The hornblendes correspond to edenitic composition, whereas the biotites correspond to annite. The modal composition of these gabbros are given in table 1 and graphically represented on plagioclasepyroxene hornblende diagram streckeisen 1976,10. The wholerock geochemistry of the gabbros indicates the presence of two distinct groups of rocks. Rock units can be outlined by an original aeromagnetic trend that can be seen from the results of the aeromagnetic survey flown from 1959 to 1960. A gabbro with plagioclase and hornblende with pyroxene. These rocks consist mainly of plagioclase and brown hornblende with minor amounts of opaques, biotite, quartz and apatite. Implication for petrogenetic process and tectonic setting. Impact of hornblende crystallization forthe genesis of calcalkalic andesites. Geochemistry of the gabbrodioritetonalite trondhjemite suite of.
Petrography and geochemistry of the love lake leucogabbro. Gabbro is mostly the result of partly melting from mantle rock, and its formation is usually related with extension tectonic, the research work on triassic gabbro from hainan island has important instruction significance to its tectonic background. It is largely composed of magmatic labradorite, clinopyroxene, and orthopyroxene, all of which are rimmed to varying degrees by cummingtonite andor hornblendic amphibole. Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the earths crust and its oceans 1 the realm of geochemistry extends beyond the earth, encompassing the entire solar system, and has made important contributions to the understanding of a number of processes including mantle convection, the formation. Impact of hornblende crystallization forthe genesis of. The awulale mountains, the conjunction point of the tarim plate, junggar plate and yilicentral tianshan block, are the crucial place to decipher the. Geochemistry and mineralisation ofthe southern part ofthe. From the bottom to the top, four zones are distinguished. Ravna3 1geological institute, kola science centre, apatity, russia 2university of massachusetts lowell, usa 3university of tromso, norway.
They are massive and devoid of any trace of igneous layering. Box 435 nelson, new zealand abstract the darran complex in northeast. The name comes from the town gabbro, a village in rosignano. Abstract the kuwei mafic intrusion, consisting of hornblende gabbro, gabbro, gabbro norite, and olivine norite, lies in the southern altai mountains, northern xinjiang.
A marginal zone consists of mainly finegrained hornblende gabbro and olivine gabbro with thickness ranging from 0 to 40m. Petrography and geochemistry of epidote alteration patches. Pdf petrology, geochemistry of hornblende gabbro and. Hornblende occurs as large poikilitic grain and constitutes around 60% of the rock. Present features of the gabbro developed in three stages. Petrology and geochemistry of late carboniferous hornblende gabbro from the awulale mountains, western tianshan nw china. Geochemistry of hornblende gabbros from sonidzuoqi, inner. Pdf hornblende gabbros of wadi az zarib area, central eastern. Partitioning of rareearth, alkali and alkaline earth elements between phenocrysts and. Bold lines are the wadi sections selected for detailed petrological and geochemical work in this study. Soil geochemistry and kimberlite indicator minerals report.
Petrology, geochemistry of hornblende gabbro and associated dolerite dyke of paharpur, puruliya. Thin dikes, typically latestage hornblende gabbro, commonly intrude parallel to layering. Petrogenesis and tectonic setting of carboniferous. Numerous mafic dikes ranging from aphyric to phyric augite, hornblende, andor plagioclase are associated with the pluton. On this diagram figure 2 the studied gabbroic rocks plot within the pyroxene hornblende gabbro norite, hornblende gabbro and anorthosite. Petrology, geochemistry of hornblende gabbro and associated dolerite dyke of paharpur, puruliya, west bengal. Pb zircon dating results for the intrusion, and these yielded an age of. The objectives here will be to gain an understanding of. Geology, geochemistry, and geochronology of gabbro from. Hornblende gabbro and gabbroic pegmatite cut by porphyritic diabase dykes. The wuling hornblende gabbro has a narrow range of low barb 6. Besides, hornblende is found as a common min eral in gabbroic rocks of ophiolite complexes all over the world beard 1986.
Petrology and chemistry of the green acres gabbro complex. The rocks range in composition from gabbro through diorite to quartz diorite. Therefore, the ba, nb and rb distributions observed from the wuling hornblende gabbro reflect geochemical or mineralogical signatures of the mantle source rather than postmagmatic alteration. It seems likely that this is the first discovery of upper mantle peridotite xenoliths in calcalkaline andesite. Petrology and geochemical characteristic of the younger. These rocks are characterized by cumulate textures, high mg contents, low traceelement abundances.
Both gabbro and associated dolerite dykes, show relatively primitive character mg no. The panzhihua gabbro body is apparently a layered intrusion. Three small stocks of gabbro shown as diorite unit td on worl and others, 1991 crop out on ridges. Petrology and geochemistry of calcalkaline andesite of. It is composed of hornblende gabbros and leucohornblende gabbros. It is composed of dunite, hornblende clinopyroxenite, hornblendite and hornblende gabbro. Geochemistry and mineralisation ofthe southern part ofthe darran complex, fiordland, newzealand 491 franco pirajno gold mines of new zealand limited p. Hornblende occupies around 60% of the rock and shows di. These rocks are commonly coarsegrained, hypidiomorphic granular and sometimes exhibit adcumulate texture. A geochemical study of the riddle peaks gabbro, north. The present work is a petrological study of the gabbroic rocks of wadi shianite southeastern desert of egypt.
Martin christ gmbh, and pressed into a tablet form specac atlas 15 t manual. Geochemistry of coexisting hornblende and biotite from the. Earth structure, materials, systems, and cycles objectives since this course is about how earth processes can adversely affect us as human beings, we need to first discuss some of the basic principles of the science of earth that is geology. Essential minerals these are minerals that are required within the classification of this rock. Geochemical evolution of arcrelated mafic plutonism in the unim naggat district 271 figure 2. A coarsegrained plutonic rock composed essentially of calcic plagioclase, pyroxene and iron oxides. The layered gabbros are represented by pyroxene and hornblende gabbros. Petrology and geochemistry from the wadi gideah cross section. A geochemical study of the riddle peaks gabbro, north cascades.
Their petrography, opaque mineralogy, and geochemistry are addressed to elucidate. Geochemistry of diorites and associated plutonic rocks of. Geochemistry of gabbros and granitoids m and itypes. Namibia thomas becker1, brigitte diedrichs2, bent t. Geochemistry and mantle sources for archean alkaline rocks. Zircon upb dating indicates that the hornblende gabbro was emplaced during the late carboniferous 311 ma. Hornblende kar ages from the diorites range from 582 to 527 ma, almost exactly the same spread as the granite ages.
A cumulate gabbro can form from a dry basaltic magma e. Geological map of the gabal umm naggat area modified after refaat, 1970. Deep and hightemperature hydrothermal circulation in the oman. Geochemistry and mantle sources for archean alkaline rocks from greenland, the baltic, and northern norway d. Geology, geochemistry, and mineral resources of the lower. The realm of geochemistry extends beyond the earth, encompassing the entire solar system, and has made important contributions to the understanding of a number of processes including mantle convection, the formation of. Patches are mainly epidote, quartz, hornblende, with minor albite, chlorite, apatite, and sphene. An experimental study using carbon and samarium as examples. Permian hornblende gabbros in the chinese altai from a. Paharpur gabbroic intrusive is an arcuate body running eastwest paralleling the foliation of chhotanagpur granite gneiss which acts as. An account of its geochemistry and differentiation trend. Platinumgroup mineral occurrences and platinumgroup. Trace element partitioning determined by betatrack mapping. They are dark green, show marked variation in grain size, from fine to coarse grained, and vary in the ratio of mafic to felsic minerals.
Petrographic continuity from hornblendite through hornblende gabbro, hornblendebiotite diorite, hornblendebiotite tonalite and trondhjemite is reflected in regular variation of major and. Although the strike of layering varies, in any map unit at any given location it is the same in all units irrespective of intrusive order. Implication for petrogenetic process and tectonic setting june 2012 journal of earth. Compared to gabbro, patches are enriched in cao, sio 2, and p 2 o 5, and depleted in feo, mgo, and alkalis. Gabbro, plagiogranite and associated dykes in the supra. Considerable petrological and geochemical evidence from the qiemuerqieke gabbro indicates that it accumulated from a waterenriched magma. Implication for an arc nascent backarc environment january 2015. Green hornblende, tremolite, actinolite, epidote, chlo. Mineralogy a summary of representative modal and mineral composition data for the bronzite picrite dykes is given in table 1. Ultrabasics olivineserpentinetremolite rocks, peridotite, olivine gabbro and norite. Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the earths crust and its oceans. Neodymium, strontium and lead isotope geochemistry project.
Geochemistry of the gabbrodioritetonalitetrondhjemite. Chemical analyses for major and trace elements showed that there are 3 main gabbro types. Implication for an arcnascent backarc environment by xw qiu, cy liu, ff wang, y deng and gz mao. System chronometry and geochemistry research on hornblende gabbro in wanning area was made in this paper, and its tectonic significance is to be. Pdf petrology and geochemistry of late carboniferous. Rocks of the proterozoic gabbrodioritetonalitetrondhjemite suite of southwest finland were analyzed for major elements, ree, rb, sr, ba, u, th, and isotopic composition of sr and o. A combined field, geochronological, and geochemical study of the kuwei intrusion is reported here. Allochthonous hornblenderich gabbroic rocks at sonidzuoqi constitute impor tant components of.
The hornblendes typically show high al2o3 contents 9691189% comparable with those from anorogenic granites. Petrology, geochemistry of hornblende gabbro and associated. An informal name for dark green to black amphiboles, mostly ferrohornblende or magnesiohornblende according to the current nomenclature. Mineral chemistry does not change in any systematic way within and between layers in any map unit. One sample rm0201042 of this unit contained 35% relict pyroxene minerals and is only mildly amphibolitized. Geochemistry of the panzhihua mafic layered intrusion sw. White and are available here with the understanding that this material will not be used for commercial purposes or reprinted in published form without prior consent of the author. Mineralogy, petrology and geochemistry of the scourie. Geochemical evolution of arcrelated mafic plutonism in. The opaque minerals study of the gabbroic rocks showed that they composed mainly of ilmenite, magnetite.
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