Structural Geological Characteristics of Karst Caves and Shilin Stone Forest of the Lunan County, Yunnan, China

Abstract

IzvlečekUDK 551.435.84:551.243(510) Stanka Šebela & Hong Liu: Strukturno geološke značilnosti kraških jam in glavnega kamnitega gozda, Kitajska Proučevali smo kraške terene v okrožju Shilin JV od Kumninga, da bi razumeli vlogo geoloških struktur pri oblikovanju kraških pojavov kot kamnitih gozdov in izbranih jam. Izvedli smo podrobno strukturno geološko kartiranje smeri razpok v izbranih kraških jamah ter v glavnem kamnitem gozdu, kar je predstavljeno z rozetami. Rezultate strukturnih geoloških elementov pridobljenih s terenskim kartiranjem smo primerjali z regionalnimi geološkimi strukturami. Obstaja dobra korelacija med površinskimi in podzemeljskimi smermi razpok ter med smerjo jamskih rovov in regionalno pomembnimi prelomnimi conami, to je s prelomom xiaojiang (smer S-J) in s prelomom Red River (smer SZ-JV). Najpogostejša smer jamskih rovov v generalni smeri S-J je povezana s kompresijo v smeri skoraj V-Z ter z ekstenzijo v generalni smeri S-J iz obdobja zgornjega Pliocena do srednjega Pleistocena. Druga tektonska faza iz zgornjega Pleistocena do danes, z napetostjo tektonskega polja predvsem s kompresijo v smeri SSZ-JJV in ekstenzijo v smeri SVV-JZZ je v skladu z najpogostejšo smerjo razpok v glavnem kamnitem gozdu v smeri S20-30°Z (11,4%). Ključne besede: strukturna geologija, rozete, kraške jame, glavni kamniti gozd, yunnan, Kitajska. Karst areas of Shilin County southeast of Kumning were studied to understand the role of geological structures in the formation of karst features as stone forest and selected caves. Detailed structural geological mapping of fissure orientations within selected caves and of the Major stone forest was accomplished and presented as rose diagrams. Regional geological structures were compared with statistical evaluation of structural geological elements obtained from field mapping. There is a good correlation between surface and underground fissure orientations and cave passage orientations with regionally important fault zones, including the xiaojiang Fault (N-S direction) and Red River Fault (NW-SE direction). The most frequent cave passages orientation, in a nearly N-S direction, is associated with nearly E-W compression and nearly N-S extension from late Pliocene to mid-Pleistocene. A second tectonic stage from latePleistocene to the present, with the tectonic stress field mainly of NNW-SSE compression and NEE-SWW extension, is in accordance with the most frequent fissure orientations in Major stone forest with a direction of N20-30°W (11.4%).

Humus soil as a critical driver of flora conversion on karst rock outcrops

“…This study was performed in Shilin County (24°30′–25°03′N, 103°10′–103°40′E), Yunnan Province, southwest China, where karst landforms are composed of Permian, Carboniferous and Devonian carbonate rocks 49 . The karst landscapes consist of rock gaps, rock ditches, small rock caves and rock slots.…”