Interactions between distal epiclastic and bio‐chemogenic sedimentation at the foothills of a mafic alkaline volcano: The case of the Oligocene Doupovské Hory Volcanic Complex (Czech Republic)

Author:

Rapprich Vladislav1ORCID,Čáp Pavel1ORCID,Erban Kochergina Yulia V.1ORCID,Kadlecová Eva1,Benkó Zsolt2,Sakala Jakub3ORCID,Rodovská Zuzana1,Matějů Jan4,Petrash Daniel A.1ORCID

Affiliation:

1. Czech Geological Survey Prague Czech Republic

2. Institute for Nuclear Research Debrecen Hungary

3. Institute of Geology and Palaeontology, Faculty of Science Charles University Prague Czech Republic

4. The Karlovy Vary Museum Karlovy Vary Czech Republic

Abstract

AbstractLate Oligocene (ca 25 Ma) volcano‐sedimentary successions exposed on the western periphery of the Doupovské Hory Volcanic Complex reveal a complex sedimentation history influenced in various ways by decay of the alkali basalt volcanic edifice. Weathering of the volcanic rocks supplied abundant reactants that promoted carbonate precipitation in the peripheral palaeolakes—as evidenced by strongly non‐radiogenic 87Sr/86Sr values (0.7038–0.7041). On the other hand, the sediments of the initial shallow lake became deformed by the bulldozing effect of a debris avalanche. The debris flow and avalanche deposits filled up the original depression, modified the basin morphology and shifted the peripheral lacustrine setting further away from the volcano. At this stage, surface water influx from the surrounding granites conferred a more radiogenic character (87Sr/86Sr values 0.7046–0.7049) to the calcrete deposits. Fossil assemblages as well as limestone textures suggest significant seasonal water‐level fluctuations, possibly reflecting the alternating rainy and dry‐seasons of a prevalently humid Central‐European Late Oligocene climate. The seasonal drying out of the ponds resulted in significant 18O enrichments. Although the ca 0‰ δ13C values might suggest mixing of atmospheric and volcanic CO2 during carbonate precipitation, no active volcanic conduits of relevant age are known in the close vicinity. The lower δ13C values are likely a result of mantle degassing through rift faults, a phenomenon observed in the magmatically extinct Ohře Rift until present. This paper demonstrates that limestones derived from weathered alkaline basalts are characterised by highly non‐radiogenic Sr isotopic ratios (87Sr/86Sr ca 0.704), suggesting a magmatic origin for the Ca within these carbonates. Contrary to the notion of carbonatites being present when highly non‐radiogenic Sr isotopes are found, these results show that Sr isotopes in carbonates formed in alkali basalt‐sourced environments only reveal the source of the Sr (and Ca) ions, not necessarily the presence of carbonatite.

Funder

Česká geologická služba

Publisher

Wiley

Subject

Paleontology,Stratigraphy,Geology,Environmental Science (miscellaneous),Oceanography

Reference102 articles.

Cited by 1 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3