Ductile shear zones related to crustal shortening and domain boundary evolution in the central Fennoscandian Shield
Ductile shear zones related to crustal shortening and domain boundary evolution in the central Fennoscandian Shield
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与芬诺斯坎迪亚地盾中部地壳缩短和域边界演化相关的延性剪切带
DOI：
10.1029/2008tc002277
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发表时间：
2009
期刊：
影响因子：
4.2
通讯作者：
S. Bergman
中科院分区：
文献类型：
--
作者：
K. Högdahl;H. Sjöström;S. Bergman
芬诺斯坎甸地盾古元古代部分由形成于不同构造环境的地壳成分组成，总体上由明确的剪切带体系分隔。通过将构造分析和地质年代学与已公布的地球物理资料相结合，研究了一个异常过渡边界。这一边界的性质被解释为中、下地壳明显堆积的结果，沿着Gävle-Rättvik带(GRZ)和相邻的剪切带(GRZ)启动了1.87-1.86Ga的右旋剪切，导致了Bergslagen省的弧形北部边界。这一界线与地球物理异常、时间和变质破裂相吻合。由于不断的会聚，GRZ上的纯剪切叠加分量增加，导致右行剪切向Hagsta片麻岩带移动，记录的剪切为1809 Ma±2 Ma。最有可能的是，这两个构造都与更东边的同时代剪切带有关，作为∼1500公里长的地壳或地体边界的一部分。
The Paleoproterozoic part of the Fennoscandian Shield is composed of crustal components formed in different tectonic settings and generally separated by well‐defined shear zone systems. An anomalous transitional boundary has been investigated by integrating structural analysis and geochronology with published geophysical data. The nature of this boundary is interpreted to be a consequence of an apparent stacking in the lower and middle crust initiating 1.87–1.86 Ga dextral shear along the Gävle‐Rättvik Zone (GRZ) and adjacent shear zones, resulting in an arcuate northern boundary of the Bergslagen province. This boundary coincides with geophysical anomalies and temporal and metamorphic breaks. Owing to continuous convergence the pure‐shear overprint component increased on the GRZ and caused a shift of dextral shear to the Hagsta Gneiss Zone with recorded shear at 1809 ± 2 Ma. Most likely, both these structures are related to coeval shear zones farther to the east as a part of an ∼1500 km long crustal, or possibly terrane, boundary.