关于我国木质复合地板发展现状与趋势刍议

介绍我国木质复合地板行业存在的问题和发展趋势,同时对木质复合地板构造、性能及应用加以介绍。

Study on Active Faults and Seismogenic Structure for the 1989 Batang M6.2～6.7 Earthquake Swarm in the Litang-Batang Region of West Sichuan,China

Fault structures in the Litang-Batang region of West Sichuan are mainly sub-longitudinal and a set of NNE- and NW-trending conjugate shear fracture zones is developed. In this paper, emphasis is put on explaining the movement patterns along the fault structures in the region since the late Pleistocene-Holocene on the basis of detailed interpretation of TM satellite images and aero-photos in geomorphologic aspect of active structures. The sub-latitudinal shortening rate along the sub-longitudinal Jinshajiang fault zone is determined to be 2～3mm/a since the late Quaternary, the horizontal dextral slip movement rate along the NNE-trending Batang fault is 1.3～2.7mm/a on average, and the horizontal sinistral slip movement rate along the NW-trending Litang fault is 2.6～4.4 mm/a on average. The general status of the recent crustal movement in the region and the regularities of block motion caused by it are analyzed in combination with data of geophysical fields, focal mechanism solutions and GPS measurements. The occurrence of the 1989 Batang M6.2～6.7 earthquake swarm is suggested to be the result of tensional rupture along the sub-latitudinal normal fault derived from the conjugate shearing along the NNE-trending Batang and the NW-trending Litang faults. It reveals a typical seismic case produced by normal faulting in a compressional tectonic environment.

The Deformation of Active Tectonic Blocks on the Chinese Mainland and Its Relationship with Seismic Activity

Based on the hypothesis of the active tectonic blocks on the Chinese continent and its adjacent regions (both the method of the DDA on a spherical surface and the GPS survey results observed from 1991 to 2001 are used), the movements and deformations of each active tectonic block are calculated. The calculation results show that although the movements and deformations of active tectonic blocks in the eastern region and in the western region of China are different, active tectonic blocks in the same active tectonic block region are coherent. Then, the relative velocities of the active tectonic blocks’ boundary zones are calculated, and the relationship between current crustal motion and strong seismic activities is discussed. Earthquakes ( M S≥7 0) on the Chinese continent since 1988 all occurred on boundary zones of active tectonic blocks with high slipping speed.

Characteristics of in situ stress field at Qingshui coal mine

In this study, the characteristics of geological structure at Qingshui coal mine were analyzed. And the hollow inclusion strain cell overcoring method was used to obtain the in situ stress. The effect of in situ stress on the stability of soft rock roadway was analyzed. The results show that the maximum principal stress is in the horizontal direction with a northeast orientation and has a value of about 1.2–1.9 times larger than gravity; the right side of roadway roof and floor is easily subject to serious deformation and failure, and the in situ stress is found to be a major factor. This paper presents important information for developing countermeasures against the large deformation of the soft rock roadway at Qingshui coal mine.

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.

Sedimentary erosive processes and sediment dispersal in Kaoping submarine canyon

The Kaoping submarine canyon, connected to the Kaoping River in the coastal plain in SW Taiwan, continues the dispersal path of modern Kaoping River sediments, from an active small mountainous drain basin to the receiving basin of the South China Sea. Using seismic reflection sections, Chirp sonar profiles, and bathymetric mapping, we reveal characteristic erosive processes responsible for multiple cut-and-fill features, deeply entrenched thalweg, and sediment dispersal that are closely related to turbidity currents in the canyon. The river-canyon connection setting, along with extreme climatic conditions and active tectonism, is favorable for generation of turbidity currents at the canyon head. The upper reach of the Kaoping Canyon is distinguished into three distinct morpho/sedimentary features. The canyon head is characterized by V-shaped axial thalweg erosion. The sinuous segment of the upper reach is dominated by a deeply incised canyon pathway with trough-like morphol- ogy. Relatively small-scaled features of cut-and-fill associated with the dominant incision process are commonly along the canyon floor, resulting in a flat-floored pathway. Sliding and slumping dominated the steep canyon walls, producing and transporting sediments to canyon floor and partially filling up canyon thalweg. The meandering segment is characterized by erosive features where deeply down-cutting occurs in the outer bend of the major sea valley, forming V-shaped entrenched thalweg. The recurrences of turbidity currents have allowed continuous incision of the canyon head and have kept the connec- tion between the canyon head and the river mouth during Holocene highstand of sea level. The upper reach of the Kaoping Canyon is linked to drainage area and maintains as a conduit and/or sink for terrigenous and shallow marine material. Sediment-laden river plume operates in the Kaoping River-Canyon system, with turbidity currents flushing fiver sediments into the canyon head where the canyon thalweg is the most erosive. Presently, the upper reach of the Kaoping Canyon can be considered as a temporal sediment sink.

Carboniferous slab-retreating subduction of backarc oceans:the final large-scale lateral accretion of the southern Central Asian Orogenic Belt

During Carboniferous time,tremendous juvenile arc crust was formed in the southern Central Asian Orogenic Belt(CAOB),although its origin remains unclear.Herein,we presented zircon U-Pb-Hf and whole-rock geochemical and Sr-Nd isotopic data for a suite of volcanic and pyroclastic rocks from the Khan-Bogd area in southern Mongolia.These Carboniferous pyroclastic rocks generally have some early Paleozoic zircons,probably derived from the granitic and sedimentary rocks of the Lake Zone and the Gobi-Altai Zone to the north,indicative of a continental arc nature.In addition,they have a main zircon U-Pb age of ca.370–330 Ma,positive Hf and Nd isotopes,and mafic-intermediate arc affinity,similar to the coeval arc magmatism.Moreover,the pyroclastic rocks of the northern area have more mafic and older volcanic components with depositional time(ca.350–370 Ma;Visean and Bashkirian stages)earlier than that in the southern area(mainly ca.350–315 Ma;Serpukhovian and Bashkirian stages).Combining a preexisting northward subduction supported by the available magnetotelluric data with a slab rollback model of the main oceanic basin of the Paleo-Asian Ocean(PAO)during Carboniferous and Triassic times,we infer that the Carboniferous arc magmatism was probably derived from a backarc ocean triggered by slab rollback.Thus,the juvenile arc volcanism of Mongolia,together with other areas(e.g.,Junggar)in the southern CAOB,represented a significant lateral accretion that terminated after the Carboniferous due to a significant contraction of the PAO.

Developing plate tectonics theory from oceanic subduction zones to collisional orogens

Crustal subduction and continental collision is the core of plate tectonics theory. Understanding the formation and evolution of continental collision orogens is a key to develop the theory of plate tectonics. Different types of subduction zones have been categorized based on the nature of subducted crust. Two types of collisional orogens, i.e. arc-continent and continent-continent collisional orogens, have been recognized based on the nature of collisional blocks and the composition of derivative rocks. Arc-continent collisional orogens contain both ancient and juvenile crustal rocks, and reworking of those rocks at the post-collisional stage generates magmatic rocks with different geochemical compositions. If an orogen is built by collision between two relatively old continental blocks, post-collisional magmatic rocks are only derived from reworking of the old crustal rocks. Collisional orogens undergo reactivation and reworking at action of lithosphere extension, with inheritance not only in the tectonic regime but also in the geochemical compositions of reworked products(i.e., magmatic rocks). In order to unravel basic principles for the evolution of continental tectonics at the post-collisional stages, it is necessary to investigate the reworking of orogenic belts in the post-collisional regime, to recognize physicochemical differences in deep continental collision zones, and to understand petrogenetic links between the nature of subducted crust and post-collisional magmatic rocks. Afterwards we are in a position to build the systematics of continental tectonics and thus to develop the plate tectonics theory.

Late Paleozoic reefs and their significance for tectonics and oil-gas exploration in the Hinggan-Inner Mongolia area

Many reefs of the Late Paleozoic have been discovered recently in the Hinggan-lnner Mongolia area. These reefs clearly are geographically extensive, and possess distinctive features and well-developed reef-facies. They have been found to contain five reef-building communities and were constructed in four periods. Colonial coral-algal reefs at Aohan and Chifeng represent a warm shallow-sea in the Carboniferous. Different reefs in the Xiwu Banner were formed in three periods： early Late Carboniferous, late Late Carboniferous and Early Permian. These reefs were built in warm sea conditions. Their buildup types include colonial coral frameworks, algae-buildings and lime-mud mounds. Bryozoan reefs in the Zhalaite and Dongwu banners were built in the late Middle Permian and thrived in a cold shallow-sea. All reefs grew independently on two kinds of sedimentary platforms, carbonate and carbonate-clastic mixed platforms. Four reef-forming periods occurred later from south to north, along a collisional course between the North China Plate and the Siberian Plate. These reefs can be arranged into three ＇reef-links＇ or reef zones that extend along plate margins. Among these, the Aohan-Chifeng reef-link indicates a northern margin of the North China Plate, the Zhalaite-Dongwu reef-link marks a southern margin of the Siberian Plate, and the Xiwu-Beishan reef-link reflects the former existence of some inter-plates. The strata of each reef-facies are thick and contain rich asphalt deposits. Overlapping and heteropic layers are very thick and contain dark oil/gas-rich horizons; TOC analyses verify that most of these are good hydrocarbon source rocks. This study shows that the study area is an excellent candidate for oil-gas exploration.