rocks and a chaotic mélange. Logged sections as in (B). SFG: sediment gravity flow deposits. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

emergent land Mediterranean Sea

Iberian Peninsula

paleoshoreline precursor of Sierra de Gádor in as Bas Tabern

Alpujarra Corridor Adra

Vera

Sorbas Carboneras

Almería present-day shoreline

10 km

Fig. 2. Sketch showing the late Tortonian palaeogeography in southern Spain. Inset marks the location of the study area (modified from Braga et al., 2003).

in a sequential failure process. The observed stratigraphical, morphological and sedimentological traits provide useful criteria for identifying and interpreting subsurface and incompletely exposed emergent submarine landslide deposits. This work also contributes to the understanding of the mechanisms involved in submarine landslide and deposition, especially in mass-transport complexes of similar dimensions. Additionally, we also focus on the palaeoenvironmental interpretation of the Miocene materials involved in the landslide and the sedimentary processes following the landslide, which suggest a new type of offshore redeposition model in temperate-water carbonate systems. 2. Methods The Alhama de Almería Slide in the vicinity of Alhama de Almería in southeast Spain was investigated through detailed field mapping at 1:10,000 scale, including the identification and distribution of the undisturbed materials and those involved in mass failure. The internal and external characteristics of the landslide deposits, their vertical and lateral changes, and relationships with the host undisturbed sedimentary succession were analysed in laterally continuous, good exposures in the semi-arid study area. Five representative stratigraphic sections, 40–230 m in thickness, were logged in selected outcrops to

characterize the lithological and lithofacies successions in the units distinguished and to reconstruct the syn- to post-depositional geomorphic variations related to the landslide emplacement. Accessibility to the outcrops determined the precise location of the sections. Bed geometry and thickness, lithology, grain size, texture, sedimentary structures, bioclastic content and matrix characteristics were recorded in each section together with the meso-scale description of the different units. Field data were complemented with petrographic analysis and identification of fossil components in 29 thin sections from representative samples of the distinguished lithofacies. Biostratigraphic dating was based on planktonic foraminifer assemblages collected from 12 washed silty-marl samples. The 3D spatial relationships between the mapped deposits were also analysed using ArcGis 10.5. The mapped area was first draped on a high-resolution (0.5 m) orthophoto (Instituto Geográfico Nacional, 2008) and then over a Digital Elevation Model of the area at 10 m grid resolution using QPS-Fledermaus v. 7.4. 3. Geological setting The study area is located south of Alhama de Almería on the northern slope of Sierra de Gádor at the transition from the north-western margin of the Neogene Almería-Níjar Basin to the Alpujarra Corridor, southeast Spain. This is a narrow, east-west elongated intermontane Neogene basin that separates the Sierra Nevada from the coastal range to the south (Fig. 1). Sierra de Gádor is a large antiform trending east–west to east-northeast–west-southwest of Palaeozoic to Triassic (Baena and Voermans, 1983) Betic basement rocks (Marín-Lechado et al., 2007; Pedrera et al., 2012). The Sierra de Gádor antiform is the result of late Miocene to Recent north-northwest–south-southeast compression due to convergence between the Eurasian and African plates (Marín-Lechado et al., 2007; Pedrera et al., 2012). This compression caused uplift of the Betic basement highs (antiforms) and eventually the complete emersion of the region (Marín-Lechado et al., 2007). The palaeo-relief of the Sierra de Gádor emerged as an island during the late Tortonian (Braga et al., 2003) (Fig. 2). This island was at that time separated from the Iberian Peninsula by the Alpujarra Corridor and the Tabernas Basin, two small marginal extensions of the Mediterranean Sea (Fig. 2). Due to continued uplift, the Alpujarra Corridor emerged in the early Messinian and Sierra de Gádor welded to the mainland (Braga et al., 2003). The Miocene rocks unconformably overlie a Betic basement. The lower four units, late Tortonian in age, comprise coarse-grained terrigenous deposits, bioclastic limestones and marls (Fig. 3). These units, the subject of this work, are described in detail below. The study

Marine & continental conglomerates, sands & silts Reef limestones & marls

Channelized polymictic breccias & intraformational blocks Heterometric basement & Miocene blocks within a phyllite-rich/marly matrix

Alpujárride carbonates 500 m

Alpujárride phyllites

eTo. Triassic

Sandstones, conglomerates, breccias, marls & silty marls

late Tortonian

Marls & silty/sandy marls Breccias & heterozoan limestones mixed with terrigenous

Plioc. Messin.

W-E

50 m

3

Fig. 3. Neogene stratigraphy of the study area at the transition from the north-western margin of the Almería-Níjar Basin to the Alpujarra Corridor. Plioc: Pliocene; Messin; Messinian; eTo: early Tortonian.

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

4

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

Fig. 4. Digital elevation model of the study area (10 m grid resolution) with draped geological map shown in Fig. 1B. Most of the landslide materials are formed by several coherent blocks of basement rocks. Also observe the canyon depression created by the rotation of the coherent blocks, subsequently filled with a chaotic mélange and post-landslide deposits. Lithology colour codes as indicated in Fig. 1B. Dashed line marks the base of the headscarp.

units are unconformably overlain by coral reefs and coeval redeposited reef-blocks, breccias, bioclastic debrites, and marls, early Messinian in age (Sola et al., 2017). The Miocene units are separated by an erosion surface from the overlying Pliocene marine and continental deposits (Baena and Voermans, 1983; Aguirre, 1998; García-García, 2004).

sedimentary characteristics, these materials can be grouped into three different units: pre-landslide, landslide, and post-landslide deposits (Fig. 1C).

4. Results

Exposures of this unit, which constitutes the non-displaced, undisturbed area adjacent to the rupture surface of the landslide, have a semicircular shape in plan-view and 3D perspective view (Figs. 1B, C, 4). The basement rocks belong to the Alpujárride Complex of the Internal Zones of the Betic Cordillera. According to geological maps of the area, they correspond to the Felix and Gádor nappes, the stacked

The study materials involved in the landslide crop out in an area 5.6 km long and 5.2 km in maximum width (Figs. 1B, C, 4). The landslide scar has a semicircular shape and a length of about 10 km. According to their geometry, stratigraphic position, internal organization and

4.1. Unit 1. Pre-landslide: basement and Miocene sedimentary cover

Table 1 Summary of facies attributes for the Miocene sedimentary cover. Lithofacies

Bedding/thickness bedsets

Structures

M1 Clast-supported Irregular, erosive bases/up to 8 m breccia M2 Clast-supported Channelized erosive bases/cm to dm conglomerates Bed packages are up to 5 m thick M3 Sandstone with clasts M4 Conglomerate with bioclasts

Irregular erosive bases dm to m bedsets are up to 5.5 m thick. Concave-plane with erosive bases/dm to m concave-plane bed sets/6 m in thickness

M5 Bioclastic sandstone

Small-scale trough cross-bedding, with troughs m in wavelength and dm in amplitude/4.5 m thick Plane-parallel and concave-plane with slightly erosive bases/cm to dm

M6 Sandstone beds with dispersed clasts M7 Sandy/silty marls with dispersed clasts

Plane-parallel, commonly eroded/cm to m

Ill-defined crosslamination Fossils concentrated at the top surface

Frequent parallel lamination; small ripples; bioturbated Bioturbated

Clasts nature/size

Matrix Occurrence

Dolostone, quartzite and phyllite/highly heterometric, granules to boulders, up to 6 m in size; commonly pebbles Quartzites and carbonate. Dolostone clasts have Gastrochaenolites and Entobia borings/granules to pebbles Dispersed dolostone and quartzite pebbles

Sandy Levels the irregular top of matrix basement and fills in dykes in the dolostone Sandy Alternating with M3 matrix Alternating with and including lenses of M2 Overlying M2 and M3

Dolostone and quartzite granules to pebbles large Sandy matrix size bioclasts of bivalves (oysters and pectinids) and echinoids, and rhodoliths; rhodoliths are made up of relatively thin coralline algal covers around pebbles common borings of Gastrochaenolites and Entobia in carbonate blocks Medium to coarse sand, dispersed pebbles Overlying M4

Quartzites and carbonate/dispersed granules to cobbles up to 15 cm

Alternating with M7

Quartzites and carbonate, common borings in carbonate clasts/dispersed rounded granules to pebbles

Alternating with M6

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

bioclastic sandstone with conglomerate lenses (facies M3) bioclastic conglomerate (facies M2)

Unit 1

Triassic

Tortonian

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

heterometric breccia (facies M1) Alpujárride dolostones

10 m

Fig. 5. Stratigraphic column of logged section on the undisturbed ground adjacent to the landslide crown showing the in situ pre-landslide Miocene deposits of Unit 1 (see Fig. 1B for location).

tectonic units forming the north-eastern Sierra de Gádor (Baena and Voermans, 1983; Sanz de Galdeano, 1985). The lithological succession of the Alpujárride nappes includes phyllites, quartzites, and gypsum at the base, followed by calcschists and dolostones with minor limestones, N600 m in thick. All these rocks are (Permo)-Triassic in age, according to Baena and Voermans (1983). This Betic basement is overlain by terrigenous marine deposits comprising seven lithofacies (Table 1), although only three of them are preserved in Unit 1 (Fig. 5). Coarse-grained terrigenous clast-supported breccias (facies M1) and conglomerates (facies M2) with a sandy matrix and sandstone with dispersed basement clasts (facies M3) are arranged in bedset packages a few metres thick with irregular and erosive bases. Facies M1 levels the irregular top and fills in dykes in the basement while facies M2 intercalates with M3. Facies M2 and M3 contain varying proportions of bioclasts, which include bivalves (oysters and pectinids), echinoids, and coralline algae. 4.2. Unit 2. Landslide deposits The materials involved in the slope failure are about 1000 m thick and comprise two distinct sub-units. 4.2.1. Subunit 2a: coherent land-slid blocks of basement rocks and Miocene cover This unit contains most of the landslide materials and is formed by several large coherent blocks (discrete slide components) derived

5

from basement rocks, hundreds of metres thick (facies B1; Figs. 1C, 4; Table 2). The large coherent blocks consist of the same stacked Alpujárride tectonic units as the bedrock with the same lithological succession. They are overlain by Miocene breccias, marine bioclastic conglomerates and sandstones, comprising clasts from the Alpujárride basement (facies M1–M3 of unit 1; Fig. 6; Table 1). The overlying facies M4 is composed of concave-plane beds of conglomerates and microconglomerates (dolostone and quartzite granules to pebbles) with bioclasts of molluscs, echinoids, and coralline algae, including rhodoliths. Rhodoliths are made up of relatively thin coralline algal covers around pebbles. The microconglomerates are overlain by bioclastic sandstones with small scale trough cross-bedding (facies M5), which gradually change to an alternation between parallellaminated, locally cross-laminated, concave-plane sandstone beds with dispersed cobbles and pebbles (facies M6; Fig. 7A) and sandy to silty marls with dispersed clasts (facies M7). Small-scale folded and rotated silty marl beds are visible locally (Fig. 7B). Planktonic foraminifer assemblages indicate a Tortonian age for the marls (see Section 4.4). The headscarp height can be estimated at a minimum of 220 m, taking into account the difference in elevation between the thin Miocene shallow-water sediment cover on the undisturbed ground at the edge of the scar (Loma de los Hinojos) and the same Miocene cover at the top of the slid-down rocks in Cerro del Mortero (Fig. 1B). 4.2.2. Subunit 2b: chaotic mélange of basement blocks, pre-landslide Miocene deposits and marls laterally changing to a suite of redeposited materials with blocks This unit, located south-east of subunit 2a, crops out over 4 km in a west-northwest–east-southeast direction (Figs. 1B, C, 4). The chaotic mélange strongly changes in gross composition over relatively short distances. In the proximal areas, closer to the landslide scar and overlying the sandy marls of subunit 2a (Fig. 6), the unit consists of jumbled stacks of megablocks of Alpujárride Complex dolostones, up to hundreds of metres in size, most of them with a marine Miocene cover at the top, randomly distributed heterometric blocks of Alpujárride dolostones and phyllites, and blocks of Miocene conglomerates and sandstones, from decimetres to tens of metres in size (Fig. 8). In the lower part, the space among the blocks is filled by sandy to silty marls with dispersed sand grains of varying size (facies C1; Table 2) or by a

Table 2 Summary of facies attributes for landslide Unit 2. Lithofacies Subunit 2a B1 Coherent basement blocks

Subunit 2b C1 Sandy to silty marls with dispersed clasts

C2 a: Matrix-supported breccia with muddy matrix b: Clast-supported breccia with muddy matrix

C3 Breccia with sandy matrix

Bedding/thickness bedsets

Structures/texture

Massive to well-stratified, dip incongruent with similar rocks in Unit 1/hundreds of metres bedsets of facies M1-M7 at the top

Stacked tectonic units of Carbonate, quartzite, and phyllite. Locally with facies M1–M7 at the top the footwall basement with the same lithological succession

Underlying facies of Subunit 2 and Unit 3

Plane-parallel, commonly eroded/cm to m

Bioturbated

Alternating with C2 and C3; intercalated as lenses in C3

Irregular erosive bases and uneven bed tops/dm to m common amalgamation of several beds; concave-plane bedsets Irregular erosive bases and uneven bed tops/dm to m common amalgamation of several beds; concave-plane and concaveconvex bedsets

Rapid and frequent changes from clast- to matrix-supported/ locally inverse grading

Clast-supported/locally Concave-plane with erosive inverse grading bases/dm to m common amalgamation; concave-plane bed sets

Clasts nature/size

Quartzites and carbonate, common borings in carbonate clasts/dispersed subangular to angular granules to boulders, up to 5 m in size; commonly pebbles Carbonate, quartzite, and phyllite fragments; common borings in carbonate blocks/granules to boulders; metric phyllite boulders Quartzites, phyllites and carbonates from the Alpujárride Complex, Miocene bioclastic sandstones, bioclasts (oysters, pectinids); common borings in carbonate blocks; clasts from angular with sharp edges (mainly phyllite fragments) to rounded/mm to dm Carbonate, quartzite, and phyllite fragments/granules to cobbles

Matrix

Occurrence

Alternating and Muddy matrix mainly derived from intercalating C1; lenses in C1 phyllite Muddy matrix mainly derived from phyllite

Sand

Alternating and intercalating C2; scarce

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

6

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

Unit 2b

decimetre- to metre-thick beds with irregular bases and uneven tops, commonly amalgamated. Bedsets are concave-plane. Clasts in this facies include phyllites, quartzites, and carbonates from the Alpujárride Complex (Fig. 9B). Facies C2a exhibits rapid and frequent changes to facies C2b (Fig. 10C). This facies, similar to facies C2a (Table 2), is composed of clast-supported breccias (Fig. 10D), locally with inverse grading. Apart from basement clasts, this facies also includes bioclastic sandstones (facies M5) and bioclasts (oysters, pectinids) from the Miocene cover of the Alpujárride basement. Both facies C2a and C2b alternate with, or are intercalated or in lenses within facies C1. Facies C3 locally occurs, alternating with and intercalated in facies C2 and composed of breccias with a sandy matrix made up of granules to cobbles of basement clasts. The distal succession of the chaotic mélange includes intraformational blocks of bed packages of the same unit and of the underlying Miocene marine sandstones (mainly facies M6) (Fig. 11A). The bed packages are rotated with steeper dips than the overlying beds or show synsedimentary folding and faulting (Fig. 11B). Shear bands are also visible in the phyllite muddy matrix.

Tortonian

4.3. Unit 3: Post-landslide: redeposited siliciclastic and carbonate sediments and marls

dolomitic breccia mud rich in phyllite debris with large blocks sandy marl with dispersed clasts (facies C1) alternating marl & sandstone with dispersed clasts (facies M6-M7)

Unit 2a

bioclastic sandstone (facies M5) bioclastic microconglomerate (facies M4) bioclastic sandstone with conglomerate lenses (facies M3) bioclastic miconglomerate (facies M2) heterometric breccia (facies M1) Alpujárride dolostones (facies B1)

10 m Fig. 6. Stratigraphic column of logged Collado Moradillo section showing the landslide deposits (see Fig. 1B for location). Miocene deposits (facies M1-M7; Subunit 2a) in the section are at the top of a large coherent bedrock block.

muddy sediment derived from basement phyllites (Figs. 6, 8A), locally showing shear bands (Fig. 8B, C). In the upper part, the mélange consists of clusters of blocks in close contact showing varying degrees of brecciation with a matrix of ground dolostone (Fig. 8B–D). The large dimensions of the Alpujárride megablocks led geologists mapping the region to consider them as to be individual imbricated tectonic units (Sanz de Galdeano, 1985). In distal areas, the size and relative volume of large bedrock blocks strongly decreases, giving way to a diverse array of lithofacies (Table 2) and dominance of individual channelized breccia beds of varying lateral continuity and thickness (facies C2; Figs. 9, 10A; Table 2), although a few outsized blocks occur in the distalmost outcrop. Facies C2a comprises matrix-supported breccias with a muddy matrix derived mainly from phyllite (Fig. 10B). This facies is arranged in

The post-landslide unit is restricted to the southern part of the study area, cropping out along the Barranco del Cuchillo ravine in west-southwest–east-northeast direction and unconformably overlaying unit 2 (Figs. 1B, 4). The unit is a roughly pyramidal sediment body of triangular section about 4500 m long and up to 1600 m wide. In the proximal areas (Balate de Murillo section; see Fig. 1B for location) the unit consists of three decametre-thick stacked bodies separated by erosive concave-up bases (Fig. 12). The successive bodies retrograde and onlap the basement to the south (Figs. 1B, 4). In distal areas, the post-event deposits reach a thickness of about 200 m but pinch out against the underlying units (in less than 0.25 km to the northwest). The lithofacies observed in this unit can be grouped into six facies types, described in detail in Table 3 and shown in Fig. 13, comprising clast- to matrix-supported breccias (facies PL1), rudstones with terrigenous clasts (facies PL2), and bioclastic grainstones (facies PL3) alternating with silty marls (facies PL4), silty marls with dispersed clasts (facies PL5), and silty sandstones with dispersed clasts (facies PL6). Facies PL1 are arranged in concave-plane beds with erosive bases and rapid changes in thickness, from centimetres to decimetres, often amalgamated and showing inverse grading (Fig. 14A). This facies includes two sub-facies according to the matrix type (Table 2): sandy matrix (facies PL1a), and rudstone (facies PL1b) (Fig. 14B, C). Beds of facies PL2 are plane-parallel to concave-plane with erosive bases, and show inverse grading, parallel lamination, and local clast pockets (Fig. 14D). Beds are commonly amalgamated and arranged in concaveplane bedsets. Bioclastic components in this facies are bryozoans, bivalves, coralline algae, echinoids, Ditrupa, benthic foraminifera (small and larger), and planktonic foraminifera. Facies PL2 changes within the same bed to facies PL1b and vertically and laterally to facies PL3. Facies PL3 exhibits parallel lamination and has a bioclastic composition similar to that of facies PL2. Dispersed clasts in facies PL5 and PL6 include granules to cobbles of basement lithologies (carbonate, quatzite, and phyllite; Fig. 14A). Facies PL5 exhibits parallel lamination and, locally, ripple cross-lamination. In contrast to the underlying landslide and pre-landslide units, bioclastic carbonate is a major component in the detrital post-landslide deposits. Bioclasts include coralline red algae, bryozoans, calcitic bivalves (pectinids and oysters), larger and small benthic foraminifers, and minor serpulids, barnacles, and sponges. This bioclast association is characteristic of heterozoan carbonates and similar to the components of upper Tortonian-lowermost Messinian carbonates cropping out to the southeast of the study area (Sola et al., 2017). These heterozoan carbonates comprise a distinctive unit of the sedimentary infill of Neogene basins in southeast Spain (Martín and Braga, 1994; Martín et al., 1996; Betzler et al., 2000; Braga et al., 2001;

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

7

Fig. 7. Facies in the upper part of subunit 2a. (A) Facies M6: sandstone with dispersed clasts showing distinctive parallel lamination. Lens cap is 6 cm in diameter. (B) Small-scale folds in facies M7 (silty/sandy marls). Coin is 2.3 cm in diameter.

Planktonic foraminifer assemblages in all fine-grained samples from the distal deposits of the Miocene basement cover, from the chaotic mélange of subunit 2b, and from unit 3 help date the study deposits. Pre-landslide deposits are characterized by the presence of Neogloboquadrina acostaensis, Globorotalia scitula group, and G. menardii group. This association indicates a Tortonian age. The landslide sediments in the upper part of the chaotic unit contain N. acostaensis, N. humerosa, G. scitula, and scarce specimens of keeled globorotalids of the G. menardii group. The first occurrence of N. humerosa is dated as 8.5 Ma (Berggen et al., 1995; Wade et al., 2011), or as 8.6 Ma (BouDagher-Fadel, 2015). According to the planktonic foraminifer (PF) events of Sierro et al. (1993), shortly before the abundant occurrence of Globorotalia menardii group II, marking PF-Event 2, there was a significant reduction in keeled globorotaliids and an overabundance of the G. scitula group (Sierro et al., 1993). This implies that the planktonic foraminifer assemblages of the upper part of the chaotic mélange are late Tortonian, most likely between PF-Event 1 and PF-Event 2, dated as 7.5 and 7.3 Ma, respectively, according to Lirer and Iaccarino (2011). In the uppermost sample of unit 3 in the Barranco del Cuchillo section, the presence of specimens of the Globorotalia miotumida group (G. dalii) indicates a Messinian age, i.e., younger than 7.24 Ma (Lirer and Iaccarino, 2011; Cohen et al., 2013).

which together with the occurrence of trough cross-bedding and fossils of bivalves (pectinids and oysters) and echinoids, which are generally fragmented, indicate a turbulent shallow-water marine palaeoenvironment of deposition with a progressive upward decrease in energy, probably due to deepening. The top of the basement failed and rotated blocks (subunit 2a) were draped by Miocene shallowwater marine deposits similar in lithology and fossil components to the Miocene in the undisturbed bedrock. In the Collado Moradillo section (Fig. 6) the transition from conglomerates to sandstones shows a concentration of large oysters and rhodoliths. The rhodoliths are made up of terrigenous-clast nuclei much larger than the relatively thin coralline-algal cover. This type of rhodoliths and the large, bouldersized oysters are characteristic of upper Tortonian shallowwater deposits in other basins in SE Spain (Braga and Martín, 1988; Jiménez et al., 1991). The sandstones change upwards into sandy marls with thin sandstone beds and bed packages, which can be interpreted as turbidite deposits (Figs. 6, 7A). Foraminifers in the marls indicate a relative deep-water slope environment of deposition. The planktonic:benthic ratio (P:P + B), a proxy for palaeobathymetric estimates, is higher than 70% in all samples, indicating offshore deep-water conditions. In addition, benthic foraminiferal assemblages are dominated by Cibicides spp., Cibicidoides spp., Siphonina planoconvexa, Planulina ariminensis, Melonis spp., Pullenia spp., Lenticulina spp., Gyroidina spp., Uvigerina spp., and Cassidulina spp. All these taxa are preferentially distributed from outer shelf to the slope environments (Murray, 2006). In summary, the pre-landslide Tortonian sediments in subunit 2a record a progressive upward change from shallow water to deeper marine deposits.

5. Discussion

5.2. Formation of the Alhama de Almería Slide

The lithofacies, lithostratigraphy, and spatio-temporal relationships of the materials in the study area, reflected in the geological map and logged sections, can be interpreted as the result of a large landslide affecting the Alpujárride basement and its initial Tortonian sedimentary cover. In the following sections the palaeoenvironmental conditions before the slope failure, the failure processes, and the sedimentological implications of the Alhama de Almería Slide are discussed.

Sedimentological and geomorphological features of the Alhama de Almería Slide provide insight on its failure evolution, depositional processes and the possible triggers.

Puga-Bernabéu et al., 2007a, 2007b; Sola et al., 2013), known as the Azagador Member of the Turre Formation, defined by Völk and Rondeel (1964) in the Vera Basin. 4.4. Age of the deposits

5.1. Pre-landslide setting: Miocene deposits in unit 1 and subunit 2a The Miocene cover over the basement in the undisturbed host rocks (unit 1) constitutes a roughly fining-upward succession of breccia with large basement boulders, breccia and conglomerate, conglomerate with sandstone lenses, and sandstone with conglomerate lenses (Fig. 5),

5.2.1. Evolution of the slope failure Sediment destabilization likely began at the lower part of the slope, as evidenced by the small-scale folded slope beds in the pre-slide unit (Fig. 7B). This process probably induced small-scale retrogressive failing of the slope sediments (e.g., Strozyk et al., 2010; Baeten et al., 2014), releasing strength at the lower slope that favoured a sudden large upslope basin-margin collapse. This main collapse event led to downslope displacement of large coherent volumes of bedrock that essentially kept their internal structure (Fig. 15). Major surfaces in the collapsed coherent Alpujárride basement block, such as lithological contacts between

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

8

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

Fig. 8. Landslide subunit 2b in the proximal areas. (A) Outcrop view showing heterometric megablocks of Alpujárride Complex dolostones, some with a Miocene cover on top. Note that some blocks are embedded within a phyllite-rich matrix. (B) Outcrop view of blocks of Alpujárride dolostone close to the contact with the alternating facies M6 and M7 of the underlying subunit 2a. Observe the varying degree of internal brecciation in the largest block. (C) Close up view of the brecciation and basal shear of the largest block shown in (B). Hammer is 33 cm in length. (D) Microphotograph showing the ground dolostone matrix among the brecciated blocks shown in (C).

phyllites and overlying carbonates within each tectonic unit, and the contact surface between the two stacked tectonic units, dip to the southeast. This dipping suggests a local rotation of the collapsed blocks (subunit 2a) around an inclined axis roughly parallel to the headscarp (Fig. 15). The backward rotation of the coherent bedrock blocks determined the spatial distribution of disaggregated collapsed materials (chaotic mélange, subunit 2b) and created an unstable steep slope that favoured subsequent sediment redeposition (e.g., Lastras et al., 2004).

The ensuing inertia-driven rock avalanche and debris flows derived from the collapse of the substrate occurred on the depocentre created by the coherent basement-block rotation. During sliding, more coherent carbonate blocks underwent brittle deformation with progressive brecciation, especially at the boundaries between the blocks (Fig. 8). By contrast, weaker disrupted phyllite blocks disintegrated to a greater degree during the downslope movement forming a cohesive matrix that engulfed and/or sustained the carbonate blocks (Ogata et al., 2012) (Figs. 6, 8A, 11A), although some matrix also formed by the erosion

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

mud rich in phyllite debris marl with dispersed clasts (facies C1)

9

concentration of blocks diminished basinwards, and individual sediment gravity flows are separated by silty marl intervals, suggesting that they took place in repeated episodic events. The large number of individual flows, together with the occurrence of intraformational blocks, indicates that the landslide displacement and subsequent shedding of reworked materials occurred in many successive events for a relatively long period. Foraminifers in the marls indicate a rather deep-water slope environment of formation for the fine-grained autochthonous matrix. The planktonic:benthic ratio (P:P + B) is higher than 70% in all samples, indicating deep-water conditions. The benthic foraminiferal assemblages are dominated by Cibicides spp., Cibicidoides spp., Siphonina planoconvexa, Planulina ariminensis, Melonis spp., Pullenia spp., Lenticulina spp., Gyroidina spp., Uvigerina spp. (particularly abundant U. auberiana in samples from the Barranco del Cuchillo section 1; Figs. 1C, 9) and Cassidulina spp. All these taxa are distributed preferentially from the outer shelf to the slope (Murray, 2006).

large blocks channelized, polymictic breccia (facies C2-C3)

rotated block

5m Fig. 9. Stratigraphic column of logged Barranco del Cuchillo 1 section showing the landslide deposits of subunit 2b in the distal part (see Fig. 1B for location). The section includes intraformational, rotated blocks of bed packages.

of the marls on the slope. During transport, bedrock blocks broke into smaller portions that travelled greater distances basinwards (e.g., Lastras et al., 2004; Alves and Cartwright, 2009). The incorporation of well-lithified sandstone beds into the chaotic mélange suggests a relatively deep erosion of the seafloor (e.g., Dykstra et al., 2011; Sobiesiak et al., 2016). Resedimented channelized clast- and matrix-supported breccias (Table 2) were deposited by high-strength cohesive debris flows originated by the continuing clast collision, bed fragmentation, and disaggregation of the failed slope. The resulting cohesive debrites (DM-2; Talling et al., 2012) formed by frictional freezing from gravel clast dispersion and en masse consolidation. Rapid and frequent changes from clast- to matrix-supported texture within a single deposit indicate a continuum and complex flow process. The absence of turbidites in the chaotic mélange suggests that these debris flows did not transform into turbulent flows (e.g., Hampton, 1972; Tripsanas et al., 2008; Felix et al., 2009), probably because the high-strength matrix prevented mixing with surrounding seawater (Felix and Peakall, 2006). However, such flow transformation might have occurred at greater distances downslope and cannot be seen in the study outcrops. The occurrence of small-scale failures within the subunit 2b, compressed and thrust at the front of the landslide (Bull et al., 2009; Ogata et al., 2014), is evidenced by the intraformational blocks of folded, faulted, and rotated bed packages of the chaotic mélange (Fig. 11). The

5.2.2. Timing, triggering mechanisms, and pre-conditioning factors Planktonic foraminifer assemblages constrain the timing of the Alhama de Almería Slide during the late Tortonian, between 8.5 and 7.5 Ma, in a period of eustatic sea-level fall and regional tectonic uplift (Miller et al., 2005; Marín-Lechado et al., 2007). Excess pore pressure, ocean wave loading, destabilization of gas hydrates, and seismic loading are among the main triggering mechanisms for initiating mass slope failures on continental margins (Piper et al., 1999; Sultan et al., 2004; Faure et al., 2006; Rogers and Goodbred, 2010; Dugan and Sheahan, 2012). In the case of the Alhama de Almería Slide, some of these mechanisms can be excluded. The landslide started in water depths that were too shallow and warm for stable gas hydrate formation in the pre-failure deposits. The role of wave-loading might have been important to generate the postlandslide sediment gravity flows funnelled through the canyon depression, but it is unlikely that this process induced instabilities at the depth of the buried basement under the Miocene sediment cover. In the absence of direct evidence of any conclusive mechanism, the most likely explanation is that the triggering mechanism of the Alhama de Almería Slide was seismic activity related to the tectonic instability of Sierra de Gádor during the late Tortonian. In this time interval, the antecedent relief of the sierra was undergoing compressive folding and concomitant uplift (Marín-Lechado et al., 2007). Northwest– southeast and west-northwest–east-southeast normal faults of variable scale related to this compression affected basement rocks and Neogene to Quaternary deposits (Marin-Lechado et al., 2005; Pedrera et al., 2012). Some of these faults were already active in the late Tortonian as they were sealed by the Azagador limestone or show synsedimentary movements during deposition of this unit (Sola et al., 2017). Seismic activity linked to these faults could induce ground acceleration responsible for triggering the Alhama de Almería Slide. The presentday shallow seismicity shows northwest-southeast lineations of epicentres along northwest-northeast normal faults (Pedrera et al., 2012), which is approximately the orientation of the scar of the Alhama de Almería Slide (Figs. 1B, C, 4). At the time of the inception of the landslide, tectonic instability is also recorded as seismites of varying dimensions in the nearby Tabernas Basin (Fig. 2) (Kleverlaan, 1987, 1989). The largest seismite (Gordo Megabed), covering an area similar to the Alhama de Almería Slide (~25 km2), is also interpreted as having originated from a single catastrophic collapse along the basin margin (Kleverlaan, 1987). The conditions leading to rock/sediment failure are difficult to elucidate from ancient outcrops, especially when there was an interaction between several processes. In the case of the Alhama de Almería Slide, the most obvious pre-conditioning factors are steep slopes and the presence of weak layers. In the study area, steep slopes were generated by the uplifting of Sierra de Gádor that determined the style of deposition of temperate-water carbonates in the western

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

10

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

Fig. 10. Facies C2 of landslide subunit 2b in the distal areas. (A) Outcrop view of channelized breccias of facies C2. (B) Outcrop view of matrix-supported breccia with muddy matrix derived from phyllite (facies C2a). Larger greyish blocks are of Alpujárride dolostones. White clasts in the background are mainly of quartzites. Hammer is 33 cm in length. (C) Outcrop close-up view of frequent changes from matrix-supported facies C2a to clast-supported facies C2b. Lens cap is 6 cm in diameter. (D) Outcrop close-up of clast-supported breccias rich in basement clasts (facies C2b). Hammer is 33 cm in length.

Almería Basin (Sola et al., 2017). Oversteepening could predetermine slope failures as slope stability often decreases with increasing slope gradient (Lawrence and Cartwright, 2009; Ai et al., 2014), especially in active margins (Lamarche et al., 2008; Harders et al., 2011). In the study case, oversteepening most likely favoured the generation of small-scale pre-landslide slope failures that progressively eroded the base of the slope. Weak layers in the sedimentary successions of continental margins may promote slope instabilities, as such beds show a mechanical behaviour different from the one of surrounding sediment (Kvalstad et al., 2005; Harders et al., 2010). We hypothesise that contacts between phyllites and underlying carbonates at the surface separating the two tectonic Alpujárride units, and between phyllites and overlying carbonates in the stratigraphic succession within each tectonic unit, acted as weakness planes that promoted the slope failure under an earthquake loading. The headscarp is fringed by basement phyllites (Fig. 4) that probably worked as “detachment” materials favouring the landslide. Phyllites together with weathered micaschists are the most common lithology acting as the determining factor for recent shallow landslides in the Alpujárride Complex outcrop area due to their low strength (Alcántara-Ayala, 1999; JiménezPerálvarez et al., 2011). 5.3. Post-landslide deposits (unit 3) The rotation of coherent basement blocks around the main axis of the landslide created a canyon-like depression along the southern margin of the collapsed structure (Fig. 15). This depression acted as a depocentre for the accumulation of post-landslide deposits as it funnelled the sediment gravity flows that had originated in shallower

areas (Fig. 15). In proximal areas, the flows accumulated in channels that migrated slightly southwards. In distal areas, poorly cohesive debris flows and high-density turbidity currents transporting a mixing of terrigenous clasts and bioclasts reached the autochthonous deep-water marls in the initial phases of depression infilling. Some debris flows transported large (up to 3 m) dolostone blocks of Alpujárride basement. Mixing with angular to subangular terrigenous clasts suggests the erosion and reworking of the basement in the upper canyon close to the landslide scarp. Coarse-grained, predominantly bioclastic flows episodically accumulated interspersed with hybrid beds (Fig. 13). The occurrence of bioclastic carbonatedominated deposits increased upwards to prevail in the upper third of the unit (Fig. 13). Sediment gravity flows occur mainly as scourand-fill structures within concave-plane bedsets of limited lateral continuity separated by thick intervals of fine-grained silty/marly sediment, suggesting that they accumulated in ephemeral submarine channels of small dimensions within the canyon-shaped depression (Fig. 15). The bioclastic particles accumulated in the post-slide canyon-like depression must have been sourced from shallower areas upslope. The main components of the breccia bioclastic matrix, rudstones and grainstones are coralline algae, bryozoans, pectinids, and oysters (Table 3), which are also the main components of shallow-water ramp deposits in the Azagador limestone in other basins in southeast Spain (Martín and Braga, 1994; Martín et al., 1996; Betzler et al., 2000; Braga et al., 2001, 2006; Puga-Bernabéu et al., 2007a, 2007b). These components also characterize Miocene shallow-water ramp carbonates elsewhere in the Mediterranean (Vecsei and Sanders, 1999; PomoniPapaioannou et al., 2002; Brandano and Piller, 2010; Brandano et al.,

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

11

Fig. 11. Outcrop views of the chaotic mélange of subunit 2b in the distal part. (A) Intraformational marly block of Miocene cover engulfed within highly disrupted phyllites covered by silty marls with dispersed clasts (facies C1). Note the presence of rotated bed packages within the marly block. (B) Intraformational blocks of bed packages showing rotation and imbrication. White lines mark the bedding planes. Dashed lines mark the boundaries between the intraformational blocks.

Fig. 12. Outcrop view of decametre-thick stacked channelized bodies of post-landslide deposits onlapping the underlying landslides deposits of subunit 2b. Stratigraphic column of logged Balate de Murillo (BM) section (marked in red) to the right (see Fig. 1B for location). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

12

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

Table 3 Summary of facies attributes for the redeposited sediments and marls of post-landslide Unit 3. Lithofacies

Bedding/thickness bedsets

PL1 a: Breccia with Concave-plane with erosive sandy matrix base/rapid changes in thickness, from cm to b2 m lenses, concave-plane Concave-plane with erosive b: Breccia with rudstone base/rapid changes in thickness, from c to dm amalgamated matrix beds; concave-plane bedsets PL2 Rudstone with Plane-parallel to concaveplane with erosive base/cm to terrigenous m amalgamated beds; clasts concave-plane bedsets

Structures/texture

Clasts nature/size

Matrix

Occurrence

Clast supported/inverse grading

Phyllite, quartzite and carbonate; carbonate clasts bioeroded/up to 3 m

Medium sand to granules, usually coarse sand, locally rich in bioclasts

Scarce

Clast- to matrix-supported/ common inverse grading

Rudstone with bryozoans, LBF, Phyllite, quartzite and carbonate, bivalve, CCA, echinoids, SBF, Miocene breccia clasts, rip-up clasts; carbonate clasts bioeroded/up to 2.1 m PF; very little muddy matrix

Inverse grading; rough to well-defined parallel lamination; locally clast pockets

Bryozoans, LBF, bivalve, CCA, echinoids, Varying content of micrite matrix, usually very little, Ditrupa, SBF, PF; clasts of phyllite, upwards richer in CCA quartzite and carbonate; rip-up clasts, locally concentrated in the upper part of BC-2 section/up to 35 cm Bryozoans, LBF, bivalve, CCA, echinoids, SBF, PF; small amounts of phyllite, quartzite and carbonate grains

PL3 Grainstone

Parallel lamination, channellike lamination

PL4 Silty marl Plane-parallel/dm to m PL5 Silty marl with Plane-parallel frequently dispersed clasts eroded/cm to dm

Bioturbated Bioturbated

Plane-parallel frequently PL6 Silty sand/ sandstone with eroded/cm to dm dispersed clasts

Plane-parallel lamination, locally small ripples

Upward transitions to PL2 in the same bed Changing vertically and laterally to PL3

Quartzites and carbonate/dispersed pebbles to cobbles up to 15 cm; clast concentration very uneven Carbonate, quatzite, and phyllite; bioclasts/granules to pebbles

LBF: larger benthic foraminifers; CCA: crustose coralline algae; SBF: small benthic foraminifers; PF: planktic foraminifers; BC: Barranco del Cuchillo.

metres

170 40

90

140

30

80

130

20

70

120

160

150

breccia with sandy matrix (facies PL1a) breccia with rudstone matrix (facies PL1b)

10

60

110

breccia with rudstone matrix & boulders (facies PL1b) rudstone with terrigenous clasts (facies PL2) grainstone (facies PL3)

0

50

100

silty sand (facies PL6) silty marl with clasts (facies PL5) marl/silt (facies PL4)

Fig. 13. Stratigraphic column of logged Barranco del Cuchillo 2 section showing the distribution of post-landslide facies of Unit 3 in the distal area. Coarser facies are commonly arranged in concave-plane beds with erosive base.

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

13

Fig. 14. Outcrop close-up views of facies of post-landslide Unit 3. (A) Concave-plane bed of breccias (facies PL1) eroding underlying silty marls with dispersed clasts (dark dolostones and pink quartzites) of facies PL5. Hammer is 33 cm in length. (B) Breccia with sandy matrix (facies PL1a) rich in Alpujárride dolostone clasts. Hammer is 33 cm in length. (C) Breccia with rudstone matrix (facies PL1b) rich in Alpujárride phyllite clasts. Lens cap is 6 cm in diameter. (D) Plane-parallel bed of rudstone with terrigenous clasts (mainly dolostones) of facies PL2 showing relatively thick parallel lamination. Lens cap is 6 cm in diameter. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Tortonian ramp carbonates crop out 10 km to the west at elevations of about 1400 m, with no possible direct connection with the remobilized post-slide carbonates. The shallow ramp sediments were either

2010; Fontana et al., 2015). No autochthonous upper Tortonian shallow-water carbonates are preserved at higher elevations upslope of the outcrops of post-slide deposits. The closest in situ upper

A) early ? Tortonian

B) early late Tortonian

C) late Tortonian-early Messinian 1

1’

1 km

D) canyon-like depression channels

folded/faulted beds

1-1’

Alpujárride phyllites

Tortonian sandstones & conglomerates

Tortonian marls & sandstones

Chaotic unit - late Tortonian

channelised polymictic breccias undifferenced basement

Alpujárride carbonates

Bioclastic redeposited sediments

megablocks

100 m

late Tortonian-early Messinian

Marls

500 m Fig. 15. Interpretative sketch showing the sequential failure process responsible for the formation of the Alhama de Almería Slide. (A) During the early (?) Tortonian an initial, shallow marine sedimentary cover on the Alpujárride basement rocks. (B) During the early late Tortonian, a main collapse event led to downslope displacement of large coherent blocks of basement rocksand created a depocentre for deposition of the chaotic mélange. (C) Post-landslide redeposited sediments filled the canyon-like depression along the southern margin of the collapsed structure during the late Tortonian and early Messinian. (D) Conceptual cross-section showing an overview of the sedimentological and geomorphological features after the Alhama de Almería Slide. Approximate location marked in (C).

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

14

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

removed by post-Tortonian erosion or never actually accumulated as significant lithified deposits. The source of terrigenous clasts was the Alpujárride basement (carbonates, quartzites, and phyllites) and underlying Miocene terrigenous rocks. Pebble- to boulder-sized clasts show borings of Gastrochaenolites (bivalves) and Entobia (sponges), indicating prolonged exposure of clasts on the shallow seafloor before re-mobilization downslope. 5.4. Implications for offshore sediment redeposition in temperate-water carbonate systems The different types of offshore redeposited facies in low-energy areas such as the Mediterranean Sea resulted from various sedimenttransport processes acting over unconfined areas of the carbonate ramps or in a confined area of the ramp, slope or basin (see PugaBernabéu et al., 2014, for a review). The latter case essentially reflects deposition in submarine canyons and channels and related lobe deposits, which are relatively poorly known in the ancient record of non-tropical carbonate deposits (Braga et al., 2001; Rankey, 2003; Vigorito et al., 2005; Puga-Bernabéu et al., 2008a, 2009). The origin and development of these features in temperate-water carbonate ramps is commonly attributed to river erosion and/or erosion under shallow-water conditions (e.g., Braga et al., 2001; Puga-Bernabéu et al., 2008a, 2008b) in a fashion similar to that of their siliciclastic counterparts (Pratson et al., 1994; Harris and Whiteway, 2011). In other few cases, channels followed and filled fault-related canyons/ depressions in the basement instead of cutting across previously accumulated deposits as in the typical channelized systems (Sola et al., 2017). In the study example, the rotation of the landslide materials created a canyon-depression at the southern edge of the landslide, which subsequently funnelled post-landslide sediment gravity flows and constituted a narrow, elongated depocentre for sediments re-worked from shallow-water areas (Fig. 15). The formation of this canyon is consistent with the model of slope failure and retrogressive (headward) erosion (Farre et al., 1983), which has been proposed for some siliciclastic systems (Ridente et al., 2007; Di Celma et al., 2010) and for other carbonate slope systems (Puga-Bernabéu et al., 2011). This model of canyon formation represents a novelty within the temperate-water carbonate systems as no comparable examples have been described previously in these systems. 6. Conclusions Continuous subaerial exposures in the vicinity of Alhama de Almería in southeast Spain reveal the presence of a late Miocene meso-scale (~25 km2) submarine slope failure, the Alhama de Almería Slide. This synsedimentary collapse was previously misinterpreted as imbricated tectonic units of compressive origin. Relationships of diverse lithologies and structures with distinct degrees of internal heterogeneity can be directly observed at the outcrops. Therefore, this study case provides a unique opportunity for analysing submarine slope failures as these mass movements commonly remain submerged and their recognition in the exposed sedimentary record is difficult. The landslide occurred on the northern slope of an actively rising Betic basement relief, the palaeo-relief of Sierra de Gádor and represents a submarine bedrock landslide not a failure of an accretionary slope. The sedimentary facies and complex internal structure of the landslide deposits provide insights to constrain the recognition and interpretation of this type of landslides, which are widespread in active tectonic margins. The failed basement and sediment slabs of the Alhama de Almería Slide were transported and disintegrated downslope following a sequential failure process and created an unstable steep slope that favoured subsequent sediment redeposition. The resulting resedimented facies capture meso- and small-scale heterogeneities, generally

irresolvable in seismic datasets, which could assist in the correlation of mass-transport sedimentary facies in the subsurface record, where assessment is often limited. Planktonic foraminifer assemblages constrain the timing of the Alhama de Almería Slide to the late Tortonian, between 8.5 and 7.5 Ma, in a period of eustatic sea-level fall and regional tectonic uplift, being seismic activity related with the latter the most likely triggering mechanism. The sharp lithological heterogeneities in the basement rocks, which acted as detachment planes, probably controlled the inception of the landslide. The topography created by the rotation of landslide basement rocks exerted an important control on subsequent sediment routing and distribution. A canyon-shaped depression funnelled sediment gravity flows generated upslope in shallower areas, promoting locally thick accumulations of bioclastic carbonates and mixed carbonate-siliciclastic sediments. This example highlights the poorly-constrained role of bedrock submarine landslides in submarine canyon initiation.

Acknowledgements This work was funded by Ministerio de Economía y Competitividad, Spain, project CGL2013-47236-P and the Fondo Europeo de Desarrollo Regional (FEDER). We are grateful to David Nesbitt for editing the English text. We thank to an anonymous reviewer, the editor Jasper Knight, and N. Roberts for their constructive suggestions which helped to improve this manuscript. References Abdurrokhim, A., Ito, M., 2013. The role of slump scars in slope channel initiation: a case study from the Miocene Jatiluhur Formation in the Bogor Trough, West Java. Journal of Asian Earth Sciences 73, 68–86. Aguirre, J., 1998. El Plioceno del SE de la Península Ibérica (provincia de Almería). Síntesis estratigráfica, sedimentaria, bioestratigráfica y paleogeográfica. Revista de la Sociedad Geológica de España 11, 297–315. Ai, F., Strasser, M., Preu, B., Hanebuth, T.J.J., Krastel, S., Kopf, A., 2014. New constraints on oceanographic vs. seismic control on submarine landslide initiation: a geotechnical approach off Uruguay and northern Argentina. Geo-Marine Letters 34, 399–417. Alcántara-Ayala, I., 1999. The Torvizcon, Spain, landslide of February 1996: the role of lithology in a semi-arid climate. Geofísica Internacional 38, 1–10. Algar, S., Milton, C., Upshall, H., Roestenburg, J., Crevello, P., 2011. Mass-transport deposits of the deepwater northwestern Borneo margin—characterization from seismicreflection, borehole, and core data with implications for hydrocarbon exploration and exploitation. In: Shipp, R.C., Weimer, P., Posamentier, H.W. (Eds.), MassTransport Deposits in Deepwater Settings. SEPM Special Publication 96, pp. 351–366. Alves, T.M., 2010. 3D seismic examples of differential compaction in mass-transport deposits and their effect on post-failure strata. Marine Geology 271, 212–224. Alves, T.M., Cartwright, J.A., 2009. Volume balance of a submarine landslide in the Espírito Santo Basin, offshore Brazil: quantifying seafloor erosion, sediment accumulation and depletion. Earth and Planetary Science Letters 288, 572–580. Armitage, D.A., Romans, B.W., Covault, J.A., Graham, S.A., 2009. The influence of masstransport-deposit surface topography on the evolution of turbidite architecture: the Sierra Contreras, Tres Pasos Formation (Cretaceous), southern Chile. Journal of Sedimentary Research 79, 287–301. Baena, J., Voermans, F., 1983. Mapa geológico de España a escala 1:50000. Memoria y Hoja geológica 1044 (Alhama de Almería). IGME, Madrid. Baeten, N.J., Laberg, J.S., Vanneste, M., Forsberg, C.F., Kvalstad, T.J., Forwick, M., Vorren, T.O., Haflidason, H., 2014. Origin of shallow submarine mass movements and their glide planes—sedimentological and geotechnical analyses from the continental slope off northern Norway. Journal of Geophysical Research - Earth Surface 119, 2335–2360. Berggen, W.A., Kent, D.V., Swisher III, C.C., Aubry, M.-P., 1995. A revised Cenozoic geochronology and chronostratigraphy. In: Berggen, W.A., Kent, D.V., Aubry, M.-P., Hardenbol, J. (Eds.), Geochronology. Time Scales and Global Stratigraphic Correlation: A Unified Temporal Framework for an Historical Geology. SEPM Special Publication 54, pp. 129–212. Betzler, C., Martín, J.M., Braga, J.C., 2000. Non-tropical carbonates related to rocky submarine cliffs (Miocene, Almería, southern Spain). Sedimentary Geology 131, 51–65. BouDagher-Fadel, M.K., 2015. Biostratigraphic and Geological Significance of Planktonic Foraminifera. Updated Second edition. UCL Press, London (306 pp.). Braga, J.C., Martín, J.M., 1988. Neogene coralline-algal growth-forms and their palaeoenvironments in the Almanzora river valley (Almería, S.E. Spain). Palaeogeography, Palaeoclimatology, Palaeoecology 67, 285–303. Braga, J.C., Martin, J.M., Wood, J.L., 2001. Submarine lobes and feeder channels of redeposited temperate carbonate and mixed siliciclastic–carbonate platform deposits (Vera Basin, Almería southern Spain). Sedimentology 48, 99–116.

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx Braga, J.C., Martín, J.M., Quesada, C., 2003. Patterns and average rates of late Neogene—recent uplift of the Betic Cordillera, SE Spain. Geomorphology 50, 3–26. Braga, J.C., Martín, J.M., Betzler, C., Aguirre, J., 2006. Models of temperate carbonate deposition in Neogene basins in SE Spain: a synthesis. In: Pedley, H.M., Carannante, G. (Eds.), Cool-Water Carbonates: Depositional Systems and Palaeonvironmental Controls. Geological Society of London, Special Publication 255, pp. 121–135. Brandano, M., Piller, W.E., 2010. Coralline algae, oysters and echinoids — a liaison in rhodolith formation from the Burdigalian of the Latium-Abruzzi Platform (Italy). In: Mutti, M., Piller, W., Betzler, C. (Eds.), Carbonate Systems During the Oligocene-Miocene Climatic Transition. IAS Special Publication 42, pp. 149–164. Brandano, M., Corda, L., Castorina, F., 2010. Facies and sequence architecture of a tropical foramol-rhodalgal carbonate ramp: Miocene of the central Apennines (Italy). In: Mutti, M., Piller, W., Betzler, C. (Eds.), Carbonate Systems During the OligoceneMiocene Climatic Transition. IAS Special Publication 42, pp. 107–128. Bull, S., Cartwright, J., Huuse, M., 2009. A review of kinematic indicators from mass-transport complexes using 3D seismic data. Mar. Pet. Geol. 26, 1132–1151. Callot, P., Odonne, F., Sempere, T., 2008. Liquification and soft-sediment deformation in a limestone megabreccia: the Ayabacas giant collapse, Cretaceous, southern Peru. Sedimentary Geology 212, 49–69. Calvès, G., Huuse, M., Clift, P.D., Brusset, S., 2015. Giant fossil mass wasting off the coast of West India: the Nataraja submarine slide. Earth and Planetary Science Letters 432, 265–272. Canals, M., Lastras, G., Urgeles, R., Casamor, J.L., Mienert, J., Cattaneo, A., De Batist, M., Haflidason, H., Imbo, Y., Laberg, J.S., Locat, J., Long, D., Longva, O., Masson, D.G., Sultan, N., Trincardi, F., Bryn, P., 2004. Slope failure dynamics and impacts from seafloor and shallow sub-seafloor geophysical data: case studies from the COSTA project. Marine Geology 213, 9–72. Cohen, K.M., Finney, S.C., Gibbard, P.L., Fan, J.-X., 2013. The ICS International Chronostratigraphic Chart. Episodes 36, 199–204. Dalla Valle, G., Gamberi, F., Rochini, P., Minisni, D., Errera, A., Baglioni, L., Trincardi, F., 2013. 3D seismic geomorphology of mass transport complexes in a foredeep basin: examples from the Pleistocene of the Central Adriatic Basin (Mediterranean Sea). Sedimentary Geology 294, 127–141. Di Celma, C., Cantalamessa, G., Didaskalou, P., Lori, P., 2010. Sedimentology, architecture, and sequence stratigraphy of coarse-grained, submarine canyon fills from the Pleistocene (Gelasian-Calabrian) of the Peri-Adriatic basin, central Italy. Marine and Petroleum Geology 27, 1340–1365. Drzewiecki, P.A., Simó, J.A., 2002. Depositional processes, triggering mechanisms and sediment composition of carbonate gravity flow deposits: examples from the Late Cretaceous of the south-central Pyrenees, Spain. Sedimentary Geology 146, 155–189. Dugan, B., Sheahan, T.C., 2012. Offshore sediment overpressures of passive margins: mechanisms, measurement, and models. Reviews of Geophysics 50, RG3001. https://doi.org/10.1029/2011RG000379. Dykstra, M., Garyfalou, K., Kertznus, V., Kneller, B., Milana, J.P., Molinaro, M., Szuman, M., Thompson, P., 2011. Mass-transport deposits: combining outcrop studies and seismic forward modeling to understand lithofacies distributions, deformation, and their seismic stratigraphic expression. In: Shipp, C., Weimer, P., Posamentier, H. (Eds.), Mass-Transport Deposits in Deepwater Settings. SEPM Special Publication 96, pp. 293–310. Farre, J.A., McGregor, B.A., Ryan, W.B.F., Robb, J.M., 1983. Breaching the shelfbreak passage from youthful to mature phase in submarine canyon evolution. In: Stanley, D.J., Moore, G.T. (Eds.), The Shelfbreak: Critical Interface on Continental Margins. SEPM Special Publication 33, pp. 25–39. Faure, K., Greinert, J., Pecher, I.A., Graham, I.J., Massoth, G.J., de Ronde, C.E.J., Wright, I.A., Baker, E.T., Olson, E.J., 2006. Methane seepage and its relation to slumping and gas hydrate at the Hikurangi margin, New Zealand. New Zealand Journal of Geology and Geophysics 49, 503–516. Felix, M., Peakall, J., 2006. Transformation of debris flows into turbidity currents: mechanisms inferred from laboratory experiments. Sedimentology 53, 107–123. Felix, M., Leszczyński, S., Ślączka, A., Uchaman, A., Amy, L., Peakall, J., 2009. Field expressions of the transformation of debris flows into turbidity currents, with examples from the Polish Carpathians and the French Maritime Alps. Marine and Petroleum Geology 26, 2011–2020. Fontana, D., Conti, S., Fioroni, C., Grillenzoni, C., 2015. Factors controlling the evolution of a wedge-top temperate-type carbonate platform in the Miocene of the northern Apennines (Italy). Sedimentary Geology 319, 13–23. Friant, A., Ishizuka, O., Boudon, G., Palmer, M.R., Talling, P.J., Villemant, B., Adachi, T., Aljahdali, M., Bretkreuz, C., Brunet, M., Caron, B., Coussens, M., Deplus, C., Endo, D., Feuillet, N., Fraas, A.J., Fujinawa, A., Hart, M.B., Hatfield, R.G., Hornbach, M., Jutzeler, M., Kataoka, K.S., Komorowski, J.-C., Lebas, E., Lafuerza, S., Maeno, F., Manga, M., Martínez-Colón, M., McCanta, M., Morgan, S., Saito, T., Slagle, A., Sparks, S., Stinton, A., Stroncik, N., Subramanyam, K.S.V., Tamura, Y., Trofimovs, J., Voight, B., WallPalmer, D., Wang, F., Watt, S.F.L., 2015. Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: first scientific drilling of submarine volcanic island landslides by IODP Expedition 340. Geochemistry, Geophysics, Geosystems 16: 420–442. https://doi.org/10.1002/2014GC005652. García-García, F., 2004. Sedimentary models of coarse-grained deltas in the Neogene basins of the Betic Cordillera (SE Spain): Tortonian and Pliocene examples. Boletín Geológico y Minero 115, 469–494. Gee, M.J.R., Uy, H.S., Warren, J., Morley, C.K., Lambiase, J.J., 2007. The Brunei slide: a giant submarine landslide on the North West Borneo Margin revealed by 3D seismic data. Marine Geology 246, 9–23. Haflidason, H., Sejrup, H.P., Nygard, A., Mienert, J., Bryn, P., Lien, R., Forsberg, C.F., Berg, K., Masson, D., 2004. The Storegga Slide: architecture, geometry and slide development. Marine Geology 213, 201–234.

15

Hampton, M.A., 1972. The role of subaqueous debris flow in generating turbidity currents. Journal of Sedimentary Petrology 42, 775–793. Harders, R., Kutterolf, S., Hensen, C., Moerz, T., Brueckmann, W., 2010. Tephra layers: a controlling factor on submarine translational sliding? Geochemistry, Geophysics, Geosystems 11, Q05S23. https://doi.org/10.1029/2009GC002844. Harders, R., Ranero, C., Weinrebe, W., Behrmann, J.H., 2011. Submarine slope failures along the convergent continental margin of the Middle America Trench. Geochemistry, Geophysics, Geosystems 12, Q05S32. https://doi.org/10.1029/2010GC003401. Harris, P.T., Whiteway, T., 2011. Global distribution of large submarine canyons: geomorphic differences between active and passive continental margins. Marine Geology 285, 69–85. Hogan, K.A., Dowdeswell, J.A., Mienert, J., 2013. New insights into slide processes and seafloor geology revealed by side-scan imagery of the massive Hinlopen Slide, Arctic Ocean margin. Geo-Marine Letters 33, 325–343. Instituto Geográfico Nacional, 2008. Mosaicos PNOA de máxima resolución o máxima actualidad. Available at. http://www.ign.es. Janson, X., Eberli, G.P., Lomando, A.J., Bonnaffé, F., 2010. Seismic characterization of large-scale platform-margin collapse along the Zhujiang carbonate platform (Miocene) of the South China Sea, based on Miocene outcrop analogs from Mut Basin, Turkey. In: Morgan, W.A., George, A.D., Harris, P.M., Kupecz, J.A., Sarg, J.F. (Eds.), Cenozoic Carbonate Systems of Australasia. SEPM Special Publication 95, pp. 73–92. Jiménez, A., Braga, J.C., Martín, J.M., 1991. Oyster distribution in the Upper Tortonian of the Almanzora Corridor (Almería, SE Spain). Geobios 24, 725–734. Jiménez-Perálvarez, J.D., Irigaray, C., El Hamdouni, R., Chacón, J., 2011. Landslidesusceptibility mapping in a semi-arid mountain environment: an example from the southern slopes of Sierra Nevada (Granada, Spain). Bulletin of Engineering Geology and the Environment 70, 265–277. Joanne, C., Collot, J.-Y., Lamarche, G., Migeon, S., 2010. Continental slope reconstruction after a giant mass failure, the example of the Matakaoa Margin, New Zealand. Marine Geology 268, 67–84. Kleverlaan, K., 1987. Gordo megabed: a possible seismite in a Tortonian submarine fan, Tabernas Basin, province Almería, southeast Spain. Sedimentary Geology 51, 165–180. Kleverlaan, K., 1989. Three distinctive feeder–lobe systems within one time slice of the Tortonian Tabernas fan, SE Spain. Sedimentology 36, 25–45. Kvalstad, T.J., Andresen, L., Forsberg, C.F., Berg, K., Bryn, P., Wangen, M., 2005. The Storegga slide: evaluation of triggering sources and slide mechanics. Marine and Petroleum Geology 22, 245–256. Lamarche, G., Joanne, C., Collot, J.-Y., 2008. Successive, large mass-transport deposits in the south Kermadec fore-arc basin, New Zealand: the Matakaoa Submarine Instability Complex. Geochemistry, Geophysics, Geosystems 9, Q04001. https://doi.org/10.1029/ 2007GC001843. Lastras, G., Canals, M., Urgeles, R., De Batist, M., Calafat, A.M., Casamor, J.L., 2004. Characterisation of the recent BIG'95 debris flow deposit on the Ebro margin, Western Mediterranean Sea, after a variety of seismic reflection data. Marine Geology 213, 235–255. Lawrence, G.W.M., Cartwright, J.A., 2009. The initiation of sliding on the mid Norway margin in the Møre Basin. Marine Geology 259, 21–35. Leslie, S.C., Mann, P., 2016. Giant submarine landslides on the Colombian margin and tsunami risk in the Caribbean Sea. Earth and Planetary Science Letters 449, 382–394. Lirer, F., Iaccarino, S., 2011. Mediterranean Neogene historical stratotype sections and global stratotype section points (GSSP): state of the art. Annalen des Naturhistorischen Museums in Wien, Serie A 113, 67–144. Macdonald, D.I.M., Moncrieff, A.C.M., Butterworth, P.J., 1993. Giant slide deposits from a Mesozoic fore-arc basin, Alexander Island, Antarctica. Geology 21, 1047–1050. Marin-Lechado, C., Galindo-Zaldivar, J., Rodriguez-Fernandez, L.R., Serrano, I., Pedrera, A., 2005. Active faults, seismicity and stresses in an internal boundary of a tectonic arc (Campo de Dalias and Nijar, southeastern Betic Cordilleras, Spain). Tectonophysics 396, 81–96. Marín-Lechado, C., Galindo-Zaldívar, J., Rodríguez-Fernández, L.R., Pedrera, A., 2007. Mountain front development by folding and crustal thickening in the internal zone of the Betic Cordillera-Alboran Sea boundary. Pure and Applied Geophysics 166, 1–21. Martín, J.M., Braga, J.C., 1994. Messinian events in the Sorbas Basin in southeastern Spain and their implications in the recent history of the Mediterranean. Sedimentary Geology 90, 257–268. Martín, J.M., Braga, J.C., Betzler, C., Brachert, T.C., 1996. Sedimentary model and highfrequency cyclicity in a Mediterranean, shallow-shelf, temperate carbonate environment (uppermost Miocene, Agua Amarga Basin, Southern Spain). Sedimentology 43, 263–277. Micallef, A., Masson, D.G., Berndt, C., Stow, D.A.V., 2009. Development and mass movement processes of the north-eastern Storegga Slide. Quaternary Science Reviews 28, 433–448. Miller, K.G., Kominz, M.A., Browning, J., Wright, J.D., Mountain, G.S., Katz, M.E., Sugarman, J., Christie-Blick, B.S.N., Pekar, S.F., 2005. The Phanerozoic record of global sea-level change. Science 310, 1293–1298. Moore, J.G., Clague, D.A., Holcomb, R.T., Lipman, P.W., Normark, W.R., Torresan, M.E., 1989. Prodigious submarine landslides on the Hawaiian Ridge. Journal of Geophysical Research 94, 17465–17484. Moscarderlli, L., Wood, L., 2007. New classification system for mass transport complexes in offshoreTrinidad. Basin Research 20, 73–98. Murray, J.W., 2006. Ecology and Applications of Benthic Foraminifera. Cambridge University Press, Cambridge (426 pp.). Ogata, K., Mutti, E., Pini, G.A., Tinterri, R., 2012. Mass transport-related stratal disruption within sedimentary mélanges: examples from the northern Apennines (Italy) and south-central Pyrenees (Spain). Tectonophysics 568–569, 185–199.

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005

16

F. Sola et al. / Sedimentary Geology xxx (2017) xxx–xxx

Ogata, K., Mountjoy, J.J., Pini, G.A., Festa, A., Tinterri, R., 2014. Shear zone liquefaction in mass transport deposit emplacement: a multi-scale integration of seismic reflection and outcrop data. Marine Geology 356, 50–64. Ogata, K., Pini, G.A., Festa, A., Pogačnik, Z., Corrado Lucente, C., 2016. Meso-scale kinematic indicators in exhumed mass transport deposits: definitions and implications. In: Lamarche, G., Mountjoy, J., Bull, S., Hubble, T., Krastel, S., Lane, E., Micallef, A., Moscardelli, L., Mueller, C., Pecher, I., Woelz, S. (Eds.), Submarine Mass Movements and Their Consequences. Advances in Natural and Technological Hazards Research 41, pp. 461–468. Pedrera, A., Galindo-Zaldivar, J., Marín-Lechado, C., García-Tortosa, F.J., Ruano, P., LópezGarrido, A.C., Azañón, J.M., Peláez, J.A., Giaonia, F., 2012. Recent and active faults and folds in the central-eastern internal zones of the Betic Cordillera. Journal of Iberian Geology 38, 191–208. Piper, D.J.W., Cochonat, P., Morrison, M., 1999. The sequence of events around the epicentre of the 1929 grand banks earthquake: initiation of debris flows and turbidity currents inferred from sidescan sonar. Sedimentology 46, 79–97. Pomoni-Papaioannou, F., Drinia, H., Dermitzakis, M.D., 2002. Neogene non tropical carbonate sedimentation in a warm temperate biogeographic province (Rethymnon Formation, Eastern Crete, Greece). Sedimentary Geology 154, 147–157. Pratson, L.F., Ryan, W.B.F., Mountain, G.S., Twichell, D.C., 1994. Submarine-canyon initiation by downslope-eroding sediment flows: evidence in late Cenozoic strata on the New-Jersey continental-slope. Geological Society of America Bulletin 106, 395–412. Puga-Bernabéu, A., Braga, J.C., Martín, J.M., 2007a. High-frequency cycles in Upper- Miocene ramp-temperate carbonates (Sorbas Basin, SE Spain). Facies 53, 329–345. Puga-Bernabéu, Á., Martín, J.M., Braga, J.C., 2007b. Tsunami-related deposits in temperate carbonate ramps, Sorbas Basin, southern Spain. Sedimentary Geology 199, 107–127. Puga-Bernabéu, Á., Martín, J.M., Braga, J.C., 2008a. Sedimentary processes in a submarine canyon excavated into a temperate-carbonate ramp (Granada Basin, southern Spain). Sedimentology 55, 1449–1466. Puga-Bernabéu, Á., Martín, J.M., Braga, J.C., 2008b. Submarine-channels system in a temperate carbonate ramp, Sorbas Basin, southeastern Spain. Geogaceta 44, 203–206 (in Spanish). Puga-Bernabéu, Á., Vonk, A.J., Nelson, C.S., Kamp, P.J.J., 2009. Mangarara Formation: exhumed remnants of a middle Miocene temperate carbonate, submarine channelfan system on the eastern margin of Taranaki Basin, New Zealand. New Zealand Journal of Geology and Geophysics 52, 73–93. Puga-Bernabéu, Á., Webster, J.M., Beaman, R.J., Guilbaud, V., 2011. Morphology and controls on the evolution of amixed carbonate-siliciclastic submarine canyon system, Great Barrier Reef margin, north-eastern Australia. Marine Geology 289, 100–116. Puga-Bernabéu, Á., Martín, J.M., Braga, J.C., Aguirre, J., 2014. Offshore remobilization processes and deposits in low-energy temperate-water carbonate-ramp systems: examples from the Neogene basins of the Betic Cordillera (SE Spain). Sedimentary Geology 304, 11–27. Rankey, E.C., 2003. Carbonate-filled channel complexes on carbonate ramps: an example from the Peerless Park Member [Keokuk Limestone, Visean, Lower Carboniferous (Mississippian)], St. Louis, MO, USA. Sedimentary Geology 155, 45–61. Ridente, D., Foglini, F., Minisini, D., Trincardi, F., Verdicchio, G., 2007. Shelf-edge erosion, sediment failure and the middle Pleistocene inception of Bari Canyon on the southwestern Adriatic margin (central Mediterranean). Marine Geology 246, 193–207. Rogers, K.G., Goodbred Jr., S.L., 2010. Mass failures associated with the passage of a large tropical cyclone over the swatch of no ground submarine canyon (Bay of Bengal). Geology 38, 1051–1054. Safranova, P.A., Laberg, J.S., Andrassen, K., Shlykova, V., Vorren, T.O., Chernikov, S., 2015. Late Pliocene–early Pleistocene deep-sea basin sedimentation at high-latitudes:

mega-scale submarine slides of the north-western Barents Sea margin prior to the shelf-edge glaciations. Basin Research 29, 537–555. Sanz de Galdeano, C., 1985. Estructura del borde oriental de la Sierra de Gádor (zona Alpujárride, Codilleras Béticas). Acta Geologica Hispánica 20, 145–154. Sierro, F.J., Flores, J.A., Civis, J., González-Delgado, J.A., Francés, G., 1993. Late Miocene globorotaliid event-stratigraphy and biogeography in the NE-Atlantic and Mediterranean. Marine Micropaleontology 21, 143–168. Sobiesiak, M.S., Kneller, B., Alsop, G.I., Milana, J.P., 2016. Internal deformation and kinematic indicators within a tripartite mass transport deposit, NW Argentina. Sedimentary Geology 344, 364–381. Sola, F., Braga, J.C., Aguirre, J., 2013. Hooked and tubular coralline algae indicate seagrass beds associated to Mediterranean Messinian reefs (Poniente Basin, Almería, SE Spain). Palaeogeography, Palaeoclimatology, Palaeoecology 374, 218–229. Sola, F., Puga-Bernabéu, Á., Aguirre, J., Braga, J.C., 2017. Heterozoan carbonate deposition on a steep basement escarpment (Late Miocene, Almería, SE Spain). Sedimentology 64, 1107–1131. Strachan, L.J., 2002. Geometry to Genesis: A Comparative Field Study of Slump Deposits and Their Modes of Formation. (Ph.D. Thesis). University of Cardiff, UK (412 pp.). Strachan, L.J., 2008. Flow transformations in slumps: a case study from the Waitemata Basin, New Zealand. Sedimentology 55, 1311–1332. Strozyk, F., Strasser, M., Krasterl, S., Meyer, M., Huhn, K., 2010. Reconstruction of retreating mass wasting in response to progressive slope steepening of the northeastern Cretan margin, eastern Mediterranean. Marine Geology 271, 44–54. Sultan, N., Cochonat, P., Canals, M., Cattaneo, A., Dennielou, B., Haflidason, H., Laberg, J.S., Long, D., Mienert, J., Trincardi, F., Urgeles, R., Vorren, T.O., Wilson, C., 2004. Triggering mechanisms of slope instability processes and sediment failures on continental margins: a geotechnical approach. Marine Geology 213, 291–321. Talling, P.J., 2014. On the triggers, resulting flow types and frequencies of subaqueous sediment density flows in different settings. Marine Geology 352, 155–182. Talling, P.J., Masson, D.G., Sumner, E.J., Malgesini, G., 2012. Subaqueous sediment density flows: depositional processes and deposit types. Sedimentology 59, 1937–2003. Tinterri, R., Magalhaes, P.M., 2011. Synsedimentary structural control on foredeep turbidites: an example from Miocene Marnoso-arenacea Formation, Northern Apennines, Italy. Marine and Petroleum Geology 28, 629–657. Tripsanas, E.K., Piper, D.W., Jenner, K.A., Bryant, W., 2008. Submarine mass-transport facies: new perspectives on flow processes from cores on the eastern North American margin. Sedimentology 55, 97–136. Vecsei, A., Sanders, D.G.K., 1999. Facies analysis and sequence stratigraphy of a Miocene warm-temperate carbonate ramp, Montagna della Maiella, Italy. Sedimentary Geology 123, 103–127. Vigorito, M., Murru, M., Simone, L., 2005. Anatomy of a submarine channel system and related fan in a foramol/rhodalgal carbonate sedimentary setting: a case history from the Miocene syn-rift Sardinia Basin, Italy. Sedimentary Geology 174, 1–30. Völk, H.R., Rondeel, H.E., 1964. Zur gliederung des jungtertaärs im becken von Vera, Südost-Spanien. Geologie en Mijnbouw 43, 310–315. Wade, B.S., Pearson, P.N., Berggren, W.A., Pälike, H., 2011. Review and revision of Cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale. Earth-Science Reviews 104, 111–142. Woodcock, N.H., 1979. Sizes of submarine slides and their significance. Journal of Structural Geology 1, 137–142.

Please cite this article as: Sola, F., et al., Origin, evolution and sedimentary processes associated with a late Miocene submarine landslide, southeast Spain, Sedimentary Geology (2017), https://doi.org/10.1016/j.sedgeo.2017.09.005