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Yu. P. Bezrodnykh B. F. Romanyuk V. M. Sorokin T. A. Yanina 《Doklady Earth Sciences》2017,473(1):277-280
This paper reports data on the Atelian horizon identified in the Caspian Sea bottom. Seismoacoustic profiling has made it possible to determine its area, position, and setting in the Upper Quaternary sequence and the relation to the host deposits. According to the drillhole core data, the Atelian horizon is composed of continental clay loam and sandy loam containing peatlike organic remains. They are depleted in biogenic residues containing rare freshwater mollusk species. The Atelian deposits were accumulated in lake reservoirs filling the depressions developed in the strata of the Upper Khazarian horizon. The radiocarbon age determined for the first time by humic acids has been used to estimate the Atelian deposition time in the range of 40 000–45 000 calibrated years BP. 相似文献
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研究地层是有效寻找沉积矿产的重要基础,将龙永煤田内关于的层位及分带性与大区域上的相似层位作了对比,并论述了本煤田的特征与变迁的基本过程。最后,结合多年来的研究成果,就煤田内的产出情况,作了两点必要的说明。 相似文献
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ABSTRACT Pebble fabric data are available from several facies of glacigenic sediments deposited by modern glaciers, where sedimentary processes can be observed or inferred with relatively little ambiguity. Over 100 samples from contemporary environments illustrate fabrics characterizing melt-out till, deformed and undeformed lodgement till, sediment flow deposits and ice slope colluvium. Lodgement till fabric variability is related to the two-layer structure of these sediments; a structureless, friable upper layer with low shear strength and high consolidation coefficient, overlying a very compact material of horizontal platy structure. Fabric strength (assessed by eigenvalue analysis) is weaker and pebble dip is more dispersed in the upper structureless horizon. Stronger fabrics in the lower platy horizon may be primary depositional fabrics which are destroyed by subglacial shearing to give weaker fabrics in the upper horizon. Alternatively, upper horizon fabrics may be characteristic of all recently-deposited lodgement tills, with stronger fabrics developing at depth by dewatering and consolidation. There is a general reduction in fabric strength and an increase in particle dip associated with the transition from melt-out tills, through undeformed and deformed lodgement tills, to sediment flow deposits and ice slope colluvium. There is, however, considerable overlap in the fabric strengths characteristic of sediment flow deposits and deformed lodgement tills. Fabric data from modern glacial sedimentary facies are used to assist in interpreting the mode of deposition of some Quaternary glacial sediments. Relatively strong fabrics characteristic of melt-out tills and undeformed lodgement tills are more likely to be diagnostic of genesis than weaker fabrics associated with deformed sediments. 相似文献
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In a dry valley near Ventnor, Isle of Wight, thick subaerial slope deposits of Devensian Late-glacial age overlie the Chalk. The deposits are crudely stratified chalk muds and rubble produced by frost-shattering, and moved downslope by the release of water from melting snow-fields and frozen ground. A laterally extensive humic horizon of a rendzina soil occurs within the sequence, clearly reflecting a period of relative slope stability. In places this horizon divides and its upper surface appears to have been disturbed, possibly by cryoturbation. Micromorphological and other analyses confirm the pedogenic origin of this humic horizon, but also demonstrate the occurrence of pedological features both above and below it. The humic horizon therefore is not a ‘buried’ soil in the strictest sense, but is part of a vertical sequence representing a single complex soil with transported, accretionary and welded components. Molluscan analyses reveal that the sequence can be divided into four local mollusc zones, showing a progressive increase in faunal diversity throughout the profile. This succession is broadly similar to other Late-glacial sequences described from south-east England. Minute fragments of charcoal from the lower part of the humic horizon have yielded an AMS date of 11690 ± 120 vr BP, demonstrating formation during the ‘Allerød phase’ of the Late-glacial Interstadial. This humic horizon is correlated provisionally with the ‘Pitstone Soil’, even though existing dates from its type-site in Buckinghamshire are somewhat younger. 相似文献
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I. A. Starodubtseva 《Stratigraphy and Geological Correlation》2013,21(2):215-221
Nikolai Andreevich Bogoslovskii (1862–1914) was a well-known soil scientist and geologist, who studied the Upper Jurassic and Lower Cretaceous deposits of Central Russia. He was the first scientist to distinguish the Ryazanian horizon and correlate it with the Berriasian deposits of Western Europe. He proposed the Lower Cretaceous stratigraphic scheme which was accepted by most Russian geologists. 相似文献
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通过对壤塘金矿带已知矿床及物化探异常等成矿信息的研究,确认“地层、岩浆岩、构造”三位一体的复合成矿条件,总结找矿标志,提出找矿方向。初步认为本区金矿的工业富集形成于晚印支期—燕山期岩浆（期后）热液活动阶段,表生淋积作用对矿床改造富集起着极为重要作用。 相似文献
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福建永定大排铁铅锌多金属矿床地质特征及找矿模式探讨 总被引：2，自引：0，他引：2
通过大量的野外地质调查,系统研究了永定县大排铁铅锌多金属矿床成矿地质背景和成矿作用、地质特征,分析了控矿地质条件,总结了找矿标志。认为大排铁铅锌多金属矿床为沉积-改造型矿床;控矿条件主要为晚石炭世经畲组至中二叠世楱霞组含矿层位及矿区内浅层次推覆构造;明确了含矿层位、控矿构造与容矿构造、岩浆岩、物化探异常、铁锰帽和古硐等作为找矿标志,结合区域其它矿床,建立该类矿床的找矿模式,以期指导闽西南地区铁铅锌多金属矿勘查工作。 相似文献
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四川扬子式铅锌矿床地质特征及资源潜力 总被引：2，自引：0，他引：2
简述了四川扬子式铅锌矿的分布特征及赋矿层位,分析了铅锌元素地球化学特征,初步总结了铅锌矿主要地质特征,圈定了找矿远景区,预测了铅锌矿资源潜力。 相似文献
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湘南红土型金矿地质特征及控矿因素 总被引：7，自引：0，他引：7
湘南红土型金矿的分布受东西向基底断裂和深源同熔型岩浆岩控制,矿体富集受浅部断裂、岩体接触带、一定的地层层位等因素控制。本文描述了已知红土型金矿的地质特征,分析了其控矿因素。 相似文献
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Using the Pauzhetka and Nizhnee Koshelevskoe geothermal deposits (South Kamchatka), we studied physical-chemical characteristics
of hydrothermal clays that form thick (on average, 1.5–1.8 m) and spacious (up to few km2 in area) subsurface horizon with peculiar petrophysical and mineralogical-geochemical properties. It was established that
the properties of hydrothermal clays are determined by their micro- and nanostructure, which is made up of nanoparticles of
aluminosilicates, sulfates, accessory and ore minerals (primarily, sulfides and iron oxides), and amorphous phases. The subsurface
horizon of hydrothermal clays represents a long-lived (up to 10 ka and more) highly dynamic colloidal-dispersed mineralogical-geochemical
system, which reflects the interaction of deep-seated metalliferous fluids with geological medium in the supergene zone of
geothermal deposits. 相似文献
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滇东北渔户村组富铅锌矿成矿地质特征及找矿标志 总被引：3，自引：4，他引：3
渔户村组为滇东北富铅锌矿的重要产出层位。通过成型或基本成型的茂租，金沙厂，五星，乐红，大海等矿床，论述了滇东北渔户村组富铅锌矿的成矿地质特征，认为其与热水沉积成矿作用和后期改造作用有关，并总结了地质找矿标志。 相似文献
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凤太矿集区是秦岭铅锌金成矿的重要组成部分,铅锌矿主要集中分布在矿集区的西部,可划分为南部的铅硐山―水柏沟铅锌(铜)矿带和北部的八方山―八卦庙―银母寺铜铅锌金矿带。目前区内发现的大、中型铅锌矿床均具有"沉积相+层位+构造"的"三位一体"的成矿规律,即热水喷流沉积是成矿的必备条件,古道岭组灰岩与星红铺组千枚岩接触面及附近是赋矿的主要层位,NWW向褶皱和断裂是控矿的重要因素。根据区域成矿规律、前人经验和野外总结,提出已知铅锌矿床的走向延伸部位、已发现矿体但勘查程度低的控矿背斜倾伏部位、受同一背斜控制的两个铅锌矿床之间的构造凹陷部位、与已知控矿背斜平行的次级隐伏背斜、白垩纪东河群下部、已知矿床两翼深部等部位是重要的找矿靶区和方向,应引起足够的重视。 相似文献
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In this work, approaches to the age of the so-called “horizon of variegated marls” are considered. Some researchers attributed
this horizon to the Triassic, while others considered it to be of Permian age. The dispute over the age of these deposits
was among the most important in the history of Russian stratigraphy in the second half of the 19th century and the early 20th
century. 相似文献
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鞍本地区鞍山群富铁矿成因类型的讨论 总被引：4，自引：0，他引：4
鞍本地区太古界鞍山群变质岩层中产出多层鞍山式铁矿,富铁矿均产在鞍山式铁矿的厚大贫矿层中。有人曾用“母大子肥”来比喻这种产出关系。本文认为厚大贫矿层是产出富矿的必要前提,但不是厚大贫矿层中均有富矿,即“母大”不一定“子肥”,还必须有后期成矿作用的叠加,才能造成“子肥”。这种后期叠加成矿作用主要是退化变质作用,有的地方混合岩化作用也造成小型富铁矿床。这两种叠加成矿作用的主要区分标准是:前者是在“封闭系统”条件下形成的富矿,矿石组分均来自含矿岩系本身,没有外来组分的加入;后者是在“开放系统”条件下形成的富矿,矿石组分中,有外来物质的加入。因此,富矿的形成必须具备两个条件:一是有形成厚大贫矿的有利层位;二是在厚大贫矿层中出现后期叠加地质 相似文献
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古河道型砂岩铀矿的主要地质特征及有关找矿工作的方针探讨 总被引：18，自引：7，他引：11
文章通过对俄罗斯、蒙古一些已知古道型铀矿床的调研,归纳了该类铀矿床空间定位的构造控制、铀源的近源性、潜水氧化成因、含矿层的单层位性等与勘查工作有关的地质特征,并在分析上述特征的基础上提出我国今后对古河道型砂岩铀矿勘查工作方面的对策和方针。 相似文献
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Oxidation of sulfide- and carbonate-rich vein gold deposits under semiarid conditions can be represented as a three-stage process, each creating supergene environments conducive to dissolution and reprecipitation of gold-silver alloys. The three-stage weathering process of sulfide-carbonate gold veins is depth-dependent, and develops from the relatively young, lowermost weathering horizon just below the water table, through an intermediate weathering horizon in the oxidation zone above the water table, and culminating in the oxide-rich upper saprolite and oxisol.Neoformed gold crystals in the weathering profile have distinct composition and morphologic characteristics from the hypogene gold crystals associated with the sulfide- and carbonate-rich ores. Two distinct types of secondary gold are present in the weathering profile: (1) gold crystals associated with sulfates and arsenates; and (2) gold crystals associated with iron and aluminum oxides/hydroxides, or with kaolinite. The distinct crystal morphologies and mineralogical associations of primary and secondary gold are useful in prospecting for gold deposits in weathered terrains. 相似文献