3D interpretation by integrating seismic and potential field data in the vicinity of the proposed COSC-1 drill site, central Swedish Caledonides
3D interpretation by integrating seismic and potential field data in the vicinity of the proposed COSC-1 drill site, central Swedish Caledonides
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通过整合瑞典中部喀里多尼德斯拟议 COSC-1 钻探地点附近的地震和位场数据进行 3D 解释
DOI：
10.1144/sp390.15
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发表时间：
2013
影响因子：
3.5
通讯作者：
D. Dyrelius
中科院分区：
文献类型：
--
作者：
P. Hedin;A. Malehmir;D. Gee;C. Juhlin;D. Dyrelius
摘要 科学钻探项目 COSC（斯堪的纳维亚喀里多尼德山脉的碰撞造山运动）旨在研究造山过程的关键问题，旨在钻探两个深度为 c 的完全取芯钻孔。在瑞典中西部精心挑选的地点，每段 2.5 公里。第一个项目 COSC-1 计划于 2014 年春末开始，目标是 Seve Nappe 综合体，该综合体的特点是倒变质作用，并且其部件明显经过了热延展性挤压。在这项研究中，现有的地震剖面与地表地质相结合，对 COSC-1 钻孔附近的构造结构进行了 3D 解释。同一区域的约束 3D 反重力模型支持了这一解释，高密度的 Seve Nappe 复合体在模型中清晰可见。解释和模型表明，Seve Naappe杂岩体最大深度范围小于2.5 km，与反射地震资料一致。重力模型还要求底层单元由低密度物质组成，与下异地体一致，但模型无法识别将异地体与结晶前寒武纪基底分开的滑脱。
Abstract The scientific drilling project COSC (Collisional Orogeny in the Scandinavian Caledonides), designed to study key questions concerning orogenic processes, aims to drill two fully cored boreholes to depths of c. 2.5 km each at carefully selected locations in west-central Sweden. The first of these, COSC-1, is scheduled for start late spring 2014 and will target the Seve Nappe Complex, characterized by inverted metamorphism and with parts that have evidently been subjected to hot ductile extrusion. In this study available seismic sections have been combined with surface geology to produce a 3D interpretation of the tectonic structures in the vicinity of the COSC-1 borehole. Constrained 3D inverse gravity modelling over the same area supports the interpretation, and the high-density Seve Nappe Complex stands out clearly in the model. Interpretation and models show that the maximum depth extent of the Seve Nappe Complex is less than 2.5 km, consistent with reflection seismic data. The gravity modelling also requires underlying units to comprise low-density material, consistent with the Lower Allochthon, but the modelling is unable to discern the décollement separating the allochthons from the crystalline Precambrian basement.