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1.
To the north of Hanoi, about a day's drive by car, lies Ha Giang Province, the northernmost region of Vietnam. Ha Giang is remote from the hustle and bustle of daily life, and beyond its eponymous provincial capital towards the border with China, mountains rise quickly to Quan Ba, ‘Heaven's Gate’. The mountains form an uneven landscape of steep‐sided karst rising from deep river‐cut gorges and form a formidable barrier on the northern frontier of Vietnam. Beyond ‘Heaven's Gate’ lies the little travelled region of Dong Van, with its majestic mountains of Palaeozoic strata rising precipitously to the sky. Here, a century ago, the French geologists Henri Mansuy and Jacques Deprat documented early finds of fossils from lower Palaeozoic strata on the border with China.  相似文献   

2.
The major tectonic zone that passes through the border regions of the Anhui, Zhejiang, and Jiangxi Provinces in southeast China has been commonly referred to as the Wan-Zhe-Gan fault zone. Geologically, this zone consists of several regional fault belts of various ages and orientations. We have categorized the faults into four age groups based on field investigations. The Neoproterozoic faults are northeast striking. They start from the northeast Jiangxi Province and extend northeastward to Fuchuan in Anhui Province, the same location of the northeast Jiangxi-Fuchuan ophiolite belt. The faults probably acted? during the Neoproterozoic as a boundary fault zone of a plate or a block suture with mélange along the faults. The nearly east-west- or east-northeast-striking faults are of Silurian ages (40Ar/39Ar age 429 Ma). This group includes the Qimen-Shexian fault and the Jiangwang-Jiekou ductile shear belt. They represent a major tectonic boundary in the basement because the two sides of the fault have clear dissimilarities. The third group of faults is north-northeast striking, having formed since the early-middle Triassic with 40Ar/39Ar ages of 230–254 Ma. They form a fault belt starting from Yiyang in northern Jiangxi and connect with the Wucheng as well as the Ningguo-Jixi faults. This fault belt is a key fault-magmatic belt controlling the formation of Jurassic-Cretaceous red basins, ore distribution, magmatic activity, and mineralization. When it reactivated during the late Cretaceous, the belt behaved as a series of reverse faults from southeast to northwest and composed the fourth fault group. Therefore, classifying the Wan-Zhe-Gan fault zone into four fault groups will help in the analysis of the tectonic evolution of the eastern segment of the Jiangnan orogen since the Neoproterozoic era.  相似文献   

3.
The Isle of Portland is one of the jewels in the crown of the ‘Jurassic Coast’ of Dorset, southern England. Thomas Hardy aptly described this limestone peninsula as the ‘Gibraltar of Wessex’, and used its stone quarries as the backdrop for one of his novels (The Well‐Beloved). Quarries then, as now, work the world‐famous Portland Stone—a Jurassic oolitic limestone—from which St Paul's Cathedral and many other well‐known buildings are constructed. Rocks exposed in the numerous disused quarries scattered across the isle, together with exposures in spectacular sea‐cliffs, paint a vivid picture of life and environments, ～150 million years ago. In addition to Jurassic patch‐reefs, coastal sabhkas, fossil forests and dinosaur footprints found in the bedrock, more recent geological phenomena include two Quaternary raised beaches, solution caves filled with vertebrates, and massive coastal landslips. The aim of this article is to provide a field guide for those wishing to explore the geology of this little‐known region for themselves.  相似文献   

4.
Previous studies have obtained some petrogenetic and metallogenic chronological data with SHRIMP (sensitive high-resolution ion microprobe) zircon U-Pb, zircon LA-ICPMS (laser-ablation–inductively coupled plasma mass spectroscopy) U-Pb, molybdenite Re-Os isochron and muscovite Ar-Ar methods in southern Jiangxi Province and its adjacent areas. Based on these, the purpose of this paper is to study the petrogenetic and metallogenic ages and their time gap for different genetic types of W-Sn deposits, and thus to research their numerous episodes, zonal arrangement and their geodynamic background. The result shows that the large-scale W-Sn mineralization in southern Jiangxi Province occurred in the middle to late Jurassic (170–150 Ma), the skarn W-Sn-polymetallic deposits formed much earlier (170–161 Ma), and all of the wolframite – quartz vein type, greisen type, altered granite type and fractured zone type tungsten deposits formed in the late Jurassic (160–150 Ma). In one ore field or ore district, greisen type tungsten deposits formed earlier than quartz vein type ones hosted in the endo- or exo-contact zone; and quartz vein type hosted in the endocontact zone formed earlier than that of exocontact zone. There is no significant time difference between tungsten-tin mineralization and its intimately associated parent granite emplacement (1–6 Ma). They all formed in the same rock-forming and ore-forming system and under the same geodynamic setting. Regionally, rock-forming and ore-forming processes of the W-Sn deposits in the Nanling region (include southern Jiangxi Province, southern Hunan Province, northern Guangdong Province and eastern Guangxi Zhuang Autonomous Region) exhibit numerous episodes. The mineralization in the Nanling region mainly occurred at (240–210) Ma, (170–150) Ma and (130–90) Ma. The tungsten-tin deposits in this region are centered by the largest scale in southern Jiangxi Province and southern Hunan Province, and become small in the east, west, south and north directions. This displays a zonal arrangement and temporal and spatial distribution regularity. Integrated with the latest research results, it is concluded that the W-Sn mineralization in southern Jiangxi Province and its adjacent areas corresponds to the second large-scale mineralization in South China. The Indosinian W-Sn mineralization formed under the extensional tectonic regime between collisional compressional stages, while the Yanshanian large-scale petrogenetic and metallogenic processes occurred in the Jurassic intraplate extensional geodynamic setting of lithosphere extension.  相似文献   

5.
The Kingston Peak Formation of the Pahrump Group in the Death Valley region of the Basin and Range Province, USA, is the thick (over 3 km) mixed siliciclastic–carbonate fill of a long‐lived structurally‐complex Neoproterozoic rift basin and is recognized by some as a key ‘climatostratigraphic’ succession recording panglacial Snowball Earth events. A facies analysis of the Kingston Peak Formation shows it to be largely composed of ‘tectonofacies’ which are subaqueous mass flow deposits recording cannibalization of older Pahrump carbonate strata exposed by local faulting. Facies include siltstone, sandstone and conglomerate turbidites, carbonate megabreccias (olistoliths) and related breccias, and interbedded debrites. Secondary facies are thin carbonates and pillowed basalts. Four distinct associations of tectonofacies (‘base‐of‐scarp’; FA1, ‘mid‐slope’; FA2, ‘base‐of‐slope’; FA3, and a ‘carbonate margin’ association; FA4) reflect the initiation and progradation of deep water clastic wedges at the foot of fault scarps. ‘Tectonosequences’ record episodes of fault reactivation resulting in substantial increases in accommodation space and water depths, the collapse of fault scarps and consequent downslope mass flow events. Carbonates of FA4 record the cessation of tectonic activity and resulting sediment starvation ending the growth of clastic wedges. Tectonosequences are nested within regionally‐extensive tectono‐stratigraphic units of earlier workers that are hundreds to thousands of metres in thickness, recording the long‐term evolution of the rifted Laurentian continental margin during the protracted breakup of Rodinia. Debrite facies of the Kingston Peak Formation are classically described as ice‐contact glacial deposits recording globally‐correlative panglacials but they result from partial to complete subaqueous mixing of fault‐generated coarse‐grained debris and fine‐grained distal sediment on a slope conditioned by tectonic activity. The sedimentology (tectonofacies) and stratigraphy (tectonosequences) of the Kingston Peak Formation reflect a fundamental control on local sedimentation in the basin by faulting and likely earthquake activity, not by any global glacial climate.  相似文献   

6.
Analyses of 3‐D seismic data reveal that pre‐Triassic basins are present underneath the Mesozoic North Træna Basin (Lofoten Margin, Norway). These are linked to a Cordilleran‐style metamorphic core complex that developed in Palaeozoic times, including rotated fault blocks with hanging wall ‘growth’ wedges, bounded by listric faults that sole into a sub‐horizontal detachment. On the basis of similarity in age, structural style and transport direction, we propose a kinematic link with a Permian mylonitic detachment documented onshore. This study presents the first offshore evidence for Palaeozoic detachment faulting, elucidating the mechanisms behind the long‐lived exhumation history of the Lofoten basement.  相似文献   

7.
程金华  马冬 《安徽地质》2013,(2):108-111,115
赋存于中元古代大谷运组上段地层中的绩溪县洪坑板岩类砚石,通过与歙砚石～歙县龙头石及江西龙尾石、九江石、大畈石、玉山石的物理化学参数测试资料对比分析,歙砚石其原岩均为泥砂质构造沉积岩,但岩性、成分、物理化学性能特征存在一定差异,与歙砚石—龙尾石属于不同成因机制的砚石。  相似文献   

8.
Detachment structures occur widely in the crust, and it is the commonest and most important deformation type developed in the region between orogenic belts and basins. The ‘comb-like’ and ‘tough-like’ fold belts in eastern Sichuan are caused by multi-layer detachment. The duplex structure is the most important deformation style in the region, exhibiting different characteristics from typical detachment structures. Different deformation styles, scales, and shortenings resulting from independent deformations of various detachment systems would lead to the phenomenon whereby most of the topographical heights in the region do not correspond to the structural heights in depth. Based on systematic structural analysis and combined with practical oil/gas prospecting, four types of structural traps are described from eastern Sichuan Province, which are: detachment and thrust trap; detachment folding trap; fault-flat blocking trap; and detachment layer trap. Meticulous studies on the deformation and distribution of detachment layers in the eastern Sichuan Province will contribute to oil/gas prospecting and selection of potential regions of marine-origin oil/gas prospecting in South China.  相似文献   

9.
The Neptunist‐Vulcanist controversy has distorted the reputations of both James Hutton and Abraham Gottlob Werner. Among English‐speaking geologists, Hutton is often presented as the Father of Modern Geology, whereas Werner's views are seen as ‘palpably absurd’. Both men made major contributions to geology, but they were men of their age, the second half of the eighteenth century, and remote in their general ideas from those current since Lyell's day in the mid‐nineteenth. Werner was greatly admired by some of his ablest contemporaries, and their admiration becomes inexplicable if we regard his views as ‘palpably absurd’. Historical research in the last few years, reviewed here, is able to show how Werner's views arose and why they seemed persuasive at the time. Some examples of Neptunist observations in Australia in the 1820's are given to show the application and later modification of the theory.  相似文献   

10.
The ‘Maresfield Map’ is a map that purports to show features pertinent to the old iron industry in the Sussex Weald of southern England in 1724. It first appeared in a journal published by the Sussex Archaeological Society in early 1913, at roughly the same time as the formal publication by the Geological Society of London of papers introducing the discovery of the ‘remains’ of what became known as ‘Piltdown Man’ to the world. Piltdown Man was eventually revealed as fraudulent in 1953, followed by the Maresfield Map in 1974. Experiments in replication now show that the Maresfield Map is a sort of ‘treasure map’ (in a negative sense), which points fairly accurately to the supposed find‐spot of Piltdown Man, along with a coded accusation against Charles Dawson. The map's compiler is thought to have been L.F. Salzmann, the editor of the journal in which the map appeared. As such, the map represents the only such denunciation to have been published in the open literature in Dawson's lifetime, albeit a cryptic one. Mr Salzmann's possible motives are explored.  相似文献   

11.
姜勇彪  郭福生  黎广荣  李蓉  楼法生  汪震  陈留勤  郄海满  闫罗彬  李益朝  凡秀君 《地质论评》2023,69(5):2023050014-2023050014
晚白垩世至古近纪期间,江西省内沿区域性断裂构造发育30余个断陷盆地,沉积了巨厚的红色陆相碎屑岩,为丹霞地貌的形成提供了物质基础。已发现的228处丹霞地貌点主要分布于江西东部武夷山北麓和西麓的红层盆地内。利用面积—高程积分法,对江西省9个盆地的丹霞地貌演化阶段进行了定量分析,结果表明省内丹霞地貌景区的面积—高程HI为0.17~0.52,平均为0.38,即其演化阶段处于壮年晚期至老年早期,在空间分布上具有由南向北,由壮年期转为老年期的趋势。该趋势可能与武夷山的构造隆升有关。构造分析显示,节理与武夷山的隆升对江西丹霞地貌演化起控制作用,具体表现为：① 龙虎山、九仙湖、仙岩、蛤蟆坞、赭亭山、龟峰等地发育的崖壁、一线天、巷谷、石墙、石寨、峰丛、峰林等丹霞典型景观均与节理有关。② 流水侵蚀等外营力的作用对丹霞地貌的剥露、削平起重要作用,统计表明距离武夷山越近,丹霞地貌山峰越密集、崖壁越陡峻,指示武夷山的隆升与丹霞地貌的发育有直接关系。总体来看,江西省内的红层为丹霞地貌的发育提供了物质基础,武夷山的隆升控制了丹霞地貌的分布。值得注意的是,丹霞地貌区的节理构造是否与武夷山的隆升存在直接因果关系还需进一步研究。  相似文献   

12.
The Miocene to Modern Baram Delta Province is a highly efficient source to sink system that has accumulated 9 to 12 km of coastal–deltaic to shelf sediments over the past 15 Myr. Facies analysis based on ca 1 km of total vertical outcrop stratigraphy, combined with subsurface geology and sedimentary processes in the present‐day Baram Delta Province, suggests a ‘storm‐flood’ depositional model comprising two distinct periods: (i) fair‐weather periods are dominated by alongshore sediment reworking and coastal sand accumulation; and (ii) monsoon‐driven storm periods are characterized by increased wave‐energy and offshore‐directed downwelling storm flow that occur simultaneously with peak fluvial discharge caused by storm precipitation (‘storm‐floods’). The modern equivalent environment has the following characteristics: (i) humid‐tropical monsoonal climate; (ii) narrow (ca <100 km) and steep (ca 1°), densely vegetated, coastal plain; (iii) deep tropical weathering of a mudstone‐dominated hinterland; (iv) multiple independent, small to moderate‐sized (102 to 105 km2) drainage basins; (v) predominance of river‐mouth bypassing; and (vi) supply‐dominated shelf. The ancient, proximal part of this system (the onshore Belait Formation) is dominated by strongly cyclical sandier‐upward successions (metre to decametre‐scale) comprising (from bottom to top): (i) finely laminated mudstone with millimetre‐scale silty laminae; (ii) heterolithic sandstone–mudstone alternations (centimetre to metre‐scale); and (iii) sharp‐based, swaley cross‐stratified sandstone beds and bedsets (metre to decimetre‐scale). Gutter casts (decimetre to metre‐scale) are widespread, they are filled with swaley cross‐stratified sandstone and their long axes are oriented perpendicular to the palaeo‐shoreline. The gutter casts and other associated waning‐flow event beds suggest that erosion and deposition was controlled by high‐energy, offshore‐directed, oscillatory‐dominated, sediment‐laden combined flows within a shoreface to delta front setting. The presence of multiple river mouths and exceptionally high rates of accommodation creation (characteristic of the Neogene to Recent Baram Delta Province; up to 3000 m Ma−1), in a ‘storm‐flood’‐dominated environment, resulted in a highly efficient and effective offshore‐directed sediment transport system.  相似文献   

13.
The British Geological Survey is home to more than three million fossils collected over two centuries and catalogued with enormous precision. However, as generations of curators have come and gone, a few collections have lain forgotten and their significance has gradually passed out of memory. Six months ago, I pulled opened some drawers marked ‘unregistered fossil plants’ in one of the Survey's windowless vaults in Keyworth, in central England. What I found inside made my jaw drop. Contained within were hundreds of beautiful thin sections of fossil wood dating from the early nineteenth century. The collection was assembled by botanist Joseph Hooker (Darwin's best friend) while he was briefly employed by the Survey in 1846. The material includes some of the first thin sections ever made by William Nicol, the pioneer of petrography, in the late 1820s, as well as specimens picked up by Darwin and Hooker on their round‐the‐world voyages in the 1830s and 1840s. The collection is particularly interesting in the way it sheds light on the vibrant and sometimes murky world of early nineteenth century science. This is the story of these fascinating fossils.  相似文献   

14.
British geology reveals many good looking rocks, both ‘soft’ and ‘hard’, some of which were once highly prized for their polished decorative uses. They were quarried, cut, shaped and finished in a locally‐based British decorative stone industry that flourished twice, first in the Middle Ages, based largely on Purbeck marble from Dorset and also alabaster from Derbyshire, and then again in the nineteenth century when diverse sources of coloured and textured stone were pursued to the far corners of the British Isles. Today only the finished products survive; the pillars, panels and pavement adorning some fine but dusty architecture, but the stones commonly languish unrecognized and unappreciated. This anonymity is quite out of line with the heritage status of their settings and it will take a bit more geological awareness to put that right. A recent project aimed at rediscovering just one regional category of British decorative stones, the Devonshire marbles, has revealed how diverse and extensively‐used the fuller range of British decorative stones actually is. Not only do they embellish buildings from the merely modest to some of our finest, they were latterly chosen, specified, designed and coordinated by some of our greatest architects. Much work needs to be done to recognize British decorative stones in architectural settings and to restore them to their proper place in our national heritage. It is hoped that this article will throw light on the task ahead.  相似文献   

15.
One of the earliest written references to zircon is from Lydgate's edition of Aesop's Fables from c.1400 where a zircon was found ‘hid in the dunghill’. Since the humble surroundings of this early record, zircon has become a popular and important mineral. The name zircon is believed to have derived from the Persian words ‘zar’ and ‘gun’ meaning gold and colour respectively. During the Middle Ages, it was believed that wearing zircon jewellery was a cure against insomnia and protected against disease. In more modern times, zircon has found uses in industrial processes and is a key mineral for geologists investigating the geological history of the Earth. It can incorporate uranium which undergoes radioactive decay to lead at a constant rate. By measuring the ratios of uranium and lead isotopes, geologists can calculate the age at which zircons formed. Physical and chemical durability makes zircon able to survive for long periods of geological time and record information about hallmark geological events in Earth history, including early crustal formation, mountain‐building events and mass extinctions. Indeed, the oldest known material on the planet is a zircon from Jack Hills in Western Australia, dated at 4.4 billion years old, a mere 0.15 billion years after the formation of the Earth. This remarkable durability has also led to zircon finding commercial applications in high‐temperature industrial processes, such as brick foundries, while its chemical inertness makes it a potential material for testing the impact of the radioactive products of nuclear waste on mineral structures.  相似文献   

16.
Multidisciplinary Quaternary investigations in the Minusinsk Basin in the upper Yenisei River region and other southern Siberian continental depressions have produced evidence of prehistoric peopling pre‐dating the last glacial stage (>100 ka BP). Abundant ‘pebble tools’ and bone artefacts exposed from eroded alluvia of the Yenisei River terraces indicate repeated occupation of this territory since the Middle Pleistocene. A new stage of expansion of the early human occupation habitat occurred around the last interglacial (OIS 5e) by a Middle Palaeolithic (Neanderthaloid?) population characterized by a core and flake stone industry and open‐air occupation sites. The key camp/kill‐processing site at Ust‘‐Izhul’, dated to c. 125 ka BP and documenting complex behavioural activities, is so far the most complete in situ pre‐Late Palaeolithic site found in Siberia. This unique record provides new insights into the timing and the palaeoenvironmental conditions of the Pleistocene colonization of north‐central Asia.  相似文献   

17.
Chlachula, J. & Serikov, Y. B. 2010: Last glacial ecology and geoarchaeology of the Central Trans‐Ural area: the Sosva River Upper Palaeolithic Complex, western Siberia. Boreas, 10.1111/j.1502‐3885.2010.00166.x. ISSN 0300‐9483. Quaternary and geoarchaeology studies from the eastern limits of the Ural Mountains provide multiple lines of evidence of the Palaeolithic peopling of this geographically marginal and still poorly explored territory of western Siberia following the mid‐last glacial (MIS 3) warming. A complex of investigated open‐air localities in the Sosva River basin (the north‐central Trans‐Ural area) at the periphery of the western Siberian Plain, distinguished by very high concentrations of Pleistocene megafaunal remains previously regarded as ‘mammoth cemeteries’, indicate, in conjunction with the associated diagnostic ivory/bone and stone industry, open occupation sites during the Last Glacial (MIS 2). Fossil faunal remains, dominated by mammoth (98%) together with bird and fish species, indicate various methods of exploitation of the Late Pleistocene natural resources and successful behavioural adaptation to the last glacial sub‐polar tundra‐steppe environment. The taphonomy and composition of the well‐preserved skeletal remains from the main occupation sites suggest both active hunting and anthropogenic ‘scavenging’ practices. The contextual geology and the cultural and biotic multi‐proxy records from the Trans‐Ural Upper Palaeolithic Complex provide new insights into the timing and palaeoecological conditions of the Pleistocene human occupation of north‐central Asia.  相似文献   

18.
This paper deals with the scientific assessment of the physical properties of sandstone used in the conservation of Sydney's historic heritage sandstone buildings. The local Hawkesbury Sandstone has been widely used for all manner of constructions since the early days of the first settlement. In the nineteenth century, dimension sandstone quarries existed all over the Sydney region, and the demand for the stone was great. During this time, a true ‘freestone’ known as ‘yellow block’ sandstone, in which bedding planes were absent, was quarried extensively. This sandstone is also known as a ‘self-colouring’ sandstone, where the rock, although grey when quarried, turns a yellow–brown after a few months exposure to the atmosphere. It can be easily carved and was eminently suitable for the ornate Victorian architecture of the time. There are very few quarries within the Sydney region today capable of producing ‘yellow block’ sandstone. Whenever possible, sandstone from suitable building excavations, particularly on the Pyrmont Peninsula, is used for this work. Conservation work is extremely expensive and the building elements that most need replacement, the overhanging and decorative elements, are usually those that cost the most. It is essential that the most durable replacement stone be selected. Thus, a strict regime of scientific testing is used for any major conservation project, in order to determine the physical properties of possible replacement stone. This is the province of the geologist and involves visual observation in the quarry or excavation, which is a simple, cost-effective means of weeding out poor quality stones, followed by laboratory engineering tests to establish the physical parameters of a sandstone and finally, petrographic analysis. The results of such tests, combined with careful sampling, ensure the best possible quality of replacement material.  相似文献   

19.
Stockwell's structural divisions of the Canadian Shield, and his Precambrian time‐classification based on major tectono‐thermal events are reviewed. The three main divisions of Proterozoic time, the Aphebian, Helikian, and Hadrynian Eras, follow the Kenoran, Hudsonian and Grenvillian Orogenies, whose terminations are currently dated on the U‐Pb scale at about 2550, 1750, and 1000 m.y. before present, respectively.

Proterozoic supracrustal sequences are most commonly of shallow marine or continental origin, and high‐level intrusions predominate. ‘Classical’ geosynclinal cycles have been restricted to the Aphebian Era.

High‐grade Aphebian rocks in the mid‐Churchill Province evidently mark the peak of Hudsonian tectonism. Subsequently, the Shield became relatively stable except for the Grenville Province, and deposition and deformation resulted from epeirogenesis, block‐faulting and rifting, mainly in the western Shield. Proterozoic sedimentation and volcanism likewise diminished in Helikian time and terminated in early Hadrynian time, about 800 m.y. ago.

The history of the Grenville Orogen remains obscure. The continuity of major Archaean to Helikian rock units into the Grenville from adjacent provinces constrains proposals for a marginal plate boundary and convincing evidence for Proterozoic plate boundaries within the Grenville Province is lacking, palaeomagnetic evidence notwithstanding.  相似文献   

20.
Several paleoseismic events are recorded in the Neogene Linqu Group, exposed in the Linqu area, Shandong Province, China. The events were interpreted on the basis of fieldwork and laboratory analysis, which showed the presence of seismites with plastically deformed soft-sediment deformation structures in the Shanwang Formation, and of seismic volcanic rocks in the Yaoshan Formation which show brittle deformation. The earthquake-triggered soft-sediment deformations in the seismites include load structures, ball-and-pillow structures, flame structures, pillow-like beds, boudinage structures, slump folds, syn-depositional faults, veins of liquefied sand, and dikes of liquefied sandy lime-mud. The seismic activity is also reflected in what might be called ‘brittle seismites'; these originated when, under the influence of seismic vibrations, semi-consolidated conglomerate was shattered. Moreover, volcanic activity is related to intense earthquakes that affected basalts intercalated with sand layers; these successions are known as ‘seismic volcanic rocks', which are characterized by veins of liquefied sand intruding the basalts. All above traces of paleoseismic activity were left from one single time span of 4 Ma with active seismicity that took place 14–10 Ma. This time span is known as ‘the Linqu Neogene Paleoseismic Active Period', which is divided into four paleoseismic episodes, which were responses to tectonic extension and basin rifting in this area. It even includes the activity of the Yishu Fault Zone during the Miocene and the Neogene. The ratios of trace elements in the seismites, w(La)/w(Sc) and w(La)/w(Th) are higher than the average value of the upper crust, but w(Th)/w(Sc) is lower; this is geochemical evidence for the basin rifting that resulted in a high sedimentation rate. The intense and frequent paleo-earthquakes are held responsible for the rapid burial of the Shanwang Biota. Secondary earthquake-induced processes(e.g. slumping of a lake shore and the strongly increased lacustrine sedimentation rate) contributed to the rapid burial of the biota.  相似文献   

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