ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA
Aluminian subsilicic orthopyroxene (Al2O3 = 16.8 wt% maximum) was found in pseudomorphs after garnet megacrysts in alkali basaltic rocks occurring at the Mt. Huangyishan, Liaoning province and at Mt. Chishan, Shandong province of northeast China. The orthopyroxene-bearing pseudomorphs are mainly com...
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european journal of mineralogy
1993
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ftpekinguniv:oai:localhost:20.500.11897/311533 2023-05-15T14:02:47+02:00 ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA ZANG, QJ ENAMI, M SUWA, K ZANG, QJ (reprint author), BEIJING UNIV,DEPT GEOL,BEIJING 100871,PEOPLES R CHINA. NAGOYA UNIV,SCH SCI,DEPT EARTH & PLANETARY SCI,NAGOYA 46401,JAPAN. BEIJING UNIV,DEPT GEOL,BEIJING 100871,PEOPLES R CHINA. 1993 https://hdl.handle.net/20.500.11897/311533 en eng european journal of mineralogy EUROPEAN JOURNAL OF MINERALOGY.1993,5,(1),153-164. 1027538 0935-1221 http://hdl.handle.net/20.500.11897/311533 WOS:A1993KQ40200015 SCI ALUMINUM ORTHO-PYROXENE GARNET MEGACRYST PYROMETAMORPHISM ALKALI BASALT NORTHEAST CHINA ENDERBY LAND ORTHO-PYROXENE METAMORPHIC EVOLUTION BEARING GRANULITES COMPLEX SYSTEMS ANTARCTICA GEOTHERMOBAROMETRY ASSEMBLAGES OSUMILITE PRESSURES Journal 1993 ftpekinguniv https://doi.org/20.500.11897/311533 2021-08-01T09:31:47Z Aluminian subsilicic orthopyroxene (Al2O3 = 16.8 wt% maximum) was found in pseudomorphs after garnet megacrysts in alkali basaltic rocks occurring at the Mt. Huangyishan, Liaoning province and at Mt. Chishan, Shandong province of northeast China. The orthopyroxene-bearing pseudomorphs are mainly composed of fine-grained (usually less than 2-3 mum in size) orthopyroxene, spinel and anorthite crystals. The pseudomorphs have many internal cracks, and aggregates of coarser-grained (20-300 mum in size) orthopyroxene, spinel and anorthite occur sporadically along the cracks. Olivine or clinopyroxene occurs rarely in the coarser-grained aggregates of a Huangyishan megacryst. In this sample, orthopyroxenes in the olivine- or clinopyroxene-bearing coarser-grained aggregates have fairly restricted Al2O3 contents of 10.5 +/- 1.2 and 10.7 +/- 1.2 wt%, respectively, and that in the olivine- and clinopyroxene-free aggregates is richer in Al2O3 (12.3 +/- 1.2 wt%). The Al enrichment of orthopyroxene is strongly controlled by the Tschermaks substitution [4]Al[6]Al(Mg, Fe)-1Si-1. The equilibrium conditions of the orthopyroxene-bearing assemblages are estimated at T = 1180-1270-degrees-C and P = 9-15 kbar. The orthopyroxene-bearing pseudomorphs have been formed by solid-state and isochemical breakdown of original garnet megacrysts during the transportation by the alkali basaltic magma. The transportation speed was high and is estimated at 3.5-7.0 km/h from a calculation of the velocities of the host magma ascent and gravitational sedimentation of the garnet megacryst. This suggests that the transportation time of the garnet megacryst from the garnet-stable depth to the surface was about 6-14 hours, which is probably sufficient for its partial decomposition. Mineralogy SCI(E) 0 ARTICLE 1 153-164 5 Journal/Newspaper Antarc* Antarctica Enderby Land Peking University Institutional Repository (PKU IR) |
institution |
Open Polar |
collection |
Peking University Institutional Repository (PKU IR) |
op_collection_id |
ftpekinguniv |
language |
English |
topic |
ALUMINUM ORTHO-PYROXENE GARNET MEGACRYST PYROMETAMORPHISM ALKALI BASALT NORTHEAST CHINA ENDERBY LAND ORTHO-PYROXENE METAMORPHIC EVOLUTION BEARING GRANULITES COMPLEX SYSTEMS ANTARCTICA GEOTHERMOBAROMETRY ASSEMBLAGES OSUMILITE PRESSURES |
spellingShingle |
ALUMINUM ORTHO-PYROXENE GARNET MEGACRYST PYROMETAMORPHISM ALKALI BASALT NORTHEAST CHINA ENDERBY LAND ORTHO-PYROXENE METAMORPHIC EVOLUTION BEARING GRANULITES COMPLEX SYSTEMS ANTARCTICA GEOTHERMOBAROMETRY ASSEMBLAGES OSUMILITE PRESSURES ZANG, QJ ENAMI, M SUWA, K ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA |
topic_facet |
ALUMINUM ORTHO-PYROXENE GARNET MEGACRYST PYROMETAMORPHISM ALKALI BASALT NORTHEAST CHINA ENDERBY LAND ORTHO-PYROXENE METAMORPHIC EVOLUTION BEARING GRANULITES COMPLEX SYSTEMS ANTARCTICA GEOTHERMOBAROMETRY ASSEMBLAGES OSUMILITE PRESSURES |
description |
Aluminian subsilicic orthopyroxene (Al2O3 = 16.8 wt% maximum) was found in pseudomorphs after garnet megacrysts in alkali basaltic rocks occurring at the Mt. Huangyishan, Liaoning province and at Mt. Chishan, Shandong province of northeast China. The orthopyroxene-bearing pseudomorphs are mainly composed of fine-grained (usually less than 2-3 mum in size) orthopyroxene, spinel and anorthite crystals. The pseudomorphs have many internal cracks, and aggregates of coarser-grained (20-300 mum in size) orthopyroxene, spinel and anorthite occur sporadically along the cracks. Olivine or clinopyroxene occurs rarely in the coarser-grained aggregates of a Huangyishan megacryst. In this sample, orthopyroxenes in the olivine- or clinopyroxene-bearing coarser-grained aggregates have fairly restricted Al2O3 contents of 10.5 +/- 1.2 and 10.7 +/- 1.2 wt%, respectively, and that in the olivine- and clinopyroxene-free aggregates is richer in Al2O3 (12.3 +/- 1.2 wt%). The Al enrichment of orthopyroxene is strongly controlled by the Tschermaks substitution [4]Al[6]Al(Mg, Fe)-1Si-1. The equilibrium conditions of the orthopyroxene-bearing assemblages are estimated at T = 1180-1270-degrees-C and P = 9-15 kbar. The orthopyroxene-bearing pseudomorphs have been formed by solid-state and isochemical breakdown of original garnet megacrysts during the transportation by the alkali basaltic magma. The transportation speed was high and is estimated at 3.5-7.0 km/h from a calculation of the velocities of the host magma ascent and gravitational sedimentation of the garnet megacryst. This suggests that the transportation time of the garnet megacryst from the garnet-stable depth to the surface was about 6-14 hours, which is probably sufficient for its partial decomposition. Mineralogy SCI(E) 0 ARTICLE 1 153-164 5 |
author2 |
ZANG, QJ (reprint author), BEIJING UNIV,DEPT GEOL,BEIJING 100871,PEOPLES R CHINA. NAGOYA UNIV,SCH SCI,DEPT EARTH & PLANETARY SCI,NAGOYA 46401,JAPAN. BEIJING UNIV,DEPT GEOL,BEIJING 100871,PEOPLES R CHINA. |
format |
Journal/Newspaper |
author |
ZANG, QJ ENAMI, M SUWA, K |
author_facet |
ZANG, QJ ENAMI, M SUWA, K |
author_sort |
ZANG, QJ |
title |
ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA |
title_short |
ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA |
title_full |
ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA |
title_fullStr |
ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA |
title_full_unstemmed |
ALUMINUM ORTHO-PYROXENE IN PYROMETAMORPHOSED GARNET MEGACRYSTS FROM LIAONING AND SHANDONG PROVINCES, NORTHEAST CHINA |
title_sort |
aluminum ortho-pyroxene in pyrometamorphosed garnet megacrysts from liaoning and shandong provinces, northeast china |
publisher |
european journal of mineralogy |
publishDate |
1993 |
url |
https://hdl.handle.net/20.500.11897/311533 |
genre |
Antarc* Antarctica Enderby Land |
genre_facet |
Antarc* Antarctica Enderby Land |
op_source |
SCI |
op_relation |
EUROPEAN JOURNAL OF MINERALOGY.1993,5,(1),153-164. 1027538 0935-1221 http://hdl.handle.net/20.500.11897/311533 WOS:A1993KQ40200015 |
op_doi |
https://doi.org/20.500.11897/311533 |
_version_ |
1766273200634724352 |