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Seismic evidence for lithospheric boudinage and its implications for continental rifting
Geology ( IF 5.8 ) Pub Date : 2022-09-01 , DOI: 10.1130/g50046.1
Luan C. Nguyen 1 , Alan Levander 1 , Fenglin Niu 1 , Julia Morgan 1 , Guoliang Li 2
Affiliation  

The continental rifting that precedes the breakup of a continent and the formation of a new ocean basin is one of the key processes of plate tectonics. Although often viewed as a two-dimensional process, rifted margins exhibit significant variations along strike. We document along-strike variations developed during the ca. 200–160 Ma continental rifting that formed the margins of the Gulf of Mexico ocean basin. Rayleigh-wave ambient noise tomography reveals a zone of high and low seismic velocity resembling large scale geologic boudins in the mantle lithosphere of the northwestern Gulf of Mexico margin. These features become progressively less prominent eastward following the transition from a magma-poor to a magma-rich passive margin. We infer that mantle refertilization and thickness of the pre-rift lithosphere control deformation style and the along-strike variations in continental rifting. Our results also suggest that deformation during rifting produces long-lived features that persist long after breakup and, therefore, can be used to study rifted margins globally.

中文翻译:

岩石圈边界的地震证据及其对大陆裂谷的影响

大陆解体和新洋盆形成之前的大陆裂谷是板块构造的关键过程之一。尽管通常被视为二维过程,裂谷边缘沿走向表现出显着变化。我们记录了 ca 期间开发的沿罢工变化。形成墨西哥湾洋盆边缘的 200-160 Ma 大陆裂谷。瑞利波环境噪声层析成像揭示了墨西哥湾西北部边缘地幔岩石圈中类似于大尺度地质布丁的高低地震速度区。随着从贫岩浆向富岩浆被动边缘的过渡,这些特征向东逐渐变得不那么突出。我们推断地幔再肥化和裂谷前岩石圈的厚度控制了大陆裂谷的变形方式和沿走向的变化。我们的研究结果还表明,裂谷过程中的变形会产生长期存在的特征,这些特征在破裂后会持续很长时间,因此可用于全球研究裂谷边缘。
更新日期:2022-08-25
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