气候变化领域集成服务门户(CCPortal): Neogene continental denudation and the beryllium conundrum

CCPortal

DOI	10.1073/pnas.2026456118
	Neogene continental denudation and the beryllium conundrum
	Li S.; Goldstein S.L.; Raymo M.E.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:42
英文摘要	Reconstructing Cenozoic history of continental silicate weathering is crucial for understanding Earth's carbon cycle and greenhouse history. The question of whether continental silicate weathering increased during the late Cenozoic, setting the stage for glacial cycles, has remained controversial for decades. Whereas numerous independent proxies of weathering in ocean sediments (e.g., Li, Sr, and Os isotopes) have been interpreted to indicate that the continental silicate weathering rate increased in the late Cenozoic, beryllium isotopes in seawater have stood out as an important exception. Beryllium isotopes have been interpreted to indicate stable continental weathering and/or denudation rates over the last 12 Myr. Here we present a Be cycle model whose results show that variations in the 9Be weathering flux are counterbalanced by near-coastal scavenging while the cosmogenic 10Be flux from the upper atmosphere stays constant. As a result, predicted seawater 10Be/9Be ratios remain nearly constant even when global denudation and Be weathering rates increase by three orders of magnitude. Moreover, 10Be/9Be records allow for up to an 11-fold increase in Be weathering and denudation rates over the late Cenozoic, consistent with estimates from other proxies. The large increase in continental weathering indicated by multiple proxies further suggests that the increased CO2 consumption by continental weathering, driven by mountain-building events, was counterbalanced by other geological processes to prevent a runaway icehouse condition during the late Cenozoic. These processes could include enhanced carbonate dissolution via pyrite weathering, accelerated oxidation of fossil organic carbon, and/or reduced basalt weathering as the climate cooled. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Be isotopes; Carbon cycle; Cenozoic cooling; Silicate weathering
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/238334
作者单位	Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, 210023, China; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10946, United States; Department of Earth and Environmental Sciences, Columbia University, Palisades, NY 10964, United States
推荐引用方式 GB/T 7714	Li S.,Goldstein S.L.,Raymo M.E.. Neogene continental denudation and the beryllium conundrum[J],2021,118(42).
APA	Li S.,Goldstein S.L.,&Raymo M.E..(2021).Neogene continental denudation and the beryllium conundrum.Proceedings of the National Academy of Sciences of the United States of America,118(42).
MLA	Li S.,et al."Neogene continental denudation and the beryllium conundrum".Proceedings of the National Academy of Sciences of the United States of America 118.42(2021).