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使用氧同位素方法 ,测试了西太平洋马里亚纳岛弧、马里亚纳海槽、冲绳海槽和东太平洋加拉帕戈斯裂谷的海底热液烟囱和硫化物全岩样品。结果表明 :马里亚纳岛弧上的埃斯梅拉尔达破火山口的热液硫化物的形成温度最高 (达 2 75℃ ) ,而成为高温产物的代表 ;冲绳海槽和加拉帕戈斯裂谷烟囱 ,表现为中高温类型 ,其氧同位素温度在 1 5 0℃左右 ;马里亚纳海槽以蛋白石为主要矿物的烟囱物 ,则显示出典型的低温热液类型 ,少量黄铁矿砂试样则表现出中温类型特征。但上述区域大都不同程度地存在有闪锌矿、黄铁矿、黄铜矿等中高温热液矿物 ,说明研究区除马里亚纳海槽明显有中低温热液活动类型外 ,其它区域皆具备中高温热液活动特征 相似文献
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The Sindong Group was deposited in the north–south trending half‐graben Nakdong Trough, southern Korean peninsula. The occurrence of detrital chromian spinels from the Jinju Formation of the Sindong Group in the Gyeongsang Basin means that the mafic to ultramafic rocks were exposed in its provenance. The chromian spinels from the Jinju Formation are characterized by extremely low TiO2 and Fe3+. Moreover, their range of Cr# is from 0.45 to 0.80 and makes a single trend with Mg#. The chemistry of chromian spinels implies that the source rocks for chromian spinels were peridotites or serpentinites, which originated in the mantle wedge. To more narrowly constrain their source rocks, the Ulsan and Andong serpentinites exposed in the Gyeongsang Basin were examined petrographically. Chromian spinels in the Andong serpentinite differ from those of the Jinju Formation and those in the Ulsan serpentinite partly resemble them. Furthermore, the Jinju chromian spinel suite is similar to the detrital chromian spinels from the Mesozoic sediments in the Circum‐Hida Tectonic zone, which includes the Nagato Tectonic zone in Southwest Japan and the Joetsu Belt in Northeast Japan. This suggests that the basement rocks, which were located along the main fault bounding the eastern edge of the Nakdong Trough, had exposures of peridotite or serpentinite. It is possible that the Nakdong Trough was directly adjacent to the Circum‐Hida Tectonic zone before the opening of the Sea of Japan (East Sea). 相似文献
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中国东部中亚构造带及向环太平洋构造带的转化 总被引:4,自引:0,他引:4
王东方 《华北地质矿产杂志》1995,10(2):135-142
中亚古亚洲洋的消失可由该地区大量晚元古后期-泥盆纪残余洋壳和高压变质带的存在来说明,其中大量800~550Ma蛇绿岩和高压变质带说明兴凯运动是主要造山期。加里东和华力西造山运动是其后续运动,早石炭世是一个转折期,早石炭世地层基本缺失,洋壳残片不再出现,变质作用突然减弱,表明中亚地区构造机制已逐渐转入大陆内部。石炭二叠纪地壳开始拉伸,形成了晚古生代裂谷并产生强烈岩浆作用。二叠纪末。早中生代全区隆起,残余海盆地消失,西伯利亚地台以其盾形前缘向南推移,形成推土机机制改变了加里东-华力西期的东西向构造格局,形成折接的类弧形构造,其东部为北东向构造,前缘为东西向,西部为北西向,总体形成宏伟的推覆断层及走滑断层系,早中生代中国东部环太平洋构造带以南北向为特征,由东而西的侧压力转换成剪切分量,加强了北东向的走滑和拖曳。在这一过程中,环太平洋构造以最接近的应力场和最低的地动能消耗、制动,继承和改造了晚末期中亚构造系,达到两个大地构造区系的交替和过渡。 相似文献
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福建紫金山铜金矿床类型与环太平洋浅成低温矿床的比较 总被引:8,自引:0,他引:8
福建省上杭紫金山铜金矿床是我国大陆发现的首例高硫型浅成低温热液矿床,在矿床深 继发现了斑岩型铜矿、中低温热液型铜矿和低硫浅成热液型银(金、铜)矿。可与环太平洋带上一系列特大型斑岩铜金和低温热液型金(铜)矿对比,它们有若干共同特征,但紫金山矿床与它们的一些不同之处,启示我们开拓找矿的新的时空领域。 相似文献
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