A Seismotectonic Zonation Map of Eastern Siberia: New Principles and Methods of Mapping

The paper reviews goals and objectives, stages and components of a seismotectonic study conducted in Eastern Siberia, Russia. Based on a comprehensive analysis of geological and geophysical data, our study establishes whether the local earthquakes are of tectonic origin and reveals relationships among earthquakes with recent geodynamic processes in the area under study. Seismic hazard assessment and evaluation of tectonic processes are the two major closely interrelated aspects of seismotectonic studies. A seismotectonic study is generally combined with a seismic study and conducted prior to the stage of detailed seismic zonation (DSZ) which is followed by seismic micro-zonation (SMZ). In three stages of the seismotectonic study, we analyze specific geological structures, reveal the regional dynamics of seismotectonic processes, clarify details of potential seismic hazard locations and identify sites of the potential instantaneous deformation of the crust which may take place due to active faulting. Based on results of our longterm studies, a seismotectonic zonation map of Eastern Siberia is compiled. The paper briefly reviews the methods of mapping and refers to data on active faults and neotectonic structures revealed in the area under study, which are closely related to regional earthquake sources.

琼州海峡跨海工程新Ⅶ线区地质条件及地质灾害因素评价

通过对琼州海峡跨海工程(固定式)新Ⅶ线调查区浅层地质—地球物理特征的研究,揭示了研究区的地形地貌特征及地质条件,并对区内主要地质灾害因素进行了评价研究,认为新Ⅶ线区内海底表面无障碍物,区内也无任何断层,目前在潮流的作用下仍在移动的沙波和沙垄是其主要的潜在地质灾害因素,而斜坡稳定性和砂土震动液化(海底以下20m范围内砂土层)在120年一遇的极端波浪荷载作用下或在地震基本烈度为Ⅶ度的情况下均不会构成该跨海工程的潜在地质灾害因素。同时还指出,虽然区内地质条件均属于不具活动能力的限制性地质条件,但其对工程设施仍具有不可忽视的潜在危险性,应给予足够重视。

Investigation of Glacial Effects and the Permanent Snow Lines on the Southern Slopes of the Hamadan Alvand Kuh

One of the issues that geomorphology researchers have focused on is to trace the geomorphic effects and the snow lines in the Quaternary glaciers in Iran. This research has been carried out in the valleys of the southern slopes of Alvand Kuh Mountains, namely the Serkan and Mobarakabad valleys. The equilibrium line altitude between current and ancient glaciers is one of the parameters that is used as a variation indicator of climate. There are several ways to rebuild this parameter (Ancient ELA). Equilibrium Line altitude requires the accurate knowledge of glacial geomorphic landforms and evidence. According to Kuhle, Hofer and Luis methods, providing and estimating the ancient and permanent snow lines were carried out in this research during field operations within several intervals and the glacial geomorphic evidences were identified such as circuses, sidebar moraines and terminal moraines. The six glacier subwatersheds were developed in a study area based on Kuhle, Hofer and Luis methods in which only two valleys of Serkan 3 and Mubarak Abad 3 had a high degree of accuracy in their ELA drop rate and old snow lines. It should be noted that the current snowlines of the current study area are 4400 m and 1400 m (based on the Schweitzer map). The results of the estimated snow lines for each of the six valleys are shown in Table 4. At the present study, the main of the Mobarak Abad valley area was divided to six glacial valleys which are called Serkan 1, 2, 3 and Mobarak Abad 1, 2, 3 and then several layers were provided, including cirque layers, moraine layers, primary and secondary crest layers, high crest layers, 10-meter DEM layer, highlight, different contour line layers and valleys profiles and finally, the ultimate map of glacial geomorphology of Serkan and Mobarak Abad valleys was prepared.

Late Quaternary fluvial terrace formation in the Luan River drainage basin,north China and its possible linkages with climate change and tectonic activation

The Luan River is the most important water system in north-eastern Hebei Province,China and is located in the transitional zone of the Eastern Yan Mountains,North China Plain and Songliao Plain.The well-developed river terraces of its tributary,the Yixun River,provide excellent information for studying neotectonics and climate change.There are seven terraces in the lower reaches of the Yixun River,numbered T7-T1.The optically stimulated luminescence dating results of 23 samples show that terraces T7-T2 formed at 111.36±5.83 ka,78.20±4.45 ka,65.29±4.15 ka,56.44±3.07 ka,40.08±2.66 ka,and 13.14±0.76 ka,respectively.A comparison with the oxygen isotope curves of deep-sea sediments reveals that the sediment formation of each terrace corresponded to cold periods of marine isotope stages MIS 4 and MIS 2 and the relatively cold periods of MIS 5e,MIS 3,and MIS 1.Since the Late Pleistocene,the incision rate of the Yixun River has ranged from 0.371-1.740 mm/a.During the formation of T7-T6,T5-T4,T4-T3,and T3-T2,the incision rate was low.However,in the two stages during which T6-T5 and T2-T1 formed(13.14±0.76 ka to 0.58±0.08 ka and 10.79±0.64 ka to 0.16±0.01 ka),these rates reached 1.554 mm/a and 1.592-1.740 mm/a,respectively.At approximately 30 ka,the activity of the Langying Fault increased,leading to footwall uplift.The river gathered in the north of Langying to form the ancient Erdaowan Lake,which resulted in the drying of the river in the lower reaches of the Yixun River during the last glacial maximum without forming river deposits.In the Early Holocene,headward erosion in the lower reaches of the Yixun River was enhanced,which resulted in the disappearance of the lake,and incised meandering formed due to increased neotectonism.Based on the analyses of river incision and the formation of ancient lakes and incised meandering,it was inferred that there have been three periods of strong tectonism in the river basin since the Late Pleistocene.

Late Quaternary Geomorphology of the Tonami Plain and Activity of the Tonami-Heiya Fault Zone, Toyama Prefecture, Central Japan

The Holocene alluvial fans and flood plains formed by the Sho and Oyabe Rivers spread out in the Tonami plain from the central through the northern parts in the Toyama Prefecture, central Japan. Along the foot of the surrounding mountains and hills, higher, middle and lower terraces of late Pleistocene-Holocene in age are distributed. These terraces have been displaced, by the reverse dip-slip activities of Tonami-heiya fault zone in a sense of upheaval in the mountains side, even during the Holocene time. We examined stratigraphic cross section utilizing borehole data and geomorphologically analyzed 5 m-DEM data in order to elucidate the fault trace of the Isurugi fault which Tonami-heiya fault zone. As the results, the northern segment of Isurugi fault seems to run along the northeastern foot of Hodatsu Hills and extends underground through the lower-most Oyabe River into the Toyama Bay. Consequently, its total length reaches about 30 km. In the southern segment, a continuous fault scarplet was recognized to cut across the lower dissected fans. The slip-rate of Isurugi fault is estimated to be 0.31 - 0.64 m/kyr. In the Hokuriku region, reverse faulting and related folding with strike in a NE-SW direction have occurred during the late Quaternary. The hinge line of block movement due to the activities of the Tonami-heiya fault zone is revealed to have shifted from the mountain side into the plain side within the Holocene time. In conclusion, the Quaternary folding and faulting associated with the crustal warping at a wavelength of about 20 km is currently in progress, causing both the subsidence of Tonami plain and the upheaval of surrounding mountains and hills.

Geomorphology and Hydrology of the Benin Region, Edo State, Nigeria

This paper examines the geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major landform features and processes of the region are highlighted. This region is a strategic and significant landscape in Nigeria. Information was gathered on the various aspects of the landscape, including the Geology, Physiography (Relief) and Geomorphology, Geomorphic processes, Weathering, Drainage processes, Landforms, Surface Water Hydrology and Water Resources. The Benin Region is underlained by sedimentary formation of the South Sedimentary Basin. The geology is generally marked by top reddish earth, composed of ferruginized or literalized clay sand. Geologically, the Benin Region comprises of 1) the Benin formation;2) alluvium;3) drift/top soil and 4) Azagba-Ogwashi (Asuba-Ogwashi) formation. Several parts of the region are surrounded by the Benin historical moats. The region has been described as a tilled plain in the south western direction. The local relief of the region is 91 m. Boreholes records in the Benin Region show evidence of deep chemical weathering overtime. Soil profile reveals that the region is composed mainly of reddish brown sandy laterite. Intermittent layers of porous sands of sandy clays may reach a large depth as found in the borehole drilled in the region. These are products of deep chemical decay of the original parent rock materials. Three river systems drain the Benin Region. They are the Ikpoba River, the Ogba River and Owigie-Ogbovben River systems. The mean annual discharge of Ikpoba River for 1982-1983 and 1993-2002 was 1411 mm/yr, which was 1.019 × 109 m3 with a mean annual baseflow of 1256.23 mm (0. 907 × 109 m3). This constitutes 87.65% of the total flow. It has a mean annual surface runoff of 225.18 mm (0.112 × 109 m3) or 24.4 % of the total discharge. The water resources of the region include surface water and underground water.

Analysis of the Geomorphology and Environmental Geological Problems of Huzhou on the Yangtze River Delta

Geomorphically, Huzhou, which is on the Yangtze River delta is characterized mainly by plains, with small hills. This paper presents a detailed analysis of the environmental geological hazards both natural and those incurred by human activities in different morphologic units. The authors point out that most of the regional environmental geological problems in the natural geologic-morphologic conditions, such as crustal stability, foundation of soft soil, soil waterlogging and soil erosion, have insignificant effects to the society, or related countermeasures of prevention and control have been adopted. But environmental geological problems incurred by human being's economic activities become more and more severe, for example, water and soil pollution and land subsidence in plain areas resulting from overexploitation of groundwater, and landslides, karst collapses and water and soil loss etc. caused by quarrying in hilly areas.

Development of Detailed Micro-Land Form Database and Its Application to Site Amplification Characteristics in Kanagawa Prefecture, Japan

Structural characteristic of surface soil ground has great effect on the ground motion amplitude when earthquake happens. Recent studies in Japan on seismic zonings use a database that covers entire Japan with 1 km mesh size, which is useful for prefecture scale researches. However, it is hard, even with 500 m or 250 m mesh sizes to consider a city, a county or award as scale studies. Kanagawa Prefecture is highly urbanized and vulnerable to seismic disaster. The prefecture suffered a wide spread damage during the 1923 Kanto earthquake. In this paper, we deploy a very fine mesh 50 × 50 m mesh to develop a general seismic intensity map useful for micro scale disaster management for local governments and educational information for earthquake preparedness promotion. In this paper, first we prepared two detailed databases for 50 × 50 m mesh size over entire Kanagawa Prefecture. One was for geologic formations and the other the geomorphologic condition. Then these databases were used for preparation of high-resolution digital soil classification maps for 15 categories of micro landforms of prefecture. The later database was used for mapping the site amplification factors for 50 × 50 m mesh by applying the empirical relations for AVS30. We could create a GIS platform with sufficient accuracy to consider potential risk analysis.

金塔南山第四纪构造地貌演化及其对青藏高原北向生长的启示

河西走廊是研究青藏高原新生代隆升和扩展的关键地区。金塔南山是位于河西走廊北部的年轻抬升山体,其构造地貌演化对理解青藏高原北向生长过程具有重要意义。本次研究以最新发现的金塔南山第四纪沉积剖面为研究对象,开展了沉积特征分析、年代学约束、构造变形分析和物源示踪等研究。结果表明,金塔南山剖面存在一期平行不整合面,将该剖面分为上下两部分:(1)下部层位为河流相地层,由来源于北祁连的碎屑物经过长距离搬运沉积而成,沉积时代为中更新世(0.64~0.60Ma);(2)上部层位为冲积扇相地层,是金塔南山山前近缘快速堆积的产物,沉积时代为晚更新世(118~80ka),明确揭示了金塔南山中更新世时期(0.6~0.1Ma)存在一期构造抬升事件,其构造变形直接控制了区域地貌演化过程:约0.6Ma之前,金塔南山还未显著抬升,来自北祁连山的碎屑物广泛沉积于该地区,形成一个大型的山前古冲洪积平原;0.6~0.1 Ma,北祁连前缘逆冲体系向北扩展至金塔南山断裂,金塔南山发生强烈的构造抬升,成为阻挡河流相地层沉积的地形屏障,造成沉积间断并形成平行不整合面;晚更新世时期(约0.1 Ma),平行不整合面之上堆积了一套来源于金塔南山的近缘冲积扇相沉积物。综合前人研究成果,认为晚新生代以来青藏高原东北缘构造变形向北渐次扩展,河西走廊第四纪以来仍进行着显著的高原北向生长过程。

Quaternary Gasfield in Qaidam Basin

ＱｕａｔｅｒｎａｒｙＧａｓｆｉｅｌｄｉｎＱａｉｄａｍＢａｓｉｎ￥ＬｅｉＢｉｎｇｚｕ（ＱｉｎｇｈａｉＰｅｔｒｏｌｅｕｍＡｄｍｉｎｉｓｔｒａｔｉｏｎ）ＰａｎＣｈａｏ（ＮｏｒｔｈｗｅｓｔｅｒｎＰｉｐｅｌｉｎｅＣｏｎｓｔｒｕｃｔｉｏｎＨｅａｄｑｕａｒｔｅｒｓ...

State Key Laboratory of Loess and Quaternary Geology

The State Key Laboratory Loess and QuaternaryGeology, Institute of Earth Environment, the ChineseAcademy of Sciences (CAS), was established in No-vember 1995. Its predecessor, CAS Xi’an-based Labo-ratory of Loess & Quaternary Geology, inauguratedin October 1984 in line with the suggestion of CASmembers Liu Dongsheng & Li Zhensheng. In March1987, the section was ratified to open to the outsideworld and honored as an outstanding laboratory forfour times in succeeding years.

Understanding the Interactions between Climate Change,Landscape Evolution,Surface Processes and Tectonics in the Earth System:What Can the Studies of Chinese Deserts Contribute?

Due to large deserts on Earth surface a thorough understanding of climate change, landscape evolution and geomorphological processes having occurred in deserts is crucial for Earth System Science. The landscapes in deserts are, however, diverse and different over the globe with regard to their geomorphological nature, human activities and geological histories. In the last decades a great number of efforts have been put to the investigation of the initial timing of the occurrence of arid climate, e. g. in northwestern China. Silty sediments in the downwind directions have been used to deduce the histories of deserts. In general, there is a lack of knowledge about processes and landscapes in Chinese drylands between the initial Miocene silt sedimentation at desert margins and the late Quaternary multiple occurrences of wetter climate with assumed large lakes in many of the deserts in northern China. The geomorphological concept of three primary triggering factors, i.e., the sediment supply, sediment availability and transport capacity of wind, and additionally the underground geology need to be fully considered for a better understanding of the environmental histories of sand seas which should not be viewed as equivalent for deserts because sand seas cover between 〈 1% and ca. 45% of the desert areas in various continents dependent on a complex interaction between various processes of both exogenous and endogenous origins.

Geomorphosite Valorization a View to Sustainable Development: Case of Ait Hajji, Oued Boulahmayel Valley, Central Morocco

The Pleistocene Fluvial-lacustrine of Ait Hajji Formation is located in South East of Tiddas, and in the Qua-ternary deposits of the Moroccan Central Plateau. These outcrops represent on a geomorphosite of great im-portance for the study of geological heritage, and for a natural eco-tourism valorization in Morocco. For to aim a natural tourism promotion, for indigenous peoples, this geomorphosite in question has an fluorescent and dense flora with a diversified fauna in the heart of one Ordovician quartzite bar and Devonian limestone ridges. In Oued Boulahmayel geomorphosite contains a memory geological Formation of a Pleistocene epi-sode, beginning firstly by a dynamic fluviatil land synchronous with a local volcanic activity (Phonolite ne-phelinc) replaced by a lake sedimentation related to the formation of a dam natural, created a few hundred meters downstream from Boulahmayel. For valorizing of the hinterland of the plains towns, it is necessary to develop a geo-eco-tourism integrated who provide its harvest and will argue the benefits resources of rural people of high-mountains in their own environment. It is proposed in the perspective to initiate a sustainable development approach, while ensuring the conservation and ensure the continued natural existence of the surroundings environments and to appreciate the potential of the region. Thus that beauty hidden in the hin-terland upstream to a tourist eager for discoveries, to encourage them to practice their stay as short as it is, in a safe space and very quiet. In order to materialize the concept of geo-eco-tourism, we must deploy the ef-forts of local people, policy makers and scientists in order to produce tourist maps with different interesting routes, to implant signal panels, to develop tracks campsites and trails within the forests, creating shelters and rest houses in private homes, as well as provide training for specialized guide’s rescuers.

QUATERNARY GEOLOGY & GEOMORPHOLOGY

20042223 Li Xian (Chengdu University of Technology, Chengdu, Sichuan ) ; YinJicheng Development and Protection of Manzhatang Wetland Natural Preservation in Sichuan Province, China (Resources Sur-

QUATERNARY GEOLOGY& GEOMORPHOLOGY

20160466Cao Fugen(No.1Geological Survey Team,Xinjiang Bureau of Geology and Mineral Resources and Development,Urumqi830013,China);Zhao Shuming Geological Characteristics and Significance of the Nanhua Period Tillite from Northern Yamansu Area in Eastern Tianshan,Xinjiang(Xinjiang Geology,ISSN1000-8845,CN65-1092/P。

QUATERNARY GEOLOGY & GEOMORPHOLOGY

20032911 Cao Jun (Regional Geological Surveying Team, BGEEMRSP, Shuangliu, Sichuan) Geological Trace Landscape Resources and Tourist Route Planning in the Hailuogou Geopark, Luding County, Sichuan Province, China (Acta Geologica Sichuan, ISSN1006-0995, CN51-1273/P, 22(3), 2002, p.175-177, 3 refs. , with English abstract)Key words: geologic remains Sichuan

中国区域地质研究的十大进展

今年,欣逢中国地质学会成立100周年,特以此文恭贺中国地质学会百年来所取得的光辉成就和对中国地质事业发展做出的卓越贡献。2008年,中国地质调查局下达了重编中国区域地质志的科研项目。经过十多年志书的编写获得了诸多创新性的区域地质研究成果,主要成果可以概括为十个方面:(1)大幅度地提高了全国地质研究程度和地质科技水平;(2)提出发展洋板块地质的学术思想,初步建立了洋板块地质构架;(3)地层研究取得重要新进展,完成全国显生宙构造-地层区划和地层格架研究;(4)开启了蛇绿岩研究新思路,拓宽了蛇绿岩研究范围;(5)前寒武纪地质研究获颠覆性科学成果,阐明了太古宙地壳演化规律,提出中—新元古界新的划分方案;(6)取得多项岩浆岩创新性科研成果,建立了中国及邻区侵入岩时空演化格架;(7)中国地质构造研究获突破性进展;(8)地球深部探测研究步入国际先进行列,建立了全方位“深地”探测研究科技支撑体系;(9)为资源环境评价开辟了新方向,海洋地质与第四纪地质调查研究取得长足进展;(10)探索了地质图件研编新模式,总结了地质制图的基本经验。

福建宁德地区第四纪年代地层时空特征及对海面变化的指示

【研究目的 】为厘定福建宁德地区晚第四纪地层框架,给予区域咸、淡水划分提供基础资料支撑,也为中国东部晚第四纪海侵研究提供可供对比的新资料。【研究方法 】通过对NDGK2孔的岩性、年代、微体古生物分析,区域钻孔对比,重建了其晚第四纪地层框架,进一步探讨了区域地层展布特征及演化过程。【研究结果 】NDGK2孔第四纪地层晚更新世以来的沉积,自下而上存在3层深灰色黏土,年龄分别为~90 ka、39~44 ka、<10 ka。【结论 】NDGK2孔第四纪地层发育于古风化壳之上,主要为中更新世末—晚更新世初以来的沉积。钻孔岩心中存在3层深灰色黏土层,很可能均为海侵时期沉积物,3层深灰色黏土层可能分别对应于MIS5、MIS3和MIS1期。深灰色黏土层发育空间差异性,MIS3较MIS5期海侵范围扩大,当时古地势已经接近现代地势,构造沉降明显,MIS3之后构造相对稳定,伴随着全新世最大海侵面的影响,形成了最广泛的一次海侵。

关于是否在地层系统中取消“第四纪”(Quaternary)一名词的讨论和危机

文章详细介绍了最近INUQA组织和INQUA地层与年代学委员会在“Episodes”杂志 2 0 0 4年第 2 7卷第 2期公布的新的地质时代标尺 ,并就关于“第四系”这个地层单位的重新定义问题提出了重要的见解。对于取消“第四纪”(Quaternary)一词 ,发表了意见以及不认同的观点 ,同时文章还呼吁 ,希望更多的从事第四纪研究的工作者踊跃发表意见、积极呼吁 ,使“第四纪”(Quaternary)一词正式保持不变。