排序方式： 共有9条查询结果，搜索用时 203 毫秒
1
1.
Rawiwan RITTISIT Arak SAENGSOMPONG Kachentra NEAWSUPARP Thanop THITIMAKORN Punya CHARUSIRI 《地球学报》2012,33(S1):7-7
Nan suture in northern Thailand, representing a complex zone with complex geology and structures, has been selected for airborne geophysical investiga-tions. The suture has been widely accepted as an early Triassic collision zone between Shan-Thai and Indo-china microcontinental blocks. Our field data suggest the occurrence of a mélange zone in response to com-pression tectonics. Moreover, previous petrochemical and field investigations suggest that the Nan suture may have been formed as a result of a subduction zone. 相似文献
2.
Punya Charusiri Suvapak Imsamut Zhonghai Zhuang Tainpan Ampaiwan Xiaoxhong Xu 《Gondwana Research》2006,9(3):310-325
A total of 400 samples (33 sites) were collected from the earliest Cretaceous to early Late Cretaceous sandstones of the Khorat Group in the Indochina block for paleomagnetic study to unravel the tectonic evolution of the region. The sites were adopted from 3 traverses located in the northern edge of the Khorat Plateau, northeastern Thailand. Results indicate that almost all the sandstones exhibit similar magnetic values with an average declination (D) = 31.7°, inclination (I) = 30.3°, λ = 59.7°, = 190.9°, K = 54.4, and A95 = 3.7 at reference point 17°30′N and 103°30′E. The calculated paleolatitude points are inferred to deviate from the present latitude point by 1.2 ± 2.3°. Only the lowermost part of the Cretaceous sandstones can pass a positive fold test at 95% confidence level. The relationship between the virtual geomagnetic poles (VGPs) of Cretaceous rocks of the Indochina plate in Thailand and those of the South China plate advocate that there is a major displacement of Indochina along the northwest-trending Red River and associated faults by about 950 ± 150 km with a 16.0–17.0° clockwise rotation relative to the South China plate during earliest Cretaceous times. Paleomagnetic results of the early Late Cretaceous Indochina plate point to a 20–25° clockwise rotation relative to the present occurring since very Late Cretaceous (65 Myrs)–Early Neogene times which may be due to the collision between India and Asia. 相似文献
3.
The study area is the Van earthquake region. It is located in the western section of the East Anatolian–Iranian plateau outside and to the east of the Karlıova triple junction. Based on the tectonic periods, the rock units exposed in the study area are classified into two common categories. These are the Pre-Late Pliocene paleotectonic units and the Plio-Quaternary neotectonic units. The Paleotectonic units are composed of the Yüksekova Complex of Campanian–Maastrichtian age and the Kırkgeçit Formation of Oligo-Miocene age. The paleotectonic units are intensely deformed (folded, thrust to reverse faulted and converted into an imbricate stack). The neotectonic units are composed of fluvio-lacustrine sedimentary facies with volcanic interclations. It is full of soft-sedimentary structures such as deltaic structure, slump fold, sand dikes to sills and normal to reverse types of growth faults which imply to a sedimentation accompanied by both a volcanic activity and active tectonics. Originally the Paleotectonic units are overlain with an angular unconformity by the nearly flat-lying neotectonic units. This angular unconformity and the big difference in the deformational patterns of both categories of rock units indicate an inversion in tectonic regime in Late Pliocene. The new tectonic regime is the strike-slip faulting-dominated neotectonic regime. It is governed by an approximately N–S-directed compression, and composed of NW- to NE-trending strike-slip faults, N–S trending oblique-slip normal faults to fissures and the E–W trending thrust to reverse faults. Most of thrust to reverse faults are inherited from the Pre-Late Pliocene paleotectonic regime. Some of them have reactivated and led to the occurrence of large and devastative earthquakes. The last devastative seismic event is the 23 October 2011 Tabanlı (Van) earthquake of Mw = 7.2 that caused 644 deaths and moderate to heavy damage of ¼ of structures (28,532) in Van earthquake region. The source of the Tabanlı earthquake is the Everek erosional reverse fault. In addition the Tabanlı earthquake is the largest seismic event occurred till now in Turkey. It was followed by a series (over 6000) of small-sized aftershocks and severeal moderate-sized indepentent earthquakes of reverse, normal and strike-slip faulting origin. Both the field and new seismic data strongly reveal that the prominent tectonic regime in the East Anatolian plateau is the strike-slip neotectonic regime, not the tensional tectonic regime as has been reported in some previous works. The strike-slip faulting and related deformation are confined into the upper shallowing part (up to 40 km) of the crust, whilst the extensional deformations are the subcrustal processes and being taking place in a squashy zone at the depths of approximately 40–60 km. 相似文献
4.
Sebastian A. Turner Jian G. Liu John W. Cosgrove 《Journal of Asian Earth Sciences》2011,40(1):394-402
The Piqiang Fault is a prominent strike-slip (tear) fault that laterally partitions the Keping Shan Thrust Belt in the NW Tarim Basin, China. In satellite images, the Piqiang Fault appears as a sharp, NW-trending lineament that can be traced for more than 70 km. It is oblique to the general structural trend of the thrust belt and subparallel to the thrust transport direction. This paper presents a structural analysis of the Piqiang Fault, based on satellite image interpretation and field data. A net loss of Late Paleozoic sediment across the fault zone implies that it was initiated as a major normal fault during the Early Permian, and corresponds to widespread extension and magmatism during this period. Differential erosion across the fault resulted in the subsequent removal of sediment from the east relative to the west. During the Middle to Late Cenozoic, contraction of the NW Tarim Basin and the formation of the Keping Shan Thrust Belt resulted in reactivation of the Piqiang Fault as a strike-slip (tear) fault. The fault has accommodated lateral differences in thrust density and spacing which have arisen due to the abrupt, pre-existing change in stratigraphic thickness across it. The Piqiang Fault provides an insight into the formation of oblique, strike-slip (tear) faults in contractional belts and demonstrates the importance of inherited basement structures in such settings. 相似文献
5.
Santi Pailoplee 《Natural Hazards》2014,74(3):1813-1827
In this study, the earthquake hazard was evaluated for all of 19 of the proposed or built dams along the Mekong River. All values representing a potential indication of hazardous earthquakes, such as the closest earthquake and seismogenic faults and including the seismic parameters required for a seismic safety evaluation, were clarified. The results will be useful in reviewing the safety of existing dams and for the design of suitable earthquake resistant specifications for any currently or future planned dam construction in this area. Seismotectonically, 14 of the 19 proposed Mekong River dams are located within an earthquake source zone. Most of faults are potentially still active, according to both seismicity and paleoseismological evidence. In addition, the maximum credible earthquakes were estimated to be in the range of 7–8 Mw for the closest fault zone of each dam. Previous isoseismal maps indicated a risk of shaking intensities of around scale III–IV (Modified Mercalli Intensity Scale) for the dams. According to the preliminary ranging of the International Commission on Large Dams, 9 of these 19 dams are classified as in an extreme hazard class and so need careful observation and monitoring of hazardous earthquakes. An effective mitigation plan should also be prepared for each operating dam. 相似文献
6.
The frequency–magnitude distributions of earthquakes are used in this study to estimate the earthquake hazard parameters for individual earthquake source zones within the Mainland Southeast Asia. For this purpose, 13 earthquake source zones are newly defined based on the most recent geological, tectonic, and seismicity data. A homogeneous and complete seismicity database covering the period from 1964 to 2010 is prepared for this region and then used for the estimation of the constants, a and b, of the frequency–magnitude distributions. These constants are then applied to evaluate the most probable largest magnitude, the mean return period, and the probability of earthquake of different magnitudes in different time spans. The results clearly show that zones A, B, and E have the high probability for the earthquake occurrence comparing with the other seismic zones. All seismic source zones have 100 % probability that the earthquake with magnitude ≤6.0 generates in the next 25 years. For the Sagaing Fault Zone (zones C), the next Mw 7.2–7.5 earthquake may generate in this zone within the next two decades and should be aware of the prospective Mw 8.0 earthquake. Meanwhile, in Sumatra-Andaman Interplate (zone A), an earthquake with a magnitude of Mw 9.0 can possibly occur in every 50 years. Since an earthquake of magnitude Mw 9.0 was recorded in this region in 2004, there is a possibility of another Mw 9.0 earthquake within the next 50 years. 相似文献
7.
Taweewath NAKCHAIYA Toshio MITZUTA Daizo ISHIYAMA Isao TAKASHIMA Krit WON-IN Veerasak LUNWONGSA Punya CHARUSIRI 《地球学报》2009,30(Z1):48-48
Akara gold mine in north-central Thailand is situated within the Loei-Phetchabun-Nakhon Nayok volcanic belt. The roughly north-south trending, Permo-Triassic volcanic rocks earlier mapped by Thailand Department of Mineral Resources were re-mapped and samples were collected from the main active open pit. Forty-four samples were petrographi-cally classified and geochemically analyzed to docu-ment their stratigraphy. Two types of volcanic rocks are recognized, namely coherent and non-coherent units, in which the former is older on the basis of stratigraphic succession. Several lines of evidence suggest that the studied rocks occurred nearby the volcanic edifices and were dominated by debris flows of submarine environment. 相似文献
8.
Hidetoshi HARA Miyuki KUNII Ken-ichiro HISADA Katsumi UENO Yoshihito KAMATA Punya CHARUSIRI Thasinee CHAROENTITIRAT 《地球学报》2012,33(S1):15-15
The accretionary complex related to the Pa-leo-Tethys subduction was developed along western margin of the Indochina Block in northern Thailand. The provenance, source rock compositions, and sedi-ment supply system of the accretionary complex were reconstructed based on the petrography and geochem-istry of clastic rocks, U-Pb dating of detrital zircons. 相似文献
9.
It has previously been proposed that the Sibumasu block of Southeast Asia, which contains glaciomarine deposits, became detached from the Gondwana margin during the Early Permian. A combination of facies analysis and the identification of dropstones and dump structures from a Lower Permian diamictite-bearing sequence at Phuket, Thailand, and adjacent islands suggests that the sediments originated as glaciomarine and debris-flow deposits. The Lower Permian diamictite-bearing sequence in the study area corresponds to the Ko Sire and Ko He Formations, both of which consist of three principal lithofacies: diamictite, sandstone, and fine-grained facies. The low-lying Ko Sire Formation is up to 400 m thick and is characterized by laminated mudstone; the presence of dropstones and dump structures associated with Cruziana ichnofacies indicates ice-rafted sedimentation in a glacially influenced offshore area. The Ko Sire Formation is overlain by a diamictite sequence of the Ko He Formation (up to 400 m thick). Poorly and well-stratified diamictites with tabular and lensoidal geometries, in combination with resedimentation textures, indicate that the diamictites within the Ko He Formation are debris-flow deposits. The similar lithology of clasts in the diamictites and dropstones possibly suggests that the debris-flow diamictite was presumably remobilized from pre-existing glacial deposits. The evidence of a glacially influenced offshore environment supports a previously proposed paleogeographic interpretation in which the Sibumasu block was most likely located at the Northwest Australian margin of Gondwana. 相似文献
1