Ž . Geomorphology 23 1998 183–191 Salt cave cross-sections and their paleoenvironmental implications Amos Frumkin Israel CaÕe Research Section, Department of Geography, The Hebrew UniÕersity of Jerusalem, Jerusalem, 91905, Israel Received 1 August 1995; revised 22 April 1996; accepted 22 May 1996 Abstract Salt caves respond rapidly to environmental changes. Direct measurement and 14 C dating show that complex cross-sec- Ž. tions may develop in a few hundred years. Two basic forms are discussed: 1 ingrowing vadose canyons where changing Ž. width may correspond to changing discharge; 2 wide low passages with flat ceilings, developed by upward dissolution, which may indicate rising base level. Some cross-sections are deformed by Holocene tectonics. q 1998 Elsevier Science B.V. All rights reserved. Keywords: salt cave; cross-sections; Dead Sea 1. Introduction Mount Sedom is a salt diapir in the Dead Sea rift Ž . valley, Israel Zak, 1967 , rising some 250 m above Ž . the Dead Sea level Fig. 1 . Extensive salt caves have developed within the rising diapir during the Ž . Holocene Frumkin, 1994a; Frumkin et al., 1991 . The cave passages are underground ephemeral chan- Ž nels, active only during rare flood events Frumkin, . Ž 1994b . They drain small catchments up to ; 0.5 2 . km developed over a relatively insoluble cap rock. The ceilings and high levels of cave passages are often well preserved, unlike subaerial channels, where older parts of the cross-section are often oblit- erated by erosion processes. The high solubility of rock salt renders it suitable for recording slight envi- ronmental changes, especially in an extremely arid environment like Mount Sedom, where present mean annual precipitation is 50 mm, and potential evapora- tion is ; 3000 mm. The geometry of a three-dimensional cave can be portrayed upon a two-dimensional plane using three kinds of orthogonal projections: horizontal projection Ž . map , vertical projection along the cave passage Ž . profile and vertical projection across the cave pas- Ž . sage cross-section . Of these, the cross-section is most valuable for reconstructing paleoenvironmental change, since it exhibits the change of width through time and the cross-section area of the channel. These parameters can be related to discharge taking into account the passage gradient. Temporal changes in cross-section width are com- mon in Mount Sedom caves. The widest cross-sec- Ž tions were dated to ; 5000 BP Frumkin et al., . 1994 . Here I discuss end member types of cross-sec- tions, some changes of their morphology occurring 0169-555Xr98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. Ž . PII S0169-555X 98 00002-6