Cave and Karst Science

ISSN 1356-191X
Contact: David Lowe d.lowe@bcra.org.uk
Website: http://www.bcra.org.uk/pub/candks/

Recent issue: 2004, 31 (3)

Stafford K., Mylroe J., Taborosi D. and Jenson J. 2004. Eogenetic karst development on a small, tectonically active, carbonate island: Aguijan, Mariana Islands.
Cave and Karst Science, 31 (3), 101-108. ISSN 1356-191X.

Aguijan is a small carbonate island in the western Pacific Ocean on the tectonically active Mariana Arc. Eogenetic karst on Aguijan includes epikarst and caves that are controlled by the interaction of fresh and saline waters and brittle deformation. Epikarst proximal to coastlines (littoral eogenetic karren) exhibits jagged, irregular surfaces, while inland karren is more subdued, with metre-scale canyons present in highly fractured regions. Caves occupy two morphologically distinct classes, mixing zone and fissure caves, with different primary controls on dissolution, freshwater lens position, and structural features respectively. Mixing zone caves occupy distinct horizons reflecting previous freshwater lens positions. The decay of organic material trapped at density horizons and the mixing of fresh and saline groundwater at the margins of the lens produces mixing zone caves with globular chambers that are commonly interconnected. Fissure caves are linear caves that develop along planes of structural weakness associated with faults, margin failures and associated tension-release structures (i.e. joints). Although caves are primarily controlled by either mixing zone dissolution or brittle failure, specific sites show contributions of both controls on dissolution.

Horizons of karst development associated with island terrace levels suggest at least three previous sea-level stillstands. The absence of exposed non-carbonate (volcanic) rocks places Aguijan within the Simple Carbonate Island category for island karst development. However, island geomorphology and elevation suggest subsurface non-carbonate rocks modify freshwater lens morphology, which would place Aguijan within the Carbonate Cover Island category. Aguijan demonstrates the utility of the Carbonate Island Karst Model for describing and explaining caves and karst features found on small islands, although Aguijan's Liyang Atkiya, a cave of complex morphology that does not fit current models for island karst, suggests that more work is needed to understand fully the complex hydrology of small, tectonically active, carbonate islands.

Uzun A. 2004. Koru Polje and karst landform evolution in the middle part of the Kure Mountains, Northern Anatolia, Turkey.
Cave and Karst Science, 31 (3), 109-112. ISSN 1356-191X.

Koru Polje and its close surroundings lie at an elevation of about 1450 to 2000m in the middle part of the Kure Mountains (the western part of the Northern Anatolia Orogenic Belt). Various karst landforms characteristic of the temperate climatic zone can be seen in this area, which is generally rainy throughout the year, with an annual precipitation of more than 1600mm, cool winter and mild summer temperatures, and an average annual temperature below 7°C. The study area is entirely within the forest zone and its karstic landforms are developed under soil and plant cover. Large closed depressions like Koru Polje and the Subatanyaylasi Depression are shaped by fluviokarstic processes. Quaternary climate changes affected the evolution of large karstic landforms in the study area. Periglacial conditions prevailed during Quaternary cold periods and development of surface karst landforms was interrupted at these times. In warm periods after the release of permafrost, surface water sank into reactivated swallow holes. Thus, karst landform evolution in the study area accelerated during the wanner periods of the Quaternary, and during recent times.

McFarlane D. A., Lundberg J. and Cordingley J. 2004. A brief history of stalagmite growth measurements at Ingleborough Cave, Yorkshire, United Kingdom.
Cave and Karst Science, 31 (3), 113-118. ISSN 1356-191X.

Early (pre-radiometric-dating) measures of growth rates of the Jockey Cap stalagmite, Ingleborough Cave, Yorkshire have been augmented by recent laser range-finder measurements. This yields a growth rate of 0.147mm/yr. Propagation of this rate yields a basal date of 4469 yr BP. C-14 dating gives a basal age (after correction for dead carbon content and carbon flux) of 3477 - 3794 yr BP and a growth rate of O18 mm/yr, comparing reasonably well with the historical estimates. This date for speleothem initiation correlates with several indices of environmental change in the region: a change to colder, wetter conditions and the beginning of significant forest clearance. U-Th data indicate a change in the type of detrital material introduced to the cave that may correlate with increased agricultural activity at -1350 yr BP.

Pentecost A. and Zhang Zh. 2004. A note on the distribution of plants in Scoska Cave, North Yorkshire, United Kingdom, and their relationship to light intensity
Cave and Karst Science, 31 (3), 119-122. ISSN 1356-191X.

The flora of a small limestone cave was investigated. A total of 59 species was recorded (4 algae, 3 lichens, 47 bryophytes, 4 ferns and 1 angiosperm) making it bryologically the richest cave in Britain and one of the richest in Europe. All but nine of the species had been recorded from other European caves. Species-richness declined irregularly from the entrance (relative irradiance with respect to open sky 12%) to 34m depth (rel. irradiance 0.004%). Bryophytes were found at 0 to 16m depth, where relative irradiance declined to 0.2%. Only algae were encountered at 34m depth. Whereas irradiance, which declined exponentially, was the major factor controlling plant distribution, substratum characteristics and surface moisture were also important.

Worthington S.R.H. 2004. Hydraulic and geological factors influencing conduit flow depth.
Cave and Karst Science, 31 (3), 123-134. ISSN 1356-191X.

There has much been speculation as to whether cave formation should occur at, above, or below the water table, but a satisfactory explanation has been lacking until recently. The last 50 years has seen extensive mapping of caves both above and, more recently, below the water table. It is now becoming apparent that there are systematic differences in depth of flow between different areas and that conduit flow to depths >100m below the water table is not uncommon. Such deep flow is facilitated by the lower viscosity of geothermally heated water at depth. Analysis of data from caves shows that depth of flow is primarily a function of flow path length, stratal dip and fracture anisotropy. This explains why conduits form at shallow depths in platform settings such as in Kentucky, at moderate depths (10-100m) in folded strata such as in England and in the Appalachian Mountains, and at depths of several hundred metres in exceptional settings where there are very long flow paths.

Craven S.A. 2004. Vested interests at Cango Cave, South Africa, in the Nineteenth Century.
Cave and Karst Science, 31 (3), 135-137. ISSN 1356-191X.

Various vested Nineteenth Century interests are described, relating to the profitable and State owned Cango Cave, viz. the local Field Comet, the civil service, the surrounding landowner and other adjacent farmers, and the Oudtshoom Divisional Council. Although it is the stated policy of successive political masters of the Cape Colony that the Cave is a national asset that shall be conserved, the management structure was not conducive to the enforcement of that policy.