It is composed of dunite, hornblende clinopyroxenite, hornblendite and hornblende gabbro. Geological map of the gabal umm naggat area modified after refaat, 1970. A coarsegrained plutonic rock composed essentially of calcic plagioclase, pyroxene and iron oxides. Mineralogy a summary of representative modal and mineral composition data for the bronzite picrite dykes is given in table 1. The wholerock geochemistry of the gabbros indicates the presence of two distinct groups of rocks. Petrology and geochemistry of late carboniferous hornblende gabbro from the awulale mountains, western tianshan nw china. It is composed of hornblende gabbros and leucohornblende gabbros. Martin christ gmbh, and pressed into a tablet form specac atlas 15 t manual. 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.
Petrology, geochemistry of hornblende gabbro and associated dolerite dyke of paharpur, puruliya, west bengal. A geochemical study of the riddle peaks gabbro, north cascades. The present work is a petrological study of the gabbroic rocks of wadi shianite southeastern desert of egypt. Partitioning of rareearth, alkali and alkaline earth elements between phenocrysts and. Pdf petrology, geochemistry of hornblende gabbro and. Geochemistry of hornblende gabbros from sonidzuoqi, inner. Present features of the gabbro developed in three stages. Petrology and chemistry of the green acres gabbro complex. Considerable petrological and geochemical evidence from the qiemuerqieke gabbro indicates that it accumulated from a waterenriched magma. Deep and hightemperature hydrothermal circulation in the oman.
The awulale mountains, the conjunction point of the tarim plate, junggar plate and yilicentral tianshan block, are the crucial place to decipher the. Ravna3 1geological institute, kola science centre, apatity, russia 2university of massachusetts lowell, usa 3university of tromso, norway. Besides, hornblende is found as a common min eral in gabbroic rocks of ophiolite complexes all over the world beard 1986. These rocks are commonly coarsegrained, hypidiomorphic granular and sometimes exhibit adcumulate texture. It is largely composed of magmatic labradorite, clinopyroxene, and orthopyroxene, all of which are rimmed to varying degrees by cummingtonite andor hornblendic amphibole. Geochemistry and mineralisation ofthe southern part ofthe darran complex, fiordland, newzealand 491 franco pirajno gold mines of new zealand limited p. Petrology and geochemical characteristic of the younger. A cumulate gabbro can form from a dry basaltic magma e. 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. 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. Zircon upb dating indicates that the hornblende gabbro was emplaced during the late carboniferous 311 ma. Geochemical evolution of arcrelated mafic plutonism in the unim naggat district 271 figure 2. Geochemistry of diorites and associated plutonic rocks of. The wuling hornblende gabbro has a narrow range of low barb 6.
Implication for petrogenetic process and tectonic setting. Geochemical evolution of arcrelated mafic plutonism in. Soil geochemistry and kimberlite indicator minerals report. Ultrabasics olivineserpentinetremolite rocks, peridotite, olivine gabbro and norite. Petrogenesis and tectonic setting of carboniferous. Implication for an arc nascent backarc environment january 2015. 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. Petrology, geochemistry of hornblende gabbro and associated dolerite dyke of paharpur, puruliya. Chemical analyses for major and trace elements showed that there are 3 main gabbro types. Neodymium, strontium and lead isotope geochemistry project.
These rocks are characterized by cumulate textures, high mg contents, low traceelement abundances. One sample rm0201042 of this unit contained 35% relict pyroxene minerals and is only mildly amphibolitized. Geochemistry and mineralisation ofthe southern part ofthe. A geochemical study of the riddle peaks gabbro, north.
Pb zircon dating results for the intrusion, and these yielded an age of. Paharpur gabbroic intrusive is an arcuate body running eastwest paralleling the foliation of chhotanagpur granite gneiss which acts as. The name comes from the town gabbro, a village in rosignano. Hornblende gabbro and gabbroic pegmatite cut by porphyritic diabase dykes. Three small stocks of gabbro shown as diorite unit td on worl and others, 1991 crop out on ridges. A combined field, geochronological, and geochemical study of the kuwei intrusion is reported here. Geochemistry and mantle sources for archean alkaline rocks from greenland, the baltic, and northern norway d. They are massive and devoid of any trace of igneous layering. The rocks range in composition from gabbro through diorite to quartz diorite. Implication for an arcnascent backarc environment by xw qiu, cy liu, ff wang, y deng and gz mao. 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. System chronometry and geochemistry research on hornblende gabbro in wanning area was made in this paper, and its tectonic significance is to be. 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. These rocks consist mainly of plagioclase and brown hornblende with minor amounts of opaques, biotite, quartz and apatite.
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. Pdf petrology and geochemistry of late carboniferous. Patches are mainly epidote, quartz, hornblende, with minor albite, chlorite, apatite, and sphene. Geochemistry and mantle sources for archean alkaline rocks. An account of its geochemistry and differentiation trend. 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. It seems likely that this is the first discovery of upper mantle peridotite xenoliths in calcalkaline andesite. Trace element partitioning determined by betatrack mapping.
The opaque minerals study of the gabbroic rocks showed that they composed mainly of ilmenite, magnetite. Impact of hornblende crystallization forthe genesis of. The layered gabbros are represented by pyroxene and hornblende gabbros. A gabbro with plagioclase and hornblende with pyroxene. Platinumgroup mineral occurrences and platinumgroup. Thin dikes, typically latestage hornblende gabbro, commonly intrude parallel to layering. Petrology and geochemistry of calcalkaline andesite of. The hornblendes correspond to edenitic composition, whereas the biotites correspond to annite. The panzhihua gabbro body is apparently a layered intrusion. Major and trace element geochemistry of coexisting hornblendes and biotites from the ambalavayal granite, northern kerala, are presented. 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. Allochthonous hornblenderich gabbroic rocks at sonidzuoqi constitute impor tant components of. Permian hornblende gabbros in the chinese altai from a.
Geochemistry of coexisting hornblende and biotite from the. Mineralogy, petrology and geochemistry of the scourie. Hornblende kar ages from the diorites range from 582 to 527 ma, almost exactly the same spread as the granite ages. Mineral chemistry does not change in any systematic way within and between layers in any map unit. Geochemistry of gabbros and granitoids m and itypes. Box 435 nelson, new zealand abstract the darran complex in northeast. 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. Petrography and geochemistry of the love lake leucogabbro. Geochemistry of the gabbrodioritetonalite trondhjemite suite of. This andesite is characterized by presence of hornblende and biotite phenocrysts. Petrology, geochemistry of hornblende gabbro and associated. Hornblende occurs as large poikilitic grain and constitutes around 60% of the rock.
The modal composition of these gabbros are given in table 1 and graphically represented on plagioclasepyroxene hornblende diagram streckeisen 1976,10. Namibia thomas becker1, brigitte diedrichs2, bent t. Implication for petrogenetic process and tectonic setting june 2012 journal of earth. Essential minerals these are minerals that are required within the classification of this rock. An informal name for dark green to black amphiboles, mostly ferrohornblende or magnesiohornblende according to the current nomenclature. The large exposure of these rocks in the western part of the study area has a pronounced northeast trend. An experimental study using carbon and samarium as examples. The hornblendes typically show high al2o3 contents 9691189% comparable with those from anorogenic granites. Bold lines are the wadi sections selected for detailed petrological and geochemical work in this study. Petrographic continuity from hornblendite through hornblende gabbro, hornblendebiotite diorite, hornblendebiotite tonalite and trondhjemite is reflected in regular variation of major and. Petrography and geochemistry of epidote alteration patches. Petrology and geochemistry from the wadi gideah cross section. Geology, geochemistry, and mineral resources of the lower.
Geology, geochemistry, and geochronology of gabbro from. Abstract the kuwei mafic intrusion, consisting of hornblende gabbro, gabbro, gabbro norite, and olivine norite, lies in the southern altai mountains, northern xinjiang. Geochemistry of the panzhihua mafic layered intrusion sw. 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. Gabbro, plagiogranite and associated dykes in the supra. On this diagram figure 2 the studied gabbroic rocks plot within the pyroxene hornblende gabbro norite, hornblende gabbro and anorthosite. Pdf hornblende gabbros of wadi az zarib area, central eastern. A marginal zone consists of mainly finegrained hornblende gabbro and olivine gabbro with thickness ranging from 0 to 40m. Numerous mafic dikes ranging from aphyric to phyric augite, hornblende, andor plagioclase are associated with the pluton. Their petrography, opaque mineralogy, and geochemistry are addressed to elucidate. Compared to gabbro, patches are enriched in cao, sio 2, and p 2 o 5, and depleted in feo, mgo, and alkalis.
838 112 263 741 537 852 1046 801 936 891 511 58 134 913 128 1398 1459 1029 914 82 1555 1465 1218 234 678 1070 103 1190 1051 1482 144 1082 202 1090 788