低温洞穴碳酸盐及其对美国犹他州冬季仙境洞穴永冻层解冻的影响。

Cryogenic cave carbonate and implications for thawing permafrost at Winter Wonderland Cave, Utah, USA.

机构信息

Geology Department, Middlebury College, Middlebury, VT, 05753, USA.

Institute of Geology, University of Innsbruck, 6020, Innsbruck, Austria.

出版信息

Sci Rep. 2021 Mar 19;11(1):6430. doi: 10.1038/s41598-021-85658-9.

DOI:10.1038/s41598-021-85658-9

PMID:33742010

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7979826/

Abstract

Winter Wonderland Cave contains perennial ice associated with two types of cryogenic cave carbonate (CCC) formed during the freezing of water. CCC is characterized by relatively high δC values, whereas CCC exhibits notably low δO values indicating precipitation under (semi)closed-system conditions in a pool of residual water beneath an ice lid. Previous work has concluded that CCC forms during permafrost thaw, making the presence of this precipitate a valuable indicator of past cryospheric change. Available geochronologic evidence indicates that CCC formation in this cave is a Late Holocene or contemporary process, and field observations suggest that the cave thermal regime recently changed in a manner that permits the ingress of liquid water. This is the first documented occurence of CCC in the Western Hemisphere and one of only a few locations where these minerals have been found in association with ice. Winter Wonderland Cave is a natural laboratory for studying CCC genesis.

摘要

冬季仙境洞穴含有与两种低温洞穴碳酸盐（CCC）相关的常年冰，这些 CCC 是在水冻结过程中形成的。CCC 的特点是相对较高的 δC 值，而 CCC 则表现出明显较低的 δO 值，表明在冰盖下的残留水池中，在（半）封闭系统条件下沉淀。先前的研究得出结论，CCC 是在多年冻土融化过程中形成的，因此这种沉淀物是过去冰冻圈变化的一个有价值的指标。现有的地质年代学证据表明，该洞穴中的 CCC 形成是全新世晚期或当代的过程，并且野外观察表明，洞穴的热状况最近发生了变化，允许液态水进入。这是西半球首次记录到 CCC，也是这些矿物质与冰相关的少数几个发现地点之一。冬季仙境洞穴是研究 CCC 成因的天然实验室。