Kaolin Deposits of Weathering-Residual in the Coastal Area of Guangdong Province

Kaolin deposits of weathering-residual type make up a large proportion in different types of kaolin depos-its and are widely used in ceramics, electron ceramics, rubber and paper industries. This paper discusses sys-tematically this type of kaolin deposit with respect to their features of occurrence, mineralogical and chemicalcomposition and transformation of minerals during supergene processes, thus providing some basic data forthe rational exploitation and utilization of the kaolin resources.

A 150-year Isotopic Record of Lead Deposition in Yancheng Coastal Wetland,China

Radioactive markers are useful in dating lead(Pb) deposition patterns from industrialization in sedimentary archives. As a well-known natural reserve in the world, Yancheng coastal wetland in Jiangsu Province is one of areas most sensitive to global sea level change and is located in the most developed and polluted region of China. Two cores were collected in Yancheng wetland in October 2013 and dated using ^(210)Pb and ^(137)Cs radiometric techniques. Sediments in both cores were sectioned into depth bands and examined systematically for dry bulk density, water content, magnetic susceptibility and grain-size. Multiple elements including Pb were also measured using inductively coupled plasma systems. Unsupported ^(210)Pb activities decreased with depth in both of the two cores, and ^(210)Pb chronologies were established(covering 150 years) using the constant rate of supply(CRS) model. The measured Pb contents ranged from 14.97 mg/kg to 29.40 mg/kg with average values of 17.17–22.79 mg/kg, and the Pb fluxes ranged from 41.70 mg/(m^2·yr) to 172.70 mg/(m^2·yr) with averages of 95.59–123.41 mg/(m^2·yr). Temporal variations of Pb flux, enrichment factors and Pb isotopes show a gradual and continuous increase over time and clearly reflect increased emissions from anthropogenic activities in the region. The Pb isotopic compositions show that most of Pb deposition in Yancheng wetland is input from natural sources by water flows and has the same levels of Pb as in the surface sediment of the Yangtze River and the Pacific mineral aerosol. We also stress the anthropogenic Pb contribution in Yangcheng wetland sediment and the reason of our Pb isotopes not showing anthropogenic signature is likely the instability of anthropogenic Pb in high Fe/Mn oxide conditions. Therefore, more attention should be paid to current local pollution problems, and society should take action to seek a balance between economic development and environmental protection.

Stratigraphic framework and sedimentary evolution during the Cryogenian-Ediacaran transition in northeastern Sichuan Basin,South China

The northeastern Sichuan area in the northern Yangtze margin has unique Ediacaran geological records,especially the Doushantuo Formation(DST),and become a hot research area in recent years.However,the Cryogenian-Ediacaran(C-E)boundary has not been precisely identified,which restricts the in-depth study of geological information during this crucial transitional period and is unfavorable for a systematic and complete understanding of the Yangtze Block and even the global paleogeographic pattern.This study conducted stratigraphy,sedimentology,and chronostratigraphy to establish the stratigraphic framework and sedimentary evolution of the C-E transition strata in northeastern Sichuan.The results showed that the Ediacaran sediments,without the cap dolomite,unconformably overlaid the Cryogenian sediments in the studied area.The Member II of the DST,characterized by 50-160 m of red-green sandstone(approximately equivalent to the original Chengkou“Guanyinya Formation”),directly overlaid the Cryogenian sediments and displayed a 623±2.3 Ma maximum depositional age from the detrital zircon U-Pb dating.Regional stratigraphic correlations indicate that the C-E transition strata in northeastern Sichuan had a consistent lithological association and sedimentary sequence characteristics but differed from the Three Gorges.Typically,the upper Nantuo massive glacial diamictites transition to the icebergs rafted lonestone-bearing mudstones at the top,then change upward to DST barrier coast sandstones.The proposed DST of the northeastern Sichuan Basin was divided into three lithostratigraphic members without the regional Member I cap dolomite:(i)Member II purple-red,gray-green sandstone strata,(ii)MemberⅢblack mudstone strata,and(iii)Member IV P-Mn bearing strata.During the C-E transition,the study area experienced(i)the global deglaciation stage in the terminal Marinoan glaciation and(ii)the filling-leveling up stage with clastic rocks in the early Ediacaran.Overall,the early Ediacaran of northeastern Sichuan succeeded the paleogeographic features of the late Cryogenian.

Excess polonium-210 in the coastal atmosphere originating from marine biogenic material

The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/（m^2· d）, with an average of 0.04 Bq/（m^2 · d）. The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 （r^2 =0. 85） and lead-210 fluxes （r^2 =0.71 ）, indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect （foam）, or mare likely, direct （ air - sea exchange） input of marine bingenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.

Sedimentological features and biostratigraphy of Jurassic/Cretaceous deposits in continental basins in Priamurie,Far East Russia

The paper describes the sedimentary features and biostratigraphy of the transitional Jurassic to Cretaceous deposits in the continental basins of Priamurie formed after the collision between the Siberian and North China blocks.In Upper Priamurie,the collision occurred in the late Early Jurassic as dated by the emplacement of the post-collisional granites (191 Ma).While in Lower Priamurie and West Priokhotie it could take place in the late Middle Jurassic on the basis of fossil evidence from an accretionary turbidite complex.This event reflected the environmental change from coastal-marine to alluvial plains,often boggy,where coals accumulated.The environmental change is in harmony with that of biota.Systematic study of floral and spores/pollen assemblages,particularly in the sections of interbedded marine and non-marine deposits,makes clear the chronostratigraphic succession of floral associations and shows the possibility of their application for subdivision and correlation of the continental deposits of Priamurie.The coastal-marine environment of the residual post-collisional sublatitudinal basins in the western part of Priamurie (Upper Amur and Dep basins) was replaced by the continental in the late Middle Jurassic and in the eastern part in the Berriasian-Valanginian (Torom Basin).Similar environmental change commenced in the submeridional rift basins:the Bureya Basin in the Callovian and the Partizansk Basin in the Hauterivian.Changes in ecosystems occurred frequently during the Middle Jurassic--Neocomian,but the most substantial changes took place in the late Middle Jurassic and in the end of Late Jurassic.

白云凹陷北坡珠江组下部储层生物遗迹及沉积演化特征

南海北部珠江口盆地的白云凹陷北坡新近系底部的陆架边缘三角洲前缘砂体有良好的油气储集条件,具有巨大的油气勘探价值。以珠江口盆地白云凹陷北坡—番禺低隆起珠江组下部为研究对象,将常规的岩心观察、地震相分析等手段与生物遗迹分析相结合,探索其沉积环境特征及演化规律。结果表明:陆架坡折处发育陆架边缘三角洲前缘亚相沉积,发育以水下分流河道和河口坝为主的沉积微相,发育Skolithos遗迹相,局部生物扰动剧烈。陆架坡折以北整体发育滨海三角洲沉积,以分流间湾和水下分流河道沉积微相为主,发育Skolithos-Cruziana遗迹相,生物扰动程度以中等—剧烈扰动为主,局部为稀少生物扰动。研究区的沉积演化可以分为海退期(21.0~19.0 Ma)和海侵期(19.0~18.5 Ma)两个阶段,海退期物源充沛,在陆架坡折处发育陆架边缘三角洲前缘亚相沉积;海侵期海平面上升,发育退积三角洲,在陆架坡折以北发育滨海三角洲前缘亚相沉积。

The bounding-surfaces record of a barrier spit from Huangqihai Lake,North China:implications for coastal barrier boundary hierarchy

Ground-penetrating radar and trenching studies of a barrier spit on the north shore of Huangqihai Lake were made,that reveal important implications for the coastal washover barrier boundary hierarchy and interpretations of this depositional record.A four-fold hierarchy bounding-surface model,representing different levels of impact and genesis,is defined.Each level of the hierarchy is enclosed by a distinct kind of surface characterized by different ground-penetrating radar reflection features,sedimentary characteristics(color,grain size,sorting,rounding and sedimentary structures) and origin.We suggest that this hierarchical model can be applied to any coastal washover barrier deposits.

近20年中国近海和海岸带大气黑碳干湿沉降及源解析

作为一种在大气中普遍存在的碳质气溶胶成分,黑碳因可对生态环境产生深远影响而备受关注。对海洋大气黑碳沉降的深入认识有助于进一步明确海洋碳循环过程。目前对中国近海和海岸带大气黑碳沉降的研究工作少且零散,相关研究数据不足以探求其规律。对该区域近20年来已报道的大气黑碳数据进行系统梳理和再分析,利用整合的数据集成估算沉降通量并分析其空间分布特征,最后评述了目前黑碳的源解析方法并评估了该区域大气黑碳的来源,对未来近海大气黑碳研究作了展望。结果表明:①中国近海和海岸带陆域大气黑碳浓度平均值分别约为1.95±1.28和5.05±2.62μg·m^(-3),具有显著的人为污染特征,由北向南,海岸带陆域黑碳浓度近似呈“V”形分布,最低值位于南黄海沿岸,而近海区则大致呈递减趋势;②中国近海和沿海陆域大气黑碳的总沉降通量分别为413.2±137.1和1422.7±721.1 mg·m^(-2)·a^(-1),以湿沉降为主,南北差异明显,主要受控于降水过程和陆源排放强度;我国近海黑碳大气沉降量可占全球海洋黑碳总沉降量的16%;③化石燃料源贡献了中国海岸带大气黑碳总排放量的62%~84%,因此,应注重从减少化石燃料源使用的角度控制大气黑碳污染。今后,应注重不同源解析方法间的集成和互校,并加强黑碳在地球不同储库间的迁移、转化和埋藏机制研究。近海和海岸带大气环境中的黑碳有着多方面的影响,其沉降入海并以惰性形式埋藏对增强海洋碳汇有着重大意义。

万宁地区近地面氯离子沉积速率的影响因素研究

目的 研究热带海洋大气环境中不同地貌下氯离子沉积速率的分布规律及主要影响因素。方法 通过挂片法采集万宁地区的氯离子沉积速率,并分析离海距离、地形地貌对氯离子沉积速率的影响,以及其与海水因素、自然环境因素间的相关性。结果 近海开阔区域氯离子沉积速率受离海距离和地貌的影响显著,在300 m处降低至90 m处的1/3左右,地貌的变化导致同一距离点处的氯离子沉积速率相差30倍。另外,高的海水有效波高、风速和东风占比使春季氯离子沉积速率高于夏季。结论 不同地貌下的氯离子沉积速率均与海水有效波高、风速间呈较强的正相关性。

Depositional Facies and Sequence Stratigraphic Study in Parts of Benin (Dahomey) Basin SW Nigeria: Implications on the Re-Interpretation of Tertiary Sedimentary Successions

Detailed fieldwork in parts of the Benin (Dahomey) Basin SW, Nigeria has allowed the recognition of sedimentary successions deposited in different continental depositional environments interpreted as fluvial sedimentation characterised by abandoned channels and subaerial exposure features. The lithofacies recognised are: conglomerates, debris flow deposits, very coarse grained sandstone, ferruginous cross bedded sandstone, siltstone, shale/clay and massive sand. The lithofacies were interpreted in terms of sequence stratigraphic elements with the recognition of sequence boundaries characterised by distinct facies dislocations and subaerial exposures. Four depositional sequences (DS I to DS IV) were identified. Depositional sequences (DS I) exhibited a complete regressive–transgressive cycle comprising LST, TST and HST, while DS II to DS IV were incomplete comprising of sediments interpreted as LST deposits. On the basis of the depositional facies and sequence stratigraphic elements, the sediments in the area of study are interpreted as predominantly of Ilaro Formation while fewer exposures are sediments of the Coastal Plain Sands/ Benin Formation. This observation suggests a re-interpretation of the Tertiary sedimentary successions, which hitherto recognised all the sediments in the area of study as Coastal Plain Sands.

基于GIS的广西北海海岸带地质环境监测数据管理与服务系统的设计与实现

针对近年来广西北海市海岸带出现的地质环境问题,基于GIS技术在空间数据管理和综合分析方面的优势,开发设计了海岸带地质环境监测数据管理与服务系统。实现了北海市海岸带侵蚀淤积数据、海水入侵数据及生态地球化学数据的在线监测、综合管理和动态模拟。该系统在北海市取得了良好的应用,为北海市海岸带地质环境问题的治理提供了有效决策支持,为其他海岸带地质环境数据管理系统提供了参考。

射阳海岸带修复工程效果数值模拟研究

近年来受黄河三角洲区域侵蚀影响,射阳海岸带湿地面积急剧减小,急需开展生态整治修复工程.应用河口海岸潮流泥沙数值模拟系统,计算分析项目建设前后海洋水文动力和泥沙冲淤环境改变,并通过物模试验进一步验证海床冲淤情况.模型计算结果表明项目建设后,潜堤两侧流速及堤后波高也出现不同程度的减小,有利于形成堤内侧床面增积的状态,潜堤内床面增加的年淤积厚度约0.02~0.45 m,工程岸段逐渐向冲淤平衡或微冲微淤状态发展.堤后波能降低,阻挡了波浪对海堤的侵蚀,近岸冲刷幅度均有降低.物模试验结果表明方案实施后南侧、北侧堤后平均冲刷深度分别减小为0.03、0.02 m.根据研究结果可知该工程能发挥对内部潮滩的保护作用.

胶西北海岸带基岩矿床分布富集规律及典型矿床主要特征

胶西北海岸带研究区70%以上被第四系覆盖,矿化信息被屏蔽和削弱,增加了发现新矿体的难度。分析研究认为,区域内构造格架自北而南呈盆-岭-盆相间出现,受该构造格架控制,区域内煤矿、金矿、铁矿按自北而南呈“北煤、中金、南铁”的“纬度分带”式产出,煤矿主要产出于区域北部的古近纪五图群地层中,属煤层与油页岩互层的湖河三角洲沉积建造;金矿主要产出于区域中部的侏罗纪玲珑花岗岩、郭家岭花岗岩侵入岩体中,是大规模岩浆活动和广泛的伸展拆离的产物;铁矿主要产出于区域南部的古元代粉子山群小宋组含铁岩系中,属区域变质作用密切相关的沉积变质铁矿床。研究区海底基岩矿床不是独立的矿床,而是与陆地矿床相连,是陆地矿床随地质构造向海洋延伸的一部分。通过研究第四系覆盖下的基岩分布规律、基岩矿床分布规律和总结海岸带基岩矿床成因规律性特征,对加强重点成矿区找矿针对性,更好地指导和推动胶西北海岸带区域找矿进展,实现产学研的紧密结合具有重要意义。

新疆西南天山伽师砂岩型铜矿床古环境分析

伽师砂岩型铜矿床位于新疆西南天山砂岩型铜成矿带中段,是该带最大的砂岩型铜矿床。通过矿床及外围实测剖面测量、路线剖面调查,及岩性、岩相鉴定,结合区域岩性、岩相及古环境分析,推断古近系早期到晚期由于陆壳的持续抬升与局部间歇性海侵、海退,其成矿环境表现了滨海潟湖及局部夹有河流三角洲相变规律。其含铜矿层应为滨海潟湖-三角洲环境的产物。至古近系始新世(45Ma),在印度板块碰撞俯冲的背景下,陆壳持续抬升,至新近纪中新世(21Ma)完全变为陆相沉积,随着近南北向持续挤压隆升,形成西南天山古近纪推覆构造带,致使含矿层位发生褶皱以至于南翼发生倒转的构造样式。据此来推动新疆伽师地区铜矿资源的进一步开采,并对研究区古环境分析提供更为有力的的论证。

莫桑比克中北部滨海锆钛砂矿成矿地质特征

莫桑比克东濒印度洋,沿海岸线赋存丰富的具有世界级规模的滨海砂矿资源,具有较好的勘探和开发投资前景。通过野外地质调查和室内综合研究,对莫桑比克中北部滨海砂矿的成矿地质背景、矿体特征、矿石特征及矿床成因进行总结。本区滨海锆钛砂矿赋存于第四系粉细砂层中,地貌上多为起伏砂地和平坦砂地,矿体沿海岸线呈条带状分布,延展连续性较好,形态较规则。沿倾向矿石品位较连续,矿体厚度总体上变化不大,各重矿物在矿体中的含量变化呈正相关关系。重矿物以钛铁矿为主,其次为锆英石、金红石、独居石,多以单矿物颗粒的状态散布在矿石中,粒度主要为0.096~0.15 mm,属易分选型矿石。矿床类型属滨海相机械沉积型矿床,其形成受成矿物质来源、气候和水动力、海岸地貌、构造运动与海岸变迁等多种因素影响,主要经历三个阶段,即重矿物原生赋存阶段、运移阶段和富集成矿阶段。本工作揭示了滨海砂矿形成规律,为莫桑比克中北部滨海砂矿矿床勘探和开发提供了参考。

滨海大型金矿床取消矿柱及房柱交替采矿的新工艺(英文)

针对三山岛金矿条件,研究了深部开采取消点柱的工艺技术。首先,调查测试了矿岩物理力学参数,并对矿岩质量进行了分级。其次,在详细分析上下盘及矿体的物理力学特性的基础上,对三山岛金矿深部开采取消矿柱进行了有限元数值模拟,研究得出-555 m水平以下矿体的开采可全面取消矿柱。最后,结合矿床条件,提出了房柱交替式盘区上向分层充填采矿新工艺。工业试验结果显示,该新工艺大幅度提高了单位面积开采强度,对岩层扰动小,盘区生产能力大,矿石损失贫化小,获得了显著的经济效益。此外,对三山岛金矿由于深部开采而导致的地表沉降利用ANSYS软件进行分析,同时对岩层变形进行了监测。结果表明,三山岛金矿深部开采取消矿柱和采用房柱交替采矿新工艺后能够有效控制岩层变形,从而可实现滨海大型金矿床安全高效低贫损开采。

东濮凹陷老第三系沙河街组盐类沉积模式新见

提出了对东濮凹陷沙河街组成盐环境解释的新观点。认为在东濮凹陷中自沙河街组四段沉积中晚期开始 ,海水随着海面升降 ,间歇性地进入由北东向的兰聊断裂和长垣断裂构成的古河谷。高位期 ,海水以相对暂时性抬高的形式淹没本区 ,致使凹陷南部成为向东南或南开口的河口湾 ,构成盐湖沉积的先期沉积环境 ;到低位期 ,海水退出凹陷区 ,部分海水因受东西向同沉积走滑断裂 (高平集—习城集一线 )高地的阻隔而潴留 ,局限在高平集—习城集断层至文明寨—范县断层的同沉积构造凹陷中 ,潴留海水蒸发、浓缩 ,形成盐类。在较深的凹地 ,受陆源淡水的影响较小 ,卤水浓度相对较高 ,依次沉积了具有深水沉积特点的碳酸盐岩、石膏、石盐等 ;而在水体较浅的凹地 (如砂坪、泥坪环境 ) ,则易受季节性洪水影响 ,卤水淡化 ,沉积了具有明显浅水特征的灰质泥岩。

上海市南汇南滩近期演变特征分析

作者利用经验正交函数(EOF)方法分析了南汇南滩近期冲淤特征,表现为随着时间推移在空间上纵向与横向的两种波动。纵向上,南汇南滩的冲淤波动以类似行进波的形式向西传播,速率约为820m/a,波动幅度沿程递减;横向上,以水下斜坡和海床的衔拉部位为节点,整个剖面以类似驻波的形式上下振动,节点上下出现相反的冲淤趋势,即上冲下淤或上淤下冲。水下斜坡带冲淤幅度最大,滩地和海床相对要小。

有机污染物在不同沿海沉积环境中积累的差异性

以浙江沿海水域为研究区域,在系统地测定水体与沉积物中有机污染物种类的基础上,研究了表层沉积物中有机污染物的积累与沉积环境、沉积物矿物组成和排放环境因素之间的相互关系.结果显示,沿海水体和表层沉积物中主要存在的有机污染物有石油烷烃类化合物、邻苯二甲酸酯化合物、有机硅氧链类化合物、氯代苯酚类、苯醚类和胺类化合物等6大类,它们在表层沉积物中的积累强度呈现出河口大于沿岸大于强潮汐河沉积环境的趋势,但在相同沉积环境的沉积物中有机污染物的积累强度存在一定的差异,这说明有机污染物在沿海沉积物中的积累除与沉积环境有关外,还与区域有机污染物的排放特点有关.

宁波镇海港区淤积机理及影响因素分析

目前重视工程前期的论证预测,而对工程后续的观测分析较少。以宁波港镇海港区为例,借助翔实的实测资料,通过镇海沿岸潮流、泥沙特性分析,对大规模围涂后宁波港镇海港区的淤积原因进行了深入分析。区分了不同因素对港区淤积贡献的大小,从而合理解释外游山深潭的淤积机理。分析结果表明:周边规模较大的围涂和外游山局部围涂使其矶头效应显著削弱,是造成该深潭持续淤积的主要原因。