共查询到20条相似文献，搜索用时 31 毫秒
1.
Sh. K. Baltybaev O. A. Levchenkov L. K. Levsky O. Eklund T. Kilpeläinen 《Petrology》2006,14(3):247-261
The Ladoga, Russia, and adjacent Sulkava, southeastern Finland, metamorphic complexes are the two largest “granulite” provinces of the Svecofennian domain. In this area, the domain is composed of outer and inner zones. Sulkava is situated in the inner zone, which principally can be compared to the accretionary arc complex of Southern Finland. Ladoga is situated in the outer zone, which is correlated with the accretionary arc complexes of central and Western Finland. The complexes contain different metamorphic assemblages, which are caused by the different composition of the sedimentary protoliths: the rocks of the Sulkava metamorphic complex are higher in Al and K than those of the Ladoga Complex. Pb-Pb step leaching dating was used to determine the age of prograde sillimanite from both complexes. The dates thus obtained constrain metamorphic peaks for the Sulkava and Ladoga complexes at 1799 ± 19 Ma and 1878 ± 7 Ma, respectively, which is consistent with the U-Pb monazite ages of gneisses from both of the complexes. The differences in the ages of the metamorphic minerals from these complexes reflect the Early Svecofennian (1.89–1.86 Ga) and Late Svecofennian (1.83–1.79 Ga) metamorphic stages in the Fennoscandian Svecofennides. 相似文献
2.
L. N. Kotova A. B. Kotov V. A. Glebovitskii V. N. Podkovyrov V. M. Savatenkov 《Stratigraphy and Geological Correlation》2009,17(1):1-19
Siliciclastic metasediments of the Ladoga Group that is the Kalevian stratotype in Karelia correlative with the Kalevian siliciclastic succession in Finland are studied in terms of geochemistry and Sm-Nd isotopic systematics. The results obtained show that rocks in the Ladoga Group lower part are enriched, as compared to rocks of the upper part, in TiO2, Fe2O3, MgO, Cr, Co, Ni, and Sc, being comparatively depleted in Al2O3 and Th that is a result of compositional changes in provenances. The Sm-Nd isotopic data evidence that siliciclastic sediments of the Ladoga Group have accumulated during the erosion of rocks, which originated at the time of the Archean and Early Proterozoic crust-forming processes. Siliciclastic material with the Archean and Early Proterozoic TNd(DM) values, which are characteristic of metasediments in the group lower part, was derived respectively from granite gneisses of the Archean basement in the Karelian megablock of the Baltic Shield and from volcanic rocks of the Sortavala Group. Volcanic rocks of island-arc terranes of the Svecofennian foldbelt represented main source of siliciclastic material that accumulated in upper part of the succession. 相似文献
3.
喀喇昆仑地区从二叠纪开始,广泛沉积不同类型的碎屑岩、泥质岩、硅岩、碳酸盐岩和混积岩。沉积层序发育完整,白垩纪之前基本上属于稳定的连续造海建造系列。经初步研究,除西部二叠系出现半深水陆架边缘-岛弧盆地相、陆架区冷水型冈瓦纳相沉积和东部下三叠统有具复理石或重力流性质的外陆架半深水碎屑岩-硅泥质岩建造沉积外,大部分都是以细屑岩-碳酸盐岩建造为主的地台型浅海陆棚相和浅海平原相沉积,直到保罗纪末才形成早白垩世,以红色粗碎屑岩为主的陆相磨拉石建造,从而结束了长达1.5亿年连续沉积历史。 相似文献
4.
A. B. Kuzmichev G. N. Aleksandrova A. B. Herman 《Stratigraphy and Geological Correlation》2009,17(5):519-543
The Aptian-Albian sediments of Kotel’nyi Island are represented by a terrigenous coaliferous complex with the apparent thickness of approximately 700 m. The upper two thirds of their section enclose ignimbrites and rhyolitic ash tuffs. The integral thickness of volcanics is 170 m. A new sequence composed largely of acidic volcanics and sedimentary rocks is defined in the upper part of the Cretaceous section. The K-Ar age estimated for ignimbrite glasses is 110–107 ± 2.5 Ma, which corresponds to the first half of the Albian. The fossil flora list is added by several previously unknown forms. The macroflora of Kotel’nyi Island is similar to its Albian counterpart from the Kolyma-Indigirka region and allows Cretaceous sediments from the lower part the Kotel’nyi Island section to be dated back to the Aptian (?)-Albian (except for the terminal Albian). The palynological characteristic of rocks immediately contacting the dated volcanics appeared to be untypical of Albian sediments of Siberia and similar to that of the Late Neocomian palynocomplexes. This is partly explained by erosion and reworking processes. The examined continental sediments accumulated in post-orogenic extension settings. They constitute the lower strata of the Aptian(?)-Tertiary post-orogenic complex filling riftogenic depressions in the New Siberian Islands and Laptev Sea. 相似文献
5.
N. B. Kuznetsov S. Yu. Orlov E. L. Miller A. V. Shazillo A. V. Dronov A. A. Soboleva O. V. Udoratina G. Gehrels 《Doklady Earth Sciences》2011,438(2):759-765
The first results of U/Pb isotopic dating (LA ICP MS) of detrital zircons from sands from the Middle Cambrian Sablinka Formation,
Upper Cambrian Ladoga Formation, Low Ordovician Tosna Formation, and calcareous sands from Syas’ Formation (Sargaevskii horizon
of the Upper Frasnian) from Baltica-Ladoga Glint (BLG) of the Southern Ladoga area are presented. The obtained ages of detrital
zircons span the intervals 492.7 ± 5.1-3196.4 ± 5.1 Ma (Sablino Formation); 577.9 ± 7–2972.6 ± 13.4 Ma (Ladoga Formation);
509.4 ± 8.5–3247.6 ± 10.1 Ma (Tosna Formation); 451.1 ± 14.7–2442.2 ± 6.9 Ma (Syas’ Formation). A comparison of the obtained
isotopic ages of detrital zircons to ages of crystalline complexes composing the Kola-Karelian, Svecofennian, and Sveconorwegian
domains of Baltic Shield and Pre-Uralian-Timanian structures of Subpolar and Polar Urals and basement of Pechora Basin was
carried out. It is proposed that the Middle Paleozoic sedimentary basin accumulated Upper Frasnian rocks of Syas’ Formation.
The basin ranged northward from the present-day BLG and occupied the eastern part of the Baltic Shield. 相似文献
6.
《Geodinamica Acta》2013,26(6):417-430
The Longi-Taormina Unit forms the “Dorsale calcaire” of the Peloritani Alpine Belt (southern Calabria-Peloritani Arc). It is made by a thick sedimentary cover of Meso-Cenozoic age overlying a Variscan weakly metamorphosed Cambrian to Carboniferous succession. The Palaeozoic series consists of pelitic to arenaceous sediments containing layers of acidic and basic volcanics. The acidic volcanics are affected by the “Caledonian” compressional deformations and are referred to Early Ordovician. The basic rocks belong to two different volcanic cycles; the first, not dated, is ascribed to the Caledonian cycle according to its geochemical signature; whereas the second, middle-late Devonian in age, is interpreted to have formed in the framework of pre-Variscan extensional tectonics. During the Variscan Orogeny (330 Ma), the area recorded metamorphism up to subgreenschist-to-greenschist facies and two main deformation phases, marked by syn-schistose early folds (Dv1), overprinted by dominantly NW-SE trending late folds (Dv2). During the Aquitanian, deformation related to the Alpine Orogeny led to imbrication of the Palaeozoic and Meso-Cenozoic series. The sedimentary cover was affected by a series of N090° to N130° trending folds. Detailed stratigraphical and structural investigations on the tectonic contact between the Longi-Taormina Unit, and the overlying Fondachelli Unit indicate that this structure is part of a frontal thrust ramp which developed during the Aquitanian. Our geological and structural studies on the Cambrian to Aquitanian rocks of the Longi-Taormina Unit of the Calabria-Peloritani Arc enable to unravel the complex geodynamic history of the central-western Mediterranean area. 相似文献
7.
In western Tasmania, Precambrian sedimentary sequences form the basement for narrow trough accumulations of Eocambrian and younger sequences. The main trough, the meridional Dundas Trough, is flanked to the west by the Rocky Cape region of Precambrian rocks within which major, apparently stratiform, exhalative magnetite-pyrite deposits are intercalated with metabasaltic volcanics and ultramafic bodies.The Eocambrian-Cambrian troughs apparently developed during extension of Precambrian continental crust. Early shallow-water deposition includes thick dolomite units in some troughs. Deepening of the troughs was accompanied by turbidite sedimentation, with minor limestone, and submarine basaltic volcanism with associated minor disseminated native copper. Ultramafic and related igneous rocks were tectonically emplaced in some troughs during a mild compressional phase. They contain only minor platinoids, copper-nickel sulphides and asbestos, but are source rocks for Tertiary secondary deposits of platinoids, chromite and lateritic nickel.In the Dundas Trough, Eocambrian-Early Cambrian rocks are separated by an inferred erosional surface from structurally conformable overlying Middle to Late Cambrian fossiliferous turbidite sequences. The structural conformity continues through overlying Ordovician to Early Devonian terrestrial and shallow-marine stable shelf deposits.A considerable pile of probable Middle Cambrian felsic volcanics accumulated between the sedimentary deposits of the Dundas Trough and the Tyennan region of Precambrian rocks to the east. A lava-dominated belt within the volcanics hosts major volcanogenic massive sulphide deposits, including those of the exhalative type, which in the south are enriched in copper, gold and silver, whereas in the north they are rich in zine, lead, copper, gold and silver. Cambrian movements along faults near the margin of the Tyennan region resulted in erosion of the mineralized volcanics, locally exposing sub-volcanic granitoids. Above the local unconformities occur unmineralized volcaniclastic sequences that pass conformably into Ordovician to Early Devonian shelf deposits. Ordovician limestone locally hosts stratabound disseminated and veined base metal sulphide deposits.Pre-Middle Devonian rocks of western Tasmania differ, for most part, from those in the northeast where deeper marine turbidite quartz-wacke sequences were deposited during the Ordovician and Early Devonian.The Eocambrian to Early Devonian rocks of Tasmania were extensively deformed in the mid-Devonian. The Precambrian regions of western Tasmania behaved as relatively competent blocks controlling early fold patterns. In northeastern Tasmania, folding is of similar age but resulted from movements inconsistent with those affecting rocks of equivalent age in western Tasmania.The final metallogenic event is associated with high-level granitoid masses emplaced throughout Tasmania during the Middle to Late Devonian. In northeastern Tasmania, extensive I-type granodiorite and S-type granite, with alkali-feldspar granites, are associated with mainly endogranitic stanniferous grelsens and wolframite ± cassiterite vein deposits. In contrast, scheelite-bearing skarns and cassiterite stannite pyrrhotite carbonate replacement deposits are dominant in western Tasmania, associated mainly with S-type granites. Several argentiferous lead-zinc vein deposits occur in haloes around tin-tungsten deposits. A number of gold deposits are apparently associated with I-type granodiorite, but some have uncertain genesis.The contrasting regions of western and northeastern Tasmania have probably been brought together by lateral movement along an inferred fracture. Flat-lying, Late Carboniferous and younger deposits rest on the older rocks, and the only known post-Devonian primary mineralization is gold associated with Creta ceous syenite. 相似文献
8.
碎屑岩与火山岩混积岩系层序地层学研究初探——以准噶尔盆地西北缘佳木河组为例 总被引：1，自引：0，他引：1
准噶尔盆地西北缘前陆冲断带是剖析西准噶尔地区盆山耦合关系、沉积体系发育的关键地段。该区二叠系佳木河组为火山岩、火山碎屑岩、碎屑岩组成的混积地层。火山岩与碎屑岩组成的地层单元有广义上的成因联系,因为它们都属于史密斯地层,并均具有旋回特征。针对不同的岩性区:碎屑岩岩性区、火山岩与碎屑岩共存区、纯火山岩区,找出由于构造火山活动、相对湖平面变化等因素形成的可作为层序界面的不整合面。碎屑岩岩性区不整合面在地震剖面上主要表现为削蚀、底超、双向下超、顶超、下切谷等;共存区为同时发育火山岩与碎屑岩的削蚀带,不整合面类型较复杂;纯火山岩区表现为相对湖平面下降形成的削蚀不整合面。故可以通过地震、钻测井资料识别各类不整合面,并依据火山喷发方式、火山旋回、沉积旋回,按照不同对比原则进行经典层序地层学划分。 相似文献
9.
《Precambrian Research》2003,120(1-2):37-53
The Puutsaari intrusion is a potassium-rich magmatic complex in the eastern part of the Svecofennian domain close to the Archaean border. The intrusion is generally undeformed in contrast to 1880–1875 Ma-old country rock tonalitic migmatites and diatectites. The main rock types are: (1) mafic rocks of a gabbro–norite–diorite–quartz monzodiorite series; (2) quartz diorite–tonalite–granodiorite; and (3) coarse-grained microcline granite. The three rock-types intruded coevally forming a peculiar three-component mingling system. The mafic rocks, enriched in K, P, Ba, Sr and LREE, have marked shoshonitic affinities (K2O=1.97–5.40, K2O/Na2O=0.6–2.37). On a regional scale they demonstrate transitional geochemistry between less enriched syn-orogenic 1880 Ma-old gabbro–tonalite complexes and strongly enriched 1800 Ma post-collisional shoshonitic intrusions. The microcline granite as well as the tonalite–granodiorite rocks are geochemically similar to crustal anatectic granitoids of the NW Ladoga Lake area. The three rock groups do not form a single trend on Harker-type diagrams and are unlikely to be related by fractional crystallisation or mixing. Zircons from the Puutsaari microcline granite and from the mafic rock series have been dated by ion-microprobe (NORDSIM) at 1868.2±5.9 and 1869±7.7 Ma, respectively. Most zircons recovered from a granite sample had zoned or homogeneous cores and unzoned fractured rims. No statistically significant variation of zircon core and rim ages from the granite was established in the course of this study. Zircons from the mafic rock are unzoned. It is suggested that the mafic rocks at Puutsaari were derived from an enriched mantle shortly after the main Svecofennian collisional event and the roughly 1.88 Ga regional metamorphic culmination. The emplacement of the mafic melt caused anatectic melting of various crustal protoliths and produced coeval granitic and tonalitic compositions. 相似文献
10.
Mesozoic syncollision siliciclastic sediments of the Bols’shoi Lyakhov Island (New Siberian Islands)
A. B. Kyzs’michev A. V. Soloviev V. E. Gonikberg M. N. Shapiro O. V. Zamzhitskii 《Stratigraphy and Geological Correlation》2006,14(1):30-48
Graywackes and shales of the Bols’shoi Lyakhov Island originally attributed to the Mesozoic were subsequently considered based on microfossils as the Late Proterozoic in age. At present, these sediments in the greater part of the island are dated back to the Permian based on palynological assemblages. In the examined area of the island, this siliciclastic complex is intensely deformed and tectonically juxtaposed with blocks of oceanic and island-arc rocks exhumed along the South Anyui suture. The complex is largely composed of turbidites with members displaying hummocky cross-stratification. The studied mineral and geochemical characteristics of the rocks defined three provenances of clastic material: volcanic island arc, sedimentary cover and/or basement of the ancient platform, and exotic blocks of oceanic and island-arc rocks such as serpentinites and amphibolites. All the rock associations represent elements of an orogenic structure that originated by collision of the New Siberian continental block with the Anyui-Svyatoi Nos island arc. Flyschoid sediments accumulated in a foredeep in front of the latter structure in the course of collision. The Late Jurassic volcanics belonging to the Anyui-Svyatoi Nos island arc determine the lower age limit of syncollision siliciclastic rocks. Presence of Late Jurassic zircons in sandstones of the flyschoid sequence in Bols’shoi Lyakhov Island is confirmed by the fission-track dating. The upper age limit is determined by the Aptian-Albian postcollision granites and diorites intruding the siliciclastic complex. Consequently, the flyschoid sequence is within stratigraphic range from the terminal Late Jurassic to Neocomian. It appears that Permian age of sediments suggested earlier is based on redeposited organic remains. The same Late Jurassic-Neocomian age and lithology are characteristic of fossiliferous siliciclastic sequences of the Stolbovoi and Malyi Lyakhov islands, the New Siberian Archipelago, and of graywackes in the South Anyui area in Chukchi Peninsula. All these sediments accumulated in a spacious foredeep that formed in the course the late Cimmerian orogeny along the southern margin of the Arctic continental block. 相似文献
11.
东南亚新生代两类埃达克岩的分布、成因和含矿性 总被引：2，自引：0，他引：2
东南亚的巽他群岛-巴布亚新几内亚是新生代埃达克岩和类埃达克岩发育的地区。这些中酸性岩浆岩广泛见于印度尼西亚几内亚岛、苏拉威西和巴布亚新几内亚, 零星见于苏门答腊、班达岛弧、西爪哇和中加里曼丹等地。本区埃达克岩和类埃达克岩岩石类型分别属于岛弧拉斑钙碱性系列和高钾钙碱性系列, 以重稀土元素Y, Yb含量低(分别为Y ≤19 ×10-6和Yb ≤1.8 ×10-6)和高Sr值(＞355 × 10-6)为特征。微量元素蛛网图上有明显的Ba、K、Sr正异常峰和负的Th、Nb (Ta)异常谷。大离子亲石元素(LILE)和高场强元素(HFSE)相对富集。本区埃达克岩和类埃达克岩的构造位置为新生代缝合线附近的大洋岛弧和陆缘造山带, 可划分为两种成因类型:第一种为岛弧拉斑/钙碱性系列, 其REE配分模式属于大洋岛弧型, 见于现代大洋岛弧, 称为岛弧型(O-型)埃达克岩; 另一种为高钾钙碱性系列, 其REE配分模式属于大陆型, 产于大陆板块边缘造山带, 与弧-陆碰撞和后碰撞构造环境有成因联系, 见于大陆边缘, 称为大陆型(C-型)埃达克岩。 研究结果表明:大陆型(C-型)埃达克岩和类埃达克岩分布区域与世界级斑岩铜-金矿分布相一致, 而大洋岛弧型(O-型)主要与浅成热泉金矿和喷气型有成因联系。 相似文献
12.
A. V. Ryazantsev 《Doklady Earth Sciences》2018,482(1):1157-1160
New data on the Vendian age of the volcanogenic–sedimentary sequence of the Uraltau zone (Southern Urals) were obtained. The U/Pb (SHRIMP-II) isotope age obtained for zircons from rhyolite tuffs is 591.5 ± 3.5 Ma. The sequence under consideration is intruded by Vendian granites and overlain unconformably by Ordovician terrigenous and volcanogenic deposits. The composition of Vendian volcanics and granites testifies that they were formed in a suprasubduction setting at the continental margin, complexes of which are known in the Middle and Northern Urals. 相似文献
13.
T.V. Donskaya D.P. Gladkochub A.M. Mazukabzov B. De Waele S.L. Presnyakov 《Russian Geology and Geophysics》2012,53(1):22-36
The Kataev volcanoplutonic association has been recognized in western Transbaikalia. It unites the volcanosedimentary rocks of the Kataev Formation and associated granites localized within the lower plates of the Buteel-Nuur and Zagan metamorphic-core complexes. The rocks of the Kataev association are dynamometamorphosed to different degrees, which is due to the tectonic exposure of metamorphic-core complexes in the Early Cretaceous. The U-Pb zircon dating of the Kataev Formation rhyolites yielded an age of 226 ± 3 Ma. The U-Pb zircon age of the granites intruding the Kataev Formation rocks is 223.4 ± 5.0 Ma. The volcanics of the Kataev Formation belong to the subalkalic basalt-andesite-dacite-rhyolite series. The trachybasalts and trachyandesite-basalts of the Kataev Formation have geochemical characteristics of igneous rocks formed as a result of subduction, e.g., they show distinct negative Nb and Ti and positive Ba and Sr anomalies on multielemental patterns. The specific composition of mafic volcanics points to their formation through the melting of a mantle source resulted from the mixing of depleted mantle and subduction components. Trachyandesites have higher Th and U contents than basaltoids. They can result from the contamination of a mantle source, similar in composition to the Kataev Formation basaltoids, with crustal material. The felsic volcanics of the Kataev Formation and granites intruding them show nearly identical geochemical characteristics corresponding to both A-and I-type granites. These rocks might have formed through the melting of a moderately water-saturated magmatic source of diorite-tonalite composition at 742–833°C. We have established that the rocks of the Kataev volcanoplutonic association in western Transbaikalia and Northern Mongolia formed in the Late Triassic synchronously with the calc-alkaline granitoids of the Henteyn–Daurian batholith and the alkali granites and bimodal volcanic associations of the Kharitonovo and Tsagaan-Hurtey volcanoplutonic associations. The synchronous formation of volcanoplutonic associations of normal and high alkalinity agrees with the geodynamic setting of the Andean-type active continental margin existing in the area of present-day western Transbaikalia and Northern Mongolia in the Early Mesozoic. This setting was the result of the subduction of the Mongol-Okhotsk oceanic plate beneath the Siberian continent. 相似文献
14.
15.
下扬子区早二叠世孤峰期泥化火山岩 总被引：8，自引：0，他引：8
下扬子区早二叠世弧峰组是以层状硅岩为主的海相层系，厚度为２０－８０ｍ。在硅岩层间产出火山岩，火山岩夹层的厚度小但层数众多，并几乎已全部泥化。但仍保留着残留的流动构造；长石、磷灰石、黑云母、角闪石等矿物或其晶屑以及各种形态的玻屑。在大量蒙脱石、伊利石、绿泥石等因泥化而形成的火山岩中特征性矿物。根据宏观及显微镜下特征、岩石化学成分的不同特征进行判断，火山岩包含有基性熔岩、酸性凝灰岩，还有大量含火山碎屑 相似文献
16.
内蒙古温都尔庙地区白音诺尔一带变质基性火山岩年代学和地球化学研究 总被引：1，自引：0，他引：1
对内蒙古中部温都尔庙地区白音诺尔变质基性火山岩进行了锆石LA-ICPMS U-Pb年代学和地球化学研究。结果表明,变质基性火山岩原岩形成于(254.8±6.2)Ma,时代为晚二叠世。地球化学特征研究显示研究区变质基性火山岩属于亚碱性拉斑系列,大离子亲石元素(LILE)Ba、Rb、Sr强烈亏损,高场强元素(HFSE)Nb、Zr富集,元素Eu为正异常,具有E-MORB地球化学特征,岩浆来源于富集的岩石圈地幔,结合地质特征应属于蛇绿岩组成部分,反映该地区在晚二叠世古亚洲洋尚未闭合,其闭合时间可能在早三叠世之后。 相似文献
17.
A. Hallberg 《Mineralium Deposita》1989,24(4):250-257
The lead isotope composition of three Cu-Zn-Pb sulfide deposits and one Au deposit in the Early Proterozoic Svecofennian of central Sweden reveals the existence of two distinct lead sources in the region. Rockliden and Enstern contain lead of upper crustal affinity and are isotopically homogeneous. Lead in these deposits probably originates from Archean-derived detritus which was well homogenized by sedimentary processes and deposited over large areas as a component in Early Proterozoic sedimentary and tuffaceous rocks. Lead isotopic homogeneity within the Tjärnberget and Enåsen deposits is less pronounced, and the less radiogenic character of the lead suggests a source of mantle affinity. In areas where metasedimentary rocks are absent or contain very little Archean-derived material the isotopic signature of mantle-derived volcanic rocks is reflected in the ore lead. This approach is also applicable to other Svecofennian deposits. Together with deposits in west-central Finland the Rockliden deposit constitutes the northern boundary for lead of upper-crustal affinity, i.e., Archean-derived lead, in Svecofennian sulfide deposits.Despite these differences the isotope ratios of the four deposits indicate that they formed roughly contemporaneously with other Svecofennian deposits in Sweden and Finland. 相似文献
18.
The Neoproterozoic Wadi Kid metamorphic belt in southeastern Sinai in Egypt represents a structurally and metamorphically complex assemblage of metasedimentary and metavolcanic rocks folded into a series of ENE–WSW-trending antiforms and synforms. Geological mapping in this region is challenging, primarily due to difficult access, complexity of structures, and lack of resolution and areal integrity of lithological differentiation using conventional mapping techniques. Spectral ratioing of selected bands of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data of the area, in synergy with geological field observation, proved effective in resolving geological mapping problems in the region. A new ASTER band-ratio image 4/7-4/6-4/10 is applied successfully for lithological mapping in the Wadi Kid area, showing improvement over previous techniques in detailing the main rock units. These are gneiss and migmatite, amphibolite, volcanogenic sediments with banded iron formation, meta-pelites, talc schist, meta-psammites, meta-acidic volcanics, meta-pyroclastics volcaniclastics, albitites and granitic rocks. Validating the use of the new ASTER band-ratio image relied on both calculating statistical optimum index factor (OIF) and matching interpreted lithological boundaries to field data and previously published geologic maps. The adopted ASTER band-ratio image demonstrates the benefit of using ASTER remote sensing data in lithological mapping of the Wadi Kid area and therefore for lithological mapping in the Arabian–Nubian shield and other arid areas. 相似文献
19.
新疆南天山奥图拉托格拉克一带前震旦系基底地质特征 总被引：5，自引：1，他引：4
1994年在新疆南天山地区奥图拉托格拉克一带 ,首次发现了晚太古代、元古宙结晶基底。晚太古代变质岩主要由变质深成岩组成 ,表壳岩组合为沙窝大沟岩组 ,岩性为一套变质火山—沉积岩。阜平期变侵入岩为巴什托格拉克片麻杂岩 ,为一套无序的 TTG岩系。五台期变侵入岩为沙窝布拉克片麻岩套。为一套基本有序的变侵入岩系列 ,包括 TTG和二长花岗岩两个岩系。三者组成太古宙古陆核。下元古界奥图拉托格拉克岩群为一套无序变质火山—沉积岩系 ,具有古老沟弧盆体系特征 ,阿牙克托格拉克岩组原岩为古蛇绿岩组合 ,具洋脊玄武岩特征 ;克孜拉格岩组原岩为杂砂岩 ,属盆地沉积 ;卡拉格兹岩组原岩为岛弧火山岩。长城系乱滩布拉克组由一套变火山岩、火山碎屑岩组成 ,属岛弧或活动陆缘沉积 ;卫东庄组为一变质碎屑岩建造 ,具弧盆碎屑岩沉积特征。长城纪末侵入了多岛滩超单元花岗岩 相似文献