EuroSpeleo 2016

Jinfo Cave and its Sediment Sequences in Jinfoshan Karst, South China

Oral|Prof Baojian Huang

Abstract

Jinfo Cave is the longest and most complicated infilled branchwork cave in the system at ~2000m a.s.l. in Jinfoshan Karst World Natural Heritage Site. Comprehensive methods including cave survey, sediment analysis, super-high-density resistivity and multiple age-dating techniques, were employed to study the relict underground river cave and elucidate its development history. Jinfo Cave is >12.8km long, including a wide corridor (trunk passage), tubes (medium-size branch passages), canyons (narrow-high maze) and vadose shafts. Its sediment sequences include fluvial clastics, collapse bedrock blocks and chemical deposits. Direct links were demonstrated amongst Jinfo Cave’s passage characteristics, its sediment sequences, and local environmental change.
Initially (pre-Miocene), trunk passage was generated by a large underground river fed by surface flow from the ancient Jinfoshan Syncline Basin. Following tectonic uplift, tubes were formed during the Miocene by diminishing subterranean flow as recharge area decreased due to slight incision by gorges surrounding Jinfoshan. Before/during early Pleistocene, breakdown enlarged the corridor passage. From early to mid-Pleistocene there was repeated deposition/removal of fluvial fine clastic sediments. From mid-Pleistocene, maze-like canyons and domepits were produced by vadose streams and Jinfoshan table mountain was dissected from the Yunnan-Guizhou Plateau, resulting in inverted topography supporting limited autogenic streams forming tiny downstream passages.