A multiphase, non-fluvial cave 1 Copyright © 2007 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms (in press) DOI: 10.1002/esp Earth Surface Processes and Landforms Earth Surf. Process. Landforms (in press) Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/esp.1507 Cathedral Cave, Wellington Caves, New South Wales, Australia. A multiphase, non-fluvial cave R. A. L. Osborne* Faculty of Education and Social Work, University of Sydney, N.S.W., Australia Abstract Cathedral Cave is an outstanding example of a class of multiphase caves with largely non-fluvial origins. It contains large cavities such as cathedrals and cupolas, characteristic of excavation by convection currents in rising waters. Smaller-scale features such as rising half-tubes, pseudonotches, curved juts, projecting corners, blades and bridges indicate inter- section and exhumation of older cavities during the formation of younger ones. It is possible to recognize at least ten significant phases of speleogenesis by morphostratigraphy, in addi- tion to the four generations of cave-filling palaeokarst deposits intersected by the cave. The cave we see today results from the progressive integration of a number of previously discon- nected or poorly connected solution cavities. Copyright © 2007 John Wiley & Sons, Ltd. Keywords: Cave; morphology; hypogene; Wellington; Australia *Correspondence to: R. A. L. Osborne, Faculty of Education and Social Work, A35, University of Sydney, N.S.W. 2006, Australia. E-mail: a.osborne@edfac.usyd.edu.au Received 11 October 2006; Revised 20 December 2006; Accepted 7 February 2007 Introduction Cathedral Cave is a small but spacious cavity with a somewhat unusual morphology. It is not a set of passages, but rather a series of interconnecting rooms. The rooms are circular or oval in plan. The cave lacks a stream, but terminates at a still pool that rises and falls over a 6 m range. Despite being the first cave in Australia to be mapped in detail by a professional surveyor, Thomas Mitchell (Mitchell, 1838), the peculiar nature of Cathedral Cave went unnoticed until the work of Ruben (Bud) Frank in the mid-1960s (Frank, 1971). Frank noticed the morphology of the cave walls and recognized that they were similar to those interpreted by Cramer (1933) as being formed by eddy currents in the phreatic zone. Francis (1973) thought that the features in Cathedral Cave were formed by the ‘injection of string currents below the water table’. Jennings (1977) considered that Cathedral Cave was the best example of caves that he described as ‘nothephreatic’, a term that he used to describe low energy phreatic environments, but is used by other workers in a completely different way (see Field, 1999). Houshold et al. (1990) suggested that Cathedral Cave resulted from solution by ‘deep phreatic waters’ during a ‘long period of stable water tables and low pressure gradients’. They proposed that mixing corrosion excavated high fissures and bell holes in the lower part of the cave. Osborne (2001) recognized that many of the features of Cathedral Cave were similar to those attributed to solution by rising hydrothermal water by Lauritzen and Lundberg (2000) or to artesian water by Klimchouk (2000). This paper arises from work carried out by the author during a geodiversity inventory study of Cathedral Cave in 2002–2003 under contract to Wellington Council, the management authority for the cave (Osborne, 2003). Location and Setting Cathedral Cave is the largest and most spacious cave known at Wellington Caves, located 7 km south of the town of Wellington in central western New South Wales, Australia (Figure 1). The caves have developed in a low ridge within the valley of the Bell River, a northward flowing tributary of the Macquarie River and part of the Murray-Darling Drainage System. The Bell River Valley is approximately 3 km wide at the caves. The floodplain has an elevation of approximately 300 m ASL. To the west, the valley is bounded by the