By Charlie Self
This issue of Cave and Karst Science contains two papers on cave research history and two technical reports on post-glacial speleogenesis. I was relieved to find that the one very long paper of this issue (at 19 pages) was a historical overview rather than a technical paper.
Until the 1970s, biologists mistakenly believed that cave-adapted animals were rare or absent in tropical regions. This opinion can be traced back to a committee of the British Association for the Advancement of Science, formed in the 1890s to study material collected from the biologically rich Batu caves. In an extraordinarily inept sequence of events, the committee chose a botanist to collect their zoological specimens and then somehow allowed a box of material collected in the caves to be mixed (in London) with material collected in the jungle outside the caves. Both boxes had to be omitted from their study (because of uncertain provenance). These eminent scientists then came to a hasty and incorrect conclusion that there were no cave-adapted animals in the Batu caves. They also gave a pessimistic prediction for finding cave-adaption elsewhere in the tropics and this became such an entrenched orthodoxy that subsequent researchers didn't even bother looking.
This may be an extreme example of "expert" error, but these gentlemen were held in such high regard at the time that tropical cave biology was held back for the best part of the next century. Transposing this problem to the present day: the small number of academics working in young and specialist sciences (such as speleology in all its aspects) means that a few people have an unusual degree of influence. In my own experience, a hostile "expert" can delay a new idea entering print for years.
This paper fills nearly half of this issue of C&KS, but there is no irony intended in the title. The China Caves Project (CCP) has been running for 28 years, so any overview of the 27 expeditions plus reconnaissance and spin-off trips must necessarily take a large number of pages to be of practical value. The report begins with a description of how the Project began in the late 1970s, through personal contacts between British and Chinese scientists. Visits to China and return visits of Chinese academics to Britain led to the first proper caving expedition in 1985.
In the next section, the expeditions are summarized in chronological order. Half a page is also given to non-CCP expeditions, providing useful additional references. The largest section of the report details the caving discoveries made by the CCP on a Province/ County/ District basis. A brief description of cave science and conservation achievements completes the paper.
This is an excellent overview of the work of the China Caves Project. The text is well-organised and clearly written, with the information duplicated in tables for "at a glance" referral. The photographic illustrations are of course outstanding. This paper should become a favourite first reference source for future expeditions.
It has been known for many years that the length of scallops on the bare rock walls of a cave passage depends on the maximum velocity of the stream that formed them. In fully phreatic conditions, it is possible to use scallop length and the cross-sectional area of the passage to calculate the peak flow volume of the stream. This formula doesn't work in vadose canyons because the stream only occupies a small part of the passage. Also, scallop lengths and passage widths can vary at different heights above the floor.
This paper attempts to get around these problems by making a number of assumptions, principally: (1) that the water during peak flow (i.e. flood conditions) has about the same depth as the passage width; (2) that the rate of downcutting of the canyon floor has remained the same since the start of vadose conditions; and (3) that this passage developed after the glaciers retreated at the end of the last (Devensian) Ice Age. The first assumption allows peak flow volume to be calculated, while the other two assumptions establish a time line down the side of the wall as the canyon developed. The method the authors used was to make a vertical sequence of photographs to determine the scallop length at different heights above the floor, at the same time noting the passage width at each station. They then calculated the flow volume through time as the canyon developed and deepened. Some correlations between higher flow values and wetter periods of our post-glacial climate were found.
This is an admittedly conjectural new technique for palaeoclimate research, based on a single survey in a single passage of just one cave. However, by publishing the concept and the methodology it is possible to test this in other caves to see if the results are reproducible elsewhere. I approve of speculative papers because new ideas need to be shared - it is good for science; proofs can sometimes take years and a whole series of papers to establish themselves.
This study focuses on four areas of limestone terrain in New York State, in the north-eastern United States. The ages of the limestones vary between areas, but all contain epigenetic (near-surface) phreatic maze caves. The areas also have "deranged" drainage (i.e. with no coherent pattern), which is typical of land that has suffered the erosional and depositional effects of continental glaciation.
The hypothetical model in question is that a floodwater maze cave is Holocene (the geological period since the end of the last Ice Age) if it is controlled by glacially deranged drainage and has no pre-Holocene signatures. The "signatures" of concern would be alignment to an earlier (i.e. Pleistocene) base level, or the presence of glacial sediments (unless recently washed into the cave).
In the main study area of Joralemon Park, the active caves are fed from glacially aligned swamps, are at the present base level and drain back into the deranged drainage; two relict caves are aligned to a higher drainage base level and contain late Pleistocene sediments. To test whether supposed post-glacial caves could develop to their present size in the time available, two active caves from Joralemon Park and two active caves and one (clearly Holocene) relict cave from elsewhere in New York State were selected for flow modelling. The calculations used an assumed rate of wall erosion and either observed or calculated (for the relict cave) number of days per year that the caves are in conduit-full (i.e. flood) conditions. Three caves could have grown to this size in present-day conditions but, if past conditions are taken into consideration, all five could have formed since deglaciation. The authors conclude that floodwater maze caves develop rapidly in the shallow subsurface during interglacial periods, but are easily stripped away by erosion during glaciation.