Preservation and retrogression of ultra high pressure (UHP) rocks: case studies of UHP metagranitoids in Western Alps and Su-Lu region

The in situ association of ultra high pressure (UHP) rocks and country gneiss, and possible mechanisms to obliterate the UHP metamorphic minerals during exhumation will be discussed for giving a new insight to a debate between in situ vs. external origin of UHP rocks. The UHP rocks associated with U...

Full description

Bibliographic Details
Main Author: Takao Hirajima
Format: Report
Language:English
Published: Department of Geology and Mineralogy, Graduate School of Earth Science, Kyoto University 1998
Subjects:
ultra high pressure rock
retrogression of metagranitoid
granulite facies over printing
Memoirs of National Institute of Polar Research
Polar Research
Online Access:https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2337
http://id.nii.ac.jp/1291/00002337/
https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2337&item_no=1&attribute_id=18&file_no=1
Description
Summary:The in situ association of ultra high pressure (UHP) rocks and country gneiss, and possible mechanisms to obliterate the UHP metamorphic minerals during exhumation will be discussed for giving a new insight to a debate between in situ vs. external origin of UHP rocks. The UHP rocks associated with UHP metagranitoids found in southern Dora Maira massif, western Alps and the Yangkou unit in the Su-Lu region, eastern China are distinct examples of the in situ origin. The deformation and accompanied fluid infiltration at lowpressure conditions pervasively erased the precursor UHP evidence without a significant heating in these areas. Granulite facies overprinting on UHP/HP metamorphic rocks is reported in some UHP terranes. Annealing at medium temperature and low-pressure conditions could be another candidate for obliterating the UHP metamorphic minerals pervasively.

Similar Items