Characteristics of gravity anomalies and tectonic analysis of Enderby Land in East Antarctica and its adjacent areas |
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| Authors: | Long Ma Chenguang Liu An Yang Baohua Liu Chenglong Xia |
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| Institution: | 1.First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China2.Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China3.Laboratory for Marine Geology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China4.National Deep Sea Center, Ministry of Natural Resources, Qingdao 266237, China5.Naval Research Institute, Tianjin 300061, China |
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| Abstract: | Enderby Land in East Antarctica and its adjacent areas, which are closely related to the Indian Plate in their geological evolution, have become one of the key zones for studies on how the Antarctic continent evolves. Based on the isostasy and flexure theories of the lithosphere and using the CRUST1.0 model as the depth constraint, this paper uses the gravity field model EIGEN-6C4 and topographic data to calculate the isostatic gravity anomalies of Enderby Land and its adjacent areas. Then, the crustal thickness of the study area is calculated, and three comprehensive geophysical interpretation profiles that vertically span the study area are plotted. The results show that the flexural isostatic gravity anomalies in Enderby Land and its adjacent areas are closely related to the regional tectonic setting, and the anomalies in different regions differ substantially, ranging from ?50×10?5 m/s2 to 85×10?5 m/s2. A zone of high isostatic gravity anomalies (30×10?5–80×10?5 m/s2) is distributed outside the Cooperation Sea and Queen Maud Land, which may be plate remnants generated by early rifting. Except for the Kerguelen Plateau, which was formed by a hotspot and has a crustal thickness of 15 km, the thickness of the oceanic crust in other parts of the study area changes slightly by approximately 4–9 km, with the thinnest part being in Enderby Basin. The thickness of the inland crust along the coastline increases with the elevation, with the maximum thickness reaching 34 km. The isostatic gravity anomalies corresponding to the zone of high magnetic anomalies along the continental margin of Queen Maud Land are negative and small, with an isostatic adjustment trend indicating Moho surface uplift, and those on the edge of central Enderby Land are near zero, approaching the isostatic state, which may be caused by the magmatism at the early stage of rifting. The continental-oceanic boundary should be close to the contour line of the crustal thickness 10–12 km on the outer edge of the coastline. |
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| Keywords: | Enderby Land and its adjacent areas flexural isostatic gravity anomalies crustal structure isostatic adjustment |
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