appendix c2 key to cave databases

Cave Inception and Development in Caledonide Metacarbonate Rocks: Appendix C2 – Key to Cave Databases

APPENDIX C2

KEY TO CAVE DATABASES

This Appendix describes the various cave attribute fields used in the cave databases, as discussed particularly in sections 5.3 and 5.6 and in Appendix B2. C2.1

External cave attribute fields

Heading

Meaning

Coordinates

Coordinates in italics Coordinates in regular font

Coordinates in regular font

Other italics

Trevor Faulkner

ED50, Black UTM grid WGS84, Blue UTM grid

Swedish 10-digit RN system

Value

Comments

Units

For each cave, a 2-alpha + 6- or 8-figure UTM grid reference commonly defines its location. These were taken from a published reference or from personal checking. In the 1998 field trip, such checking was assisted by the use of a Garmin 12 GPS system that could be relied on to give a co-ordinate accurate to 100m. Final determination of an 8-figure co-ordinate was then made from all available information, including altitude. The fourth digit of each East and North field is commonly set to either 0 or 5, so that accuracy to ±25m is attempted. The use of other fourth digit numbers is usually reserved to distinguish between several proximal cave entrances. Coordinates given to the nearest 10m are from GPS readings in year 2000, or are relative to another cave coordinate, or are from the local economic map. 6 or 8 digit coordinates. The original M711 series 1:50000 maps used a black UTM grid based on European Datum (ED50) in UTM grid zone 33. 6 or 8 digit coordinates for sites based on Norwegian 1:50000 maps. From about the late 1980s, purchased M711 series maps commonly used a blue UTM grid based on World Geodetic System 1984 (WGS84), also in grid zone 33. A typical conversion is as follows: EWGS=EED-66m; NWGS=NED-202m. Special care is required in the use of the GPS for each type of map. In Norway, Navigational Set Up is set to Position Format: UTM/UPS and Map Datum: European 50 or WGS84. In practice, the instrument used always gave co-ordinates for the WGS84 datum. The 2000 field trip benefited from improved GPS accuracy, as a random perturbation signal was removed earlier that year. For each Swedish cave that can be mapped on a bordering 1:50000 Norwegian M711 series map, the 2-alpha + 6- or 8-figure UTM grid reference defines its location for that map. These grid references were commonly translated manually from published references based on the Swedish grid system, or from personal checking. In the 1998 field trip, such checking was assisted by the use of a Garmin 12 GPS system that was set up as though in Norway, where appropriate. Where a bordering Norwegian map is not available, a Swedish 1:100000 Fjällkartan map was used, and the cave position recorded using the Swedish 10-digit RN system, but with Eastings presented before Northings to be consistent with UTM. The fifth digits of the East and North fields define a 100m square and hence an accuracy of ±50m is attempted for these cave locations. In order to use the GPS with the Fjällkartan maps, Navigational Set Up is set to Position Format: Swedish Grid and Map Datum: RT90. It was only necessary to use Swedish maps in the Övre Ältsvattnet (KU) and Södra Storfjället (KU) areas. The author's best (gu)estimate

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Cave Inception and Development in Caledonide Metacarbonate Rocks: Appendix C2 – Key to Cave Databases Heading

Meaning

Alt.

Altitude

Alt.

Altitude

Value

Kommune Area Lst. Strike and Dip OW

Outcrop Width

Ext. Colour Other Int. Rock R

‘Remetamorphosed’

1

T

Thrust

0 1 0

Trevor Faulkner

Comments

Units

The altitude for each cave was taken from published references or from personal observation assisted by the use of a Pretel Altiplus D2 digital altimeter. When used in the field, this was set to an easily-identified altitude (usually a road or a lake), as read from the appropriate map, and the time noted. Readings at cave locations were then recorded and timed. On return to an identified altitude, a new reading for this altitude was noted with the time, to determine the drift due to change in air pressure. The altitudes for the cave locations were then corrected using a linear interpolation of the change during the day. When, in one area, it was possible to compare 1997 measured altitudes with those measured again in 1998, the altitude differences were: 0, +1, +2, +3, 0, +1, -1m. Hence, altitudes are commonly recorded to the nearest metre, and are probably accurate to better than ±5m, when compared to the maps in use. Sink caves and Through caves: the highest point (the highest entrance if several). Resurgence caves: the lowest point (water level). Relict caves: floor level at entrance The administrative district within the Norwegian or Swedish county. A geographical description of the cave's locality. The strike and dip of the carbonate foliation is usually taken from personal measurements made inside the cave, or from published survey information, rather than from such data marked on geological maps, which may differ. If the values vary within the cave, then a typical value is quoted. [Some Scandinavian geological maps quote dip in 400 grad circles]. The width of the carbonate outcrop across the strike at the cave location is commonly taken from geological maps or from personal observation. Accurate probably to within a factor of 2. The colour of the weathered face of the limestone sample. Many internal cave samples of carbonate bedrock were also tested with dilute HCl: these are almost universally calcitic. Those with a yellow, weathered, appearance are assumed to comprise HMC or DL. Where internal cave samples of any aquiclude rock were studied, such as from a schist wall or from a dyke forming a nonsolutional barrier, then identifications by the author or a colleague are given. The carbonate outcrop containing the cave has probably been 'remetamorphosed' (with loss of foliation) by high temperature, low pressure, contact metamorphism from an adjacent igneous pluton. The cave lies within the contact aureole, less than 250m from the pluton. The carbonate outcrop lies away from any igneous pluton. The carbonate outcrop containing the cave lies along or near to a major tectonic thrust. The carbonate outcrop does not lie along or near to a major tectonic thrust.

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Metres Metres Metres

Degrees (Circle = 360o) Metres

June 2005


Meaning

GS

Glacial Situation

Value C D

E G

H K

The cave is situated west of a major ridge and between the deglaciation marine limit and the probable glaciation marine limit. At the start of a previous glacial, the cave would have been invaded by the sea, which would then freeze perennially inside the cave. The glaciation marine limit is difficult to determine, as its evidence may be destroyed by the subsequent glaciation. It is assumed to be everywhere 120m higher than the deglaciation marine limit (section 8.1.3). The cave is situated east of a major ridge and between the deglaciation marine limit and the probable glaciation marine limit.

F

Valley Floor cave

T U

W

Hanging Valley Wall cave

R

Ridge Crest cave

S

Valley Shoulder cave, referred as a "Sva" position in parts of the study area (e.g. Photos C2.4, C2.5 and C2.6).

G

Gently sloping surface cave, where 20m contours are over 100m apart, excluding paleic surfaces.

P

Paleic surface cave, as inferred from Rudberg (1997). Only applies in the eastern part of the area.

Note:

Trevor Faulkner

A coastal cave along the Atlantic-facing strandflat (commonly below 25m). The cave has been invaded by the sea for much of the Holocene. Includes littoral caves, formed without dissolution, and sea caves, which may have experienced dissolution. The cave is situated west of a major ridge and between the strandflat and the deglaciation marine limit (section 8.1.2). The cave was invaded by the sea at least at the start of the Holocene, prior to major isostatic uplift (section 8.4.7). This limit varied from c. 125m at 12000 14Ca BP at YD isobase 100m off the coast, via 150m at 10000 at YD isobase 150m at Langfjord, to 133m at 9080 at YD isobase 200m at Svenningdal. Most of these caves function, or have functioned, as resurgences. The cave is situated east of a major ridge and between the strandflat and the deglaciation marine limit.

C

S

Cave Location

Units

The cave is situated west of a major ridge and between the glaciation marine limit and the level of the lowest local col. The cave was probably only immersed by a westward, forward-flowing, ice-dammed lake (IDL) during deglaciation (section 8.4.5). The cave is situated east of a major ridge and between the glaciation marine limit and the level of the lowest local col. The cave was probably only immersed by backward and eastward, forward-flowing, IDLs during deglaciation (sections 8.4.8 and 8.4.9). The cave is situated west of a major ridge and between the levels of the lowest and the highest local col. The cave was probably only immersed by westward, forward-flowing, IDLs during deglaciation (section 8.4.5). The cave is situated east of a major ridge and between the levels of the lowest and the highest local col. The cave was probably only immersed by backward-flowing IDLs during deglaciation (section 8.4.8). An uppermost situation, above the level of the highest local col, so that the cave could only have been immersed beneath a static nunatak IDL during the Holocene deglaciation (section 8.4.4). Coastal cave, as under Glacial Situation above.

L

CL

Comments

The above 7 classes are based on a classification proposed by Lauritzen (1981c and 1990b) with the addition of types C, R and G, which are necessary to include the extreme topographical locations that occur in the study area. The cave location classification is strongly linked to surface topography and, except for the P and C extremes, only weakly linked to altitude. For inland caves, a judgement is applied to the appropriate valley to consider. For active caves in minor side valleys, the appropriate valley is usually taken to be the major glaciated valley to which the cave stream flows.

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Meaning

Value

KT

Karst Type

V or VSK A or ASK L or LAK C or CFK X

SR

OR

Slope relationship

Strike orientation

CA

Catchment Area

Ref. No

Reference number

Trevor Faulkner

Comments

Units

Vertical stripe karst. The generally homoclinal angle of dip varies commonly between 81o and 90o (e.g. Photos B1.10 and B1.12) and the outcrop is much longer than its width. The widest outcrop in the group is c. 800m in width, in Z7 (section 4.2.3). Angled stripe karst. The generally homoclinal angle of dip varies commonly between 31o and 80o (Photo C2.1) and the outcrop, or the outcrop limb of a complex outcrop, is much longer than its width. Low angle karst. The angle of dip is 30o degrees or less, may be varying or homoclinal, and the outcrop is quite broad in relation to its length. Complexly folded karst, at a scale so that folds are visible or may be inferred within a cave. Surprisingly, only three such caves are recorded: Kvitfjellgrotta (Z4), Nedre Helveteshullet (Z7) and Labyrintgrottan (ZA). This type is probably underrepresented, especially in short caves. Carbonate outcrops also sporadically display CFK, as at the central part of Elgfjell (Z4) and as shown in Photos C2.2–C2.4. Unknown karst type

D

The dip of the foliation is down slope

N U

The dip of the foliation is not related to the slope. This always applies to vertical stripe karst, and to angled stripe karst and low angle karst if the cave is in location R or F. The dip of the foliation is upslope

X

Unknown relationship

P

The outcrop strike is parallel to the topographical structure, a judgement being made about local scale.

A

The outcrop strike is angled to the topography

O

The outcrop strike is orthogonal to the topography

N

The outcrop strike is not related to the topography

X

Unknown relationship The approximate surface catchment area for each cave was obtained by ‘eyeballing’, or by making measurements with a ruler on, each applicable topographical map. A regional interpretation was used, so that, in general, a cave entrance on the side of a valley is shown as having the catchment area for the whole valley upstream of it. In order to permit the use of logarithmic charts, the smallest catchment areas are recorded as 0.01km2. An accuracy of perhaps ±30% is expected for these data. Because the catchment areas vary by over four orders of magnitude, any statistical analysis on them should be little affected by this range of approximation. As used by referenced authors

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km2

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Photo C2.1 Entrance to Krokgrotta (Z4), Eiterådal A resurgence cave formed in angled stripe karst.

Photo C2.2 Complexly folded karst Recumbent folds near Skånvik (Z2).

Photo C2.4 Kvitfjell resurgences (Z4) Two separate resurgences (arrowed), 3m apart and 200m above the main valley floor but only 30m below the skyline. The cave systems are at the valley shoulder, in cave location S. The limestone in the upper right corner of the picture exhibits complex folding, which is rare within the study area. Trevor Faulkner Page C2 – 5

Photo C2.3 Double anticline Road cutting beside lake Över-Uman (ZC). Narrow marble layers within mica schist.

Photo C2.5 Sørlielvgrotta (Z4), Photo C2.6 Naeverskardhullet Elgfjell Waterfall (ZA) The sink entrance is at cave location S. The water flows from an unexplored potential through-cave at CL=S June 2005

Cave Inception and Development in Caledonide Metacarbonate Rocks: Appendix C2 – Key to Cave Databases C2.2

Internal cave attributes fields

Headin g

Meaning

Valu e

CT

Cave Type

S

Predominantly a single shaft

See also section 5.2.5.

a

Single linear passage, including those with simple staircase profiles

b

Single meandering passage, including those with simple staircase profiles

c

One level rectilinear network One level dendritic network, including those with simple staircase profiles

e

Tiered linear passages, connected by shafts

f

Multilevel rectilinear network

g

Multilevel dendritic, including those with distributary passages

h

Complex multilevel network with steeply sloping (phreatic) passages

I J L R T Note:

Cave Length

Trevor Faulkner

Unit s

d

Hy

LENG.

Comments

Hybrid cave: formed by an obvious combination of at least two of the possible Tectonic, Littoral and Dissolutional processes. Excludes long solutional caves with entrances modified by marine action. Interstratal cave: apparently not solutional, but perhaps formed by collapse into a solutional void beneath. Jettegryten: a 'giant pot', formed by swirling stones during powerful deglacial outflows. Most are formed in non-carbonate rocks, but only jettegryter in carbonates are recorded here. Not included in dimensional analysis. Littoral cave: probably formed primarily by wave action, supplemented by ice wedging Collapsed roof cave: apparently has solutional walls and floor, but with a roof of collapsed blocks along its length, which was perhaps initially formed as a 'gull' feature. Tectonic cave: in carbonate bedrock, but with little apparent dissolution, and an opening created apparently by bedrock movement Refer to Ford and Williams (1989, Table 7.1, p243: Some classifications of solution caves). Classifications S and a–h (which generally increase in complexity) use approach A3: internal characteristics. These are identifiable quickly from cave surveys, and do not pre-judge the method of cave or passage formation. Classifications Hy, I, J, L, R and T make assumptions about the process of formation, and apply to a few known caves in the study area. Cave Length is taken from published survey or other reported information. In the Norwegian part of the study area, at least, the usual convention is to include in the length the sum of the survey legs (including laddered shafts) with manual additions and corrections for oxbows, side passages, avens, pits and survey duplications. Lengths should be accurate to a few metres for BCRA Grade 3 (or better) surveys, which are measured using a tape measure. The accuracy may be ±25% or worse for Grade 1 and 2 surveys, which rely on estimates of length made outside and inside the cave. Generally, the longer caves are surveyed to a higher grade, although parts of these caves may be surveyed to a lower accuracy. Open passages are normally explored as far as humanly possible, because cave explorers are motivated to maximise the reported cave length. Caves are commonly recorded down to 5m length or depth. Unpassed boulder chokes are quite rare in these caves (only c. 25 were counted in the Norwegian part of the study area) and hence it is passage size, sediment fill and water level that commonly limit exploration. Thus, there is probably some consistency in the reporting of cave length.

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Headin g

Meaning

VR

Cave Range

XS

Cave Section

VOL.

Cave Volume

Min. HG

Minimum Hydraulic Gradient

C

Caves

SE

Sink Entrance

Trevor Faulkner

Valu e

Vertical

Cross-

n n

Comments

Unit s

The vertical difference between the highest and lowest explored points in a cave, which may equal the cave 'depth'. Cave vertical range is more difficult to measure accurately than length, and in many caves estimates of vertical range on sub-horizontal survey legs were agreed between the surveyor and his assistant, rather than by use of instruments, as this could double the time to measure each leg. Where possible, vertical ranges were checked using information from topographical maps and by reference to water levels. They are probably accurate to 10%. For the less deep caves, cave reports may not state the vertical range. In this case, an estimate was made from general field experience, and such data placed in the database in italics. These estimates are probably accurate to ±5m. A rapidly-formed estimate of the mean cross-section of all the passages in a cave was commonly made by ‘eyeballing’ published cave surveys and by considering other reported information. This may be accurate to ±30%. If there is no adequate information to do this, rather than leave the field blank, which would further derogate any statistical analysis, a crude estimate was made from practical field experience, and shown in the database in italics. The total number of caves for which cross-sections have been crudely estimated is c. 200, i.e. c. 27% (Sweden: c. 90, i.e. c. 60%). This applies mainly to the shorter caves without adequate surveys, and so these cross-sections may only be accurate to +100/-50%. [The author tends to under-estimate cross-sections that are not measured]. For cave surveys drawn from data calculated by a spreadsheet (see below) the mean cross-section is derived from the ratio of the total cave volume to the total cave length (i.e. VOL./LENG.), giving a probable accuracy of ±10%. These cross-sections are presented in bold in the cave databases. The cross-sections refer to the explorable parts of passages, which might therefore be larger if there were no clastic sediments. The approximate cave volume is commonly recorded as the product of the cave length and the mean cross-section (LENG. x XS). Accuracy may vary from ±30% to +100/-50%. Some recent cave surveys were drawn from data calculated by a spreadsheet that also calculates total cave volume from the volumes of individual survey legs. These volumes are presented in bold, with a probable accuracy of ±10%. Hydraulic gradient (HG) is an important parameter for determining flow characteristics and dissolutional behaviour within karst conduits, especially during cave inception and phreatic enlargement (Chapter 8). To determine the exact internal HG for all the >1000 caves of the study area would be an enormous task, and instead a short-cut approach was adopted to gain some understanding of the range of HGs that might apply. The minimum HG for each cave is recorded automatically in the cave database by simply representing it as the ratio of vertical range (VR) to the total cave length (i.e. VR/LENG.), expressed as a percentage. For a simple cave tube that has one upper and one lower entrance, this value equals exactly the correct HG (which is defined here as the ratio of the hydraulic head to the path length along a tube), because total cave length is represented by the sum of the survey legs, which therefore includes twists and turns along the passage, and upward and downward sections along their slopes. Alternative passages increase the measured total cave length in more complex caves and so reduce the value of the HG calculated by this method, giving a minimum HG (assuming that the head remains equal to the VR). However, as shown in section 5.2.5, over half the caves of the study area are of the single passage types, and probably most of the others do not have a true HG that is more than a factor of 2 or 3 greater than this calculated value. Hence, it is hoped that this easy method of estimation gives consistent results of practical utility. From its definition, HG can range from 0% for a horizontal tube of any length up to 100% for a vertical shaft of any depth. However, the calculated minimum HG is not related to the HG that would apply if a cave was submerged totally below water during some stages of the glacial cycle, as discussed in Chapter 8. The number of explored and adequately-reported carbonate caves. (1 per utilised reference). If blank, the cave is not represented in totals and summaries. The number of such entrances, including places where daylight is visible. Entrances within the same doline are counted as separate entrances.

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m2

m3 %

Cave Inception and Development in Caledonide Metacarbonate Rocks: Appendix C2 – Key to Cave Databases RE

Resurgence Ent.

n

The number of such entrances, including places where daylight is visible. Entrances within the same doline are counted as separate entrances.

DE

Relict (Dry) Ent.

n

The number of such entrances, including places where daylight is visible. Entrances within the same doline are counted as separate entrances.

Headin g

Meaning

CS

Cave Streams

RC SP

Relict Cave Sump Pools

Ch

Chambers:

Sh

Shafts

n 0 n

BC

Boulder Chokes

0 n

Sh

Shafts

0 n

RV

Relict Vadose

n

MV

Mainly Vadose

0 1

DC

Chemical Deposits

FS

Fluvial Sediments

P

Personally visited

Trevor Faulkner

Valu e n

Comments

Unit s

0 1

The maximum number of cave streams flowing in the cave during normal summer discharges, including tributaries, roof inlets, impenetrable inlets and presumed flows at apparently static sumps. Active caves have n>0. The whole cave is normally dry in summer The number of sump pools in the cave. (2 for a sump explored at each end). A sump pool is defined here as the place where the roof of a cave passage descends below normal water level in July and August. More of the passage may 'sump' during spring melt between April and June, and during floods. Some sumps near entrances dry out in winter. Each sump pool is active, i.e. it has a visible water flow, unless noted separately as a static sump. Very few of the many sumps have been dived, especially in Norway. The number of significant internal chambers in the cave that are large compared to passage dimensions, excluding entrance chambers. The cave does not contain such a chamber. The number of significant vertical or near vertical shafts in the cave, including relict entrance shafts, but excluding pitches along vadose passages and at sink entrances. The value includes all other explored and unexplored avens and pits. The cave does not contain avens or pits. The number of internal chokes of boulders or large blocks of bedrock in the cave, excluding at entrances and where daylight is visible. Each such choke hinders or prevents further exploration The cave does not contain any boulder chokes. The number of significant vertical or near vertical shafts in the cave, including relict entrance shafts, but excluding pitches along vadose passages and at sink entrances. The number of apparently abandoned vadose passages in the cave, as observed during normal summer discharges. The value may include vadose-appearing entrances, where the stream has sunk underground upstream of the explorable cave. The cave does not contain apparently relict vadose passages. The cave passages appear to have developed primarily under vadose conditions, including active phreatic sections without relict upper levels, and short, mainly submerged, caves. Commonly only applies to cave types S,a,b,c,d and Hy, and only if CR>0. The cave contains relict phreatic passages or phreatic upper levels. The cave is reported to contain significant stalactite and / or stalagmite growth.

0 1

The cave contains little speleothem growth, or none has been reported. The cave is reported to contain significant fluvial sediments

0 1

The cave is reported to contain little fluvial sediments The cave report is silent about fluvial sediments The cave has been visited Personally by the author, at least to the entrance.

CS=0 n

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SG

Survey Grade

Trevor Faulkner

n

The cave has not been visited by the author The Survey Grade represents the BCRA grade for each published or available cave survey used in this thesis.

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