Facies (2013) 59:133–148 DOI 10.1007/s10347-012-0349-6
ORIGINAL PAPER
Tracking paleoenvironmental changes in coralline algal-dominated carbonates of the Lower Oligocene Calcareniti di Castelgomberto formation (Monti Berici, Italy) James H. Nebelsick • Davide Bassi Julia Lempp
•
Received: 3 May 2012 / Accepted: 29 October 2012 / Published online: 1 December 2012 Ó Springer-Verlag Berlin Heidelberg 2012
Abstract Lower Oligocene, shallow-water carbonates of the Calcareniti di Castelgomberto formation (Monti Berici, Italy, Southern Alps) are studied in detail with respect to fabric and component distributions in order to trace paleoecological changes along a monotonous sedimentary stacking pattern. The carbonates are dominated by coralline algal rudstones with a packstone to wackestone matrix. Non-geniculate coralline algae include six genera: Lithoporella melobesioides, Mesophyllum, Neogoniolithon, Spongites, Sporolithon, and Subterraniphyllum. The algae are found in the form of encrusting thalli, rhodoliths, and coralline debris. Non-algal components include larger, small benthic, and planktonic foraminifera associated with bryozoans, zooxanthellate corals, and echinoderms. Four carbonate facies are distinguished: (1) coralline algal facies, (2) coralline algal-coral facies, (3) coralline algallarger foraminiferal facies, and (4) coralline algal debris facies. Marly horizons also occur in the section. The facies and coralline algal content are interpreted with respect to light intensity, hydrodynamic energy, biotic interactions, and substrate stability. Facies development along the studied section shows systematic variations, suggesting asymmetric sea-level changes with rapid regressions and gradual transgressions.
J. H. Nebelsick (&) J. Lempp Institut fu¨r Geowissenschaften, Universita¨t Tu¨bingen, Sigwartstrasse 10, 72076 Tu¨bingen, Germany e-mail:
[email protected] D. Bassi Dipartimento di Fisica e Scienze della Terra, Universita` di Ferrara, via Saragat 1, 44122 Ferrara, Italy e-mail:
[email protected]
Keywords Microfacies Carbonates Coralline red algae Paleoenvironment Northeast Italy Oligocene
Introduction Interpreting carbonate facies in the geological record can often be relatively straightforward, if a wide variation of fabrics and readily identifiable component types are present. The effects of varying environmental parameters such as light, hydrodynamic energy, and substrate characteristics often leads to standard differences in fabric and components as has been shown by the long tradition of facies description and interpretations (e.g., Buxton and Pedley 1989; Pedley 1998; Flu¨gel 2004). Interpreting carbonate environmental disparity in sediments, which at first glance show a homogeneous lithology and fabric, can be challenging. In this study, seemingly monotonous carbonate sediments dominated by a single component type (coralline red algae) are investigated in detail to show how careful analysis of taxonomy, growth form morphologies, and taphonomy can be used to track environmental changes otherwise hidden from view. Recent coralline red algae (Corallinales, Rhodophyta) occur in a wide range of marine habitats. They live from the intertidal to the lower photic zone, from the Arctic to the tropics. Colonization takes place on both hard and soft substrates and at different levels of water turbulence. Studies of coralline algae have documented the correlation of taxonomic diversity, growth forms, and taphonomic signatures to various ecological parameters such as water depth, light intensity, hydrodynamic energy, substrate stability, and biotic interactions (e.g., Adey and MacIntyre 1973; Bosence and Pedley 1982; Bosence 1983a, b, 1991; Steneck 1986; Minnery 1990; Basso 1996; Rasser and
123
134
Piller 1997; Nebelsick and Bassi 2000). Coralline algae are common throughout the Cenozoic and peaked in diversity in the Early Miocene (Aguirre et al. 2000). Coralline algae are correspondingly abundant in Cenozoic shallow-water carbonates and dominate different facies types (Adey 1986; Nebelsick et al. 2005). Coralline algal assemblages have thus been increasingly used to analyze and interpret ecological parameters in Cenozoic sediments (e.g., Braga and Martı´n 1988; Perrin et al. 1995; Bassi 1998, 2005; Nebelsick et al. 2000; Rasser 2000). There are still relatively few studies concerning Oligocene coralline algal assemblages. These studies primarily concern floras from the northern margin of the Western Tethys (e.g., Braga et al. 2010; Braga and Bassi 2011) including a number of taxonomic studies from the Piedmont and Ligurian Basins (northwestern Italy) and the Venetian area (northeastern Italy) (e.g., Airoldi 1932; Conti 1950; Mastorilli 1968; Francavilla et al. 1970; Fravega et al. 1987). More recent papers from the circum-alpine region have not only applied new taxonomic concepts to document Oligocene algal assemblages (Bassi and Nebelsick 2000; Rasser and Nebelsick 2003), but also used the coralline algal assemblages for sedimentological and paleoenvironmental interpretation (Nebelsick et al. 2000, 2001; Nebelsick and Bassi 2000; Rasser and Nebelsick 2003; Bassi and Nebelsick 2010). The aim of this paper is to show how variations in environmental parameters including light availability, hydrodynamic energy, substrate characteristics, biotic interactions, and paleobathymetric changes related to sealevel variation can be recognized in monotonous carbonate sediments dominated by a single component. Coralline algae are well suited to such an approach as their differential diagnostic characters can be readily distinguished in thin-section along with growth form features, encrusting strategies, and taphonomic features.
Geological setting The sedimentary succession of the Monti Berici consists of Upper Cretaceous to Upper Oligocene deposits (Bosellini 1967; Ungaro 1969, 1978; Geister and Ungaro 1977; Bassi et al. 2007; Bassi and Nebelsick 2010). During the Rupelian (Early Oligocene), shallow-water carbonates occurred over a wide area on the eastern margin of the Lessini Shelf, a paleogeographic unit of the Southern Alps (Ungaro 1978; Geister and Ungaro 1977; Frost 1981; Antonelli et al. 1990; Bosellini and Trevisani 1992). These Rupelian platformrelated carbonate deposits correspond to the ‘‘Calcareniti di Castelgomberto’’ formation and are rich in coralline red algae as well as small benthic porcelaneous foraminifera. Other locally characterizing components are larger
123
Facies (2013) 59:133–148
foraminifera such as nummulitids and hermatypic corals. This formation overlies the Marne di Priabona formation of Late Eocene age (Ungaro 1969; Bassi 2005) and is overlain by sandstones and mixed carbonate-siliciclastic deposits of the Arenarie e calcari di S. Urbano formation, Late Oligocene in age (Bassi et al. 2008; Bassi and Nebelsick 2010). The sedimentary environments of the Calcareniti di Castelgomberto formation have been debated with Geister and Ungaro (1977) and Ungaro (1978), suggesting differentiated facies distributions, and Frost (1981) assigning the carbonates to a barrier reef-type setting. The morphology of the eastern edge of the Monti Berici is characterized by a sudden morphological change from the hilly morphology of the Monti Berici (ca. 500 m a.s.l.) to the seaboard plain (starting at 30 m) leading to the Adriatic Sea. This morphological break, in fact, corresponds to a large fault, which essentially cuts off the transition from the shallowwater carbonates towards the west to the basinal sediments towards the east (Bassi et al. 2008). The presence of this fault and the resulting lack of a gradual transition from shallow- to deeper-water conditions make it difficult to assess, if a rimmed shelf or a homoclinal ramp (or something in between) was present on the eastern edge of the Monti Berici. The most detailed facies analysis of the Calcareniti di Castelgomberto deposits carried out in the Monti Berici to date by Ungaro (1978) shows a number of different facies types generally dominated by coralline algae and small benthic porcelaneous foraminifera along with corals and larger foraminifera. The coralline algal flora of the Calcareniti di Castelgomberto formation has never been studied in detail apart from a cursory comparison of coralline assemblages crossing the Eocene/Oligocene boundary at its base by Francavilla et al. (1970) and a systematic description of a few taxa by Bassi et al. (2000). The coral fauna of the Calcareniti di Castelgomberto formation has been studied not only by Frost (1981) but also by Bosellini and Trevisani (1992), Bosellini and Russo (1995), and Bosellini and Stemann (1996) from localities on the Lessini Shelf further to the north.
Materials and methods The study area lies in the Monti Berici, situated south of Vicenza in northeastern Italy (Fig. 1). The studied section was first described by Ungaro (1969, 1978) and consists of a uniform bioclastic limestone with a few marly intercalations and shows a thickness of 100 m. The biostratigraphic setting of the studied section is based on the occurrence of the larger foraminifera Nummulites fichteli, N. vascus, Operculina complanata, Praerhapydionina
Facies (2013) 59:133–148
135
Fig. 1 Geographic map of northern Italy and the Monti Berici with the location of the studied section
delicata, Spirolina cylindracea, Peneroplis glynnjonesi, and Asterigerina rotula haeringensis (Ungaro 1969). These larger foraminifera are biomarkers for the SB21-22A, Rupelian in age (Cahuzac and Poignant 1997). The section itself crops out just above the village of Longare, at Costozza, along the westward road (via Santa Tecla from Costozza up to Monte Brosimo (Fig. 1). Fifty samples were taken along the road section, spaced two vertical meters apart. Microfacies analysis was performed on thin-sections (48 9 48 mm) cut perpendicular to the bedding plane using a Leica MZ8 microscope. Semiquantitative data on the component distribution of thinsections were collected using the comparison charts depicted in Flu¨gel (2004). Five different areas of the thinsections were analyzed per thin-section and the results averaged (see Rasser and Nebelsick 2003). The textural classification of Embry and Klovan (1972) was used allowing for a general component and matrix description. Taxonomic uncertainties concerning fossil coralline taxonomy as discussed by Braga and Aguirre (1995), Rasser and Piller (1999), and Bassi and Nebelsick (2000) are avoided by using generic names only. Coralline red algal family and subfamily circumscriptions follow Braga et al. (1993), Aguirre and Braga (1998), Bassi and Nebelsick (2000), Braga (2003), and Iryu et al. (2009, 2012). Coralline algal growth form terminology follows Woelkerling et al. (1993). All thin-sections are deposited at the Institute of Geosciences, University of Tu¨bingen, Germany.
Results The results are presented with respect to biogenic components, microtaphofacies, and facies as derived from thinsection analysis and modal distribution of components. Biogenic components The biogenic components are totally dominated by coralline red algae. Larger foraminifera, small benthic foraminifera,
encrusting foraminifera, corals, and bryozoans are subordinate, but can be common. Echinoderms, bivalves, brachiopods, and serpulids are rare. Although often well preserved, many components show taphonomic alteration due to fragmentation and abrasion. Encrustation, especially by coralline algae, can be pervasive. Coralline algae Coralline algae are the most characteristic and dominant components and are found not only constructing rhodoliths and within encrustation sequences around other components but also as branch fragments in debris material. Nongeniculate coralline algae are present with representatives of Corallinaceae (Mastophoroideae), Hapalidiaceae (Melobesioideae), and Sporolithaceae. Six different coralline algal taxa were distinguished in the studied section, two of these were determined to species level, four to genus level (Table 1). These taxa are Neogoniolithon sp. (Fig. 2a), Lithoporella melobesioides (Foslie) Foslie, 1909 (Fig. 2b), Spongites sp. (Fig. 2c), Mesophyllum sp. (Fig. 2d), Sporolithon sp. (Fig. 2e), and Subterraniphyllum thomasii Elliot, 1957 (Fig. 2f). Small disarticulated and abraded intergeniculate fragments of undetermined geniculate corallines are also present. Coralline algae occur in a variation of growth forms with two types of encrusting forms on soft and hard biogenic substrate (see Nebelsick and Bassi 2000), which are associated with two types of small rhodoliths. Encrusting type 1 (Fig. 2a) is typically produced by Neogoniolithon and is associated with soft substrates. The usually well-preserved, relatively thick (up to 500 lm) single plants are up to a few centimeters long and are characteristically undulated. These encrusting plants grew parallel to the bedding plane. Encrusting foraminifera can be found on the outer surface of the coralline plant. Encrusting type 2 (Fig. 2b–e), which is more common than the encrusting type 1, shows single to multi-layered encrusting sequences around small biogenic substrates, especially around coral branches and bryozoans. The
123
136
Facies (2013) 59:133–148
Fig. 2 Calcareous algae from the Early Oligocene Calcareniti di Castelgomberto formation, Monti Berici. a Crust of Neogoniolithon sp.; sample CT20; scale bar 1 mm. b L. melobesioides (Foslie) Foslie with multiple overgrowths of dimerous cell filaments; sample CT29; scale bar 300 lm. c Protuberance of Spongites sp. with uniporate conceptacle; sample CT02/1; scale bar 500 lm. d Protuberances of
Mesophyllum sp. with multiporate conceptacle; sample CT31/1; scale bar 1 mm. e Transverse section through protuberances of Sporolithon sp. with sori; sample CT27; scale bar 1 mm. f Transverse section through a branch of S. thomasii Elliot; sample CT21; scale bar 300 lm
encrusting sequences are common among numerous different coralline algal taxa such as L. melobesioides (Foslie) Foslie, Spongites, Mesophyllum, and Sporolithon. Rhodolith type 1 shows sub-discoidal to sub-ellipsoidal shape, up to 1.5 cm maximum diameter, with loosely arranged laminar thalli. The nuclei are no longer preserved
and are replaced by a packstone matrix. These rhodoliths, which are multigeneric and multi-specific, show encrusting and warty growth forms. Encrusting bryozoans and foraminifera can contribute to the rhodolith construction. Rhodolith type 2, which is more common than rhodolith type 1, consists of densely packed laminar to protuberant thalli
123
Facies (2013) 59:133–148
showing warty, lumpy, and fruticose growth forms. Rhodoliths are sub-spheroidal/sub-ellipsoidal in shape with a mean rhodolith diameter of 1 cm. The core is often represented by coral fragments, though they can be represented by voids filled by packstone matrix. As in Rhodolith type 1, encrusting foraminifera and bryozoans contribute to the rhodoliths. Abrasion is common on the outer rhodolith surface. Benthic foraminifera Small benthic foraminifera are common including agglutinated (textulariids; Fig. 3a), porcelaneous (miliolids; Fig. 3b), and hyaline-perforated (rotaliids) forms (Fig. 3h). A detailed list of the small benthic foraminifera is provided by Ungaro (1978). Encrusting foraminifera, especially Acervulina (Fig. 3d) and rarely Haddonia (Fig. 3k), occur around coral branches and coralline algal thalli. Larger foraminifera can be facies-determining, but are usually present in a small number. The hyaline-perforated forms include Nummulites (Fig. 3f–g), Asterigerina (Fig. 3j), Operculina (Fig. 3i), and Neorotalia. The porcelaneous imperforated foraminifera are represented by Praerhapydionina, Penarchaias, and Spirolina. Sphaerogypsina (Fig. 3e) can also occur. In general, small benthic and larger foraminifera are well preserved. Planktonic foraminifera (Fig. 3c) are rarely present.
137
encrustation, and bioerosion (Fig. 4a–d). Components are generally well preserved though abrasion and fragmentation can occur in specific facies. Fragmentation especially affects thin coralline algal thalli; abrasion is common on the rims of larger foraminifera. Bioerosion is present as (1) narrow tubelike borings assigned to the ichnogenus Trypanites attributed to the activity of worms, and as (2) rounded, often connected, chambers assigned to the ichnogenus Entobia, which is known to be produced by bioeroding clionid sponges. Encrustation is pervasive given the encrusting nature of the dominating coralline algae. Encrustation sequences can be multigeneric including various taxa (see above) and can include encrusting foraminifera (Haddonia, acervulinids) and bryozoans. Thecideidinid brachiopods, which are present as rare fragments, are also encrusting organisms. Diagenesis affected primary aragonitic skeletons of corals that are replaced by sparite. Carbonate facies
Solitary and colonial coral branches (Figs. 4a, c, 5b) are commonly present and can be facies-determining. They are often highly encrusted by coralline algae, foraminifera, and bryozoans. Coral fragments constitute the majority of the nuclei in rhodolith type 2. The original aragonitic skeleton of the corals have been replaced by sparry calcite.
The studied carbonates mainly consist of rudstones with a packstone to wackestone matrix. Three layers of ca. 1–2m-thick, yellowish marl deposits, barren in macrofossils are also present (Fig. 5). Four different carbonate microfacies were distinguished on the basis of component distribution and coralline algal growth forms: coralline algal facies (CA), coralline algal-coral facies (CA-CO), coralline algal-larger foraminiferal facies (CA-LFO), and coralline algal debris facies (CAD). Textures, dominant and subordinated components, coralline algal assemblages and growth forms as well as larger foraminifera for each facies are shown in Table 2. The modal distribution of biogenic components within the different facies is shown in Table 3. The distribution of the facies in the section is shown in Fig. 5.
Other components
Coralline algal facies (CA)
Bryozoans (Fig. 4d) are common and occur in different growth forms as colonies in the matrix or are included in encrusting sequences around coral branches and coralline algal thalli. Bryozoans are often encrusted by coralline algae (Fig. 4d). Echinoderms are usually present in a small number and represented by spine cross sections and plates of echinoids. Other components include serpulids, ostracods, and fragmented bivalves. Rare complete and fragments of thecideid brachiopods (see Nebelsick et al. 2011a) are also present.
This facies (Fig. 5a) is characterized by the strong dominance of coralline algae (mean: 90.55 %; L. melobesioides, Mesophyllum, Neogoniolithon, Spongites, S. thomasii; Tables 1 and 3) in a wackestone to packstone matrix. Accessory components are represented by larger foraminifera (3.60 %) of the genera Nummulites, Operculina, and Spiroclypeus as well as bryozoans (3.54 %). Corals, small benthic foraminifera, especially miliolids, and bivalves are present as subordinate components, echinoderms, brachiopods, and ostracods are rare. Coralline algae are present in all the described growth forms. Rhodolith type 1 is very common, rhodolith type 2 and encrusting type 1 and 2 are also common. Algal branches and algal debris are rare. The majority of the investigated thin-sections belong to this facies.
Corals
Microtaphofacies A microtaphofacies approach (Nebelsick et al. 2011b; Silvestri et al. 2011) reveals abrasion, fragmentation,
123
138
Facies (2013) 59:133–148
Fig. 3 Foraminifera from the Early Oligocene Calcareniti di Castelgomberto formation, Monti Berici. a Textulariid foraminifer; sample CT21; scale bar 500 lm. b Quinqueloculine porcelaneous foraminifer; sample CT41; scale bar 200 lm. c Planktonic globigerinid foraminifer; sample CT44; scale bar 200 lm. d Acervulinid foraminifera encrusting Neogoniolithon sp.; sample CT20; scale bar 1 mm. e Sphaerogypsina sp.; sample CT44; scale bar 300 lm. f Nummulites,
oblique section; sample CT22/1; scale bar 1 mm. g Nummulites sp.; sample CT22/1; scale bar 1 mm. h Operculina sp.; sample CT22; scale bar 200 lm. i Small rotaliid foraminifera; sample CT18/2; scale bar 1 mm. j Asterigerina sp.; sample CT36/1; scale bar 300 lm. k Haddonia sp. encrusted by a coralline alga; sample CT42; scale bar 1 mm. l Larger agglutinated conical foraminifer; sample CT04; scale bar 300 lm
Coralline algal-coral facies (CA-CO)
with a packstone matrix. The coralline algae are present with all the described growth forms. The colonial corals are highly encrusted by coralline algae, foraminifera including Haddonia, and bryozoans. Further subordinate components are larger foraminifera (2.55 %) of the genera Nummulites,
This facies consists of dominating coralline red algae (mean: 72.30 %; L. melobesioides, Spongites; Fig. 5b) and subordinate corals (22.66 %) in rudstones to floatstones
123
Facies (2013) 59:133–148
139
Fig. 4 Microtaphofacies of the Lower Oligocene Calcareniti di Castelgomberto formation, Monti Berici. a Type 2 rhodolith with coral core encrusted by multi-specific coralline crusts of Neogoniolithon sp.; sample CT12/3; scale bar 1 mm. b Bioeroded coralline algae showing geopetal fabric; sample CT06; scale bar 1 mm.
c Leached coral encrusted by coralline algae; sample CT12, scale bar 2 mm. d Cheilostomate bryozoans showing encrustation and fragmentation next to fragmented thalli of coralline algae; sample CT44; scale bar 300 lm
Operculina, Praerhapydionina, Penarchaias, and Spirolina, small benthic foraminifera (0.78 %), and bryozoans (1.20 %). Sphaerogypsina is also present in this microfacies.
Coralline algal debris facies (CAD)
Coralline algal-larger foraminiferal facies (CA-LFO) Biogenic components are dominated by coralline algae (mean: 72.10 %; Spongites, Mesophyllum, Sporolithon) and larger foraminifera (up to 23.46 %) in a packstone matrix (Fig. 5c). Larger foraminifera are dominated by Nummulites, often abraded in the outer part of the shells. They can reach sizes up to 5 mm in diameter and are associated with Operculina, Spiroclypeus, Amphistegina, and Neorotalia. Rhodolith type 2 is very common, while Rhodolith type 1 is not present. Encrusting types 1 and 2 and algal debris commonly occur. Other components include bryozoans (2.55 %), corals (0.94 %) and small benthic foraminifera (0.60 %) as well as rare echinoderms, bivalves, and planktonic foraminifera.
This microfacies (Fig. 5d) is characterized by the highest amount of coralline algal branches and their debris within a packstone to grainstone matrix. The coralline fruticose branches occur as small abraded fragments a few millimeters long. Rhodoliths are only rarely present. The coralline taxonomic assemblage is represented by the genera Spongites and Sporolithon associated with subordinate S. thomasii. The modal distribution of the components shows dominant coralline algae (mean: 83.98 %) along with subordinated larger foraminifera (7.88 %; Nummulites, Operculina, Amphistegina) and corals (4.59 %). Bryozoans (1.84 %) and small benthic foraminifera (0.93 %) are also present.
Discussion The carbonates of the Calcareniti di Castelgomberto formation of the Monti Berici were deposited in a fully
123
140
Facies (2013) 59:133–148
Fig. 5 Microfacies of the Lower Oligocene Calcareniti di Castelgomberto formation, Monti Berici. a Coralline algal facies with type 1 rhodolith consisting of Neogoniolithon sp. crusts; sample CT06; scale bar 1 mm. b Coralline algal-coral facies with encrusted corals; sample CT19; scale bar 1 mm. c Coralline algal-large foraminiferal
facies with Nummulites sp. and coralline algal fragments; sample CT01; scale bar 1 mm. d Coralline algal debris facies dominated by highly fragmented coralline algal thalli; sample CT26/1; scale bar 1 mm
Table 1 Identified coralline algae and their growth forms, inhabited substrate types, and microfacies Encrusting
Warty
Lumpy
Fruticose
Substrate
Facies CA-CO
L. melobesioides
X
Hard, other corallines
Neogoniolithon sp.
X
Soft, sediment surface
CA, CA-CO
Spongites sp.
X
X
Hard, other corallines
CA, CA-CO, CA-LFO
Mesophyllum sp.
X
X
X
Hard, other corallines, bivalves, bryozoans
CA, CA-LFO
Sporolithon sp.
X
X
X
Hard, other corallines
CAD
X
Coarse grained
CAD, CA
S. thomasii
X
CA coralline algal facies, CA-CO coralline algal-coral facies, CA-LFO coralline algal-larger foraminiferal facies, CAD coralline algal debris facies
marine environment as indicated by coralline algae, bryozoans, corals, and echinoderms. All the carbonate facies lie within the photic zone shown by the dominance of coralline algal plants as well as the presence of symbiontbearing forms such as zooxanthellate corals (z-corals) and larger foraminifera. The micritic matrix throughout the facies indicates relatively low energy conditions. The interpretation of the different facies is based on
123
the distribution of biogenic components as well as microtaphofacies. A homoclinal ramp is reconstructed for the general depositional environment as there is no geological and sedimentary data suggesting for a rimmed shelf. A distinct facies development along the section can be followed despite the fact that all samples are totally dominated by coralline algae. Detailed investigations show differences not only in
Facies (2013) 59:133–148
141
Table 2 Texture, dominant and subordinated components, coralline algal and larger foraminiferal assemblages, growth forms and interpretations of four recognized facies Facies
Coralline algal
Coralline algal-coral
Coralline algal-larger foraminiferal
Coralline algal debris
Texture
Wackestone/packstone
Rudstone/packstone
Packstone
Packstone/grainstone
Dominant components
Corallines
Corallines, corals
Corallines, larger foraminifera
Corallines
Subordinate components
Larger foraminifera, bryozoans, corals, miliolids, bivalves
Larger foraminifera, small benthic foraminifera, bryozoans
Bryozoans, corals, small benthic foraminifera, echinoderms
Larger foraminifera, corals, small benthic foraminifera
Coralline algal assemblages
Neogoniolithon, Spongites, Lithoporella, Lithothamnion
Spongites, Lithoporella, Lithothamnion, Mesophyllum
Neogoniolithon, Spongites, Lithoporella, Lithothamnion, Sporolithon
Spongites, Lithothamnion, Mesophyllum, Sporolithon
Coralline algal growth-forms
Encrusting, rhodolith type 1, rhodolith type 2
Encrusting
Rhodolith type 2
Fruticose, rare rhodoliths
Larger foraminiferal assemblages
Nummulites, Operculina, Spiroclypeus
Nummulites, Operculina, Asterigerina, Neorotalia, Praerhapydionina, Penarchaias, Spirolina
Nummulites, Operculina, Spiroclypeus, Amphistegina, Neorotalia
Nummulites, Operculina, Amphistegina
Paleoenvironmental interpretation
Distal inner ramp
Proximal inner ramp
Distal inner ramp
Proximal inner ramp
Table 3 Mean, standard deviation (SD), minimum (min.), and maximum (max.) values of percentages of biogenic components in the four facies
Coralline algae
Larger foraminifera
Small foraminifera
Corals
Bryozoans
Echinoderms
Others
CA (n = 28) Mean
90.55
3.60
0.47
1.39
3.54
0.25
0.20
SD
5.67
2.72
0.70
2.48
3.31
0.33
0.46
Min
75.51
0.00
0.00
0.00
0.26
0.00
0.00
Max
99.07
9.45
3.06
9.29
15.06
1.02
2.04 0.06
CA-CO (n = 8) Mean
72.30
2.55
0.78
22.66
1.20
0.45
SD
11.30
3.11
0.56
10.45
0.95
0.71
0.16
Min
59.49
0.00
0.00
8.02
0.00
0.00
0.00
Max
90.42
9.79
1.62
38.38
3.31
1.68
0.49
CA-LFO (n = 6)
n number of samples Facies: CA coralline algal facies, CA-CO coralline algalcoral facies, CA-LFO coralline algal-larger foraminiferal facies, CAD coralline algal debris facies
Mean
72.10
23.46
0.60
0.94
2.55
0.30
0.05
SD Min
12.88 46.27
13.86 10.21
1.06 0.00
0.97 0.00
1.57 0.43
0.57 0.00
0.11 0.00
Max
85.23
52.70
2.95
2.25
5.29
1.57
0.29
CAD (n = 3) Mean
83.98
7.88
0.93
4.59
1.84
0.00
0.78
SD
2.26
3.46
0.82
6.49
1.72
0.00
1.11
Min
80.82
3.00
0.00
0.00
0.42
0.00
0.00
Max
85.95
10.59
2.00
13.77
4.25
0.00
2.35
subordinate components but also in dominant corallines (i.e., growth forms) and microtaphofacies. A general increase of hydrodynamic energy can be considered to take place along a gradient from the marls, with the lowest hydrodynamic energy intensity to the (1) coralline algal facies, to the (2) coralline algal-coral facies, to the (3) coralline algal-larger
foraminiferal facies, to finally the (4) coralline algal debris facies. This facies succession mirrors a gradient also in the light conditions of the depositional setting. The most pronounced facies change is present as the marls are followed abruptly by the coralline algal debris facies, interpreted to represent the highest energy conditions. This change occurs
123
142
at least two times in the section and may suggest rapid periods of increasing energy followed by relatively slow periods of decreasing energy conditions. Carbonate facies interpretation Coralline algal facies This shows the highest presence of well-preserved, fragile rhodolith type 1 suggesting relative low energy conditions. The dominating coralline alga is Neogoniolithon, which was able to grow directly on the soft substrate (Nebelsick and Bassi 2000; Quaranta et al. 2007). Low abrasion rates as well as paucity of coralline algal debris support low energy conditions. This facies is similar to other Paleogene facies with single encrusting Neogoniolithon plants characterized by thick ventral core and even constructing rhodoliths with a high percentage of constructional voids (Bassi 1995; Nebelsick et al. 2001) where relatively deep, lower energy and low light intensity are interpreted (e.g., Rasser and Piller 2004; Bassi 2005; Quaranta et al. 2007; Braga and Bassi 2011). The colonization of the sediment surface by coralline algae is an important indicator of stabilized bottom substrate (Bosence 1983a, b). Local early cementation processes cannot be excluded. The occurrence of three nummulitid genera (Nummulites, Operculina, Spiroclypeus) along with the common presence of miliolids supports the additional interpretation of a lower energy environment in a distal inner ramp setting (e.g., Beavington-Penney and Racey 2004; Bassi et al. 2008; Brandano et al. 2009; Bassi and Nebelsick 2010). Coralline algal-coral facies The coralline algal-coral facies offers both a hard and a soft substrate, which leads to a high number of encrusting types 1 and 2. Encrusting type 1 of the genus Neogoniolithon points out, together with the well-preserved encrusting sequences around corals, a relatively quiet environmental setting (e.g., Nebelsick and Bassi 2000; Braga et al. 2009, 2010). This is also shown by the presence of Haddonia, which is highly susceptible to detachment and destruction by water energy (Matteucci 1996). The relatively high percentage of rhodolith type 2 and algal debris in this facies suggests, however, higher energy conditions than in the coralline algal facies. The type 2 rhodoliths are interpreted to result from higher energy conditions than the type 1 rhodoliths as they are more compact and show higher degrees of abrasion on their surfaces. This facies is similar to other examples of coral-rich facies in the Oligocene that also show high amounts of encrustation by coralline algae in turbid environments (see Silvestri et al. 2011 and references therein).
123
Facies (2013) 59:133–148
Coralline algal-large foraminiferal facies This facies is regarded as reflecting deposition within or at the vicinity of sea-grass meadows in a distal inner ramp setting. Soritids and flat nummulitids such as O. complanata are known to be epiphytic organisms living on the leaves of sea grasses. Rotaliids and amphisteginids are also common in modern sea-grass environments (Sen Gupta 1999). Sea-grass meadows represent an important factor in carbonate systems in Recent environments (e.g., Nelsen and Ginsburg 1986; Nakamori et al. 1992; Perry and Beavington-Penney 2005; Mateu-Vicens et al. 2010) and their interpreted presence in fossil sediments has been the subject of a number of investigations (e.g., Brasier 1975; Eva 1980; Ivany et al. 1990; Cann et al. 2002; Pomar et al. 2004; James and Bone 2005; Reuter and Piller 2011; Reuter et al. 2012; Riordan et al. 2012). Direct evidence of sea-grass meadows is possible, if exceptional preservation is present (Moisette et al. 2007), if leaf indentations as a result of bioimmuration are found at the base of encrusting organisms especially bryozoans and encrusting foraminifera (Reuter et al. 2010; Moisette 2012), or if specific growth forms of encrusters are present (Beavington-Penney et al. 2004). Direct evidence of this nature is missing from the study material, but would not be expected to be preserved in the two-dimensional plane of thin-sections that form the basis for the present analysis. Further evidence for sea grass can be given by associated biogenic components, which can be typical for seagrass meadows (e.g., Langer 1993). The common occurrence of discoidal larger foraminifera has been used as an indication for the presence of sea grass (Reuter et al. 2010). Moreover, high mud content and very poor grain sorting are common features of sea-grass facies, though this does not always have to be the case (Perry and BeavingtonPenney 2005). With respect to crustose coralline algae, sea grass presence has also been interpreted as a prerequisite for coralline algal and rhodolith preservation preventing these components from being transported into other environments (Piller and Rasser 1996). The presence of abundant Nummulites within this facies, pointing to a shallow-water, well-illuminated environment (e.g., Hottinger 1997), argues against deposition under dense sea-grass cover, and suggests either deposition in a sparsely colonized area, or in close proximity to sea grass (Beavington-Penney and Racey 2004; Beavington-Penney et al. 2004). The existence of compact type 2 rhodoliths, which require regular turning (e.g., Braga and Martı´n 1988; Bosence 1991; Matsuda and Iryu 2011), suggests a higher energy environment than the previously described facies. The identified foraminifera, especially Nummulites, point to a shallow-water, well-illuminated environment (e.g., Hottinger 1997; Beavington-Penney and Racey 2004; Bassi
Facies (2013) 59:133–148
et al. 2007). Microtaphofacies evidence including abrasion of the outer protuberances of the coralline algae as well as abrasion and some fracturing of the larger foraminiferal shells may result from episodes of higher energy or biological activity. Coralline algal debris facies This facies with its high abundance of coralline algal debris and algal fruticose branches is interpreted as having been deposited in environments with the highest energy among the described facies in more exposed proximal inner ramp setting. High energy conditions lead to a breakage of coralline algal fruticose protuberances into the respective fragments. The low occurrence of mud is regarded as indicative of moderate to high bottom currents, an interpretation that is further supported by the abundance of robust benthic foraminifera such as Sphaerogypsina and amphisteginids. Epiphytic forms such as the soritids could reflect derivation from adjacent sea-grass communities. This facies can be compared to a mae¨rl habitat, which comprises loose-lying non-jointed coralline red algae that can build up over millennia to create carbonate-rich gravel deposits forming isolated habitats of high benthic biodiversity (e.g., Grall and Hall-Spencer 2003; Grall et al. 2006). Mae¨rl beds have been recorded from a variety of depths, ranging from the lower shore to 30 m depth (Wilson et al. 2004; Nebelsick et al. 2005). Distribution of facies along the section The development along the section (Fig. 6) shows the following pattern of limestones interrupted by marls. The section begins with a large number of samples belonging to the CA facies interrupted by a single sample of the CA-CO facies. This is followed by abrupt occurrence of marl. This is followed by the first occurrence of the CAD facies (CT018), followed by CA-CO, CAS, CA-LFO and, once again following the CA facies, a marly horizon. These marls are similar to the previous example followed by the CAD facies. The top half of the section is characterized by intercalation of the CA, CA-CO, and CA-LFO facies leading to the last marly horizon, which is followed by two samples of the CA facies. The first two marls are thus preceded by the CA facies, interpreted as the deepest of the limestones facies with the lowest energy conditions, and are followed by the CAD facies, interpreted as representing the highest energy conditions. If this pattern is interpreted in terms of sea-level variation, then this could represent transgressions culminating in deeper marls followed by abrupt regressions leading to shallower-water conditions represented by the higher-energy CAD facies.
143
Facies development on a homoclinal ramp The distribution of facies, their interpretation with respect to energy conditions, and the lack of build-ups suggests that a homoclinal ramp is present as opposed to a rimmed shelf, at least in this part of the Monti Berici. The changes in taxonomic composition, especially of the coralline algae as well as their growth forms and taphonomic traits, can be used to assess ecological gradients in current strength, substrate stability, light intensity, and nutrient availability. The fact that the facies are totally dominated by lightdependent organisms (coralline algae, larger foraminifera, corals) demonstrates the origin of these components within the photic zones, thus determining an inner ramp position in the upper euphotic zone. Taxonomic distributions and growth forms of specific taxa can then be used to differentiate between proximal and distal inner ramp positions. Following the interpretation of facies, the first part of the section, which is dominated by the CA facies, shows lower energy conditions. There then follows a short middle section including both marls and CAD facies displaying a rapid change from lower and higher energy conditions. The top of the section then displays alternating facies showing both lower (CA, CA-LFO) and higher energy (CA-CO) facies. There are at least two different, though not necessarily mutually exclusive, possibilities to explain the variations of ecological parameters leading to differences in facies content and the specific distribution of facies along the studied section. One of these possibilities is a patchy facies distribution model with slight variation in hydrodynamic energy levels; the other is based on facies being controlled by variations in sea level and associated deviations in water energy and illumination. The first possibility considers the sediments to have been deposited under fairly uniform conditions at more or less constant depths with slight variations of ecological parameters leading to a patchy distribution of facies (e.g., Riegl and Piller 2000). Somewhat lower energy conditions led to soft substrate that could be colonized by coralline algae, especially Neogoniolithon (CA facies), along with Spongites, Lithoporella, and Lithothamnion. Sea-grass meadows supported the proliferation of specific larger foraminifera and trapped sediment (CA-LFO facies). More stable substrates created by corals led to complex encrustation sequences with diverse corallines (CA-CO facies), and rare higher energy conditions present in channels (e.g., Bassi et al. 2006, 2010) led to fragmented coralline material in grainstone/packstones of a mobile substrate (CAD facies). The depositional environment of the marls is difficult to clarify due to the lack of observed features in these sediments, but most probably represent quiet protected environments.
123
144
Facies (2013) 59:133–148
Fig. 6 Section of the Calcareniti di Castelgomberto formation in the Monti Berici with modal analysis of biogenic components as well as assessment of growth forms and detritus of the coralline algae. CA Coralline algal facies, CA-CO coralline algal-coral facies, CA-LFO coralline algal-larger foraminiferal facies, CAD coralline algal debris facies
A second possibility represents a more dynamic scenario with sediments reacting to changes in sea level leading to hemicycles related to transgressions and regressions (e.g., Vail et al. 1991; Mitchum and Van Wagoner 1991; Lehrmann and Goldhammer 1999). In this model, the marly sediments represent deeper-water conditions too poorly illuminated to allow for the growth of the light-dependent organisms (coralline algae, larger foraminifera, and corals), which totally dominate the biogenic components of the carbonate facies. The CA facies is interpreted as occurring in deeper-water, though illuminated settings (distal inner ramp) with quieter water, allowing coralline algal crusts to grow on the sediment surface and allowing for loose rhodoliths to be formed by a genus (Neogoniolithon) that is adapted to lower illumination than other coralline algae.
123
The CA-LFO and CA-CO facies could represent shallower, more proximal inner-ramp facies whose characteristics are determined by the presence of either sea-grass meadows, which allow larger foraminifera to proliferate (CA-LFO facies), or corals which serve as substrates for encrusters (CA-CO facies). The differentiated substrates of these two latter facies allow for the development of more highly diverse coralline algal assemblages. The CAD facies would then represent the shallowest and highest-energy facies, analogous to modern mae¨rl-type sediments with highly fragmented branches of a less diverse coralline algal flora. The fact that the marls are preceded by the CA facies (the carbonate facies deposited under the lowest waterenergy condition) would suggest progressive deepening of the environment. The abrupt change from the marls to the
Facies (2013) 59:133–148
CAD facies (the highest-energy facies) would then suggest a sudden shallowing-upward trend. This pattern is repeated at least two times and could thus represent a transgressionregression cycle with a gradual transgression, the highstand represented by marl, followed by a rapid regression leading to the shallowest-water conditions. This interpretation depends on the interpretation of the marls as the deepest sediments for which there is, however, no outright evidence. Both models do not necessarily exclude one another and can be expected to contribute to the development of facies patterns in shallow-water environments. To what extent which of these models reflects more closely the original conditions will remain ambiguous until more data is collected from other localities in the Monti Berici (compare Geister and Ungaro 1977).
Conclusions (1)
(2)
(3)
(4)
Changes in diversity, growth forms, and microtaphofacies of coralline algal-dominated facies were analyzed using standard microfacies techniques on the carbonates of the Lower Oligocene Calcareniti di Castelgomberto formation of the Monti Berici. Coralline algae are present as rhodoliths, encrusting thalli, algal fruticose branches, and algal debris. Larger benthic foraminifera and z-corals are also present. The carbonates consist of biogenic rudstones with wackestone to packstone matrix and a few marly intercalations. Four carbonate facies were distinguished: (1) coralline algae facies, (2) coralline algal-coral facies, (3) coralline algal-larger foraminiferal facies, and (4) coralline algal debris facies. Fully marine conditions within the euphotic zone in a generally quiet environment are reconstructed for all facies. The coralline algal facies represents the highest water energy, coralline algal-coral and coralline algallarger foraminiferal facies represent intermediate energy conditions in a well-illuminated environment, while the coralline algal facies represent lower water energy and light conditions. This trend continues into the marls, which represent the deepest facies. The facies sequence in the studied sections shows systematic changes between the facies, which may reflect patchy facies distribution with the influence of channels, or sea-level fluctuations with asymmetric cycles of slow transgressions and rapid regressions, or both.
Acknowledgments We thank Per Jeisecke for preparing thin-sections. Yasufuni Iryu, Lucia Simone, and an anonymous reviewer are thanked for their thorough reviews. D. B. was funded by a local research fund (FAR) from the University of Ferrara.
145
References Adey WH (1986) Coralline algae as indicators of sea-level. In: Van de Plassche O (ed) Sea level research: a manual for the collection and evaluation of data. Free University of Amsterdam, Geo Book, Norwich, pp 229–279 Adey WH, MacIntyre IG (1973) Crustose coralline algae: a reevaluation in the geological sciences. Geol Soc Am Bull 84:883–904 Aguirre J, Braga JC (1998) Redescription of Lemoine’s (1939) types of coralline algal species from Algeria. Palaeontology 41:489–507 Aguirre J, Riding R, Braga JC (2000) Diversity of coralline red algae: origination and extinction patterns from the Early Cretaceous to the Pleistocene. Paleobiology 26:651–667 Airoldi M (1932) Contributo allo studio delle corallinacee del terziario italiano. 1. Le Corallinacee dell’Oligocene LigurePiemontese. Paleontogr Ital Mem Paleont 33:55–83 Antonelli R, Barbieri G, Dal Piaz GV, Dal Pra A, De Zanche V, Grandesso P, Mietto P, Sedea R, Zanferrari A (1990) Carta Geologica del Veneto 1:250.000: una storia di cinquecento milioni di anni. Regione Veneto, Dipart Geol Paleont Geofis Univ Padova, Padova, 31 p Bassi D (1995) Crustose coralline algal pavements from Late Eocene Colli Berici of northern Italy. Riv Ital Paleontol Stratigr 10:81–92 Bassi D (1998) Coralline algal facies and their palaeoenvironments in the Late Eocene of northern Italy (Calcare di Nago, Trento). Facies 39:179–202 Bassi D (2005) Larger foraminiferal and coralline algal facies in an Upper Eocene storm influenced, shallow-water carbonate platform (Colli Berici, north-eastern Italy). Palaeogeogr Palaeoclimatol Palaeoecol 226:17–35 Bassi D, Nebelsick JH (2000) Calcareous algae from the Lower Oligocene Gornji Grad Beds of northern Slovenia. Riv Ital Paleontol Stratigr 106:99–122 Bassi D, Nebelsick JH (2010) Components, facies and ramps: redefining Upper Oligocene shallow water carbonates using coralline red algae and larger foraminifera (Venetian area, northeast Italy). Palaeogeogr Palaeoclimatol Palaeoecol 295:258–280 Bassi D, Cosovic V, Papazzoni CA, Ungaro S (2000) The Colli Berici. In: Bassi D (ed) Shallow Water Benthic Communities at the Middle–Upper Eocene Boundary. Southern and NorthEastern Italy, Slovenia, Croatia, Hungary. Field Trip Guidebook of the 5th Meeting IGCP 393 IUGS-UNESCO. Ann Univ Ferrara, Suppl Sci Terra, pp 43–57 Bassi D, Carannante G, Murru M, Simone L, Toscano F (2006) Rhodalgal/bryomol assemblages in temperate type carbonate, channelised depositional systems: the Early Miocene of the Sarcidano area (Sardinia, Italy). In: Pedley HM, Carannante G (eds) Cool-water carbonates: depositional systems and palaeoenvironmental control. Geol Soc Lond Spec Publ 255:35–52 Bassi D, Hottinger L, Nebelsick JH (2007) Larger foraminifera from the Late Oligocene of the Venetian area, north-eastern Italy. Palaeontology 50:845–868 Bassi D, Bianchini G, Mietto P, Nebelsick JH (2008) Southern Alps in Italy: Venetian Pre-Alps. In: McCann T (ed) Geology of Central Europe. Geol Soc Lond, pp 56–62 Bassi D, Carannante G, Checconi A, Simone L, Vigorito M (2010) Sedimentological and palaeoecological integrated analysis of a Miocene canalized coralline red algal carbonate margin (Matese Mountains, Central-Southern Apennines, Italy). Sediment Geol 230:105–122 Basso D (1996) Adaptive strategies and convergent morphologies in some Mediterranean coralline algae. In: Cherchi A (ed)
123
146 Autoecology of selected fossil organisms: achievements and problems. Boll Soc Paleontol Ital spec 3:1–8 Beavington-Penney SJ, Racey A (2004) Ecology of extant nummulitids and other larger benthic foraminifera: applications in palaeoenvironmental analysis. Earth Sci Rev 67:219–265 Beavington-Penney SJ, Wright VP, Woelkerling WJ (2004) Recognising macrophyte-vegetated environments in the rock record: a new criterion using ‘hooked’ forms of crustose coralline red algae. Sediment Geol 166:1–9 Bosellini A (1967) Calcareniti di Castelgomberto. In: Bosellini A, Carraro F, Corsi M, de Vecchi GP, Gatto GO, Malaroda R, Stuvani C, Ungaro S, Zannettin B (eds) Note illustrative della Carta geologica d’Italia, Foglio 49, Verona. Servizio Geologico d’Italia, Roma Bosellini FR, Russo A (1995) The Scleractinian genus Actinacis. Systematic revision and stratigraphic record of the Tertiary species with special regard to Italian occurrences. Riv Ital Paleontol Stratigr 101:215–230 Bosellini FR, Stemann TA (1996) Autoecologic significance of growth form in the scleractinian Actinacis rollei Reuss (Oligocene, Lessini Mountains, northern Italy). Boll Soc Paleontol Ital vol spec 3:31–43 Bosellini FR, Trevisani E (1992) Coral facies and cyclicity in the Castelgomberto Limestone (Early Oligocene, Eastern Lessini Mountains, northern Italy). Riv Ital Paleontol Stratigr 98:339–352 Bosence DWJ (1983a) Description and classification of rhodoliths (rhodoids, rhodolites). In: Peryt TM (ed) Coated grains. Springer, Berlin Heidelberg New York, pp 217–224 Bosence DWJ (1983b) The occurrence and ecology of recent rhodoliths—a review. In: Peryt TM (ed) Coated grains. Springer, Berlin Heidelberg New York, pp 225–242 Bosence DWJ (1991) Coralline algae: mineralization, taxonomy, and palaeoecology. In: Riding R (ed) Calcareous algae and stromatolites. Springer, Berlin Heidelberg New York, pp 98–113 Bosence DWJ, Pedley HM (1982) Sedimentology and palaeoecology of a Miocene coralline algal biostrome from the Maltese Islands. Palaeogeogr Palaeoclimatol Palaeoecol 38:9–43 Braga JC (2003) Application of botanical taxonomy to fossil coralline algae (Corallinales, Rhodophyta). Acta Micropalaeontol Sin 20:47–56 Braga JC, Aguirre J (1995) Taxonomy of fossil coralline algal species: Neogene Lithophylloideae (Rhodophyta, Corallinaceae) from southern Spain. Rev Paleobot Palynol 86:265–285 Braga JC, Bassi D (2011) Facies and coralline algae from Oligocene limestones in the Malaguide Complex (SE Spain). Ann Naturhist Mus Wien Ser A 113:291–308 Braga JC, Martı´n JM (1988) Neogene coralline-algal growth forms and their palaeoenvironments in the Almanzora River Valley (Almeria, S.E. Spain). Palaeogeogr Palaeoclimatol Palaeoecol 67:285–303 Braga JC, Bosence DW, Steneck RS (1993) New anatomical character in fossil coralline algae and their taxonomic implications. Palaeontology 36:535–547 Braga JC, Vescogni A, Bosellini FR, Aguirre J (2009) Coralline algae (Corallinales, Rhodophyta) in western and central Mediterranean Messinian reefs. Palaeogeogr Palaeoclimatol Palaeoecol 275:113–128 Braga JC, Bassi D, Piller WE (2010) Palaeoenvironmental significance of Oligocene-Miocene coralline red algae—a review. In: Mutti M, Piller WE, Betzler C (eds) Carbonate systems during the Oligocene-Miocene climatic transition. Int Assoc Sediment Spec Publ 42:165–182 Brandano M, Frezza V, Tomassetti L, Cuffaro M (2009) Heterozoan carbonates in oligotrophic tropical waters: the Attard member of the lower coralline limestone formation (Upper Oligocene, Malta). Palaeogeogr Palaeoclimatol Palaeoecol 274:54–63
123
Facies (2013) 59:133–148 Brasier MD (1975) An outline history of seagrass communities. Palaeontology 18:681–702 Buxton MWN, Pedley HM (1989) A standardized model for Tethyan Tertiary carbonate ramps. J Geol Soc Lond 146:746–748 Cahuzac B, Poignant A (1997) Essai de biozonation de l’OligoMioce`ne dans les bassins europe´ens a` l’aide des grands foraminife`res ne´ritiques. Bull Soc Ge´ol Fr 168:55–169 Cann JH, Harvey N, Barnett EJ, Belperio AP, Bourman RP (2002) Foraminiferal biofacies eco-succession and Holocene sea levels, Port Pirie, South Australia. Mar Micropaleontol 44:31–55 Conti S (1950) Alghe corallinacee fossili. Pubbl Inst Geol Univ Genova, Paleont 4(Ser A):1–156 Embry AF, Klovan JE (1972) Absolute water depth limits of Late Devonian palaeoecological zones. Geol Rundsch 61:672–686 Eva AN (1980) Pre-Miocene seagrass communities in the Caribbean. Palaeontology 23:231–236 Flu¨gel E (2004) Microfacies of carbonate rocks. Analysis, interpretation and application. Springer, Berlin Heidelberg New York, xx?976 p Francavilla F, Frascari Ritondale Spano F, Zecchi R (1970) Alghe e macroforaminiferi al limite Eocene-Oligocene presso Barbarano (Vicenza). Giorn Geol 36:653–686 Fravega P, Giammarino S, Piazza M, Russo A, Vannucci G (1987) Significato paleoecologico degli episodi coralgali a Nord di Sassello. Nuovi dati per una ricostruzione paleogeograficaevolutiva del margine meridionale del Bacino Terziario del Piemonte. Atti Soc Toscana Sci Nat Mem Ser A 94:19–76 Frost SH (1981) Oligocene reef coral biofacies of the Vicentin, northeast Italy. Soc Sediment Geol Spec Publ 30:483–539 Geister J, Ungaro S (1977) The Oligocene coral formations of the Colli Berici (Vicenza, Northern Italy). Ecl Geol Helv 70:811–823 Grall J, Hall-Spencer JM (2003) Problems facing maerl conservation in Brittany. Aquat Conserv Mar Freshw Ecosyst 13:S55–S64 Grall J, Le Loc’h F, Guyonnet B, Riera P (2006) Community structure and food web based on stable isotopes (d15N and d13C) analyses of a North Eastern Atlantic maerl bed. J Exp Mar Biol Ecol 338:1–15 Hottinger L (1997) Shallow benthic foraminiferal assemblages as signals for depth of their deposition and their limitations. Bull Soc Ge´ol Fr 168:491–505 Iryu Y, Bassi D, Woelkerling WJ (2009) Re-assessment of the type collections of fourteen corallinalean species (Corallinales, Rhodophyta) described by W. Ishijima (1942–1960). Palaeontology 52:401–427 Iryu Y, Bassi D, Woelkerling W (2012) Typification and reassessment of seventeen species of coralline red algae (Corallinales and Sporolithales, Rhodophyta) described by W. Ishijima during 1954–1978. J Syst Palaeontol 10:171–209 Ivany LC, Portell RG, Jones DS (1990) Animal–plant relationships and paleobiogeography of an Eocene seagrass community from Florida. Palaios 5:244–258 James N, Bone Y (2005) A late Pliocene–early Pleistocene, inner-shelf, subtropical, seagrass-dominated carbonate: Roe Calcarenite, Great Australian Bight, Western Australia. Palaios 22:343–359 Langer MR (1993) Epiphytic foraminifera. Mar Micropaleontol 20:235–265 Lehrmann DJ, Goldhammer RK (1999) Secular variation in parasequence and facies-stacking patterns of platform carbonates: a guide to application of stacking-patterns analysis in strata of diverse ages and settings. In: Harris PM, Simo JA (eds) Advances in carbonate sequence stratigraphy: application to reservoirs, outcrops and models. SEPM Spec Publ 63:187–225 Mastorilli VI (1968) Nuovo contributo allo studio delle Corallinacee dell’Oligocene Ligure-Piemontese: i reperti della tavoletta Ponzone. Atti Ist Geol Univ Genova 5:153–406
Facies (2013) 59:133–148 Mateu-Vicens G, Box A, Deudero S, Rodrı´guez B (2010) Comparative analysis of epiphytic foraminifera in sediments colonized by seagrass Posidonia oceanica and invasive macroalgae Caulerpa spp. J Foram Res 40:134–147 Matsuda S, Iryu Y (2011) Rhodoliths from deep fore-reef to shelf areas around Okinawa-jima, Ryukyu Islands, Japan. Mar Geol 282:215–230 Matteucci R (1996) Autecological remarks on Recent and fossil Haddonia (Textulariida, Foraminifera). In: Cherchi A (ed) Autoecology of selected fossil organisms: achievements and problems. Boll Soc Paleont Ital spec 3:113–122 Minnery GA (1990) Crustose coralline algae from the Flower Garden Banks, northwestern Gulf of Mexico: controls on distribution and growth morphology. J Sediment Petrol 60:992–1007 Mitchum RM, Van Wagoner JC (1991) High-frequency sequences and their stacking patterns: sequence-stratigraphic evidences of high-frequency eustatic cycles. Sediment Geol 70:131–160 Moisette P (2012) Seagrass-associated bryozoan communities from the Late Pliocene of the Island of Rhodes (Greece). In: Ernst A, Scha¨fer P, Scholz J (eds) Bryozoan studies 2010. Lect Notes Earth Syst Sci 143:187–201 Moisette P, Koskeridou E, Corne´e JJ, Guillocheau F, Le´cuyer C (2007) Spectacular preservation of seagrasses and seagrass associated communities from the Pliocene of Rhodes. Palaios 22:200–211 Nakamori T, Suzuki A, Iryu Y (1992) Water circulation and carbon flux on Shiraho coral reef of the Ryukyu Islands, Japan. Cont Shelf Res 12:951–970 Nebelsick J, Bassi D (2000) Diversity, growth forms and taphonomy: key factors controlling the fabric of coralline algal dominated shelf carbonates. In: Insalaco E, Skelton P, Palmer T (eds) Carbonate platform systems: components and interactions. Geol Soc Lond Spec Publ 178:89–107 Nebelsick JH, Bassi D, Drobne K (2000) Microfacies analysis and palaeoenvironmental interpretation of Lower Oligocene, shallow-water carbonates (Gornjia Grad Beds, Slovenia). Facies 43:157–176 Nebelsick JH, Stingl V, Rasser M (2001) Autochthonous facies and allochthonous debris flows compared: early Oligocene carbonate facies patterns of the Lower Inn Valley (Tyrol, Austria). Facies 44:31–46 Nebelsick JH, Rasser M, Bassi D (2005) Facies dynamics in Eocene to Oligocene circumalpine carbonates. Facies 51:197–216 Nebelsick JH, Bassi D, Rasser MW (2011a) Cryptic relicts from the past—taphonomy and palaeoecology of encrusting thecideid brachiopods in Paleogene carbonates. Ann Naturhist Mus Wien Ser A 113:525–542 Nebelsick JH, Bassi D, Rasser MW (2011b) Microtaphofacies: exploring the potential for taphonomic analysis in carbonates. In: Allison P, Bottjer DJ (eds) Taphonomy: process and bias through time. Topics in Geobiol 32:337–377 Nelsen JE Jr, Ginsburg RN (1986) Calcium carbonate production by epibionts on Thalassia in Florida Bay. J Sediment Petrol 56:622–628 Pedley HM (1998) A review of sediment distribution and processes in Oligo-Miocene ramps of southern Italy and Malta (Mediterranean divide). In: Wright WP, Burchette TP (eds) Carbonate ramps. Geol Soc Lond Spec Publ 149:163–179 Perrin C, Bosence D, Rosen B (1995) Quantitative approaches to palaeozonation and palaeobathymetry of corals and coralline algae in Cenozoic reefs. In: Bosence DWJ, Allison PA (eds) Marine palaeoenvironmental analysis from fossils. Geol Soc Lond Spec Publ 83:181–229 Perry CT, Beavington-Penney SJ (2005) Epiphytic calcium carbonate production and facies development within sub-tropical seagrass beds, Inhaca Island, Mozambique. Sediment Geol 2005:161–176
147 Piller WE, Rasser M (1996) Rhodolith formation induced by reef erosion in the Red Sea, Egypt. Coral Reefs 15:191–198 Pomar L, Brandano M, Westphal H (2004) Environmental factors influencing skeletal grain sediment associations: a critical review of Miocene examples from the western Mediterranean. Sedimentology 51:627–651 Quaranta F, Vannucci G, Basso D (2007) Neogoniolithon contii comb. nov. based on the taxonomic re-assessment of Mastrorilli’s original collections from the Oligocene of NW Italy (Tertiary Piedmont Basin). Riv Ital Paleontol Stratigr 113:43–55 Rasser MW (2000) Coralline red algae limestone of the Late Alpine Foreland Basin in Upper Austria: component analysis, facies and palecology. Facies 42:59–92 Rasser MW, Nebelsick JH (2003) Provenance analysis of Oligocene autochthonous and allochthonous coralline algae: a quantitative approach towards reconstructing transported assemblages. Palaeogeogr Palaeoclimatol Palaeoecol 201:89–111 Rasser MW, Piller WE (1997) Depth distribution of calcareous encrusting associations in the northern Red Sea (Safaga, Egypt) and their geological implications. In: Lessios HA, Macintyre IG (eds) Proceedings of the 8th international coral reef symposium 1:743–748 Rasser MW, Piller WE (1999) Application of neontological taxonomic concepts to Late Eocene coralline algae (Rhodophyta) of the Austrian Molasse Zone. J Micropaleontol 18:67–80 Rasser MW, Piller WE (2004) Crustose algal frameworks from the Eocene Alpine Foreland. Palaeogeogr Palaeoclimatol Palaeoecol 206:21–39 Reuter M, Piller WE (2011) Volcaniclastic events in coral reef and seagrass environments: evidence for disturbance and recovery (Middle Miocene, Styrian Basin, Austria). Coral Reefs 30: 889–899 Reuter M, Piller WE, Harzhauser M, Kroh A, Ro¨gl F, Coric S (2010) The Quilon Limestone, Kerala Basin, India: an archive for Miocene Indo-Pacific seagrass beds. Lethaia 44:76–86 Reuter M, Piller WE, Erhart C (2012) A Middle Miocene carbonate platform under silici-volcaniclastic sedimentation stress (Leitha Limestone, Styrian Basin, Austria)—depositional environments, sedimentary evolution and palaeoecology. Palaeogeogr Palaeoclimatol Palaeoecol 350–352:198–211 Riegl B, Piller WE (2000) Biostromal coral facies—a Miocene example from the Leitha Limestone (Austria) and its actualistic interpretation. Palaios 15:399–413 Riordan NK, James NP, Bone Y (2012) Oligo–Miocene seagrassinfluenced carbonate sedimentation along a temperate marine palaeoarchipelago, Padthaway Ridge, South Australia. Sedimentology 59:393–418 Sen Gupta BK (1999) Foraminifera in marginal marine environments. In: Sen Gupta BK (ed) Modern foraminifera. Kluwer, Dordrecht, pp 141–159 Silvestri G, Bosellini FR, Nebelsick JH (2011) Microtaphofacies analysis of Lower Oligocene turbid-water coral assemblages. Palaios 26:805–820 Steneck RS (1986) The ecology of coralline algal crusts: convergent patterns and adaptive strategies. Ann Rev Ecol Syst 17:273–303 Ungaro S (1969) E´tude micropale´ontologique et stratigraphique de l’E´ocene supe´rieur (Priabonien) de Mossano (Colli Berici). Me´m Rech Geol Min 69:267–280 Ungaro S (1978) L’Oligocene dei Colli Berici. Riv Ital Paleontol Stratigr 84:199–278 Vail PR, Auderman SA, Bowman PN, Eisner PN, Perez-Cruz C (1991) The stratigraphic signatures of tectonics, eustasy and sedimentology—an overview. In: Einsele G, Ricken W, Seilacher A (eds) Cycles and events in stratigraphy. Springer, Berlin Heidelberg New York, pp 618–659
123
148 Wilson S, Blake C, Berges JA, Maggs CA (2004) Environmental tolerances of free-living coralline algae (maerl): implications for European marine conservation. Biol Conserv 12:283–293
123
Facies (2013) 59:133–148 Woelkerling WJ, Irvine LM, Harvey AS (1993) Growth forms in nongeniculate coralline red algae (Corallinales, Rhodophyta). Aust Syst Bot 6:277–293
