Elastic Flexure of Young, Overlapping Basaltic Lava Flows Offshore the Galápagos and Hawaiian Islands: Observations, Modeling, and Thermal/Chronological Analysis
Elastic Flexure of Young, Overlapping Basaltic Lava Flows Offshore the Galápagos and Hawaiian Islands: Observations, Modeling, and Thermal/Chronological Analysis
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加拉帕戈斯和夏威夷群岛近海年轻、重叠的玄武岩熔岩流的弹性弯曲：观测、建模和热/年代分析
DOI：
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发表时间：
2020
影响因子：
3.5
通讯作者：
M. Richards
中科院分区：
文献类型：
--
作者：
K. Abbott;M. Richards
最近在加拉帕戈斯群岛进行的一次多波束测深调查在圣克鲁斯岛和圣地亚哥岛之间有了一项新发现：在两个火山流之间形成了一个陡峭的弯曲海沟，近50米深，约500米宽。海底观测和弹性板模拟与这一特征相符，即一次膨胀流覆盖在另一个较新的流之上后形成了该特征，使下方的熔岩流发生偏转，呈现出一种典型的弹性弯曲模式。我们利用薄板近似法对这个海沟特征进行了弯曲分析，以确定下方熔岩流的有效弹性厚度。此外，我们提出，这种弹性厚度可作为熔岩流偏转时冷却凝固的上地壳厚度的一个替代指标，这是一种与时间相关的热特性。这种方法提供了一种确定两个重叠熔岩流之间所经历时间的年代学工具。我们将这种方法应用于加拉帕戈斯海沟，以确定其形成的时间历程。此外，我们利用多波束测深技术在夏威夷群岛和加拉帕戈斯群岛识别出了另外七个可能的弯曲海沟，并对其进行了建模。对这些特征的弹性/热历史分析得出了海底熔岩流之间从几年到约600年不等的相对时间间隔，这表明存在一个关键的时间间隔，在此期间下方熔岩流的弹性偏转可能会被“冻结”。这种方法可能会对相继快速形成的重叠熔岩流之间的时间关系提供有用的约束。
A recent multibeam bathymetry survey in the Galápagos archipelago revealed a novel observation between the islands of Santa Cruz and Santiago: a steep flexural moat formed between two volcanic flows, nearly 50 m deep and about 500 m wide. Submarine observations and elastic plate modeling are consistent with this feature forming after one inflationary flow overlapped another young flow, deflecting the underlying lava flow in what appears to be a classical elastic flexural pattern. We present a flexural analysis of this moat feature using a thin‐plate approximation to determine the effective elastic thickness of the underlying flow. Moreover, we propose that this elastic thickness serves as a proxy for the thickness of the cooling, solidifying upper crust of the lava flow at the time of deflection, a time‐dependent thermal property. This approach offers a chronological tool to put bounds on the elapsed time between two overlapping lava flows. We applied this method to the Galápagos moat to constrain the time history of its formation. Additionally, we identified and modeled seven additional flexural moat candidates in the Hawaiian archipelago and in the Galápagos using multibeam bathymetry. Elastic/thermal history analysis of these features yields relative time intervals between submarine lava flows ranging from a few years to about 600 years, which suggests that there is a critical time interval during which elastic deflection of the underlying lava flow may become “frozen in.” This methodology may provide helpful constraints on the temporal relations between overlapping lava flows wherever they form in relatively rapid succession.
海山侵蚀台地的识别：对加拉帕戈斯群岛岛间连通性和沉降的影响
影响因子：
2.9
作者：
Schwartz, Darin M.;Soule, S. Adam;Wanless, V. Dorsey;Jones, Meghan R.
通讯作者：
Jones, Meghan R.