Study on System of Faults in the Gulf of Mexico and Adjacent Region based on Gravity Data

摘要

In the Gulf of Mexico and adjacent landmasses,faults are very complex,and their distribution is closely related to plate tectonics,ocean-land boundary,and former structure.The plane position of the faults can be identified by the maximum characteristic of the vertical derivative of the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)of the Bouguer gravity anomaly.The apparent depth of the faults is inverted by the Bouguer gravity anomaly curvature property.Based on tectonic evolutionary processes and the plane distribution and apparent depth characteristics of the faults,a complete fault system for the Gulf of Mexico and adjacent areas has been established,including 102 faults.The apparent depths of 33 first-class faults are 16-20 km and for 69 second-class faults are 12-16 km.The F_(1-2)and F_(1-3)subduction fault zones are two caused by the subduction of the Cocos Plate into the old Yucatan and Chorti landmasses;F_(1-11)and F_(1-12)fault zones extend westward to the coast of Guatemala and do not extend into the continent;F_(1-17)and F_(1-20)faults,which control the boundary of the oceanic crust,do not extend southward into the continent.The fault system,which radiates in a"fan-shaped"structure as a whole,unfolds to the northeast.Faults of different nature and sizes are distributed in the Cocos Plate subduction zone,Continental,Gulf of Mexico,Yucatan old landmass and Caribbean Plate in NW,NNW,NS,NE and NEE directions.In the Gulf of Mexico region,the fault system is a comprehensive reflection of former tectonic movements,such as plate movement,drift of old landmasses and expansion of oceanic crusts.The first-class faults control the plate and ocean-continental boundaries.The second-class faults are subordinate to the first-class faults or related to the distribution of different sedimentary layers.