排序方式: 共有2条查询结果,搜索用时 0 毫秒
1
1.
Modelling Diverse Processes in the Petrogenesis of a Composite Batholith: the Central Bohemian Pluton, Central European Hercynides 总被引:5,自引:1,他引:5
JANOUSEK VOJTECH; BOWES D. R.; ROGERS GRAEME; FARROW COLIN M.; JELINEK EMIL 《Journal of Petrology》2000,41(4):511-543
The multiple intrusions making up the Central Bohemian Plutonin the Central European Hercynides have petrographic and geochemicalfeatures consistent with the presence of four main granitoidsuites. Major-element, trace-element and SrNd isotopiccompositions are used to model their petrogenesis. Partial meltingof metabasic rocks or of a CHUR-like mantle source are interpretedto have produced melts parental to the most primitive calc-alkalineSázava suite. Interaction of basic with more acidic magmasfollowed by extensive amphiboleplagioclase-dominatedfractionation accounts for the production of trondhjemites.Alternatively, the trondhjemites correspond to small-degreemelts of a metabasic source. AFC (assimilationfractionalcrystallization) modelling with a paragneiss as a contaminantand increasing DNd values simulates the characteristics of theBlatná suite. Closed-system fractionation of stronglyenriched mantle-derived magmas or their interaction with leucograniticmelts is deduced for the petrogenesis of the shoshonitic 相似文献
2.
JANOUSEK VOJTECH; GERDES AXEL; VRANA STANISLAV; FINGER FRITZ; ERBAN VOJTECH; FRIEDL GERTRUDE; BRAITHWAITE COLIN J. R. 《Journal of Petrology》2006,47(4):705-744
The Liov Granulite Massif differs from neighbouring granulitebodies in the Moldanubian Zone of southern Bohemia (Czech Republic)in including a higher proportion of intermediatemaficand orthopyroxene-bearing rocks, associated with spinel peridotitesbut lacking eclogites. In addition to dominantly felsic garnetgranulites, other major rock types include quartz dioritic two-pyroxenegranulites, tonalitic granulites and charnockites. Minor bodiesof high-pressure layered gabbroic garnet granulites and spinelperidotites represent tectonically incorporated foreign elements.The protoliths of the maficintermediate granulites (quartz-dioriticand tonalitic) crystallized 360370 Ma ago, as indicatedby laser ablation inductively coupled plasma mass spectrometryUPb ages of abundant zircons with well-preserved magmaticzoning. Strongly metamorphically recrystallized zircons giveages of 330340 Ma, similar to those of other Moldanubiangranulites. For the overwhelming majority of the Liov granulitespeak metamorphic conditions probably did not exceed 800900°Cat 45 kbar; the equilibration temperature of the pyroxenegranulites was 670770°C. This is in sharp contrastto conditions of adjacent contemporaneous Moldanubian granulites,which are characterized by a distinct HPHT signature.The maficintermediate Liov granulites are thought tohave originated during Viséan metamorphic overprintingof metaluminous, medium-K calc-alkaline plutonic rocks thatformed the mid-crustal root of a Late Devonian magmatic arc.The protolith resembled contemporaneous calc-alkaline intrusionsin the European Variscan Belt. KEY WORDS: low-pressure granulites; geothermobarometry; laser-ablation ICP-MS zircon dating; whole-rock geochemistry; SrNd isotopes; Moldanubian Zone 相似文献
1