变质岩定向薄片采制及构造要素的测定与分析
COLLECTION AND PREPARATION OF ORIENTED THIN SECTIONS OF METAMORPHIC ROCKS AND MEASUREMENT AND ANALYSIS OF THEIR STRUCTURAL ELEMENTS
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摘要: 作者对定向标本采集及薄片制作,提出一套严格的程序和方法。并指出:利用XZ薄片测定剪切角(θ),计算出剪切应变值(γ);XZ薄片和XY(或YZ)薄片中的变形矿物颗粒,可求得有限应变富林指数(K)。此外,在定向薄片中测量S与C面理夹角,从赤平投影网上计算出S面理及拉伸线理(La)的产状,进一步推算出韧性剪切带的运动方向及倾角。Abstract: Oriented thin sections of metamorphic rocks are of important significance for qualitative and quantitative studies of revealing the origin, structural nature and structural elements of metamorphic rocks. The author proposes a set of rigid procedures and steps for the collection of oriented specimens and preparation of thin section. He points out that XZ thin sections may be used to measure the shear angle (θ)and calculate the shear strain value (γ) and that grains of deformed minerals in XZ and XY (or YZ) thin sections may be used to find the Flinn index (K) of finite strain. Besides, the angle between the foliations S and Chas been measured in oriented thin sections and the attitudes of foliation S and stretching lineation (La) have been calculated in the steriographic net, and then the direction of movement and dip of the ductile shear zone are estimated.