墨西哥湾盆地东南部区域构造演化过程探讨

Tectonic Evolution of the Southeastern Gulf of Mexico Basin

墨西哥湾盆地东南部位于北美板块与加勒比板块碰撞交汇区域,是墨西哥湾地区构造最为复杂区域。涉及两大板块,北美板块和加勒比板块;两个二级板块,尤卡坦板块和巴哈马-佛罗里达板块。在总结前人研究成果基础上,结合深海钻探计划(DSDP)钻井资料以及最新二维地震数据,通过地震相特征识别,分析研究区构造演化过程,探讨板块之间相对运动对墨西哥湾盆地东南部区域的控制作用。结果表明:(1)墨西哥湾盆地东南部现今包含北古巴前陆盆地以及盆地北部被动大陆边缘的不规则中央裂陷区;(2)该区域经历多期构造活动,早侏罗世至中侏罗世中期南美板块与北美板块之间背向分离,白垩纪加勒比板块逆冲北美板块,晚白垩世早期海平面上升以及尤卡坦台地与佛罗里达台地抬升,白垩纪末期加勒比板块北侧古加勒比弧与北美板块碰撞拼合;(3)在早白垩世晚期,由于北美板块内部尤卡坦板块与巴哈马-佛罗里达板块之间的张裂运动,发育大量张性断层,产生NW-SE走向的地堑、半地堑构造样式。

The southeastern Gulf of Mexico(GoM)basin is located in the collision zone and tectonic junction of the North American and Caribbean plates.It involves two major plates(North American and Caribbean)and two minorplates(Yucatan and Bahamas-Florida).We summarized previous research findings,including Deep-Sea Drilling Program(DSDP)data and the latest two-dimensional(2D)seismic data.We discussed the controlling effect of relative plate movement on the southeastern GoM basin,through identifying the seismic phase features and analyzing the tectonic evolution processes.Our main findings are as follows:(1)The southeastern GoM basin now contains the northern Cuba foreland basin,and the irregular central rifts of the passive continental margin in the northern part of the basin.(2)The region has experienced multiphase tectonism,and the South American and North American plates were separated from each other during the Early to mid-Middle Jurassic.The Cretaceous Caribbean plate thrust over the North American plate.Sea-level rose in the early Late Cretaceous and the Yucatan and Florida platforms uplifted.The northern Caribbean arc collided with the North American plate at the end Cretaceous.(3)In the late Early Cretaceous,many extensional faults were developed due to the extension/rifting between the Yucatan and Bahamas-Florida plates in the North American plate,forming the NW-trending(semi-)graben tectonic patterns.