{"title":"外喀尔巴阡山脉西部(捷克摩拉维亚东南部)中新世次火山岩的岩石成因","authors":"D. Buriánek, Kamil Kropáč","doi":"10.3190/jgeosci.286","DOIUrl":null,"url":null,"abstract":"Neogene subvolcanic rocks in southeastern Moravia form numerous dykes and laccoliths, ranging from clinopyroxene–amphibole and amphibole trachybasalt, through trachyandesite, to biotite–amphibole trachydacite. Leucocratic and melanocratic cumulate gabbro and basalt enclaves up to 70 cm in diameter are rarely present, respectively, within the trachydacite and trachyandesite. The parental magmas rose along tensional fissures spatially related to the Nezdenice Fault but probably never reached the surface. The range of major (e.g., SiO2 44–62 wt. %, mg# 20–65) and trace-element compositions can be explained through magma mixing and mingling and subsequent fractional crystallization. Mineral chemistry shows limited compositional variation of mafic minerals. Diopside phenocrysts indicate narrow ranges of XMg (0.65–0.84) and usually display normal zoning with small Mg-rich cores and Fe-rich rims. Phlogopites from the trachydacite and gabbro enclaves show a mutually similar composition (XFe 0.36–0.43 and IVAl 2.44–2.59). Amphiboles from individual samples of basalt, trachybasalt and trachyandesite are likewise chemically relatively homogeneous (XMg 0.51–0.86, Si 5.78–6.55). Chemical compositions of amphibole phenocrysts from the trachybasalts and trachyandesites indicate multi-stage crystallization at depth of 32 to 21 km for this magmatic system. Systematic changes in Si, Ti, VIAl, XMg contents in amphiboles from trachydacites and gabbro enclaves can be explained by fractional crystallization in a shallower magma reservoir (~20–10 km).","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.1000,"publicationDate":"2019-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":"{\"title\":\"Petrogenesis of Miocene subvolcanic rocks in the Western Outer Carpathians (southeastern Moravia, Czech Republic)\",\"authors\":\"D. Buriánek, Kamil Kropáč\",\"doi\":\"10.3190/jgeosci.286\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Neogene subvolcanic rocks in southeastern Moravia form numerous dykes and laccoliths, ranging from clinopyroxene–amphibole and amphibole trachybasalt, through trachyandesite, to biotite–amphibole trachydacite. Leucocratic and melanocratic cumulate gabbro and basalt enclaves up to 70 cm in diameter are rarely present, respectively, within the trachydacite and trachyandesite. The parental magmas rose along tensional fissures spatially related to the Nezdenice Fault but probably never reached the surface. The range of major (e.g., SiO2 44–62 wt. %, mg# 20–65) and trace-element compositions can be explained through magma mixing and mingling and subsequent fractional crystallization. Mineral chemistry shows limited compositional variation of mafic minerals. Diopside phenocrysts indicate narrow ranges of XMg (0.65–0.84) and usually display normal zoning with small Mg-rich cores and Fe-rich rims. Phlogopites from the trachydacite and gabbro enclaves show a mutually similar composition (XFe 0.36–0.43 and IVAl 2.44–2.59). Amphiboles from individual samples of basalt, trachybasalt and trachyandesite are likewise chemically relatively homogeneous (XMg 0.51–0.86, Si 5.78–6.55). Chemical compositions of amphibole phenocrysts from the trachybasalts and trachyandesites indicate multi-stage crystallization at depth of 32 to 21 km for this magmatic system. Systematic changes in Si, Ti, VIAl, XMg contents in amphiboles from trachydacites and gabbro enclaves can be explained by fractional crystallization in a shallower magma reservoir (~20–10 km).\",\"PeriodicalId\":15957,\"journal\":{\"name\":\"Journal of Geosciences\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.1000,\"publicationDate\":\"2019-01-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"3\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Geosciences\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.3190/jgeosci.286\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geosciences","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.3190/jgeosci.286","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Petrogenesis of Miocene subvolcanic rocks in the Western Outer Carpathians (southeastern Moravia, Czech Republic)
Neogene subvolcanic rocks in southeastern Moravia form numerous dykes and laccoliths, ranging from clinopyroxene–amphibole and amphibole trachybasalt, through trachyandesite, to biotite–amphibole trachydacite. Leucocratic and melanocratic cumulate gabbro and basalt enclaves up to 70 cm in diameter are rarely present, respectively, within the trachydacite and trachyandesite. The parental magmas rose along tensional fissures spatially related to the Nezdenice Fault but probably never reached the surface. The range of major (e.g., SiO2 44–62 wt. %, mg# 20–65) and trace-element compositions can be explained through magma mixing and mingling and subsequent fractional crystallization. Mineral chemistry shows limited compositional variation of mafic minerals. Diopside phenocrysts indicate narrow ranges of XMg (0.65–0.84) and usually display normal zoning with small Mg-rich cores and Fe-rich rims. Phlogopites from the trachydacite and gabbro enclaves show a mutually similar composition (XFe 0.36–0.43 and IVAl 2.44–2.59). Amphiboles from individual samples of basalt, trachybasalt and trachyandesite are likewise chemically relatively homogeneous (XMg 0.51–0.86, Si 5.78–6.55). Chemical compositions of amphibole phenocrysts from the trachybasalts and trachyandesites indicate multi-stage crystallization at depth of 32 to 21 km for this magmatic system. Systematic changes in Si, Ti, VIAl, XMg contents in amphiboles from trachydacites and gabbro enclaves can be explained by fractional crystallization in a shallower magma reservoir (~20–10 km).
期刊介绍:
The Journal of Geosciences is an international peer-reviewed journal published by the Czech Geological Society with support from the Czech Geological Survey. It accepts high-quality original research or review papers dealing with all aspects of the nature and origin of igneous and metamorphic rocks. The Journal focuses, mainly but not exclusively, on:
-Process-oriented regional studies of igneous and metamorphic complexes-
Research in structural geology and tectonics-
Igneous and metamorphic petrology-
Mineral chemistry and mineralogy-
Major- and trace-element geochemistry, isotope geochemistry-
Dating igneous activity and metamorphic events-
Experimental petrology and mineralogy-
Theoretical models of igneous and metamorphic processes-
Mineralizing processes and mineral deposits.
All the papers are written in English, even though they may be accompanied by an additional Czech abstract. Each contribution is a subject to peer review by at least two independent reviewers, typically at least one from abroad. The Journal appears 2 to 4 times a year. Formally it is divided in annual volumes, each of them including 4 issues.