An alternative interpretation of the Cayman trough evolution from a reidentification of magnetic anomalies
An alternative interpretation of the Cayman trough evolution from a reidentification of magnetic anomalies
复制标题
重新识别磁异常对开曼海槽演化的另一种解释
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
B. Lépinay
中科院分区：
文献类型：
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作者：
S. Leroy;A. Mauffret;P. Patriat;B. Lépinay
在Wilkes（1973年）和Seacarib II（1987年）到开曼海槽的航行中收集了磁性数据。对磁测资料进行了新的解释。根据我们对异常的识别，绘制了等时线图。提出开曼海槽开启的时代为早始新世（49Ma，Ypresian），而不是以往研究所认为的渐新世晚期或始新世中期。我们的板块构造重建更简单，适合陆地地质（牙买加和古巴）和构造。我们的重建表明，向南传播的磁异常8和6（26和20马）之间的扩展中心。在此期间，槽宽增加了30公里。从中渐新世到早中新世，开曼扩张中心向南扩展，导致了天鹅群岛约束弯曲的发展，在开曼海槽转换断层（沃尔顿断层）的东部轨迹上形成了1 km高的陡坎，并形成了拉分盆地（亨德里克斯拉分）。磁异常和磁化图提供了有关变形和岩石的信息。开曼海槽从海底扩张的开始到目前的配置的拟议的演化模型，介绍了从马斯特里赫特到现在的加勒比板块的北方边界的构造逃逸。
Magnetic data were collected during the Wilkes (1973) and Seacarib II (1987) cruises to the Cayman trough. A new interpretation of magnetic data is carried out. An isochron pattern is drawn up from our anomaly identifications. An early Eocene age (49 Ma, Ypresian) for Cayman trough opening is proposed instead of the late Oligocene or middle Eocene ages suggested by previous studies. Our plate tectonic reconstruction is simpler and fits the on-land geology (Jamaica and Cuba) and the tectonics. Our reconstruction shows a southward propagation of the spreading centre between magnetic anomalies 8 and 6 (26 and 20 Ma). The trough width increases by 30 km in this period. The southward propagation of the Cayman spreading centre from the Middle Oligocene to the Early Miocene induced the development of the restraining bend of the Swan Islands, the formation of a 1 km high scarp on the eastern trace of the Cayman trough transform fault (Walton fault) and the formation of a pull-apart basin (Hendrix pull-apart). Magnetic anomalies and magnetization maps give information about the deformation and the rocks. The proposed evolutionary model of the Cayman trough from the inception of seafloor spreading to the present configuration is presented in relation to the tectonic escape of the northern boundary of the Caribbean plate from the Maastrichtian to the Present.