ISSN:
0016-7835
Keywords:
Key words Eclogites
;
Granulites
;
Garnet zoning
;
Diffusion modelling
;
Bohemian Massif
;
Moldanubian Zone
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract The petrology and geochemistry of a newly discovered suite of high-pressure garnet+clinopyroxene-bearing rocks from the Monotonous Series of the Moldanubian Zone of the Bohemian Massif, south-west Czech Republic have been investigated. Three types [common eclogites, quartz±kyanite±(clino)zoisite eclogites and garnet–hornblende–clinopyroxenites] are distinguished by petrography and geochemistry. All underwent a significant degree of partial breakdown under granulite and amphibolite facies conditions during exhumation. Important features include the growth of orthopyroxene in breakdown domains after garnet and omphacite and anorthite+spinel±corundum±exceedingly peraluminous sapphirine replacing kyanite. Garnet zoning and inclusion patterns support a prograde evolution from low pressures for at least some of the samples. The post-eclogite stage granulite facies overprint indicates that high temperatures prevailed during exhumation, but preservation of zoning in some garnets and the results of diffusion modelling suggest that this overprint took place over a very short time-scale. The geochemical and petrological results allow characteristic differences to be recognized between these eclogites and metabasites found in other tectonic units of South Bohemia and consequently the assigning of all high-pressure rocks to a single, now disrupted, tectonic unit is a gross simplification that seriously misrepresents the tectono-metamorphic history of the region.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00284515
Permalink
