The largest Tan-Lu active fault system in northeastern Asia, spans approximately 3500 km in length and varies in width from 10 km to 200 km. In 1668, an earthquake with a magnitude of 8.5 occurred in Tancheng, causing the loss of over 50000 lives. To constrain the timing and process of the Tan-Lu fault system on eastern Asian margin, this study presents the field mapping, thin section observation,geochronology, and microanalysis of Weiyuanpu-Yehe ductile shear zone(WYSZ) of the northern Tan-Lu fault system. Kinematic indicators and microstructures suggest a sense of sinistral strike-slip. The deformation temperature of the mylonite is mediate to high based on the quartz deformation, c-axis fabrics. The differential stress of the shear zone is 20-40 MPa using quartz paleopiezometry. The dikes within the shear zone yielded zircon U-Pb ages of 165-163 Ma. However, due to the ambiguous geological relationship between the dikes and shear zone, additional geochronology is warranted. Since the Mesozoic era, based on the exposure of mylonite and dikes, the upper crust has been extensively eroded,exposing the ductile shear zone. Moreover, the understanding of the geometry and process of pre-existing structures has fundamental implications for predicating the potential earthquakes for the Tan-Lu fault system.

The Tan-Lu fault zone (TLF) is a major strike-slip fault with a long and complex history in East Asia, whose evolution provides a new perspective on the formation of large-scale faults (> 1000 km long). Fault displacement analysis, geological mapping and U-Pb LA-ICP-MS dating have been performed to understand the evolution of the TLF. Along-strike displacement variation reveals that the TLF consists of two kinematically independent segments, the northern and southern TLF, with opposite long-term propagation directions. Structural and geochronological studies in the eastern Yanshan belt, located around the linkage area of the southern and northern TLF, indicate that NNE-trending sinistral strike-slip faults initiated at 167-164 Ma and were reactivated at 124-121 Ma. Structural analysis suggests that these early NNE-trending strike-slip faults transferred sinistral motion along the northern TLF into southward thrusting along the Yanshan belt, representing the Middle Jurassic southern termination of the northern TLF. Our studies suggest that the through-going TLF formed when the younger southward-propagating northern TLF merged with the older northward-propagating southern TLF in the Late Jurassic. A new model is thus proposed for the Mesozoic evolution of the TLF. The initiation and southward propagation of the northern TLF is interpreted to have resulted from the southward indentation of the Siberian craton into the amalgamated Central Asian Orogenic Belt and North China block. The divergent mega-splays of the northern TLF likely resulted from westward-younging formation during the clockwise rotation of northeast Asia. Coalescence of two genetically unrelated faults could be an alternative mode for large-scale fault formation.

The subduction of the paleo-Pacific plate beneath the North China block has been well documented in terms of magmatic activity, geophysical investigations, and numerical modeling, but the timing of its onset along the eastern Asian margin and the tectonic processes involved remain poorly understood. We have now reconstructed the structural evolution and sedimentation of the Shihuiyao-Gangzidian-Yuantai region of the southern Liaodong Peninsula, on the overriding plate at the eastern Asian margin, using geologic mapping, borehole data sets, field structural studies, and zircon geochronology. In the Shihuiyao area, based on geologic mapping and drilling, top-to-the-NW thrust faults truncated earlier top-to-the-NE reverse faults and then were subsequently overprinted by normal faults. In the Gangzidian area, geologic mapping and 40 boreholes allowed us to construct eight cross sections revealing the top-to-the-WNW/W thrust faults from the surface to a depth of at least 0.5 km; the sections show that the thrust faults extend to the basement and that subsequent normal faults dip subvertically. In the Yuantai thrust system, the top-to-the-NW thrusts, expressed as four tectonic windows and a duplex on the map scale, were intruded by late porphyry and diabase sills. Integration of the data from the three study areas allowed us to identify one angular unconformity and at least two phases of later deformation (D-1 and D-2). The pre-D-1 unconformity is marked by a foreland basin that was filled with Middle Jurassic clastic rocks that unconformably overlie the Neoproterozoic and Cambrian basement. The D, deformation is represented by NE-SW-striking thrust faults that displaced Neoproterozoic or Cambrian strata onto the Middle Jurassic strata. The D-2 deformation is defined by kilometer-scale, high-angle normal faults with variable dips and strikes. Although three samples from the Middle Jurassic clastic rocks did not yield ideal maximum deposition ages (MDAs; ca. 246 Ma), a porphyry dike and a diabase sill that intruded the Yuantai thrust system and remain undeformed yielded zircon U-Pb ages of ca. 124 and 117 Ma, respectively. Detrital zircon geochronology yielded a MDA of ca. 129 Ma for Cretaceous deposits in graben structures with hanging walls formed by D-2 normal faults. Thus, the D, and D-2 deformation events can be constrained to the Late Jurassic and Early Cretaceous, respectively (D-1 between ca. 174 and 124 Ma, and D-2 after ca. 129 Ma). The provenance of the detritus in the Middle Jurassic Wafangdian Formation suggests that the deposits in the retroarc foreland basin had a source in a thrust sheet of the Paleoproterozoic basement, but the source of deposits in a minigraben (D-2) was possibly the nearby Neoproterozoic rocks. Therefore, we reconstructed the retroarc foreland basin and fold-and-thrust belt of the southern Liaodong Peninsula in terms of a subduction margin and constrained a Toarcian-Aptian (ca. 174-124 Ma) age for the onset of paleo-Pacific plate subduction. We interpret the foreland basin system and the subsequent synconvergent extension to have been the result of slab flattening and rollback during episodic subduction of the paleo-Pacific plate.

After the collision of the Mongolian arc terranes with the amalgamated Bainaimiao arc and North China Craton in the latest Permian to earliest Triassic, the northern North China Craton ended the Andean-type accretionary orogenesis. The nature of the subsequent post-collision tectonic setting in early Mesozoic in the northern North China Craton remains controversial. Some workers proposed that the northern North China Craton evolved into a post-orogenic extensional stage. However, this view was mainly built on geochemistry studies of Triassic plutonic rocks in northern North China Craton while it had never received support from studies of tectonic deformation. In contrast, our recent field mapping combining with geochronological studies in the Yanshan belt suggest that the northern North China Craton was in an overall polyphase multi-directional contractional settings in early Mesozoic. We have identified four stages of contractional deformation (D-1-D-4) in this region. D-1 (250-231 Ma) is the intracratonic response to the collision of the Mongolia arc terranes with the NCC. D-2 (214 -207 Ma) and D3 (204 -195 Ma) are post-collisional intracratonic contractional deformation which occurred synchronously with the lithosphere thinning. D-2 and D-3 and the intervened plutonism might be a crustal response to the delamination and sinking of the over-thickened lithosphere of the northern North China Craton. D-4 is the result of the westward subduction of the Izanagi plate beneath the eastern Asian continent plate in the Early Jurassic. These findings together with previous studies indicate that the northern North China Craton experienced a long period of polyphase contractional deformation before its final destruction in the Early Cretaceous. The early stage of the destruction of the North China Craton is characterized by coeval lithosphere thinning and crustal thickening.

The Qiangtang terrane preserves an important record of the growth of the Tibetan Plateau since the Mesozoic; however, its deformation and cooling history remain poorly understood. To unravel this issue, we conducted geological mapping in the Esima area and detrital apatite fission track and (U–Th)/He analyses of the Esima–Rongtang region in the east segment of Central Qiangtang terrane. Our results indicate that the east segment underwent two stages of structural deformation and rapid cooling during 120–110 Ma and 55–38 Ma. By combining our results with those of previous studies of the deformation and cooling history in the west segment, we reconstructed the early spatial and temporal geological evolution of the Central Qiangtang terrane since the Late Jurassic–Early Cretaceous. The structural deformation and cooling of the west segment at 150–130 Ma was related to northward flat subduction of the Bangong–Nujiang oceanic slab. The structural deformation and cooling of the east segment at 120–110 Ma and the west segment at 110–70 Ma was controlled by oblique convergence between Lhasa and Qiangtang terranes. The structural deformation and cooling of the west and east segments at 55–38 Ma was associated with northward intracontinental subduction beneath the Qiangtang terrane induced by the Indo–Asian collision.

Accretionary kinematic history of the Central Asia Orogenic Belt (CAOB) remains unclear in previous geological studies. Based on detailed structural analysis of newly identified folds on the northern margin of the North China Craton (NCC), we propose a tectonic model suggesting that Paleozoic accretion of the orogenic belt includes two phases of deformation. The first phase of deformation is oblique collision of the Bainaimiao Arc and the NCC, which was followed by orthogonal subduction of the Paleo-Asian Ocean in the second phase of deformation. The change of plate kinematics is supported by two generations of folding, namely D1 (DB) and D2 (DA). Both D1 (DB) and D2 (DA) folds developed in the Bayan Obo Group (BOG), a Meso- and Neoproterozoic rift sequence deposited on the passive continental margin of the NCC. D1 (DB) folds were superimposed by the east-west trending D2 (DA) folds. The D1 (DB) folds developed as a result of oblique collision of the Bainaimiao arc and the NCC. The D2 (DA) folds developed in response to the southward orthogonal subduction of the Paleo-Asian Ocean Plate. They formed between latest Silurian and Early Permian, coeval with the two accretion events at the northern edge of the NCC. Our study suggests that multiphase deformation of sedimentary layers on the subducting plates provide important constraints for kinematic evolution of plate tectonics.

Mesozoic tectonics of the North China Craton (NCC) is characterized by craton modification and destruction that resulted in varied degrees of craton instability. The change from the end of the latest modification to the start of the final destruction of the NCC is regarded to be related to the subduction and roll-back of the Izanagi plate. However, the timing of this tectonic transition remains debated, and the extent of the area where cratonic destruction occurred is still poorly constrained. The joint part of the Yanshan and Taihang Mountain belts has been viewed as the northwest margin of the destructed eastern NCC. Detailed geological mapping and geochronological studies of this area reveal two groups of transform structures: (1) the dextral transform structures developed before 143 Ma and (2) the sinistral transform structures formed after 129 Ma. The western boundary of the dextral transform structures separate the intact NCC and the modified NCC, whereas the sinistral transform structures define the northwestern and northern boundaries of the destructed NCC. The switching from dextral to sinistral movement occurred at ca. 143-129 Ma, which is roughly coeval with the initial volcanism of the Zhangjiakou Formation, whose age becomes younger eastward. The western boundary of the sinistral transform structures migrated to the east for more than 120 km with respect to that of the dextral transform structures. These indicate that the transition from the end of the latest modification to the start of the final destruction of the NCC occurred in 143-129 Ma. In regional geology, this transition is consistent with the geodynamic setting of the transformation from the Late Jurassic flat-slab subduction to slab roll-back of the Izanagi plate since similar to 144 Ma.

Liaodong Peninsula on the northeastern North China Block that witnessed the spectacular Late Mesozoic tectonics is a key area to probe the transition from compression to extension. Borehole data clearly reveals that the Cambrian limestone overlay the Jurassic limestone, which identified the Yuantai thrust system in Liaodong Peninsula. Zircon grains from a granodiorite dike that intruded the thrust system yielded U-Pb age of 128.3 +/- 1.3 Ma, further constraining the timing of the thrusting between Late Jurassic to early Early Cretaceous. A detailed field study of three-dimensional fault-zone exposures in the Zhayao tectonic window are conducted to decipher the thrust tectonics before the extension in Liaodong Peninsula. The key observations are: (1) meter-scale asymmetric folds in deformed mid-Cambrian rocks; (2) decameter-scale recumbent folds and secondary imbricate thrusts in deformed Middle Jurassic rocks; and (3) non-foliated breccia, fault gouge, and brittle porphyroclasts adjacent to fault planes. The combined brittle ductile style of deformation indicates that the fault zone operated under near-surface conditions. In addition, we infer that the folds were formed first at the propagating fault tip and subsequently dismembered by normal faults. We interpret the Zhayao thrust, which is located around the margin of the tectonic window, as the frontal thrust of the Yuantai thrust system. Furthermore, by applying the theory of fault-related folds, we deduce that the Zhayao frontal thrust is a secondary duplex. Based on our field observations and borehole data, we propose an imbricate thrust model for the fold-and-thrust belt of the southern Liaodong Peninsula. The structural data indicate that the transport direction of the Yuantai thrust system was top-to-the-southeast, suggesting that the thrust system was resulted due to northwest-ward subduction of the paleo-Pacific plate during the Mesozoic.

Building aggregation is an important part of large-scale map generalization. A triangulation-based building aggregation approach is proposed here. To improve aggregation’s efficiency and accuracy, a six-feature filtering process is integrated to screen the triangles in the constructed constrained Delaunay triangulation (CDT). After filtering, the contours of retained triangles, as the connecting parts between buildings, are rectangularized and aggregated with buildings. Our experiments using diverse and real-world data have proved that this method is efficient and practical.

The increasing discharge of pharmaceuticals and personal care products (PPCPs) into the environment has generated serious public concern. The recent awareness of the environmental impact of this emerging class of pollutants and their potential adverse effects on human health have been documented in many reports. However, information regarding uptake and intracellular distribution of PPCPs in hydrophytes under hydroponic conditions, and potential human exposure is very limited. A laboratory experiment was conducted using 14C-labeled triclosan (TCS) to investigate uptake and distribution of TCS in six aquatic plants (water spinach, purple perilla, cress, penny grass, cane shoot, and rice), and the subcellular distribution of 14C-TCS was determined in these plants. The results showed that the uptake and removal rate of TCS from nutrient solution by hydrophytes followed the order of cress (96%) > water spinach (94%) > penny grass (87%) > cane shoot (84%) > purple perilla (78%) > rice (63%) at the end of incubation period (192 h). The range of 14C-TCS content in the roots was 94.3%-99.0% of the added 14C-TCS, and the concentrations in roots were 2-3 orders of magnitude greater than those in shoots. Furthermore, the subcellular fraction-concentration factor (3.6 × 102-2.6 × 103 mL g-1), concentration (0.58-4.47 μg g-1), and percentage (30%-61%) of 14C-TCS in organelles were found predominantly greater than those in cell walls and/or cytoplasm. These results indicate that for these plants, the roots are the primary storage for TCS, and within plant cells organelles are the major domains for TCS accumulation. These findings provide a better understanding of translocation and accumulation of TCS in aquatic plants at the cellular level, which is valuable for environmental and human health assessments of TCS.

The EW trending Yanshan belt, an intraplate fold-thrust belt located in the northern North China Craton that has experienced several episodes of deformation widely separated in time, is characterized by out-of-sequence thrusts. According to detailed mapping in the central Yanshan belt, five geometric and stratigraphic criteria used to aid in determining whether a thrust has an out-of-sequence geometry or not can be recognized. They are (1) unconformable relationships, (2) inclination of fault surfaces, (3) irregular changes in apparent offset along strike, (4) short fault length relative to apparent offset, and (5) in-sequence geometry. With the help of these criteria, two generations of out-of-sequence thrusts that postdate the original in-sequence thrusting in the central Yanshan belt are recognized. The ancestral southward verging fold-and-thrust belt that formed prior to 180Ma was deformed and cut by two younger generations of faults that are probably more deeply rooted and are constrained to between 172-165Ma and 152-135Ma. A series of thrusts with opposite vergence formed during the last period, resulting in abundant abnormal field relationships such as younger-on-older thrust relations, fold truncation, and cutting down-section. The nature and occurrence of faults in the Yanshan belt implies that superimposed deformation, a common feature in polycyclic orogenic belts, is a mechanism for the generation of out-of-sequence thrusting. This adds to mechanisms already described in the literature, such as maintaining constant critical taper at an orogenic scale, inhibition of the deformation front, and lateral changes in the nature of the decollement horizons.

The Mesozoic structural deformation and sedimentation as well as the volcanism in the Chengde area, central part of intraplate Yanshan orogenic belt, have been systematically investigated in the last two decades. The paleostress fields leading to these complicated tectonic deformations remain unrevealed. Paleostress inversion of fault slip vectors, combining with the newly defined structural levels and the latest age dating results on the key lithostratigraphic units, is employed to establish the paleostress fields in the Chengde area during Middle Jurassic and Early Cretaceous. Three generations including five phases of paleostress fields have been identified in this study. The first generation is believed to be the Middle Jurassic NNW compression (D1) after the sedimentation of the Xiahuayuan Formation and previous to that of the Tiaojishan Formation volcanism (~173 Ma–165 Ma); The second generation includes two phases, the Late Jurassic and earliest Cretaceous N-S compression (D2-1) during and after the sedimentation of the Tuchengzi Formation(~152 Ma–139 Ma) followed by the NNE compression (D2-2) post to the Tuchengzi Formation and predate the Zhangjiakou Formation (~139 Ma–135 Ma). The third generation of paleostress field is inferred to be later than 125 Ma and characterized by a widespread multidirectional extension (D3-1) induced from vertical compression, followed by a leading and weak NW-NNW compression (D3-2). It is inferred that the contraction regime dominated in the Chengde area during the Middle Jurassic and the early Early Cretaceous, with the maximum principal stress axes (σ1) rotated ca 60° clockwise from NNW to NNE, and the sedimentation of the Tuchengzi Formation occurred in this compressive tectonic setting. Extension regime characterized the Early Cretaceous in the central Yanshan belt, even a weak compression once occurred during this period. There is no nearly W-E or NW-SE compressional stress field previously inferred as far-field response to the suspected subduction of paleo-Pacific Plate or Izanagi Plate have been identified in this area, which is likely resulted from intracratonic heterogeneous deformation or strain.

The complicated and enigmatic Jurassic folds and thrusts around Chengde Basin in central intraplate Yanshan Orogenic Belt were previously interpreted as a synclinal deformed thrust sheet with large-displacement(~>40-45km) formed after Late Jurassic Tuchengzi Formation.This model has been challenged by many new findings in paleogeographic and provenance analysis of Tuchengzi Formation and Proterozoic Changcheng System,together with the research result in tectonic deformations.Meanwhile no new model has been proposed so far to account reasonably for the structural style and tectonic framework as well as the evolution process of this structurally complicated region.Detailed mapping have been conducted in last several years to reveal systematically the geometric and kinematic features of the Chengde syncline and thrust faults developed in its both limbs and around its exposed hinge zone to the east.U-Pb age dating with LA-MC-ICPMS method on zircons from key terranes of Chengde Basin has been employed to constrain the timing of major deformations.We found that the thrust faults in northern and southern limbs of the Chengde syncline are independent thrust faults moving away from the core of the syncline.They died out around the hinge zone separately other than connected to each other to form a unified thrust fault as expected by synclinal deformed thrust sheet model.Age dating results suggested that both the Chengde syncline and the major thrust faults formed around 139-136 Ma.Based on recent research results aforementioned,an out-of-syncline thrust model has been proposed in this paper.The complicated geometric and kinematic features of folds and thrust faults in Chengde Basin as well as the provenance features of Tuchengzi Formation can be interpreted reasonably with this new model.This research implies that there is no large-scale thin-skinned thrust tectonics in intraplate Yanshan Orogenic Belt as those in foreland fold and thrust belt of collision orogenic belt.Fold-accommodation fault is supposed to be treated as an important alternative model in dealing with the relationship between large-scale folds and thrust faults as well as tectonic framework and evolution in contraction regime.

燕山-太行山中生代收缩构造变形主要表现为基底卷入的逆冲构造、基底为核的大型纵弯褶皱构造,以及韧性逆冲推覆构造.构造形迹展布方向主要有近WE,NWW和NE-NNE向.在总体构造线呈NNE向展布的太行山构造带和辽西燕山东段,均发现有近WE向和NWW向收缩构造变形.收缩变形发生在二叠纪晚期、三叠纪、侏罗纪及早白垩世.它们的发生已经使克拉通遭受破坏.燕山中部近NS向构造剖面复原表明,在135 Ma之前的构造变形缩短率约为38%,华北东部晚古生代和早中生代岩相古地理研究显示,收缩变形前的地壳厚度约为35 km.如果将上述地质历史时期韧性剪切收缩变形反映的变形深度(20～25 km)作为卷入收缩变形的地壳厚度,并假定水平缩短变形量由垂向地壳加厚所调节,则在南北向缩短变形之后地壳厚度可达47～50 km,已经接近拆沉构造模型下地壳榴辉岩化所需的地壳厚度.同时,加厚地壳均衡抬升产生的重力势能差,与地壳加厚期间持续不断的岩浆活动导致的岩石圈强度弱化,为在区域构造应力状态不发生改变的情形下产生中浅部地壳的伸展垮塌创造了充分条件.因此,燕山-太行山中生代收缩构造变形,一方面直接导致了克拉通岩石圈浅层稳定状况的破坏,另一方面为在深部可能发生的拆沉作用和在浅部产生强烈伸展变形创造了有利条件.拆沉作用和伸展变形可能同是早期收缩变形导致地壳强烈加厚的结果.伸展变形既可以与拆沉作用相伴发生,也可以单独出现,不宜将浅层伸展变形作为深部拆沉作用曾经发生的直接证据.

Mesozoic contraction deformation in the Yanshan and Taihang mountains is characterized by basement-involved thrust tectonics, basement-cored buckling anticlines and ductile thrust and nappe tectonics. Most of these deformations are orientated west-east, west-northwest and northeast to north-northeast. The contraction deformations began in the Permian, continued through the Triassic and Jurassic and terminated in the Early Cretaceous, and constitute an important part of the destruction of the North China Craton. It is estimated, from balanced cross-section reconstructions, that the north-south shortening of the central part of the Yanshan belt before 135 Ma was around 38%. The initial crust thickness, pre-dating the major contraction deformation in late Paleozoic and early Mesozoic, was estimated to be around 35 km based on paleogeographic characteristics. Assuming that the inferred depth of ductile thrusting deformation, 20–25 km, was the crust thickness involved in the contraction deformation, and also assuming that the N-S contraction deformation was accommodated by vertical crust thickening, the thickness of the crust after the contraction deformation was expected to be around 47–50 km. This was the approximate crust thickness required for the eclogitization of the lower crust for delamination. The gravity potential accumulated by the isostatic uplift of the thickened crust, together with the decrease in crustal strength caused by the coeval magmatisms associated with the contraction deformation, led to the subsequent extensional collapse of the middle and upper crust although the regional stress regime associated with the plate interactions remained constant. It is inferred that the Mesozoic contraction deformations in the Yanshan and Taihang mountains were not only a significant tectonic process contributing to the destruction of the craton in middle and upper crust but also stimulated delamination at a deep level and the extension of the shallow crust. In other words, both the suspected delamination of the lower crust and upper mantle and the well constrained extension deformations of the shallow crust in the eastern North China Craton during the late Mesozoic are a consequence of crust thickening due to previous contractions. Extensional deformations could be expected to occur independently in the shallow crust, and are not necessarily associated with or responding to delamination at a deep level.

Polymethacrylate mit dicht gepfropften Seitenketten aus Poly-N-isopropylacrylamid ändern oberhalb der unteren kritischen Entmischungstemperatur ihre Form von zylindrischen Bürsten (links) zu kugelförmigen Strukturen (rechts). Anhand dieses Beispiels wurde zum ersten Mal ein temperaturinduzierter Zylinder-Kugel-Übergang von einzelnen Makromolekülen beobachtet.