Sequence-stratigraphic comparison of the upper Cambrian Series 3 to Furongian succession between the Shandong region, China and the Taebaek area, Korea: high variability of bounding surfaces in an epeiric platform

Jitao Chen,S.K. Chough,이정현,Zuozhen Han 한국지질과학협의회 2012 Geosciences Journal Vol.16 No.4

This study focuses on the stratigraphic sequences and the bounding surfaces in the upper Cambrian Series 3 to Furongian Gushan and Chaomidian formations in the Shandong region, China. The bounding surfaces are compared with those of the coeval succession in the Taebaek area, Korea. According to the vertical arrangement of the facies associations and the identification of the bounding surfaces, three stratigraphic sequences are recognized, representing dynamic changes in accommodation versus sedimentation. The bounding surfaces can be traced in the Shandong region for about 6,000 km2 in area, but cannot be correlated with those of the Taebaek area (eastern margin of the platform, about 1,000 km apart). Surface 1 is characterized by an abrupt facies change from carbonate to shale, representing a distinct drowning surface. The drowning surface is also diagnosed in the Taebaek area but highly diachronous. Surface 2 is a cryptic subaerial unconformity, reflected by an erosion surface, missing of a trilobite biozone (Prochuangia Zone), and an abrupt increase in carbon isotope value. It is not identified in the Taebaek area where the Prochuangia Zone is present. Surface 3 is a marine flooding surface, indicated by a subtle transition from flat-bedded microbialite to domal microbialite (or grainstone). It may be correlated with that in the Taebaek area, which is, however, represented by an abrupt facies change from sandstone to limestone-shale alternation. The high variability of the sequence-bounding surfaces is indicative of variable regional factors such as topographic relief, carbonate production, siliciclastic input, and hydrodynamic conditions. It suggests that the sequence-bounding surfaces are invalid for a basin-scale correlation, especially in an epeiric carbonate platform

Limestone pseudoconglomerates in the Late Cambrian Gushan and Chaomidian Formations (Shandong Province, China): soft-sediment deformation induced by storm-wave loading

CHEN, JITAO,CHOUGH, SUNG KWUN,CHUN, SEUNG SOO,HAN, ZUOZHEN Blackwell Publishing Ltd 2009 Sedimentology Vol.56 No.4

<P>Abstract</P><P>This paper focuses on the formative processes of limestone pseudoconglomerates in the Gushan and Chaomidian Formations (Late Cambrian) of the North China Platform, Shandong Province, China. The Gushan and Chaomidian Formations consist mainly of limestone and shale (marlstone) interlayers, wackestone to packstone, grainstone and microbialite as well as numerous limestone conglomerates. Seventy-three beds of limestone pseudoconglomerate in the Gushan and Chaomidian Formations were analysed based on clast and matrix compositions, internal fabric, sedimentary structures and bed geometry. These pseudoconglomerates are characterized by oligomictic to polymictic limestone clasts of various shapes (i.e. flat to undulatory disc, blade and sheet), marlstone and/or grainstone matrix and various internal fabrics (i.e. intact, thrusted, edgewise and disorganized), as well as transitional boundaries. Limestone pseudoconglomerates formed as a result of soft-sediment deformation of carbonate and argillaceous interlayers at a shallow burial depth. Differential early cementation of carbonate and argillaceous sediments provided the requisite conditions for the formation of pseudoconglomerates. Initial deformation (i.e. burial fragmentation, liquefaction and injection) and subsequent mobilization and disruption of fragmented clasts are two important processes for the formation of pseudoconglomerates. Burial fragmentation resulted from mechanical rupture of cohesive carbonate mud, whereas subsequent mobilization of fragmented clasts was due to the injection of fluid materials (liquefied carbonate sand and water-saturated argillaceous mud) under increased stress. Storm-wave loading was the most probable deformation mechanism, as an external triggering force. Subsequent re-orientation and rounding of clasts were probably prolonged under normal compactional stress. Eventually, disrupted clasts, along with matrix materials, were transformed into pseudoconglomerates by progressive lithification. Soft-sediment deformation is prevalent in alternate layers of limestone and mud(marl)stone and/or grainstone, regardless of their depositional environments.</P>

중국 산동 만터우층에서 나타나는 고생대 전기-중기 캄브리아기의 생물상

강임성,Chen Jitao,Han Zouzhen,최덕근 한국고생물학회 2006 정기총회 및 학술발표회 Vol.2006 No.-

Demise of an extensive biostromal microbialite in the Furongian (late Cambrian) Chaomidian Formation, Shandong Province, China

이정현,Jitao Chen,S.K. Chough 한국지질과학협의회 2012 Geosciences Journal Vol.16 No.3

This study focuses on an extensive biostromal microbialite (10–20 m in thickness and over 6,000 km2 in area) and the overlying grainstones in the Furongian Chaomidian Formation, Shandong Province, China in order to understand the demise of the microbialite. The microbialites are characterized by centimeter- to decimeter-scale maze-like maceria structures and/or chaotic mesostructures. According to the megastructures of microbialites and the proportion of non-microbial carbonate sediment, the biostromal microbialite is generally divided into the lower and the upper parts, separated by a distinct surface. The lower part is laterally continuous and generally flat-bedded, whereas the upper part shows variable domal megastructures and locally co-occurs with abundant non-microbial carbonate sediment. The entire microbialite bed is sharply overlain by grainstone-dominated deposits via an erosion surface which is either irregular with significant relief or flat with hematitic coating. The lower part of the biostromal microbialites with flat-bedded megastructures most likely deposited contemporaneously during sea-level highstand in the early middle Furongian, as evinced by well-correlated flat-bedded units separated by distinct bounding surfaces. The microbialites formed regional topographic variation, generally deepening toward southeast. The flat-bedded microbialites were drowned by subsequent rapid rise in sea level. In the topographic highs, the microbialites caught up with sea-level rise, forming large-scale domal megastructures. In the topographic lows, however, domal microbialites formed together with abundant non-microbial sediment, which were frequently reworked by storm-induced waves and currents. Subsequent deposition and migration of coarse-grained non-microbial sediment during sea-level rise terminated the entire microbialites

Electrospun SrO-Incorporated Nanofiber Membranes for Biomedical Applications

Zhe Chen,Jitao Fan,Yangfan Ding,Yunlong Zhang,Ahmed I. Abd‑Elhamid,Jinglei Wu,Binbin Sun 한국섬유공학회 2023 Fibers and polymers Vol.24 No.11

Bioactive ceramics have gained increasing interest in biomedical applications. Strontium (Sr)-based ceramics show unique bioactivity in stimulating cell proliferation and migration and promoting angiogenesis. Incorporation of bioactive ceramics into nanofibers represents a facile approach to alter the material properties of electrospun nanofiber membranes. Herein, we prepared SrO-incorporated nanofiber membranes by electrospinning and investigated the effects of SrO particles on the physicochemical properties and cytocompatibility of these membranes. Our results indicate that simple one-stream electrospinning could smoothly introduce SrO particles into poly(L-lactic acid) (PLA)/gelatin nanofibers. SrO-incorporated membranes showed significantly improved wettability but became brittle compared with PLA/gelatin nanofiber membranes. Cells differentially responded to SrO-incorporated membranes: endothelial cells showed greater cell area and coverage on SrO-incorporated membranes; in contrast, fibroblasts were inhibited on these membranes. These findings suggest that SrO-incorporated membranes might find opportunities in specific biomedical applications in which pro-angiogenesis and antiadhesion are simultaneously demanded.

Flexural Properties of Lithium Slag Concrete Beams Subjected to Loading and Thermal-Cold Cycles

Liuzhuo Chen,Jitao Yao,Guangtai Zhang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.2

This paper presents the flexural test results of 10 lithium slag reinforced concrete beams (120 × 200 × 1,100 mm3) subjected to the combined effect of loading and Thermal-Cold (TC) cycles. The parameters include the polypropylene (PP) fibers, number of TC cycles and level of flexural loading. The results show that the cracking load, ultimate load, maximum crack width and deflection improve significantly after 100 TC cycles and deteriorate slightly after 300 TC cycles. As the percentage of the peak moment, which is an experimental value, increases from 0.20 to 0.35, the deflection decreases, the cracking load increases, and there is no noticeable change in the ultimate load. Further, the addition of PP fibers to the concrete beams enhances both the cracking load and the ultimate load, reduces the maximum crack width, and improves the resistance to erosion.

Depositional processes and environmental changes during initial flooding of an epeiric platform: Liguan Formation (Cambrian Series 2), Shandong Province, China

이현석,Jitao Chen,Zuozhen Han,조성권 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.6

This paper focuses on the depositional processes and environmental changes during initial marine flooding recorded in the lower Cambrian succession of the North China Platform in Shandong Province, China. In order to understand imbalance of accommodation and sediment supply in the initial stage of basin-fill, a detailed analysis of sedimentary facies was made for the lowermost siliciclastic deposits of the Liguan Formation. It reveals ten siliciclastic lithofacies in three large-scale outcrops (Jinhe, Anqianzhuang, and Zhangjiapo sections). These facies are grouped into four facies associations, representing siliciclastic foreshoreshoreface (S1), siliciclastic offshore (S2), distributary mouth bars (S3), and coastal plain (S4). The siliciclastic components occur in a linear belt, emanating from a major drainage system in the northeastern part of the platform. Deposition of siliciclastic sediments was largely controlled by regional topography of the unconformable surface and shoreline configuration as well as strong effect of waves and currents. With ensued rise in sea level and decrease in siliciclastic sediment supply, carbonate sediments prevailed, filling the accommodation created by epeirogenic subsidence and sediment loading.

Energy Efficiency and Economy Analysis of a Range-extended Electric Bus in Different Chinese City Driving Cycles

Xiaogang Wu,Chen Hu,Jitao Wang,Jiuyu Du 보안공학연구지원센터(IJUNESST) 2014 International Journal of u- and e- Service, Scienc Vol.7 No.2

The Statistical Methods of Membership Function in Structural Serviceability Failure Criterion

Jun Gao,Jitao Yao,Liuzhuo Chen 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

The failure criterion of structural serviceability is often fuzzy, which has a direct impact on the results of structural reliability analysis. Membership function is a basic mathematical tool to describe the fuzziness of failure criteria. At present, the fuzzy statistical method for generating the fuzzy set membership function is to take the numerical interval of the fuzzy set as a sample, and directly generate the membership function through statistics. However, this kind of sample will cover the uncertainty of the individual's understanding of fuzzy boundaries to a certain extent, and its statistical results are difficult to truly reflect the characteristics of fuzzy sets. The fuzzy boundary is described by the membership density function, and the numerical interval covering the fuzzy boundary is taken as the sample. The fuzzy statistical method for generating the membership density function is proposed, and the indirect statistical method for generating the membership function is established. The comparative analysis results show that the membership functions generated by the two statistical methods are different. The membership function generated by indirect statistical method can fully reflect the uncertainty of the individual's understanding of the fuzzy boundary, more truly reflect the characteristics of the fuzzy set, and provide a more solid foundation for the fuzzy probability analysis of structural serviceability.

Generation of subsurface injection flow in a carbonate platform

S.K. Chough,Jitao Chen 한국지질과학협의회 2013 Geosciences Journal Vol.17 No.1

In order to diagnose emplacement of discordant breccia body in carbonate platform, we here describe sedimentary structures and texture as well as bed geometry of two beds of the Chaomidian Formation (Frongian) in Shandong Province, China. Each breccia body consists of granule- to cobble-size clasts of peloidal grainstone and matrices of dolomitic marlstone and/or micritic limestone, showing a tunnel geometry. Marlstone in the matrix is homogeneous, whereas micritic limestone shows irregular and disoriented laminations. It is hypothesized that the breccia body formed by subsurface in situ fluidization and fragmentation and further injection into the ambient deposits. Subsurface sediment remobilization occurred most likely under cyclic loading of large storm waves. The laminated matrix is strongly suggestive of hydroplastic deformation (flowage) of fluidized material during injection. This study suggests that there exists a full spectrum of subsurface deformation from liquefaction/fluidization to injection flow.