Sedimentary facies of the subaqueous Changjiang River delta since the late Pleistocene

The sedimentary facies of the subaqueous Changjiang(Yangtze) River delta since the late Pleistocene was studied based on lithology and foraminifera analysis for two boreholes,CJK07 and CJK11,along with14C dating.Four sedimentary facies were identified,namely fluvial,tidal flat,offshore,and prodelta facies.The fluvial sedimentary facies is comprised of fluvial channel lag deposits,fluvial point bar deposits,and floodplain deposits,showing a fining-upward sequence in general with no benthic foraminifera.A layer of stiff clay overlies the fluvial deposits in core CJK07,indicating a long-term exposure environment during the Last Glacial Maximum(LGM).During the postglacial sea-level rise around 13-7.5 cal ka BP,the tidal flat facies was deposited in core CJK11,characterized by abundant silt-clay couplets.Euryhaline species dominate the subtidal flat foraminiferal assemblages,while almost no foraminifera was found in the intertidal flat.The offshore environment was the major sedimentary environment when the sea level reached its highest level around 7.5 cal ka BP,with a maximum accumulation rate of 10 mm/a found in core CJK11.Prodelta sediments have been deposited in core CJK11 since ~3 cal ka BP,after the formation of the Changjiang River delta.The difference in sedimentary facies between core CJK07 and CJK11 is due to their location: core CJK07 was in an interfluve while core CJK11 was in an incised valley during the LGM.Furthermore,AMS14C dating of core CJK07 shows poor chronological order,indicating that the sediments were reworked by strong tidal currents and that sediment deposited since ~7.7 cal ka BP in core CJK07 was eroded away by modern hydrodynamic forces caused by the southward shift of the Changjiang River delta depocenter.     

鄂尔多斯盆地中部上古生界沉积相演化

利用钻井资料和地质资料对鄂尔多斯盆地上古生界沉积相演化进行详细的研究。分析了本溪期（海侵）、太原期（海侵扩大）、山西期（海退）、石盒子期（海陆交互）和石千峰期（陆缘湖泊）等5个时期的古地理环境、岩石类型、沉积相类型和平面展布特征。得出这5个时期在盆地内构成了一个海侵海退旋回，形成了从滨浅海相到海陆过渡的三角洲相、河流湖泊相陆源沉积。控制生成了三角洲相分流河道砂砾岩、水下分流河道砂砾岩以及潮坪相砂坝等有利储集岩带，潮坪相发育的煤系地层为烃源岩。上石盒子组洪泛平原形成泥质岩盖层。生油岩和储集岩叠置或互侧式组合关系，形成本区受砂体分布控制的岩性气藏。     

太子河流域早寒武世馒头期沉积环境及硬石膏矿床成因

太子河流域下寒武统馒头组可划分4个相带,即潮上膏云岩相,潮上白云岩相,潮间灰岩白云岩相,潮下云斑灰岩相,属障壁海碳酸盐潮坪沉积。石膏形成于潮上带萨布哈,是干旱、燥热环境下的产物。成矿有利的古地理环境是古岛的前缘。     

Coatal salt marshes and mangrove swamps in China

Based on plant specimen data, sediment samples, photos, and sketches from 45 coastal crosssections, and materials from two recent countrywide comprehensive investigations on Chinese coasts and islands, this paper deals with China’s vegetative tidal-flats: salt marshes and mangrove swamps. There are now 141700 acres of salt marshes and 51000 acres of mangrove swamps which together cover about 30% of the mud-coast area of the country and distribute between 18°N (Southern Hainan Island) and 41 °N (Liaodong Bay). Over the past 45 years, about 1750000 acres of salt marshes and 49400 acres of mangrove swamps have been reclaimed. The 2.0×10⁹ tons of fine sediments input by rivers into the Chinese seas form extensive tidal flats, the soil basis of coastal helophytes. Different climates result in the diversity of vegetation. The 3∼8 m tidal range favors intertidal zone development. Of over 20 plant species in the salt marshes, nativeSuaeda salsa, Phragmites australis, Aeluropus littoralis, Zoysia maerostachys, Imperata cylindrica and introducedSpartina anglica are the most extensive in distribution. Of the 41 mangrove swamps species,Kandelia candel, Bruguiera gymnorrhiza, Excoecaria agallocha andAvicennia marina are much wider in latitudinal distribution than the others. Developing stages of marshes originally relevant to the evolution of tidal flats are given out. The roles of pioneer plants in decreasing flood water energy and increasing accretion rate in the Changjiang River delta are discussed. The project was supported by the NSFC (No. 49476281).     

Types and distribution patterns of modern tidal channels along the Huanghe River Delta coast

INTRODUCTIONTidalchannelsareimportantgeomorphologicunitsalongsiltcoasts.Theyhaveanevidentfunc tionfortidalflatbecausetheyareassociatedwithitsrapidbayheadwarderosionandlateralswing ing.Thetidalchannelsdevelopalongthecoastandplayanimportantroleinseaandlandinterac tion .Manyscientistsresearchedthetidalchannels (Bayliss Smith ,1 978;Shao ,1 988;Zhang ,1 995) .TheScientificandTechnicalCommitteeofShandongProvince (1 991 )investigatedthecoastoftheHuanghe (Yellow)RiverDeltaandresearchedtheti…     

Change in Sediment Provenance Near the Current Estuary of Yellow River Since the Holocene Transgression

Sedimentary sequence and sediment provenance are important factors when it comes to the studies on marine sedimentation. This paper studies grain size distribution, lithological characteristics, major and rare earth elemental compositions, micropaleontological features and ~(14)C ages in order to examine sedimentary sequence and sediment provenance of the core BH6 drilled at the mouth of the Yellow River in Bohai Sea. According to the grain size and the micropaleontological compositions, 4 sedimentary units have been identified. Unit 1(0–8.08 mbsf) is of the delta sedimentary facies, Unit 2(8.08–12.08 mbsf) is of the neritic shelf facies, Unit 3(12.08–23.85 mbsf) is of near-estuary beach-tidal facies, and Unit 4(23.85 mbsf–) is of the continental lake facies. The deposits from Unit 1 to Unit 3 have been found to be marine strata formed after the Holocene transgression at about 10 ka BP, while Unit 4 is continental lacustrine deposit formed before 10 ka BP. The provenances of core BH6 sediments show properties of the continental crust and vary in different sedimentary periods. For Unit 4 sediments, the source regions are dispersed while the main provenance is not clear, although the parent rock characteristics of a few samples are similar to the Luanhe River sediments. For Unit 3, sediments at 21.1–23.85 mbsf have been mainly transported from the Liaohe River, while sediments above 21.1 mbsf are mainly from the Yellow River and partially from the Liaohe River. For Unit 2, the sediments have been mainly transported from the Yellow River, with a small amount from other rivers. For Unit 1, the provenance is mainly the Yellow River catchment. These results help in better understanding the evolution of the Yellow River Delta.     

米仓山南坡寒武系沉积相分析

本文确认米仑山南坡的寒武系以潮坪相为主,并有浅海、生物礁和三角州相。文中阐述了这些相的特征和它们的时空分布,提出了该区寒武纪近岸盆地沉积模式,并指出寒武纪沉积为一海进一海退沉积旋回。文章还对寒武纪的地理景观和气候演变作了探讨。     

沁水盆地晚古生代含煤沉积体系及其控气作用

沁水盆地晚古生代含煤地层主要为晚石炭世太原组和早二叠世山西组,可采煤层有太原组第15号煤层和山西组第3号煤层,两者均为高煤阶无烟煤。对含煤地层内部各成因相及其组合的综合分析表明,太原组为陆表海多堡岛与碳酸盐台地复合沉积体系。第15号煤层形成于海退持续时间较长的潮汐三角洲环境,其中三角洲平原沼泽相中煤层较厚,滞留泻湖相中煤层较薄,障壁沙坝一带煤层厚度较稳定。山西组为河控三角洲沉积体系。三角洲平原沼泽环境中均衡补偿沉积持续时间较长,形成的第3号煤层厚度较大,结构简单。三角洲前缘沙坝中煤层厚度稍薄,分流河道中煤层不稳定。煤层气勘探实践表明,在同一口试气井中,盆地内大部分地方第3号煤层比第15号煤层厚度大,生气能力强,煤层气保存条件优越,气体质量浓度、含气饱和度、煤层气资源量高。因此,第3号煤层应是沁水盆地煤层气试采和商业化开发的首选目标层。     

长江三角洲滩涂信息的遥感提取及时空变化

海岸带滩涂是重要的生态资源,对于环境保护和区域可持续发展具有重要意义,是学术界研究的热点区域。但由于滩涂周期性地被潮水淹没,通达性较差,传统的测量方式难以满足这一高度动态环境的变化监测需求,因此遥感观测方式成为一个潜在的选择。但遥感观测受成像方式、大气条件和潮情的影响,其应用仍面临很大的挑战。本文以苏北至上海南汇边滩沿岸作为研究区域,首先选择了1975年以来每年潮位最低的Landsat影像数据作为数据源,利用水边线作为滩涂的外边界,植被线或围垦大堤作为内边界提取滩涂面积;然后利用ArcGIS软件对获取的滩涂数据进行分析,以此来研究长江口滩涂的时空变化特征。结果表明：① 1975年以来研究区域滩涂面积整体上呈降低趋势;1990s之前滩涂面积基本保持稳定,1990s之后降低趋势较为明显;1995年前后研究区圆陀角以北的江苏海岸和以南的长江河口区域滩涂面积达到最大值,分别为1101.2 km²、1495.5 km²,至2017年,二者面积分别降为649.5 km²、1043.4 km²,1990年至今总体降低速率为21.7 km²/a;② 流域来沙减少和围垦、深水航道等河口工程是长江口滩涂面积减少的主要控制因素。     

内蒙古雅布赖盆地红柳沟中侏罗统沉积相及沉积环境研究

野外考察发现,雅布赖盆地红柳沟发育一套较完整的中侏罗统扇三角洲沉积地层。其中沉积亚相有扇三角洲平原、扇三角洲前缘及前扇三角洲亚相;沉积微相包括辫状河道、天然堤、决口、沼泽、水下分流河道、水下分流河道间、河口坝、席状砂等沉积微相。从沉积构造特征分析可以看出,河道沉积发育于水动力条件较强的沉积环境,扇三角洲前缘河口坝沉积发育于强与弱水动力条件交替出现的沉积环境,而前扇三角洲则在比较稳定的水动力条件下沉积。对野外6个泥岩样品的微量元素化验结果用蜘蛛图解分析处理,得到样品所含微量元素V、Sr、Rb、B相对富集,而Zr、Cr、Ni相对亏损。通过对该地区样品w(Fe2+)/w(Fe3+)及气候指数计算表明,当时为弱氧化、半干旱的沉积环境。     

SEDIMENTARY EVOLUTION OF MODERN HUANGHE RIVER DELTA LOBE

The sedimentary history of a Huanghe(Yellow)River delta lobe can be divided into four stages.In the first stage,the crevasse splays and short-lived distributary channel deposits in the subaerial deltaand sheet silt in the subaqueous delta were well developed.In the second stage,further differentiationof sedimentary environments occurred in the subaerial delta lobe(distributary channel,natural levee,flood plain,central lower delta plain and lateral lower delta plain)and the subaqueous delta lobe(prodelta,delta front and delta lateral).In the third stage,crevasse splay and short-lived distributarychannel deposits mostly occurred in the lower or lower-middle part of the subaerial delta lobe,andsheet silt accumulated off the river mouth.In the fourth stage,the abandoned lobe was reworked.The common vertical sequence of the modern Huanghe River delta showed alternating clayey silt andsilt layers.A complete sequence from prodelta to upper delta plain was commonly composed of twoor more delta lobes.     

豫西渑池地区中元古界兵马沟组沉积环境分析

华北克拉通南缘中元古代早期发育陆源碎屑-碳酸盐岩沉积,豫西地区兵马沟组作为其早期陆源碎屑充填沉积,对于探讨中元古代早期华北克拉通南缘沉积环境演化有重要意义。在野外地质剖面实测基础上,结合岩性及粒度特征划分沉积相,探讨渑池地区兵马沟组沉积环境演化,为华北克拉通南缘中元古代早期沉积环境演化提供约束。豫西渑池地区兵马沟组剖面自下而上主要岩性为含砾砂岩-粉砂岩、泥岩-含砾砂岩,垂向上沉积物粒度特征具粗-细-粗的变化,概率累计曲线揭示其水动力条件先减小后变大,兵马沟组下段为河控三角洲的三角洲平原-三角洲前缘-前三角洲-三角洲前缘亚相,上段为滨海相的临滨-前滨亚相,其代表华北克拉通南缘构造活跃期-稳定盖层沉积期之间初期海进-海退旋回;中元古代早期,华北克拉通南缘表现为北东高南西低的古地形特征,兵马沟组是该时期熊耳群或华北克拉通古老基底遭受快速剥蚀的产物;对比不同地区的兵马沟组沉积特征,其在区域上的沉积差异可能是沉积时间及古地形差异性造成的。渑池地区兵马沟组在该时期仍受华北克拉通熊耳裂谷活动的影响,兵马沟组记录了裂谷盆地充填早期的演化过程,对研究华北克拉通南缘中元古代早期大地构造演化具有重要意义。     

沾化-车镇地区古近纪东营组沉积相特征及沉积演化

综合钻井、测井和古生物等资料,依据沉积学基本原理和方法,对济阳坳陷沾车地区古近纪东营组沉积相特征及空间展布进行研究。结果表明:沾车地区东营组发育冲积扇相、曲流河相、三角洲相、扇三角洲相、辫状河三角洲相、湖泊相、滩坝和湖底扇8种沉积相,以湖泊相为主。东营组三段盆地持续下陷,深湖相、滨-浅湖相发育,沉积范围广。东营组二段湖盆重新开始抬升,湖水收缩,沉积范围缩小,沉积相以滨浅湖相为主,伴有小规模的扇三角洲及滩坝沉积。东营组一段湖盆继续抬升,沉积范围进一步缩小,主要为冲积扇-河流沉积,凸起边缘发育一系列的冲积扇。     

MONITORING THE DIFFUSION OF SUSPENDED SEDIMENTS AND STABILITY OF TIDAL RADIAL SAND RIDGES AREA USING MULTI-SATELLITE REMOTE SENSING DATA

Nine Landsat TM tapes and images and MSS images, 10 NOAA tapes and images and 1 SAR image from 1973 to 1997 were used to analyse the diffusion of suspended sediments and the change of tidal radial sand ridges in the northern part of the Changjiang River delta, the South Yellow Sea. The results showed that the diffusion of suspended sediments was controlled by the tide, net current, and submarine topography in this area. The distribution of suspended sediments had close relationship with thesubmarine topography. The old Huanghe River delta and the Changjiang River comprise the main sediment supply for the formation of radial sand ridges, whose evolution can be divided into three stages since the Huangbe River changed its course and flowed northward into the Bohai Sea.     

Factorial analysis of annual erosion-accretion cycles of tidal flats in the front area of the southern Changjiang river delta

ＦＡＣＴＯＲＩＡＬＡＮＡＬＹＳＩＳＯＦＡＮＮＵＡＬＥＲＯＳＩＯＮＡＣＣＲＥＴＩＯＮＣＹＣＬＥＳＯＦＴＩＤＡＬＦＬＡＴＳＩＮＴＨＥＦＲＯＮＴＡＲＥＡＯＦＴＨＥＳＯＵＴＨＥＲＮＣＨＡＮＧＪＩＡＮＧＲＩＶＥＲＤＥＬＴＡＹａｎｇＳｈｉｌｕｎ（杨世伦）Ｃｈｅ...     

尼日尔深水区海底扇水道地震形态与迁移历史

尼日尔下陆坡深水区的水道发育具多期次特征,内部结构与外形复杂多变,其地理位置与沉积环境不利水道体系的研究.通过地层切片、RMS振幅属性等方法展示不同时间单元水道形态,分析水道体系的期次变换与内部结构的变形过程,探讨水道体系的迁移演化历史.结果表明:中新世中期多发育孤立水道,晚期二级海平面大幅度下降引发大规模浊积事件,促使大量加积式水道形成,在平直处以垂向加积为主,弯曲处呈现垂向加积同时伴随侧向迁移特征.水道演化大致可分为3个阶段:初始侵蚀、切割与充填交替进行、废弃阶段,伴随3个阶段水道弯度发生由中到高再下降的变化.水道的交互式切割与充填基本贯穿第2阶段,切割与充填作为水道弯曲变形一对驱动力,使水道在平面上发生3种迁移方式:侧向摆动、下行迁移、侧向与下行混合迁移.     

Sources of sediment in tidal fl ats off Zhejiang coast,southeast China

The growth of tidal fl ats off Zhejiang coasts in southwestern China has provided substantial areas for local agriculture and construction activities. To evaluate modern and future development of tidal fl ats in the region, a good understanding of sediment sources is necessary. Previous research has concluded that the Changjiang(Yangtze) River is the dominant supplier of sediments to this part of the southeast Chinese coast, despite the fact that sediment delivery from this source has been decreased markedly in the past two decades. In this study, we investigated the sources of tidal fl at sediments, and the magnetic and geochemical properties of recent tidal fl at sediments along the Zhejiang coast were compared with those discharged from rivers. Magnetic and geochemical properties of the tidal fl at samples reveal statistically distinct sediment provenance groups. The magnetic and geochemical scatter plots show that the suspended sediment samples are naturally divided into two diff erent groups, one including the Changjiang River and Qiantang River material, and the other including the Jiaojiang, Oujiang, and Feiyun Rivers that located in the central and southern parts of the study areas. At last, a binary source of tidal fl at sediments along the Zhejiang coast was determined, with the substantial majority originating from local rivers, while a much smaller proportion emanates from the Changjiang River to the north. We conclude that the sediment contribution of the Changjiang River to tidal fl at development in the region has been markedly overestimated, with important implications for management.     

太子河流域本溪期沉积相特征

太子河流域是华北地台区本溪组最发育的地区之一。本文从典型剖面分析入手,对本溪期的沉积相进行分析讨论。本溪的牛心台剖面海相层位出现最早,晚期出现浅水生物碎屑滩沉积,底部之滨海湖沼相中的铝土矿厚度大品位高;大葫芦套村剖面以泥岩广泛发育,且灰岩层数多而薄为特征,代表滨海平原湖泊的沉积;田师付太平沟剖面以下部发育一完整的三角洲沉积而有别于其它地区;在最北部的暖河子剖面,下部为滨岸冲积平原的沉积,代表了近陆环境中的沉积。本溪期沉积可分为两个演化阶段,早期沉积受古地形的制约,为一填平补齐作用,沉积环境主要为滨岸冲积平原、滨海湖泊、沼泽以及三角洲;晚期是随着海侵范围的扩大和地形差异的缩小,基本上为一海湾—泻湖环境,但局部有浅水生物碎屑滩的存在。     

Revisiting and rethinking regional urbanization in Changjiang River Delta, China

China is entering a critical and accelerating phase of urbanization.As one of the most urbanized regions in China,the Changjiang(Yangtze)River Delta has experienced dramatic urbanization and urban transformation.However,in the recent years,many changes have taken place in this region and there is limited attention to the regional urbanization path evolution,its problems and the way to solve these problems.Therefore,we should revisit the urbanization process in the Changjiang River Delta again.In this paper,we revisited urbanization paths of the Changjiang River Delta by data analysis,influence factors of urbanization by the Gray Relational Analysis,and major challenges to urbanization of the Changjiang River Delta by theoretical considerations.We found that the urbanization of the Changjiang River Delta had experienced several stages of large-scale spatial and urban system restructuring.Within the Changjiang River Delta,Shanghai,Zhejiang and Jiangshu had experienced different urbanization path with local characteristics.But with their development model gradually converging,their urbanization model is also converging.We also found that the major influence factors affecting the Changjiang River Delta urbanization were dynamic change and urbanization was driven by different key factors in different socio-economic development stages.Meanwhile,the Changjiang River Delta urbanization is facing many problems such as existing institutional arrangements,including the hukou(household registration)system and others which can not meet the needs of current socioeconomic development and urbanization.Therefore,it is imperative to promote institutional innovation and adopt a new urbanization development strategy for the sake of the orderly and sustainable urbanization development in the Changjiang River Delta.