期刊
JOURNAL OF PETROLOGY
卷 56, 期 10, 页码 2069-2087出版社
OXFORD UNIV PRESS
DOI: 10.1093/petrology/egv066
关键词
granulites; prograde zoning; trace element distribution; UHP; Y plus REE
资金
- Czech Science Foundation [13-06958S]
Major and trace element distribution in garnet crystals from felsic granulites of the Kutna Hora Complex provides evidence of two metamorphic events, the first related to continental subduction at ultrahigh-pressure (UHP) conditions and the second to a granulite-facies overprint that occurred at mid- to lower crustal levels. To reconstruct P-T paths of both metamorphic events, pseudosection modeling was combined with major and trace element zoning in garnet. The granulites contain lenses and boudins of mantle-derived garnet peridotite and eclogite. UHP conditions are confirmed by the presence of inclusions of micro-diamond and coesite in garnet and zircon in the granulites. Compositional zoning in garnet provides evidence for a pre-granulite-facies high-pressure (HP)-UHP metamorphic history of the rocks. The two distinct metamorphic events are documented by high Y + HREE concentrations in the garnet cores and annuli in the mantle part of the garnet grains. The cores of large garnets with relatively high Ca contents and bell-shaped Mn profiles suggest formation during a prograde low- to medium-temperature metamorphic event that was coeval with HP-UHP metamorphism. Decompression and cooling during exhumation of the rocks led to partial resorption of garnet and release of trace elements into the matrix. The new garnet with high Y + HREE in the annuli was formed during the granulite-facies event at crustal levels.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据