Cenozoic Tectonic Evolution of the Arcuate Structures in the Northeast Tibetan Plateau

The northeast Tibetan plateau contains important inlbrmation on the northeastward growth of the Tibetan plateau. It is bounded by the Ordos Block to the east, the Alxa Block to the north, and the Tibetan Plateau to the south （inset in Fig. 1; Tapponnier et al., 2001）, and has undergone complex intracontinental deformation during the Cenozoic. In this region, the northeast-convex arcuate structures developed northeastward, and are composed of a series of Cenozoic NW-SE-trending basin-and-range terrain, i.e., the Haiyuan-Xingrenbu basin, Tongxin basin and Hongsipu basin, the Yueliang Shan-Nanhua Shan- Huangjiawa Shan, Xiang Shan-Xiangjing Shan, Yantong Shan and Luo Shan-Niushou Shah, which is geometrically similar with the American basin-range tectonics.

Geometric Structure and Tectonic Activities of Wanquan Fault,Hebei Province

Based on detailed investigations and prospecting,this paper describes the geometrical characteristics and tectonic activities of Wanquan fault in northwest of Beijing. This fault strikes mainly northeast or northeast to north,dipping southeast,and extends over a length of 15km. It is a major geological and geomorphological margin,controlling the neotectonic movement in this region. On the southeast side of Wanquan fault are the Late Quaternary unconsolidated deposits,forming a basin or deposition; but on the other side is Mesozoic volcano debris,forming lower-mountains and hills. Wanquan fault is a mid- to-high-angle normal fault dipping southeast. This fault was more active in the Quaternary. Since the middle-late part of the alate Pleistocene,the average rate with vertical slip of a single fault is over 0. 03 ～ 0. 3mm /a,but the fault has multiple slipping surfaces,and a total rate with vertical slip will be estimated.

Research on the Characteristics of Deep and Shallow Structures in Shenyang City and Their Relationship with Seismic Activities

Deep and shallow tectonic data in Shenyang and its relationship with seismic activity shows that the NE trending faults developed on the surface control the formation and development of the fault-uplift and fault-depression. The uplift and depression of the bedrock at a depth of 7km underground are＇consistent with the surface structure. 12 planar listric normal faults have developed above a depth of 18km -20km and two deep faults have developed in the lower crust. Because of the deep incision and new activities, the surface Wanggangpu-Xinehengzi fault and Yongle-Qingshuitai fault, which correspond to the deep F3 fault and F6 fault, might be related to seismic activity in Shenyang.

The characteristics of geophysical field and tectonic evolutionin the Bransfield Strait

Having analysised the data collected by our survey ship'Ocean IV 'in the Bransfield Strait in 1991,we recognized that the geomorphology,gravity and magnetic anomalies trending NE direction along bandings. The sediments in the Bransfield Strait can be subdivided into two sequences:the first rifting equence and the second rifting sequence.The basement was faulted into a half-graben in northwestern side of the Bransfield trough. Considering the crustal structure crossing the South Shetland Islands,the Bransfield Strait and the Antarctic Peninsula, we propse a two-phase rifting tectonic evolution model and a layered-shear model for the lithospheric deformation under the effects of extensional stress field.

Structural Geology and Tectonics in Marine Science:Perspectives in the Research of Deep Sea and Deep Interior

The fields of structural geology and tectonics have witnessed great progress over the last decade and are poised for further expansion in the future. One of the significant breakthroughs is the establishment of the 'Beyond Plate Tectonics Theory' where a combination of conceptual models and numerical modeling on plume tectonics and plate tectonics has enabled new insights into the structural and tectonic architecture and processes in the deep interior and deep sea. This paper synthesizes developments of structural geology and tectonics from a macroscopic perspective in deep interior and deep sea. Four key techniques are also reviewed: satellite altimetry for surface structures in deep-sea multi-beam sea-floor mapping; tomography for tectonics of the deep interior; diverse modeling approaches and software for unfolding dynamic evolution; and techniques for HT/HP experiments on material rheology and in situ component measurements.

A review of mechanism and prevention technologies of coal bumps in China

Coal bump refers to a sudden catastrophic failure of coal seam and usually can cause serious damages to underground mining facilities and staff. In this circumstance, this paper focuses on the recent achievements in the mechanism and prevention techniques of coal bumps over the past five years in China.Based on theoretical analysis, laboratory experiment, numerical simulation and field test, the characteristics of coal bumps occurrence in China's coal mines were described, and the difference between coal bumps and rockbursts was also discussed. In addition, three categories of coal bumps induced by'material failure' were introduced, i.e. hard roof, floor strata and tectonic structures, in which the mechanism of coal bumps induced by geological structures was analyzed. This involves the bump liability and microstructure effects on bump-prone coal failure, the mechanism of coal bumps in response to fault reactivation, island face mining or hard roof failure. Next, the achievements in the monitoring and controlling methods of coal bumps were reviewed. These methods involve the incorporated prediction system of micro-seismicity and mining-induced pressure, the distributed micro-seismic monitoring system, energy absorption support system, bolts with constant resistance and large elongation,and the 'multi-stage' high-performance support. Finally, an optimal mining design is desirable for the purpose of coal bump mitigation.

Geological Study of Dasht-e-Top Sedimentary Basin, Wardak Province, Afghanistan

This study is conducted to investigate the occurrence of various geological features, and to study the geology and soil characteristics of the study area. To achieve the objective of this research collection, different samples from different locations in study area were collected, analyzed in laboratory, and the results are compared with each other. The main rock types found in the study area were metamorphic rock (Gneiss) and igneous rock (Granite), and the main soil types found were Loam, sandy and silty soils with different soil structures (e.g. crumbling, platy, single grain, granular and prismatic). Calcium carbonate, Iron oxides and different sizes of sediments were also seen in the soil profile, where the size of sediments were changing as it was course size sediments and gravels near the mountain range and as going far from the mountain it was changed to fine size sediments like sand, silt and clay. The river terraces present in the area cover different geological structures such as angular and erosional unconformities, thinning out of strata and potholes. The mountain range surrounded the study area contains different observable tectonic structures such as anticline, syncline, vines (dyke, sill and apophasis). Furthermore, different types of valleys also existed in this area.

Geology of Northern Sulaiman Foldbelt, Shirani and Waziristan Regions (South Punjab, Balochistan and Khyber Pakhtunkhwa): New Tomistominae (Miocene False Gharial) from Sakhi Sarwar Area of Dera Ghazi Khan (South Punjab), Pakistan

Northern Koh Sulaiman foldbelt, Shirani, North and South Waziristan (South Punjab, Balochistan and Khyber Pakhtunkhwa) comprised mostly PermoTriassic to Recent sediments with subordinate igneous and metamorphic rocks. These sedimentary strata folded and faulted by geodynamic and tectonic forces occurred during Late Cretaceous to Recent revealed through anticlinal and synclinal foldings and active faultings. The Northern Koh Sulaiman foldbelt, Shirani, North and South Waziristan areas host many economic minerals like copper and chromite, construction stones, marble limestones, gypsum and cement resources, uranium and other radioactive mineral resources, low-quality iron, phosphate and muddy coal, high-quality gemstones, petroleum potential and excellent water resources and many other rocks and minerals. High-quality window and faden quartz crystals deposited in fractures and fissures as vugs and veins deposited by high-temperature hypothermal solution created by the tectonic compression process. The area has economic chromite and magnesite deposits. The Northern Koh Sulaiman foldbelt, Shirani, North and South Waziristan areas have large cement raw materials/resources (limestones, gypsum and shale/clays available mostly on same sites) which vitally need to install many cement industries in these areas because the ideal central location and now only one cement industry (Dera Ghazi Khan cement industry) is in operation. The Northern Koh Sulaiman foldbelt, Shirani, North and South Waziristan consists of excellent surface water resources which need the construction of smaller and medium-sized dams on different rud kohi/streams/rivers for the development of the area. Sakhi Sarwar area of Dera Ghazi Khan (South Punjab) yielded fossil of new Tomistominae (False Gharial) Gavialidae and further its surroundings recently yielded fossils of famous vertebrates like reptiles (dinosaurs, crocodiles, pterosaur and snake), birds and mammals, and tracks/trackways of Late Cretaceous archosaurs like Sauropaonia, Ornithopaonia and Pteropaonia.

Crustal structure of Gondwana-and Yangtze-typed blocks:An example by wide-angle seismic profile from Menglian to Malong in western Yunnan

The wide-angle seismic profile between Menglian and Malong crosses the Baoshan block (Gondwana-typed), and Simao and southwestern Yangtze blocks (Yangtze-typed). By in-terpreting the wide-angle seismic data, we obtained the seismic crust/upper mantle structure of P-wave velocities together with the seismic reflections of these three blocks, Changning- Menglian and Mojiang suture zones among the mentioned three blocks. Our interpreting results demonstrate that the P-wave crustal velocity of Simao block is slower than that of Baoshan and southwestern Yangtze block and the crustal thickness gradually thickens from the Baoshan block, Simao to southwestern Yangtze block. Crustal reflection patterns of these three blocks have dis-tinct differences too. For the Gondwana-typed blocks, seismic reflections in the upper crust are well developed while in middle-lower crust they are very weak. The crustal reflections in the Yangtze block are very well developed. The crustal reflection patterns in Simao and southwest-ern Yangtze blocks are distinguishable. The average thickness of the crust in the studied area is about 40 km. And we make some discussions on the crustal thickening model of the three blocks in western Yunnan and tectonic setting of seismic developing and interaction of Gondwana and Yangtze blocks.

Activity of the Lenglongling fault system and seismotectonics of the 2016 MS6.4 Menyuan earthquake

The MS6.4 Menyuan earthquake occurred on the northern side of the Lenglongling fault(LLLF) in the mid-western of the Qilian-Haiyuan fault zone on January 21, 2016. The earthquake epicenter was distant from the Minle-Damaying and Huangcheng-Shuangta faults, eastern of the Northern Qilian Shan fault zone. A near northwest-striking rupture plane intersects the two faults at a certain angle. The focal mechanism solution shows that this was a thrust-type earthquake, slightly different from the strike-slip movement with a thrust component of the LLLF. Field geological mapping, tectonic geomorphology analysis, trench excavation and 14 C dating reveal that(1) the LLLF has been obviously active since the Holocene, and may behave with characteristic slip behavior and produce M_W7.3–7.5 earthquakes;(2) the LLLF appears as a flower structure in terms of structure style, and dips NNE at a steep angle; and(3) the most recent earthquake event occurred after 1815–1065 a BP. An associated fault, the Northern Lenglongling fault(NLLLF), is located at the northwestern end of the LLLF. Consequently, the NLLLF was continually subject to tectonic pushing effects from the left-lateral shear at the end of the LLLF, and, accordingly, it bent and rotated outward tectonically.Subsequently, the fault deviated from the dominant rupture azimuth and activity weakened. In the late Quaternary, it behaved as a thrust fault with no obvious deformation at the surface. This is indicated by the arc shape, with a micro-protrusion northeastward,and no geologic or geomorphic signs of surface rupturing since the late Quaternary. However, such faults could still rupture at depth, producing moderate-strong earthquakes. The geometric and kinematic properties of the NLLLF are in good agreement with the occurrence and kinematic properties of nodal plane 2, and with the distribution characteristics of the aftershocks and seismic intensity. Therefore, the NLLLF is a more suitable seismogenic structure for the MS 6.4 Menyuan earthquake. In addition, the thrust movement of the NLLLF accommodates subsequent movement of the LLLF. During the historical evolution of the NLLLF,the LLLF and the NLLLF have affected the local topography through tectonic uplift.