| 从五台山下前寒武系变形特征论某些构造形迹的运动学意义 |
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| ON KINEMATIC SIGNIFICANCE OF SOME STRUCTURAL FEATURES IN VIEW OF DEFORMATION FEATURE OF THE LOWER PRECAMBRIAN IN WUTAI MOUNTAIN |
| The early Precambrian Wutai Group and Hutuo Group of the Wutai Mountain region underwent multiple deformation and polymetamorphism; from subgreenschist fades to amphibolite fades. Small-scale structures (planar and linear fabrics and minor folds) are developed there as those preserved in the deformed and metamorphosed early Precambrian terrains elsewhere.The bedding furnishes an internal marker whose geometric confinguration reflects the nature and degree of deformation. The cleavage and schistosity acted as an axial plane role in the early generation of compressed shear fold, and changed into a slip plane in the later generation of flexural slip fold. The kinematic significance of some linear fabrics, such as elongated pebbles and mineral streaks, is still under discussion, In the Wutai Group, the flattened and elongated pebbles from the metaconglomerate, the amygdales from meta-basalt and some mineral aggregates are all perpendicular or nearly perpendicular to the hinge of early generation minor fold, indicating that these linea-tions display the a-axis of kinematic coordinate in the early deformation of each tectonic stage. This property is reflected more or less in the microscopic fabrics.Some new types of displacing path of fold hinge are discovered in the Wutain Mountain region, including "refracted displacement", "non-planar reflected displacement" and "co-planar reflected displacement".All these features can ben used as evidences of kinematic analysis.Apparently correct understanding and interpertation of small-scale structural features can help us to get a much more comprehensive understanding of major features of an orogenic belt.A thorough investigation of structural features provides foundamental gro-ds for kinematic analysis. |
| BAI Jin.1987.ON KINEMATIC SIGNIFICANCE OF SOME STRUCTURAL FEATURES IN VIEW OF DEFORMATION FEATURE OF THE LOWER PRECAMBRIAN IN WUTAI MOUNTAIN[J].Acta Geoscientica Sinica,9(2):201-213. |
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