西罗斯海阿黛尔盆地新生代构造特征及指示意义
投稿时间:2016-08-03  最后修改时间:2016-09-29  点此下载全文
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作者单位E-mail
张峤 国家海洋局第二海洋研究所 zhangqiao0317@163.com 
基金项目:“南极周边海域海洋地球物理考察”(编号:ChinARE 2016-01-03); “由罗斯海岩浆活动时空分布研究西南极裂谷系统特征”(编号:14260-10)
中文摘要:本文根据西罗斯海北端阿黛尔盆地及周缘地球物理资料,对地震数据进行二维F-K频率与波数滤波处理,获得噪音被压制,同相轴更连续以及深部信号被明显揭露的数据资料。基于此分析了该区新生代构造特征和岩浆活动,并结合该区冰川作用,总结了与冰川有关的沉积相。研究发现,16 Ma时受到残余岩浆加热造成的阿黛尔海槽隆升作用以及阿黛尔盆地最开始不对称扩张的双重影响,在阿黛尔海槽两翼外分别形成隆起褶皱区和掀斜隆升区。隆起褶皱区以高角度断层和褶皱为特征,分布在阿黛尔海槽东翼南部,覆盖范围较小。掀斜隆升区则以雁行断层和掀斜断块为特征,分布在阿黛尔海槽西翼南部,向南一直伸到陆地边缘。利用火成岩体与围岩间的接触关系,将本区火成岩形成时代大体分为两期:早期和晚新生代火山。早期火山形成时间不易确定,只零星散落在掀斜隆升区内,推测其形成可能与残余岩浆活动有关。晚新生代火山形成时间至少晚于5.5 Ma,分布范围广且分散,基本覆盖整个研究区。这期岩浆活动无论从时间还是空间上可能都与裂谷作用无关,而是受到上新世以来大规模冰川消退造成的地幔减压熔融作用的影响。
中文关键词:阿黛尔盆地  西罗斯海  地震识别  岩浆活动  冰川运动
 
Cenozoic tectonic characteristics in the Adare Basin, West Ross Sea
Abstract:Based on the geophysical data in the Adare Basin and its adjacent region, West Ross Sea, frequency wave-number filtering technique has been employed to recover the newly processed dataset with high signal noise ratio and complete seismic event which highly contributes to reveal more detailed deep-seated geological structures than previously thought. The structural features and magmatism of the study area in Cenozoic have been classified and analyzed. Combined with glaciation, the associated sedimentary faciesare summarized systematically. Our analysis find that at 16 Ma, under the influence of the thermal effect due to residual magmatism and asymmetric spreading of Adare Basin in the initial period, surrounding area of two flanks of the Adare troughis characterized withuplift folds and tilted uplift zone, respectively. The small-scale uplift folds zone features nearly upright faults and folds which is located in the south part of eastern flank. While the tilted uplift zone dominates in the corresponding districtof western flank that reaches to continental margin. By utilizing the contact relationship between igneous rocks and surrounding rocks, igneous rocks can be divided into two periods: early-stage and late Cenozoic igneous rocks. The early-stage rocks are generally located dispersedly in the tilted uplift zone and the age is poorly known. We suggest they are related to the residual magmatism. On the other hand, the spatial distribution of late Cenozoic igneous rocks, forming not earlier 5.5 Ma, is extensive and scattered with almost covering the entire study area, which indicates they maybe unrelated to the rifting in spatial and time, instead they are affected decompression melting of the mantle because of the large-scale deglaciation since Pliocene.
keywords:Adare Basin  West Ross Sea  Seismic recognition  Magmatism  Glaciation
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