Pervasive Hydrothermal Events Associated with Large Igneous Provinces Documented by the Columbia River Basaltic Province
Pervasive Hydrothermal Events Associated with Large Igneous Provinces Documented by the Columbia River Basaltic Province
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哥伦比亚河玄武岩省记录的与大型火成岩省相关的普遍热液事件
DOI：
10.1038/s41598-020-67226-9
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发表时间：
2020
影响因子：
4.6
通讯作者：
Colón, D. P.
中科院分区：
文献类型：
--
作者：
Bindeman, I. N;Greber, N. D.;Melnik, O. E.;Artyomova, A. S.;Utkin, I. S.;Karlstrom, L.;Colón, D. P.
与大型火成岩省喷发有关的地壳热液蚀变的程度和程度在野外鲜为人知，也不易辨认。我们在这里报告了来自美国西部哥伦比亚河玄武岩群(16-15‰Ma)的岩脉和熔岩的新的δ18O数据集，并记录了岩脉在δ18O中的平均消耗比玄武岩流动多1-2 GbO。我们表明，这一观察结果最好的解释是，在地壳冷却过程中，被加热的大气降水参与其中。最大的6-8‰损耗出现在一个10米厚的岩脉周围和内部，该岩脉侵入了125 Ma Wlowa英云闪长岩基。根据其围岩的加热和融化程度，这一堤坝可能作为岩浆管道运行了4-7年。我们发现，该岩脉还在其接触面周围形成了一个热液系统，延伸到周围的基岩中，最高可达100 m。一个考虑了(A)岩脉周围的热液循环、(B)岩浆流和(C)氧同位素交换率的模型表明，在岩浆流停止后，热液系统运行了约150年。与以前发表的(U-Th)/He热年代学剖面相一致，我们的模型表明，距离这类岩脉100 m的岩石可以受到热液作用的改变。总体而言，我们的样本集是关于哥伦比亚河玄武岩省岩脉和岩床侵入引起的浅部地壳广泛热液蚀变的第一份文件。据估计，富含有机质和碳酸盐的沉积物在堤防和岩床周围的加热和热液改造释放出18亿吨温室气体(CH4和CO2)。此外，堤防周围岩石的热液δ18O亏损约为500-600km3，按规模计算，这构成了低δ18O岩石的31,000 km3。这些在δ18O中亏损的地壳体积足以解释俄勒冈州东部和爱达荷州西部丰富的低δ18O岩浆。这项研究工作还表明，堤坝周围δ18O消耗的宽度和大小可以确定它们是喂食者。鉴于此，我们在这里解释了卡雷利亚的古元古代岩脉，其δ18O耗竭是世界上最低的(−27.8‰)，是在雪球地球冰川条件下运行的2.2-2.4Ga的同世大型火成岩省的补给者。
The degree and extent of crustal hydrothermal alteration related to the eruption of large igneous provinces is poorly known and not easily recognizable in the field. We here report a new δ18O dataset for dikes and lavas from the Columbia River Basalt Group (16–15 Ma) in the western USA, and document that dikes on average are 1–2‰ more depleted in δ18O than basalt flows. We show that this observation is best explained with the involvement of heated meteoric waters during their cooling in the crust. The largest 6–8‰ depletion is found around and inside a 10 m-thick feeder dike that intruded the 125 Ma Wallowa tonalitic batholith. This dike likely operated as a magma conduit for 4–7 years, based on the extent of heating and melting its host rocks. We show that this dike also created a hydrothermal system around its contacts extending up to 100 m into the surrounding bedrock. A model that considers (a) hydrothermal circulation around the dike, (b) magma flow and (c) oxygen isotope exchange rates, suggests that the hydrothermal system operated for ~150 years after the cessation of magma flow. In agreement with a previously published (U-Th)/He thermochronology profile, our model shows that rocks 100 m away from such a dike can be hydrothermally altered. Collectively, our sample set is the first documentation of the widespread hydrothermal alteration of the shallow crust caused by the intrusion of dikes and sills of the Columbia River Basalt Province. It is estimated that heating and hydrothermal alteration of sediments rich in organic matter and carbonates around the dikes and sills releases 18 Gt of greenhouse gases (CH4and CO2). Furthermore, hydrothermal δ18O depletion of rocks around dikes covers 500–600 km3, which, when scaled to the total CRB province constitutes 31,000 km3of low-δ18O rocks. These volumes of crust depleted in δ18O are sufficient to explain the abundant low-δ18O magmas in eastern Oregon and western Idaho. This work also demonstrates that the width and magnitude of δ18O depletion around dikes can identify them as feeders. Given this, we here interpret Paleoproterozoic dikes in Karelia with the world’s lowest δ18O depletions (−27.8‰) as feeders to the coeval large igneous province aged 2.2–2.4 Ga that operated under the Snowball Earth glaciation conditions.
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两个 8~10 m 宽哥伦比亚河洪水玄武岩堤周围低温年代学的贝叶斯马尔可夫链蒙特卡罗反演
影响因子：
2.9
作者：
L. Karlstrom;Kendra E. Murray;P. Reiners
通讯作者：
P. Reiners
影响因子：
5
作者：
C. Beier;W. Bach;A. Busch;F. Genske;Christian Hübscher;S. Krumm
通讯作者：
C. Beier;W. Bach;A. Busch;F. Genske;Christian Hübscher;S. Krumm
哥伦比亚河玄武岩喷发主相释放的硫
影响因子：
5.8
作者：
K. Davis;J. Wolff;M. C. Rowe;O. Neill
通讯作者：
O. Neill
影响因子：
5.3
作者：
Armstrong McKay, David I.;Tyrrell, Toby;Foster, Gavin L.
通讯作者：
Foster, Gavin L.
大洋中脊的热液过程：尺度分析和单程模型的结果
DOI：
10.1029/148gm09
发表时间：
2013
期刊：
Geophysical monograph
影响因子：
--
作者：
R. Lowell;L. Germanovich
通讯作者：
L. Germanovich