Cave Levels Research Articles

Relict caves as evidence of landscape and aquifer evolution in a deeply dissected carbonate terrain: Southwest Edwards Plateau, Texas, U.S.A.

Caves lying well above valley floors and within narrow ridges of carbonate rocks in the deeply dissected southwest Edwards Plateau, Texas, provide considerable information about the geomorphic history of the region and the evolution of the Edwards-Trinity aquifer. In the Sonora area, horizontally extensive cave passages occur at three distinct levels along massive burrowed dolomitic beds in the Cretaceous Segovia Formation. Passages lying beneath a resistant caprock consist of long corridors, barren of speleothems. However, in the vicinity of the caprock edge, passages are modified by collapse and stoping, mazework, and speleothem deposition. Conduits are generally oriented down the regional dip and guided by dominant NE-trending fractures. Upper cave levels developed first, but lower passages were excavated as piezometric surfaces dropped in response to valley cutting. Cavern collapses blocked flowpaths in places and ensuing floodwaters enlarged passages, formed maze sections, and promoted development of diversion routes around these constrictions. Collapse at the caprock edge has enhanced retreat of valley slopes and headward erosion of streams. In the Langtry area, caves developed in the Cretaceous Devils River Formation are up to 113 m deep. The Devils River Formation is a stratigraphically-homogeneous high-purity limestone, in which fractures are few but vertically extensive. Incision of the Rio Grande and nearby streams has locally exposed up to 70 m of the Devils River Formation, inducing steep hydraulic gradients that have promoted bathyphreatic circulation and development of deep cave systems. Horizontal passages are relatively short and are connected by vertical shafts and steeply inclined corridors. The two localities have experienced similar climates and dissection in topography, but the relationship of stream incision to geologic structure, stratigraphy and lithology has differed significantly enough to produce long horizontal caves within the shallow phreatic zone around Sonora and deep vertical caves in the deep phreatic zone around Langtry.

Speleothem dates, Quaternary terraces and uplift rates in New Zealand

Previous isotopic research on calcite stalagmites, stalactites and flowstones (speleothems) from New Zealand caves has focused on palaeotemperature reconstruction1,2. I report here the use of 230Th/234U and 14C age data from speleothems to investigate the relationships between cave levels, emerged coastal terraces and uplift rates. In the north-west of the South Island of New Zealand, at least seven terraces, provisionally assigned to various stages in the Quaternary, are known to occur to at least 200m above sea level3,4. The terraces sometimes cut across limestones which contain caves formed in association with past sea levels. Uplift, followed by water table lowering and abandonment of cave passages by active streams, permitted speleothem deposition. Dating of these deposits gives a minimum age for the cave level and hence also for any terrace to which it may be related, while successive dates at different levels yield an uplift rate for the area. Data are presented from two localities, which suggest differential emergence rates of 0.27+0.28 −0.09 mm yr−1 and 0.14+0.05 −0.03 mm yr−1. Thus re-evaluation is required of other largely qualitative evidence on the uplift of these parts of the Southern Alps5.

Cave Levels and Erosion Surfaces in the Transvaal, South Africa

Abstract Work in Europe has shown that the horizontal development of caves at different depths may be associated with erosion surfaces. Since the South African landscape is composed of erosion surface remnants dating back to, the Jurassic period, it was felt that the hypothesis, that cave levels are associated with specific erosion .surfaces could usefully be tested in the Transvaal. aves from two areas of the Transvaal dolomites were analysed and found to fall into three groups. The validity of these groupings was statistically tested and it was shown that the groups were highly significant at the 99% level and that the cave levels were most unlikely 10 have occurred by chance. Correlation of these groups of caves with the African, Post African I and a 3650 foot surface, which tentatively has been designated Proto-Quaternary, has been made. It appears that cave system.s in the Transvaal are related to erosion surfaces and ;that therefore the hypothesis can be accepted.

Analyse pollinique des niveaux paléolithiques de l'abri Fritsch

The Fritsch rock shelter is located on “côteau des Roches”, above the Creuse valley (Indre). It contains a sequence of Upper Palaeolithic levels: Solutrean and Early Magdalenian (Badegoulian). This last industry seems to be contemporaneous with the Lascaux cave level in which pollen analysis and 14C have detected an interstadial; this same interstadial was also found and dated by Menendez Amor and Florschütz (1964) in Padul (Spain). In Fritsch shelter, the “Lascaux Interstadial” is located between very cold layers immediately underlying earliest Magdalenian (approx. 16.500 B.C.) and the uppermost Early Magdalenian, similarly cold and corresponding probably to Oldest Dryas Time (approx. 13.500 B.C.). The amount of treepollen in the diagram and the occurrence of pollen of thermophilous species such as Pinus pinaster are striking features in middle-west France, in the beginning of the Late Glacial.

Officer's Cave, a Pseudokarst Feature in Altered Tuff and Volcanic Ash of the John Day Formation in Eastern Oregon

Officer9s Cave is the uppermost of four rapidly eroding cave levels constituting a cavern complex about 700 feet long developed chiefly in clay and silt. Its outer room is 35 feet by 43.5 feet by 100 feet and slopes about 45° east into the western end of a narrow linear hill called Officer9s Cave Ridge. Dry valleys, blind valleys, hanging valleys, sinkholes, pipes, caves, and natural bridges are abundant. These, together with subterranean drainage, give the area a karstlike development. For such terrains the term “pseudokarst” is applied. These pseudokarsts are the product of piping and are fairly widespread over the world9s drylands.