The late Palaeoproterozoic Eskolabreen granitoids of southern Ny Friesland, Svalbard Caledonides - geochemistry, age, and origin
The late Palaeoproterozoic Eskolabreen granitoids of southern Ny Friesland, Svalbard Caledonides - geochemistry, age, and origin
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斯瓦尔巴喀里多尼群岛纽约弗里斯兰南部古元古代晚期的 Eskolabreen 花岗岩 - 地球化学、年龄和起源
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
D. Gee
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文献类型：
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作者：
Å. Johansson;D. Gee
芬兰维根推覆体的Eskolabreen杂岩是新弗里斯兰-加里东尼构造带南部最下部暴露的构造地层单元，出露于Atomfjella Antiform的核心。主要由层间花岗质片麻岩和和合角闪岩组成的条带状层序。较早的一段花岗质片麻岩U-Pb锆石测年结果为1766±10 Ma，下部截距为404±8 Ma，反映了加里东期的叠印。本文报道了Eskolabreen杂岩中3个花岗质片麻岩样品的U-Pb锆石数据，其上截距年龄分别为1749±18、1748±21和约1770 Ma，这被解释为其原岩的火成岩结晶年龄，其中1个混染岩新生体样品的上截距年龄为1734±5 Ma。这些样品的下部截距范围在350 ~ 400 Ma之间，可能反映了角闪岩级加里东变质作用期间U-Pb系统的部分重置。一种红色正长岩，出现在一个小晶状体中，可能在…
Abstract The Eskolabreen Complex of the Finlandveggen Nappe, outcropping in the core of the Atomfjella Antiform, is the lowermost exposed tectonostratigraphic unit in the southern Ny Friesland Caledonides. It is a banded sequence composed mostly of interlayered granitic gneisses and concordant amphibolites. Earlier U-Pb zircon dating of a band of granitic gneiss yielded an age of 1766±10 Ma, with Caledonian overprinting reflected in a lower intercept of 404±8 Ma. Here, we report additional U-Pb zircon data from three samples of granitic gneiss within the Eskolabreen Complex, yielding upper intercept ages of 1749±18, 1748±21, and c. 1770 Ma, interpreted as the age of igneous crystallization of their protoliths, and one sample of migmatitic neosome yielding 1734±5 Ma. The lower intercepts for these samples range between 350 and 400 Ma, probably reflecting partial resetting of the U-Pb system during amphibolite-grade Caledonian metamorphism. A red syenite, occurring in a small lens, probably at the base of t...