摘要
雷克雅内斯洋中脊是北大西洋洋中脊的重要组成部分,在演化过程中受到其北部冰岛热点的影响,而地壳厚度是评价热点对洋中脊影响程度的重要参数。为更好地理解热点对洋中脊扩张过程的影响,利用雷克雅内斯洋中脊及其邻区的空间重力异常和地形等数据反演了研究区的地壳厚度,通过与地震确定的地壳厚度对比,得到研究区地壳厚度模型。模型显示雷克雅内斯洋中脊平均地壳厚度约10 km,地壳由北向南逐渐减薄。根据对雷克雅内斯洋中脊地壳厚度分析,认为地壳演化过程可分为3个阶段:①40 Ma之前,平均地壳厚度12 km,地壳厚度随时间逐渐减薄,表明洋中脊的岩浆活动随时间逐渐减弱;②40~20 Ma,洋中脊的平均地壳厚度8 km,北部的地壳减薄不明显(<1 km),而南部地壳减薄显著(约3~4 km),南北地壳厚度的差异可能与冰岛热点的逐渐靠近有关;③20 Ma至今,平均地壳厚度10 km,此时冰岛热点位于洋中脊,熔融物沿洋中脊向南运移,使得洋中脊的地壳逐渐增厚。
As an important part of the Atlantic Ocean Ridge,the Reykjanes Ridge is influenced by the Iceland hot spot in the north during its evolution.And crustal thickness is an important parameter to evaluate the influence of the hot spot on the mid-ocean ridge.To better understand the influence of hotspots on the expansion of the mid-ocean ridge,the crustal thickness in the Reykjanes Ridge and its surrounding regions was reversed by using the data of free air gravity anomaly and topography.By comparing the crustal thickness with that determined by seismic data,the best crustal thickness model was established.The model shows that the average crustal thickness of the Reykjanes Ridge is 10 km and the crust thins gradually from north to south.Based on the analysis of the crustal thickness of the Reykjanes Ridge,the crustal evolution was divided into three stages.①The average crustal thickness was about 12 km before 40 Ma and gradually decreased with time,which indicates that the magmatic activity of the Reykjanes Ridge gradually weakened with time.②The average thickness is about 8 km between 20 and 40 Ma.The crustal thinning in the north is not significant(<1 km)while that in the south is obvious(about 3-4 km).The difference between the north and the south may be related to the gradual approaching of Iceland hotspot.③The average crustal thickness was about 10 km between 0 to 20 Ma.Iceland hotspot is now located on the Reykjanes Ridge and the southward migration of melt along the mid-ocean ridge leads to the thickening of the crust along the axis.
作者
曲彦丞
赵俐红
李一泉
彭祎辉
凌子龙
马媛媛
QU Yancheng;ZHAO Lihong;LI Yiquan;PENG Yihui;LING Zilong;MA Yuanyuan(College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266590, China;Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, Shandong 266237, China;Qingdao Geological and Mineral Geotechnical Engineering Co. Ltd, Qingdao, Shandong 266100, China)
出处
《山东科技大学学报（自然科学版）》
CAS
北大核心
2021年第4期21-27,共7页
Journal of Shandong University of Science and Technology(Natural Science)
基金
中国-东盟海上合作基金项目(12120100500017001)
国家自然科学基金项目(41676039)。
