| 内蒙古温都尔庙群高压变质带中几个标型矿物特征 |
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| 引用本文：颜竹筠,唐克东.1984.内蒙古温都尔庙群高压变质带中几个标型矿物特征[J].地球学报,6(3):179-194. |
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| 中文摘要:<正> 温都尔庙群分布于内蒙古集二线朱日和地区,西起五一台,向东经温都尔庙、汗白庙到白音诺尔、图林凯一带。 自1975年内蒙古区测队在这里发现蓝闪石以来,内蒙古地质局实验室,天津地质矿产研究所和河北地质学院在这里进行过大量研究工作,发现了迪尔石,铁滑石,黑硬绿泥石等矿物。1981年,笔者在这里工作,又发现了硬柱石,多硅白云母和文石等矿物。至此,温都尔庙群中已发现较完整的高压低温变质矿物组合,为研究和确定中朝陆台北侧早古生代板块俯冲带提供了矿物学资料。 |
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| THE NATURES OF SEVERAL TYPOMORPHIC MINERALS FROM HIGH PRESSURE METAMORPHIC ZONE OF ONDOR SUM GROUP, NEI MONGOL |
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| Abstract:The Ondor Sum Group includes two metamorphic facies, greenschist and glaucophane facies. The former is characterized by common presence of cham. Icodite and extreme lack of biotite, indicating a high-pressure subfacies syste-The latter belongs to typic high-pressure facies system as the occurrence of glaucophane, lawsonite, aragonite and phengite. Thus undoubtedly, there exist lawsonites in the Ondor Sum Group to constitute lawsonite + aragonite + calcite + albite + chlorite + quartz and lawsonite + epidote + chlorite + spinelline assemblages.Phengite occurs in glaucophane-quartz-schist aad is associated with glau cophane, anorthose, chalcodite and quartz. Texture of 2M, type and some 3T type were determined with X-ray diffraction method; phengite was determined by infrared spectrum;and an endothermic effect before 1100℃ was displayed by the method of differential thermal analysis.Aragonite occurs in aragonite-lawsonite-chlorite schist and is associated with lawsonite, calcite, chlorite, anorthose and quartz.Galucophane occurs in phengite-anorthose-glaucophane-quartz-schist and hematitized glaucophane-quartzite and is associated with phengite, chalcodite, anorthose, deerite and minnesotaite, including glaucophane, crossite, Toren -drikite and riebeckite (only crossite and rare riebeckite recognized previous-ly).The presence of various types of glaucophane in the glaucophane schists of the Ondor Sum Group indicates the uneven pressure and temperature in the subduction zone.Garnet occurs in the eclogite by two stages.The mineral assemblage in the metamorphic zone of the Ondor Sum Group may be useful to researching the nature of plate movement as mineral evidence.The ions of A1V1 in all the metamorphic minerals, such as glaucophane, lawsonite and garnet, indicate their formation under a condition of high-pressure and low-temperature in one aspect.The number of Si ion in the phengite is 3.52 and 3.42, and 3.46 in a-verage, indicating the T-P gradient of 40℃/Kb and geothermal gradient of 12℃/Km, which is the geothermal gradient of subduction zone. In the diagram of P-T steady curves of phengite, it is roughly estimated that the pressure is 6-7Kb and the temperature between 380℃ and 425℃ while Si= 3.46.The facies diagram of calcite and aragonite shows 220℃ at 6 Kb and 300℃ at 7Kb.Based on the above analyses, the writers estimate the temperature of 250-400℃ at pressure of 6-7 Kb in the metamorphic zone of the Ondor Sum Group.The mineral assemblage of glaucophane facies, especially lawsonite, occurring in the Ondor Sum Group provides a new support for the inference of presence of the plate movement in the Early Paleozoic, even as early as in the Late Precambrian time. |
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