Abstract

An analysis of deep structure for the East Greenland margin (Blosseville Kyst – Liverpool Land) and the Jan Mayen microcontinent yielded a common crustal model for the time before their dispersal. The joint model presents a visual picture of the net result from the Paleozoic, Mesozoic, and Cenozoic rifting phases. Beginning from the Devonian, a graben-like depression approximately 180 km wide has existed between Liverpool Land and the Jan Mayen Ridge. The depression resulted from downwarping of the crystalline basement that was not compensated by sedimentation. The sea basin was approximately 2 km deep at the end of the Devonian. The joint deep crustal section (from west to east) clearly shows three depths to the top of the upper mantle that can be fitted by dome-like surfaces superposed on one another. We interpret these surfaces as temperature fronts resulting from the formation of mantle plumes that took place during different epochs (Paleozoic, Mesozoic–Cenozoic, and Late Cenozoic). A basement high was identified beneath the edge of the present-day Blosseville Kyst and Liverpool Land shelf; the high correlates with the axis of a positive free-air gravity anomaly. East of the high, a continent–ocean boundary is tentatively identified along the axis of the anomaly. The present-day phase in the geological evolution of the Greenland–Norwegian region north of Iceland is characterized by a higher thermal state of the lithosphere and by intraplate tectonic occurrences.

中文翻译：

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东格陵兰大陆边缘在柯布因西山脊上传播之前的结构和演变

摘要

对东格陵兰边缘（布洛斯维尔·凯斯特-利物浦土地）和Jan Mayen微大陆的深层结构进行分析后，得出了它们扩散之前的一个通用地壳模型。联合模型显示了古生代，中生代和新生代裂谷阶段最终结果的可视化图像。从泥盆纪开始，利物浦土地和扬马延岭之间约有一个宽约180公里的a陷状凹陷。凹陷是由于结晶基底的翘曲导致的，而翘曲并没有通过沉积来补偿。在泥盆纪末期，海盆深约2公里。联合的深部地壳剖面（从西到东）清楚地显示出上地幔顶部的三个深度，这些深度可以由彼此叠置的圆顶状表面拟合。我们将这些表面解释为在不同时期（古生代，中生代-新生代和晚新生代）形成的地幔柱形成的温度锋。在今天的Blosseville Kyst和利物浦土地架子的边缘下方发现了一个地下室高处；高与正的自由空气重力异常的轴相关。在高地以东，沿着异常轴初步确定了一个大陆-海洋边界。冰岛北部格陵兰-挪威地区地质演化的当今阶段以岩石圈的较高热态和板内构造发生为特征。在今天的Blosseville Kyst和利物浦土地架子的边缘下方发现了一个地下室高处；高与正的自由空气重力异常的轴相关。在高地以东，沿着异常轴初步确定了一个大陆-海洋边界。冰岛北部格陵兰-挪威地区地质演化的当今阶段以岩石圈的较高热态和板内构造发生为特征。在今天的Blosseville Kyst和利物浦土地架子的边缘下方发现了一个地下室高处；高与正的自由空气重力异常的轴相关。在高地的东部，沿着异常轴初步确定了一个大陆-海洋边界。冰岛北部格陵兰-挪威地区地质演化的当今阶段以岩石圈的较高热态和板内构造发生为特征。