L. Medaris, M. Svojtka, L. Ackerman, Spencer J. Cotkin
{"title":"美国克拉马斯山脉晚侏罗纪钙碱性深成岩体杂岩的岩石成因演化:通过主元素和微量元素模型进行量化","authors":"L. Medaris, M. Svojtka, L. Ackerman, Spencer J. Cotkin","doi":"10.3190/jgeosci.285","DOIUrl":null,"url":null,"abstract":"This investigation illustrates the use of major and trace elements to evaluate the petrogenetic evolution of the Late Jurassic Russian Peak Plutonic Complex in the Klamath Mountains Province, northern California, U.S.A. The two principal plutons in the complex consist of quartz diorite and granodiorite, both of which were most likely derived by partial melting of amphibolitic oceanic crustal sources and ultimately emplaced at a shallow level of ~10 km (Ptotal ~ 3 kbar). The major-element compositional variations in quartz diorite are consistent with crystallization of plagioclase (45 %) and amphibole (69 %) and resorption of clinopyroxene (–14 %). Major-element variations in granodiorite could have resulted from crystallization of plagioclase (60 %), amphibole (26 %), and biotite (14 %). Trace elements in whole-rocks and amphibole record different degrees of fractional crystallization, whole-rocks reflecting differentiation on a plutonic scale, and amphibole crystals reflecting differentiation on the scale of an individual sample. Quartz diorite experienced 10% fractional crystallization for the suite as a whole and 45% for individual samples; in contrast, granodiorite experienced 40% crystallization for the suite and 80% for individual samples. For both quartz diorite and granodiorite, comparisons of whole-rock REE patterns with those for melts calculated to be in equilibrium with amphibole demonstrate that the whole-rock REE compositions represent a combination of crystals and melts from evolving magmas, rather than melts alone.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.1000,"publicationDate":"2019-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Petrogenetic evolution of a Late Jurassic calc-alkaline plutonic complex, Klamath Mountains Province, U.S.A.: quantification by major- and trace-element modelling\",\"authors\":\"L. Medaris, M. Svojtka, L. Ackerman, Spencer J. Cotkin\",\"doi\":\"10.3190/jgeosci.285\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"This investigation illustrates the use of major and trace elements to evaluate the petrogenetic evolution of the Late Jurassic Russian Peak Plutonic Complex in the Klamath Mountains Province, northern California, U.S.A. The two principal plutons in the complex consist of quartz diorite and granodiorite, both of which were most likely derived by partial melting of amphibolitic oceanic crustal sources and ultimately emplaced at a shallow level of ~10 km (Ptotal ~ 3 kbar). The major-element compositional variations in quartz diorite are consistent with crystallization of plagioclase (45 %) and amphibole (69 %) and resorption of clinopyroxene (–14 %). Major-element variations in granodiorite could have resulted from crystallization of plagioclase (60 %), amphibole (26 %), and biotite (14 %). Trace elements in whole-rocks and amphibole record different degrees of fractional crystallization, whole-rocks reflecting differentiation on a plutonic scale, and amphibole crystals reflecting differentiation on the scale of an individual sample. Quartz diorite experienced 10% fractional crystallization for the suite as a whole and 45% for individual samples; in contrast, granodiorite experienced 40% crystallization for the suite and 80% for individual samples. For both quartz diorite and granodiorite, comparisons of whole-rock REE patterns with those for melts calculated to be in equilibrium with amphibole demonstrate that the whole-rock REE compositions represent a combination of crystals and melts from evolving magmas, rather than melts alone.\",\"PeriodicalId\":15957,\"journal\":{\"name\":\"Journal of Geosciences\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":1.1000,\"publicationDate\":\"2019-01-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Geosciences\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.3190/jgeosci.285\",\"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.285","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}
Petrogenetic evolution of a Late Jurassic calc-alkaline plutonic complex, Klamath Mountains Province, U.S.A.: quantification by major- and trace-element modelling
This investigation illustrates the use of major and trace elements to evaluate the petrogenetic evolution of the Late Jurassic Russian Peak Plutonic Complex in the Klamath Mountains Province, northern California, U.S.A. The two principal plutons in the complex consist of quartz diorite and granodiorite, both of which were most likely derived by partial melting of amphibolitic oceanic crustal sources and ultimately emplaced at a shallow level of ~10 km (Ptotal ~ 3 kbar). The major-element compositional variations in quartz diorite are consistent with crystallization of plagioclase (45 %) and amphibole (69 %) and resorption of clinopyroxene (–14 %). Major-element variations in granodiorite could have resulted from crystallization of plagioclase (60 %), amphibole (26 %), and biotite (14 %). Trace elements in whole-rocks and amphibole record different degrees of fractional crystallization, whole-rocks reflecting differentiation on a plutonic scale, and amphibole crystals reflecting differentiation on the scale of an individual sample. Quartz diorite experienced 10% fractional crystallization for the suite as a whole and 45% for individual samples; in contrast, granodiorite experienced 40% crystallization for the suite and 80% for individual samples. For both quartz diorite and granodiorite, comparisons of whole-rock REE patterns with those for melts calculated to be in equilibrium with amphibole demonstrate that the whole-rock REE compositions represent a combination of crystals and melts from evolving magmas, rather than melts alone.
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.