Crystallization Conditions and Petrogenesis of the Paleoproterozoic Basement Rocks in Bangladesh:An

来源 :Journal of Earth Science | 被引量 : 0次 | 上传用户:dancingkingb
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The Paleoproterozoic(~1.73 Ga)basement rocks from Maddhapara,Bangladesh show a large range of chemical variations including diorite,quartz diorite,monzodiorite,quartz monzonite and granite.These are composed of varying proportions of quartz+plagioclase+K-feldspar+biotite+hornblende±epidote+titanite+magnetite+apatite and zircon.Amphibole and biotite,dominant ferromagnesian minerals,have been analyzed with an electron microprobe.The biotite,Mg-dominant trioctahedral micas,is classified as phlogopitic nature.Relatively high Mg(1.33–1.53 pfu),Mg#(0.52–0.59)and low AlVI(0.13–0.25 pfu)contents in the biotite reflect slightly fractionated magma,which might be a relative indicator for the origin of the parental magma.Biotite is also a very good sensor of oxidation state of the parental magma.Oxygen fugacity of the studied biotites estimate within the QFM and HM buffers and equilibrate at about-12.35 and-12.46,which exhibit the source materials were relatively higher oxidation state during crystallization and related to arc magmatism.Whereas,calcic amphiboles,a parental member of arc-related igneous suite,display consistent oxygen fugacity values(-11.7to-12.3),low Al#(0.16–0.21)with H2Omelt(5.6 wt.%–9.5 wt.%)suggest their reliability with the typical values of calc-alkaline magma crystallization.The oxygen fugacity of magma is related to its source material,which in turn depends on tectonic setting.Discrimination diagrams and chemical indices of both biotite and amphibole of dioritic rocks reveal calc-alkaline orogenic complexes;mostly I-type suite formed within subduction-related environments.Moreover,igneous micas are used as metallogenic indicator.The biotites with coexisting amphibole compositions show an apparent calc-alkaline trend of differentiation.The study suggests that the trend of oxidized magmas is commonly associated with compressive tectonic and convergent plate boundaries. The Paleoproterozoic (~ 1.73 Ga) basement rocks from Maddhapara, Bangladesh show a large range of chemical variations including diorite, quartz diorite, monzodiorite, quartz monzonite and granite.These are composed of increasing proportions of quartz + plagioclase + K-feldspar + biotite + hornblende ± epidote + titanite + magnetite + apatite and zircon. Amphibole and biotite, dominant ferromagnesian minerals, have been analyzed with an electron microprobe.The biotite, Mg-dominant trioctahedral micas, is classified as phlogopitic nature. Relatively high Mg (1.33-1.53 pfu), Mg # (0.52-0.59) and low AlVI (0.13-0.25 pfu) contents in the biotite reflect slightly fractionated magma, which might be a relative indicator for the origin of the parental magma.Biotite is also a very good sensor of oxidation state of the parental magma. Oxygen fugacity of the studied biotites estimate within the QFM and HM buffers and equilibrate at about-12.35 and-12.46, which exhibit the source materials were relatively higher oxidation state duri ng crystallization and related to arc magmatism. Hereas, calcic amphiboles, a parental member of arc-related igneous suite, display consistent oxygen fugacity values ​​(-11.7to-12.3), lowAl # (0.16-0.21) with H2Omelt % -9.5 wt.%) Suggest their reliability with the typical values ​​of calc-alkaline magma crystallization. The oxygen fugacity of magma is related to its source material, which in turn depends on tectonic setting. Discrimination diagrams and chemical indices of both biotite and amphibole of dioritic rocks reveal calc-alkaline orogenic complexes; mostly I-type suite formed within subduction-related environments. Moreover, igneous micas are used as metallogenic indicator. biotites with coexisting amphibole compositions show an apparent calc-alkaline trend of differentiation. study suggests that the trend of oxidized magmas is commonly associated with compressive tectonic and convergent plate boundaries.
其他文献
“沟通”在我的眼中是一个美妙的词,充满了魅力!最早,“沟通”是指将两条河流的水连合起来,后来泛指使两方能通连.河流因有河道得以沟通,中西方的文化因人们的交流而得到沟通
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
期刊
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
期刊
查字典,关于“路”的解释,词义倒是简单明了,然而,真正弄懂路的含义,却是在走过四季,走过风雨之后.rn我已走过人生大半.但经历其实简单,不过是读书、教书.读书的过程是一段段
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
期刊
The Earliest Triassic Yinkeng Formation is exposed at the well-known Meishan Section,South China,which contains the Global Stratotype of Section and Point(GSSP)
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
期刊