Abstract:

Many caves within carbonate (and perhaps other) rock sequences display marked spatial organization, particularly a tendency to group within vertical clusters. Most past explanations of clustering involve "recent" effects and interactions. New ideas, based on study of "denuded" or "unroofed" caves, acknowledge but re-interpret features and relationships that were observed long ago and commonly dismissed as "atypical", "irrelevant" or "impossible". Some traditional explanations of vertical clustering must now be re-assessed. Assumptions that any stratigraphical (bedding plane) or joint/fault fissure in carbonate rock provides (or provided) a de facto route for fluid transfer, and hence a focus for void development, are not confirmed by observation. Primitive pre-cave, but potentially cavernous, carbonate masses are not inevitably active hydrologically; nor are they geologically homogeneous. New evidence, and re-evaluation of earlier observations, implies that dissolutional void "inception" is related to a minor subset of all stratigraphical partings, which dominate initially, imprinting incipient guidance for later cave development. Recognition of this fundamental role provides a possible key to understanding the organization of cave systems and necessitates acceptance of an expansion of speleogenetic timescales back to the time of diagenesis.