Structural Evolution of the Southern Lesser Antilles Arc

加勒比构造演化模型一般表明，在整个新生代的大部分时间里，加勒比海板块前缘上方有一个古近纪的小安的列斯弧和空间上相同的后继弧，这意味着它们的大部分时间都是东西汇聚的。然而，格林纳达和格林纳丁斯最近的研究结果表明，在大西洋向西俯冲到加勒比海岩石圈之下的弧形岩浆活动开始之前，新近纪以前的岩石经历了南北挤压。这项研究将检验另一种假设，即较早的变形与离散的南小安的列斯岛弧有关，该弧在中新世加勒比海板块从西到达之前，容纳了北美和南美板块之间的南北会聚。这项工作将包括野外构造制图、研究现有的海洋地震数据、岩石学和古地磁数据。这些结果将对理解北美、南美和加勒比板块之间的新生代相互作用具有相当重要的意义。

Models of Caribbean tectonic evolution generally indicate a Paleogene Lesser Antilles arc and a spatially identical successor Neogene arc above the leading edge of the Caribbean plate throughout much of the Cenozoic, implying east-west convergence for most of their time period. However, recent findings in Grenada and the Grenadines indicate that the pre-Neogene rocks experienced north-south compression prior to onset of arc magmatism related to westward subduction of the Atlantic below Caribbean lithosphere. This research will test an alternative hypothesis that the earlier deformation was related to a discrete southern Lesser Antilles arc that accommodated north-south convergence between the North American and South American plates prior to the arrival of the Caribbean plate from the west in the Miocene. The work will include field structural mapping, study of existing marine seismic data, petrology and paleomagnetic data. Results will be of considerable importance in understanding Cenozoic interactions between the North American, South American and Caribbean plates.