oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
黑龙江东部滚突岭地区斜长角闪岩的原岩性质与变质作用演化
Protolith Property and Metamorphic Evolution of Amphibolites in Guntuling Area, Eastern Heilongjiang
 [PDF]

杨岩,郑常青 ,徐学纯,韩玉宝,郭柏源
Yang Yan
, Zheng Changqing, Xu Xuechun, Han Yubao, Guo Boyuan

地球科学(中国地质大学学报) , 2018, DOI: 10.3799/dqkx.2018.563
Abstract: 黑龙江杂岩主要出露于牡丹江断裂以东,并沿其呈南北向带状展布于佳木斯地块西缘.有关于该杂岩的矿物成分和变质作用演变方面的报道很少,且前人的研究多集中在变质程度为绿片岩相-蓝片岩相的典型黑龙江杂岩.通过对出露于黑龙江东部滚突岭地区的斜长角闪岩进行了地球化学与变质演化研究,其岩石类型主要包括石榴黝帘斜长角闪岩和石榴黑云角闪片岩,结果表明该地区石榴黝帘斜长角闪岩样品明显富集元素K、Ti,亏损Hf,Ta/Yb比值低(0.09~0.16),轻稀土(LREE)相对重稀土(HREE)稍有弱亏损,稀土元素配分曲线为平坦型,类似于MORB的特征.石榴黑云角闪片岩样品微量元素K、Th、Ti明显富集,轻稀土(LREE)相对重稀土(HREE)弱富集,稀土元素配分曲线为右倾型,与洋岛玄武岩相似.斜长角闪岩的原岩既有形成于洋中脊环境的大洋拉斑系列玄武岩,也有少量形成于板内(大陆边缘)或洋岛环境的钙碱性系列玄武岩.斜长角闪岩经历了3个变质演化阶段,分别为高绿片岩相的进变质阶段(T=400~500℃,P=400~500MPa)、低角闪岩相的峰期变质阶段(T=550~640℃,P=590~630MPa)和高绿片岩相的退变质阶段(T=530~560℃,P=530~560MPa),记录了从早期升温升压到后期近等温降压的顺时针P-T演化过程,表明斜长角闪岩的变质作用可能与佳木斯地块与松嫩地块的碰撞有关.
The Heilongjiang complex which mainly outcrops to the east of Mudanjiang fault, is distributed in band trending northsouth along the western margin of Jiamusi massif. However, there are few reports about the mineral composition and evolution of the metamorphism of the Heilongjiang complex, and the previous studies are mostly concentrated in the typical Heilongjiang complex with metamorphic degree of greenschist facies to blueschist facies. Therefore, geochemical characteristics and metamorphic evolution of amphibolite are studied in this paper. Amphibolites consist mainly of garnetzoisitebearing amphibolite and garnetbiotiteamphibolebearing schist outcopped in Guntuling area, eastern Heilongjiang. Garnetzoisitebearing amphibolite is characterized by the enrichment of K and Ti, distinctly depleted Hf, and low ratio of Ta/Yb at (0.09-0.16). Furthermore, LREE has weakly negative anomalies relative to HREE, chondritenormalized REE diagram shows a flat pattern and has no obvious abnormality, which is similar to the features of MORB. Garnetbiotiteamphibolebearing schist is characterized by the enrichment of K, Th and Ti; furthermore, LREE has weakly enrichments relative to HREE in the chondritenormalized REE pattern and has no obvious abnormality, which is almost consistent with OIB. Geochemistry and metamorphic evolution of amphibolites show that majority of them are oceanic tholeiite originated from the environment of the midocean ridge, and minority of them are calcalkaline basalt originated from the environment of intraplate (continental margin) or oceanic island. The amphibolites have undergone three successive stages: the progressive metamorphic phase of the high greenschist facies (T=400-500℃, P=400-500MPa), peak metamorphic stage of low amphibolite facies (T=550-640℃, P=590-630MPa) and near isobaric cooling stage of highgreenschist facies (T=530-560℃,P=530-560MPa). It records a clockwise P-T path from early increased temperature
Cosi, sto  [cached]
Barbara Garlaschelli
Altre Modernità , 2010,
Abstract: Così, sto di Barbara Garlaschelli
西南天山超高压变质带的两类石榴角闪岩
Metamorphic Evolution of Two Types of Garnet Amphibolites from UHP Terrane of Southwestern Tianshan, NW China
 [PDF]

吕增,王凯
Lü Zeng
, Wang Kai

地球科学(中国地质大学学报) , 2018, DOI: 10.3799/dqkx.2018.009
Abstract: 角闪岩是西南天山超高压变质带变基性岩的常见岩石类型之一.野外关系和矿物反应结构表明,大多数角闪岩是由榴辉岩或蓝片岩受到不同程度的钠长绿帘角闪岩相退变质叠加形成的.但对于一些平衡结构发育良好且孤立产出的角闪岩类型(如石榴角闪岩)仍缺乏系统的岩石学研究.本次从岩相学、矿物成分以及热力学模拟几个方面对哈布腾苏河下游地区超高压带内不含钠长石的石榴角闪岩开展了详细的工作.这些石榴角闪岩的主要矿物为绿色角闪石(钙质-钠钙质闪石)、帘石(黝帘石-绿帘石)和石榴石,三者总体积占80%~90%,明显有别于大多数由榴辉岩退变而成的含有钠长石变斑晶的石榴角闪岩.虽然这些角闪岩化学成分十分相近,都具有富钙贫钠和高的Mg/(Mg+Fe)比值,但在结构、构造和矿物组成等方面存在显著差异,据此将它们划分为两类.第一类角闪岩基质中不含石英,保存在变斑晶中的少量残余矿物组合为石榴石+绿辉石+硬柱石+蓝闪石+金红石,指示峰期硬柱石榴辉岩相变质条件,富钛矿物全部为金红石.第二类角闪岩强烈面理化,面理由绿色角闪石、绿帘石和绿泥石以及条带状石英集合体构成.石榴石粒度呈双峰式分布,粗粒比细粒低钙低锰.基质和包体中均未发现高压变质特征矿物绿辉石和蓝闪石.富钛矿物以榍石为主,金红石和钛铁矿仅存在于个别石榴石中.两类角闪岩的石榴石成分具有较大区分度,前者的钙含量较高而镁含量较低.P-T视剖面计算显示它们的峰期条件为480~520℃,30~33kbar,均达到超高压范围,与哈布腾苏河下游及以西地区的榴辉岩相似,表明西南天山超高压变基性岩构成沿中天山南缘断裂延伸数十千米的独立地质单元,不存在所谓的俯冲隧道混杂现象.
Amphibolite is one of the common metabasic rock types exposed in the the UHP metamorphic belt of southwestern Tianshan. It is found in the field relationship and mineral reaction textures that most of such amphibolites are retrograded after eclogites or blueschists to various extents at albite epidote amphibolite facies conditions. However, petrological studies are not systematic and sufficient for those with equilibrated textures from homogeneous blocks. In this paper, it is presented a detailed study of petrography, mineral chemistry and thermodynamic modelling on some albite free garnet amphibolites in the UHP unit at the lower part of the Habutengsu valley. Results show that they largely consist of green amphibole (Ca or Na-Ca amphibole), epidote (or zoisite) and garnet (80% to 90% total volume), substantially different from the equivalents that retrograded from UHP eclogites contain albite porphyroblast. Though these garnet amphibolites are similar in bulk compositions, with high CaO and low Na2O and high Mg content, based on contrasting differences in terms of texture, structure and mineral assemblage, two types are divided herein. Type Ⅰ garnet amphibolite is quartz free and relict or inclusion assemblage of Grt+Omp+Lws+Gln+Rt indicating peak lawsonite eclogite facies conditions. Rutile is the only Ti-rich phase as inclusion or in the matrix. Type Ⅱ garnet amphibolite is strongly foliated shown by oriented green amphibole, epidote, chlorite and banded quartz aggregates. Garnet is characterized by bimodal grain size and the larger ones have lower Ca and Mn. No HP indicator such as omphacite or sodic amphibole has been detected. Ti-rich phase is dominated by titanite and rare rutile and ilmenite are only found in some garnets. Generally, garnet compositions are distinguishable between the two types of amphibolites, Type Ⅰ with higher Ca but lower Mg. P-T
Ultrahigh Pressure Metamorphic Traces Hidden in Zircons from Amphibolites of Sulu Terrane,Eastern China
隐藏在苏鲁地体斜长角闪岩锆石中超高压变质作用的信息

刘福来,张泽明,许志琴,杨经绥,S.Maruyama
地球学报 , 2003,
Abstract: Using the Laser Raman spectroscopy,cathodoluminescence method and electron microprobe analysis,the authors recognized coesite inclusions together with garnet, omphacite, phengite, magnesite, rutile and apatite inclusions in zircons from all amphibolite samples in pre pilot drillhole CCSD PP1 and CCSD PP2 as well as in outcrops of Sulu terrane. The mineral inclusion assemblage preserved in zircons is similar to that in the matrix of eclogites formed during the UHP metamorphism. These data indicate that amphibolites might have been formed by the retrogression of UHP eclogites in the uplifting of Sulu terrane. The research is of great significance in probing into the genetic mechanism of amphibolites and the fluid rock interaction during the tectonic uplift of Sulu terrane.
Petrology of the Garnet Amphibolites from the Teji i Village - Povlen Mt., Western Serbia  [PDF]
Sre?kovi?-Bato?anin Danica R.,Milovanovi? Dragan,Balogh Kadosa
Geolo?ki Anali Balkanskog Poluostrva , 2002, DOI: 10.2298/gabp0264187s
Abstract: Different metamorphic rocks discovered near the village of Teji i (Povlen Mt., Western Serbia) represent members of the olistostrome mélange metamorphosed during the obduction/emplacement of some still hot ultramafic body. They occupy the area of about 2 km2. The garnet amphibolites are of highest metamorphic grade in the area of Teji i and were chosen as the most convenient rocks for determination the pressure-temperature conditions of metamorphism and of ultramafics during their emplacement.
O obnovi stare glazbe  [cached]
Lucy Hallman Russell
Radovi Zavoda za Znanstveni Rad Vara?din , 2010,
Abstract: U ovom radu autorica razmatra univerzalnu i bezvremensku vrijednost ljepote i glazbe jo od razdoblja neolita i anti ke Gr ke. U 18. stolje u u injeni su napori za revitalizacijom glazbe stare tek 150 godina. Od sredine 20. stolje a velik je napredak postignut u istra ivanju povijesnih glazbala i izvodila ke prakse, to je danas postalo predmetom podu avanja irom svijeta. Spominjanjem zna ajnih interpreta Stare glazbe te osobnih iskustava u Hrvatskoj zaokru uje se ovaj kontemplativni komentar o irenju Rane glazbe.
The neodymium isotopic characteristic and geological significance of Kuokesu plagioclase amphibolites from the Kuruktag, Xinjiang, China
Zhicheng Zhang,Zhaojie Guo,Shuwen Liu,Haifei Zheng
Chinese Science Bulletin , 1998, DOI: 10.1007/BF03186993
Abstract: The plagioclase amphibolites from Kuokesu area, Kuruktag, Xinjiang occur as enclaves embedded in the granodioritic gneiss. In the light of major elements and REE data, the parent rocks of the plagioclase amphibolites belong to weak-alkaline basalts. Their Nd model ages mainly range from 2 832 to 3 075 Ma. The seven plagioclase amphibolites yield a reasonable good isochron age of (828 ±86) Ma(2σ) with INd= 0.510 981 ±82, εNd(t) = 11.5±1.6. Such a case shows the existence of great proportion of the Archaean mafic crustal basement on the Kuokesu area. The strong tectonic-thermal event at about 820 Ma made the Sm-Nd isotope of the metamorphic rocks homogenization. This event would be associated with the Tarim Movement.
The STARE Project: A Progress Report  [PDF]
C. A. Katz,J. N. Hewitt,C. B. Moore,B. E. Corey
Physics , 1997, DOI: 10.1063/1.55381
Abstract: The Survey for Transient Astronomical Radio Emission (STARE) is a wide-field monitor for transient radio emission at 611 MHz on timescales of fractions of a second to minutes. Consisting of multiple geographically separated total-power radiometers which measure the sky power every 0.125 sec, STARE has been in operation since March 1996. In its first seventeen months of operation, STARE collected data before, during, and after 173 gamma-ray bursts. Seven candidate astronomical radio bursts were detected within +/-1hr of a GRB, consistent with the rate of chance coincidences expected from the local radio interference rates. The STARE data are therefore consistent with an absence of radio counterparts appearing within +/-1hr of GRBs, with 5sigma detection limits ranging from tens to hundreds of kJy. The strengths of STARE relative to other radio counterpart detection efforts are its large solid-angle and temporal coverage. These result in a large number of GRBs occuring in the STARE field of view, allowing studies that are statistical in nature. Such a broad approach may also be valuable if the GRBs are due to a heterogenous set of sources.
The aplication of Sanchez method in the science-development network Stare Mesto sub Sneznik
Roman Turowski
Acta Montanistica Slovaca , 2007,
Abstract: In this paper there is address relative new method determination influence of refracion to measurement zenit angle (Sanchez method) and your results on mearesument in science-development network Stare Město sub Sneznik. Sanchez method is nontraditional way of determination heavy altitude diference in mountain terrain. This method were completed by measurement via GPS and precise levelling.Atmospheric refraction separate after character measurebles objects in astronomic and terrestrial refraction. Terrestrial refraction is cause by influence bottom ground layer in the course of measuring in terrestrial objects.
Tectonic affinity and timing of two types of amphibolites within the Qinling Group, north Qinling orogenic belt
秦岭岩群中两类斜长角闪岩的性质和时代及其地质意义

YAN QuanRen,WANG ZongQi,YAN Zhen,CHEN JunLu,XIANG ZhongJin,WANG Tao,ZHANG HongYuan,
闫全人
,王宗起,闫臻,陈隽璐,向忠金,王涛,张宏远

岩石学报 , 2009,
Abstract: There are two types of amphibolites within the Qinling Group, north Qinling orogenic belt. One is layer-liked or blocked amphibolites involved in marbles, another is the dikes of amphibolites intruding into mica-schist, indicative of significant differences of petrogenesis and time between two types of amphibolites. Geochemistry shows that the protolithes of two types of amphibolites are basaltic. The dikes of amphibolites were formed in a tectonic setting of the within-plate, and isotopes of strontium and neodymium indicate that magma of those dikes sourced from depleted mantle. SHRIMP U-Pb analyses for zircons show that the dikes were formed in the Late Ordovician, ca.449±11Ma, and 40Ar/39Ar dating results reveral that those dikes underwent amphibolite facies metamorphism at the end of the Carboniferous, ca.301.3±6.4Ma. In comparison, layer-liked or blocked amphibolites involved in marbles of the Qinling Group show the geochemical and isotopic affinity with oceanic island basalts, or seamount basalts. 40Ar/39Ar dating results show that this type of amphibolite underwent amphibolite facies metamorphism in the Late Permian, ca.258.1±5.7Ma, later about 40Ma than the dikes. Difference of tectonic affinities and timings, and similar metamorphism and ages suggest that two types of amphibolites in the Qinling Group are belonged to different tectonic blocks, and then assembled together to constructed a high-graded metamorphic terrane, that is the Qinling Group. In conclusion, this paper suggests that the dikes of amphibolites intruding into the mica-schist were products of crust extension or lithospheric delamination and thinning triggered by thermal contraction during the post Caledonian orogen in the north Qinling orogenic belt. While layer-liked or blocked amphibolite involved in marbles might be the assemblages of basic extrusive rocks and carbonate cap of the oceanic rises, such as the OIBs and seamounts, most likely. Those oceanic rises were allochthonous in the Middle Permian.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.