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[en] Full text: Character of the spread of the plate-tectonic structures of Paleotethys and its oceanic basins including plan and age of the deformation as well as relation between Paleotethys and Mesotethys and the other issues are urgent debatable problems of the Paleozoic-Triassic geology in the region. As a result of complex geologic, magmatic, tectonic, paleo bio geographic, geophysical and cosmotectonic studies in the Caucasus, Zacaspian and Iran there were constructed geo dynamic maps on the paleo tectonic basis for certain time sections starting from the Cambrian transition stage till the Triassic models of Paleotethys evolution for two near-meridional geo traverses Arabian margin of Gondwana and in the north it crosses the East-European platform. In the Cambrian the change of the carbonaceous facies by the arkosicsandstones and quartzites in the Gondwana and in the East-European platforms is associated with the absolute elevation and washout of the Caspian-Caucasian shield. This is a precursor of more significant events and processes. There probably occurred a large structural reconstruction in the boundary of the Cambrian and the Ordovician associated with the beginning of the opening of the Caucasian, Turkestan and Ural pale oceans. As a result of the continental riftogenesis that in the next stage is transformed from the rifting into the spreading of the oceanic crust the double deep-water basins of Paleotethys were separated. The closure of neo-Paleotethys in the late Triassic was preceded by the crack of Gondwana and location of a system of the branching rifting and spreading of Mesotethys
[en] Complete text of publication follows. Kutch is demarcated as zone V in the seismic zoning map of India and the Bhuj earthquake of 26th January, 2001 with a magnitude of 7.8, is considered as one of the largest intraplate earthquakes. Major part of the basin is covered by the inaccessible Great Rann of Kutch and the little Rann of Kutch due to which the existing geophysical data coverage is very poor. To have a clear picture of the structural and tectonic frame work and understand the lithology of the region a semi detailed high-resolution airborne magnetic survey, at an altitude of 200m and line spacing of 1km, was conducted during the period January to May 2008, covering an area of 56593 sq. km over the Kutch basin and surrounding areas. The anomaly map depicts several major E-W, NE-SW and NW-SE oriented lineaments and faults, which are extending up to the Indian plate boundary. All major geologic and tectonic elements including the trap flows, the Kutch Main land Fault, the volcanic islands, extension of the Cambay basin towards north and Delhi-Aravalli towards the west, etc. find expression on the anomaly map. The shallow level magnetic sources are identified as trap flows and volcanic plugs. At deeper level, the whole region can be divided into two units corresponding to the Dharwarian and Delhi-Aravalli trends. These two tectonic units are separated by a NW-SE trending transition zone. Similar pattern is evident in the seismic tomography map at depths of 20 and 25km. Few magnetic and gravity profiles have been selected across this transition zone to throw light on its tectonic setting. Available MT, GPS, Gravity and Heat flow data have been utilized to arrive at a geodynamical model of the seismically active Kutch region. Results of this analysis will be presented.
[en] Six hundreds and eighty earthquakes causing significant damage have been recorded since the 7. century in Japan. It is important to recognize faults that will or are expected to be active in future in order to help reduce earthquake damage, estimate earthquake damage insurance and siting of nuclear facilities. Such faults are called 'active faults' in Japan, the definition of which is a fault that has moved intermittently for at least several hundred thousand years and is expected to continue to do so in future. Scientific research of active faults has been ongoing since the 1930's. Many results indicated that major earthquakes and fault movements in shallow crustal regions in Japan occurred repeatedly at existing active fault zones during the past. After the 1995 Southern Hyogo Prefecture Earthquake, 98 active fault zones were selected for fundamental survey, with the purpose of efficiently conducting an active fault survey in 'Plans for Fundamental Seismic Survey and Observation' by the headquarters for earthquake research promotion, which was attached to the Prime Minister's office of Japan. Forty two administrative divisions for earthquake disaster prevention have investigated the distribution and history of fault activity of 80 active fault zones. Although earthquake prediction is difficult, the behaviour of major active faults in Japan is being recognised. Japan Nuclear Cycle Development Institute (JNC) submitted a report titled 'H12: Project to Establish the. Scientific and Technical Basis for HLW Disposal in Japan' to the Atomic Energy Commission (AEC) of Japan for official review W. The Guidelines, which were defined by AEC, require the H12 Project to confirm the basic technical feasibility of safe HLW disposal in Japan. In this report the important issues relating to fault activity were described that are to understand the characteristics of current fault movements and the spatial extent and magnitude of the effects caused by these movements, and to estimate the spatial extent of future fault movements and their effects on the geological environment. One conclusion from the report is that present active faults in Japan have moved repeatedly for at least the last several hundred thousand years and are likely to continue to do so under the same stress field in the next a hundred thousand years. The latest knowledge relating to active faults and features of active faults to be considered for the stability of geological environments are described. (author)
[en] The Uruguay and magmatic associations with alkaline affinity are locally developed related either to final distensional events of the Brasiliano Cycle or to the Mesozoic tectonics. Preliminary results correspondent to the plutono-volcanic activity recognized in the Valle Chico Alkaline Massif, focusing petrographical and geochemical variations from Shoshonitic Associations to potassic transitional alkaline, associations, are presented in this paper.(author)
[en] In the Sierra Arana area, dextral transcurrent faults form a set of long and narrow E-W tectonic bands, some of which are filled by Oligo-Aquitanian and Cretaceous sediments deeply squeezed among Jurassic carbonates. These bands form a “flower structure” which higher blocks, cut by the faults, fallen over Oligo-Aquitanian sediments, forming a tectonic mélange. The crest zone of Sierra Arana indicates the position of a great reversed south verging anticlinal. The elements situated directly to the south of Sierra Arana, are attributed to a very internal Subbetic or to the Dorsal, and seem to correspond to the paleogeographic passage from the Subbetic to the Malaguide Complex. (Author)
[en] By now fewer research works have been done in Qimantage area, western section of Eastern Kunlun Mountains. A little published dating data fell into Indosinian period. A series of zircon fission track ages from granitoid samples were achieved and multiphase tectonic-magmatic activities were revealed in this paper. The zircon fission track age range from 201 Ma to 109 Ma might be divided into four groups, i. e. 201 Ma, 185 Ma, 164-16.3 Ma and 139-109 Ma. These ages indicate two compressional and two stretching tectonic activities. The 201 Ma and 139-109 Ma ages present northward subductions of Qiangtang Terrane and Gangdise Terrane in Middle-Later Triassic and Late Jurassic respectively, resulting in collision-convergencies with north-side terranes. The ages of 185 Ma and 164-163 Ma reflect postorogenic stretching events in Early Jurassic and Late Jurassic, respectively. (authors)
[en] Complete text of publication follows. The Gujarat State in the northwestern part of India is composed of Kutch-Saurashtra block, Cambay basin and Gujarat Main Land. Most of the region is covered by recent alluvium and Deccan traps. Ground and available aeromagnetic data were utilized for deciphering the nature and source of the magnetic crust. Crustal anomaly map depicts the NE-SW trends representing the continuation of the Precambrian Aravalli trend, E-W trend related to westward extension of the Narmada-Son lineament and NW-SE trends (Saurashtra region) associated with coastal tectonics which is terminated further north by the Gulf of Kutch. Jasdon Plateau and the region to the east, reflects smooth anomalies possibly representing the basement and very thin trap cover. In addition to the signatures of volcanic plugs of Junagad, Barda and Alech within Saurashtra, few new plugs with similar magnetic signature were identified in Kutch and in the northern part of Saurashtra. An elliptical feature was identified within the Gulf of Kutch that can possibly represent a batholith that might have acted as feeder to the dyke swarms towards its east and south. Four major faults were identified in the Saurashtra region; that appears to control the magnetic anomalies. Major magnetic sources are concentrated to the west of F1. The identified NW-SE fault F1 and NE-SW fault F2 are deeper compared to the EW faults F3 and F4. DSS studies, in the Saurashtra region, have interpreted a deep seated fault, going up to the Moho, to the either side of which there is considerable change in the thickness of Moho. This subsurface fault when projected falls on F1. To have a better understanding of the structural and tectonic configuration of Gujarat, the available Gravity, MT, DSS etc. was also utilized. Results of these will be presented in terms of the structure and tectonics of the region.
[en] By summing up the former research findings of the tectonics, this paper concludes that the structure identification, structure stress field, balanced cross section, paleomagnetism, isotope chronology, geographic information system(GIS)are the major research methods for the structure analysis in U-bearing basin analysis, puts forward the structure research idea that from small to large, from local to region; from simple to complex, from individual to systematic and from single scientific research to mult-study crossed research, and introduces the application of the structure analysis to uranium resources asasessment by studying on the south edge of Yili basin and the northeast of Erdos basin. (authors)