Preliminary study of microscale zircon oxygen isotopes for Dabie-Sulu metamorphic rocks: Ion probe i

来源 :科学通报 | 被引量 : 0次 | 上传用户:weiguoliaaaa
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
151 in situ analyses of oxygen isotopes were carried out by ion micro-probe for zircons from 8 localities of HP-UHP metamorphic rocks including eclogites in the Dabie-Sulu terrane. The results show significant heterogeneity inδ18O values, with variation in different rocks from -8.5‰ to +9.7‰ and within one sample from 2‰ to 12‰. No measurable difference inδ18O was observed between protolith magmatic (detrital) zircons and metamorphic recrystallized zircons within analytical uncertainties from the ion micro-probe measurements. This indicates that the metamorphic zircons have inherited the oxygen isotopic compositions of protolith zircons despite the HP to UHP metamorphism. According to their protolith ages from zircon U-Pb in situ dating by the same ion micro-probe, two groups of oxygen isotope composition are recognized, with one having δ18O values of 6‰-7‰ for old protolith of 1.9-2.5 Ga ages and the other 0‰-2‰ for young protolith of 0.7-0.8 Ga ages. The latter anomalously lowδ18O values of zircons indicate that the magma has had the obvious involvement of meteoric water when forming the young protolith of high-grade metamorphic rocks. This may be correlated with the snowball Earth event occurring in South China and the world elsewhere during the Neoproterozoic.
其他文献
房地产初始登记属于房地产所有权的范畴,是对房地产权利,领取房地产权利的证书的土地及建筑物、附有物的所有权进行的登记.基于这一定义,农村房地产初始登记,所指向的即是对
李庄案发生后,辩护制度成为全国媒体关注的热点,辩护律师在庭审中的价值受到了质疑。他们揭露了案件的真相、保障了被告的权益,是法律权威的捍卫者;同时,受主观认知、客观社
应用现有的中子与原子核Sn及其同位素反应的总截面 ,去弹性散射截面 ,弹性散射截面和弹性散射角分布的实验数据 ,获得一组普适的中子与Sn及其同位素反应的光学模型势参数 .利
"唱读讲传"实现了群众主体化和主体群众化的统一,抓住了社会主义核心价值体系大众化的根本;实现了思想政治引导与精神文化服务的统一,找到了社会主义核心价值体系大众化的现
Si3N4/BN nanocomposite powders with the microstructure of the micro-sized α-Si3N4 particles coated with nano-sized BN particles were synthesized via the chemic
The problems of robust l2-l∞ and H∞ filtering for discrete-time systems with parameter uncer- tainty residing in a polytope are investigated in this paper. Th
In this paper we consider the estimating problem of a semiparametric regression modelling whenthe data are longitudinal. An iterative weighted partial spline le
In this paper we study the Cauchy problem for a class of semi-linear parabolic type equations withweak data in the homogeneous spaces. We give a method which ca
A 1-(m in diameter polystyrene bead coated with lectin is trapped by optical tweezers which is formed by a focused laser beam (740 nm). A leucocyte adhered to t
SiC with fiber-reinforced composites, which are presently considered as the primarystructural materials in some fusion reactor conceptual designs, are more attr