岩心声速垂向变化对古海水进退的指示意义

钻孔岩心声速Cp垂向变化与地质历史中的海进、海退事件有关;南海北部大陆架及东海大陆架的钻孔岩心声速垂向变化曲线,为揭示西太平洋边缘海在更新世以来至少发生过3次海进和3次海退的3次沉积旋回事件提供了佐证。海进时所带来的海相沉积物的声速较低(1450—1510m·s-1),海退时所形成的陆相沉积物的声速较高(1650—1720m·s-1)。     

现代黄河口晚更新世以来沉积地球化学特征

对现代黄河口KD4孔岩心进行了粒度与地球化学分析,结果表明KD4孔的化学元素随深度变化表现出一定的分层性,自上而下可划分为10层,分别为黄河三角洲沉积、全新世浅海相沉积、晚更新世玉木Ⅲ冰期陆相地层、玉木上亚冰期海相沉积、玉木Ⅱ冰期陆相地层、玉木下亚间冰期的浅海相沉积、玉木Ⅰ亚冰期的陆相沉积以及上玉木—里斯间冰期的海相沉积及其后波动期的陆相、海相地层。对各层元素含量与变化进行了描述。对常、微量元素进行R-型聚类分析,可将元素组合初步分成4个聚类。R-型因子分析反映常、微量元素变化主要受5个因子控制,分别反映沉积物粒度、水动力、物源、地球化学作用和自生作用等因素的影响。研究结果揭示出本区自晚更新世以来的玉木—里斯间冰期及其波动期、玉木Ⅰ亚冰期—下亚间冰期、玉木Ⅱ亚冰期—上亚间冰期、玉木Ⅲ亚冰期—冰后期4次大的冷暖交替旋回,较好地响应了区域和全球气候变化。     

西江三角洲岩心中的硅藻及其记录的古环境

通过对西江三角洲ZXZ1,ZXZ2两岩心沉积物样品的硅藻分析,共鉴定出硅藻168种和变种,隶属48个属;ZXZ1岩心可划分为六个硅藻带,ZXZ2岩心可划分为五个硅藻带。根据硅藻组合特征,结合粒度和14C测年结果,ZXZ1岩心的Ⅳ,Ⅴ,Ⅵ硅藻带和ZXZ2岩心的Ⅲ,Ⅳ,Ⅴ硅藻带属于全新世沉积;ZXZ1岩心的Ⅰ,Ⅱ,Ⅲ硅藻带和ZXZ2岩心的Ⅰ,Ⅱ硅藻带属于晚更新世沉积。分析了晚更新世以来沉积物的沉积相和沉积环境,结果表明,晚更新世时期ZXZ1岩心的沉积物属于近岸低盐海相沉积环境,而ZXZ2岩心的沉积物属于陆相沉积;在全新世时期两岩心均属近岸低盐的海相沉积环境。造成晚更新世时期两岩心沉积相的差异主要与断裂构造的升降运动有关。     

威海南部近岸泥质区晚更新世以来的重矿物组合特征及对物源的指示

对威海南部近岸泥质区WHZK01孔（孔深25.1 m）岩心开展重矿物分析，结果表明，WHZK01孔主要以普通角闪石（22.1%）、磁铁矿（20.0%）和绿帘石（17.7%）为主，晚更新世以来自下而上可分为3个矿物组合带。氧同位素3期晚期河流相沉积（DU3）主要矿物组合为普通角闪石-绿帘石。末次冰后期河漫滩-河口湾相沉积（DU2）主要矿物组合为普通角闪石-绿帘石-钛铁矿-褐铁矿。全新世滨-浅海相沉积（DU1）主要矿物组合为磁铁矿-绿帘石-片状矿物-自生黄铁矿。重矿物物源判别表明，DU3和DU2层沉积物主要来自山东半岛南部沿岸河流输入。DU1层沉积物主要来自沿岸流输运的大量黄河细粒物质，沿岸河流物质和岛屿侵蚀物也有少量贡献。     

山东半岛南部滨浅海区晚第四纪声学地层

通过对山东半岛南部滨浅海区高分辨率浅地层剖面的分析解译,将研究区晚第四纪的地层划分成具有层序意义的6个声学反射地层单元(SU1—SU6),通过典型浅地层剖面与研究区内QDZ03孔和QDZ01孔进行对比,发现声学反射地层单元的划分与钻孔岩心沉积物沉积单元的划分具有很好的对应关系,依据钻孔岩心沉积相特征和沉积物测年数据,我们认为SU1、SU3和SU5分别对应于氧同位素1期、3期和5期的海相沉积,SU2和SU4对应于氧同位素2期和4期的陆相沉积。     

渤海海峡及周边海域浅地层结构及地层声速的拾取

通过系统分析渤海海峡及周边海域的高分辨率浅地层剖面与3口钻孔的资料,将研究区地层自上而下划分为T0、T1、T2、T3、T4、T5、T6、T7、T8共9个反射界面及SU11、SU12、SU13、SU2、SU3、SU41、SU42、SU43、SU5共9个声学地层单元,SU1地层单元对应全新世海相沉积,其底界为一海进侵蚀面,削蚀对应晚更新世晚玉木冰期陆相沉积的SU2地层单元。SU3地层单元对应晚更新世晚玉木间冰期的海相沉积,通过侵蚀间断面与上覆SU2呈不整合接触。SU41地层单元对应晚更新世早玉木冰期晚期的陆相沉积,SU42地层单元对应晚更新世早玉木亚间冰期的海相沉积,与上覆SU41呈侵蚀不整合接触,SU43地层单元对应晚更新世早玉木冰期早期的陆相沉积,其顶界面为海进侵蚀面,与下伏地层呈不整合接触,SU5对应晚更新世玉木—里斯间冰期的海相沉积。对比分析浅地层剖面地层单元与钻孔沉积地层,确定了研究区海底面之下不同地层单元对应的平均声学速度,为后续的地层层序的研究奠定了基础。研究区"海侵-海退-海侵-海退-高水位"的沉积过程,决定了地层平均声速随深度自下而上呈现由高-低-高-低的变化模式。     

辽东湾北部LH01孔晚更新世24Ka以来古环境演变

通过对辽东湾北部LH01孔柱状岩芯样品进行粒度、孢粉、有孔虫和测年多项环境指标测试,探讨了辽东湾北部晚更新世24ka BP以来的古环境演变。LH01孔沉积环境经历了晚更新世晚期河湖相沉积—全新世早期海陆交互相沉积—全新世中期浅海相沉积—全新世晚期河口滨海相沉积;气候经历了晚更新世晚期冷较干—晚更新世晚期凉稍润—新仙女木降温—全新世早期凉稍润—全新世中期温暖较润—全新世中期温暖较干—全新世晚期温较干的变化;LH01孔在大约7.5ka BP发生了盘山海侵。     

大凌河河口地区晚更新世晚期以来的沉积环境演化

对大凌河河口地区ZK3钻孔(孔深36.7 m)岩心开展粒度分析、AMS14C年代测定、有孔虫鉴定分析等综合研究,同时结合该地区5口工程钻孔的岩心以及部分测年资料,初步建立了大凌河河口地区晚更新世晚期以来典型的地层序列格架和时空对比框架,揭示该地区晚更新世晚期以来河道-湖沼-滨海/河口湾-浅海-三角洲的沉积演化过程。研究结果表明:大凌河河口地区在8 500 cal a BP前后开始接受海相沉积,并约在4 000 cal a BP之后进入三角洲沉积阶段;晚更新世晚期以来的海平面变化是大凌河河口沉积演化和沉积环境演变的主要控制因素;大凌河对现代辽河三角洲的形成和演化过程可能有较重要的影响。     

辽河三角洲晚更新世以来的地层层序及沉积环境变迁

通过分析辽河三角洲获取的长41.4m的ZK2孔岩心的岩性、粒度、有孔虫丰度及分子标志物等资料的基础上,结合精确的测年数据、海面变化等资料,并与其他钻孔资料分析对比,构建了辽河三角洲晚更新世33ka BP以来的年代地层框架,将ZK2孔自下而上划分为U1-U4这4个沉积相段:U1为河道相,U2为河漫滩相,U3为海相(全新世海侵)和U4为上三角洲平原相。U3段的海相沉积自下而上又可进一步分为U3~1、U3~2、U3~3、U3~4、U3~5 5个沉积层,分别对应了河口湾相、浅海相、前三角洲相、三角洲前缘相、下三角洲平原相(潮坪相)。沉积物的粒度、有孔虫及生物标志物BIT等指标在不同沉积环境中出现了较为明显的变化,且变化趋势相似,揭示了辽河三角洲晚更新世33ka BP以来的海平面变化的沉积历史,其中U3段沉积物(15.75~2.65m)沉积连续,地层完整,测年数据可靠,较完整地反映了辽河三角洲9 100cal.a BP以来全新世海侵期的沉积历史。     

中更新世以来新疆罗布泊地区气候演化过程

综合罗布泊LS2孔的碳酸盐含量、总有机碳、总氮和碳氮比的多指标分析,重建了该地区中更新世以来的沉积环境和气候环境的演化过程。结果表明,中更新世以来罗布泊地区沉积环境经历了中更新世的浅湖相沉积(厚度为12m)—滨湖相沉积(厚度约为46m)—浅湖相沉积(厚度为11m)—滨湖相沉积(厚度为28m)—晚更新世至今的滨湖相向风成相沉积(厚度约为18m)环境的演变过程;气候演化过程可以分为7个阶段:阶段Ⅰ(深度115～103m)气候由暖干向冷干气候转变;阶段Ⅱ(深度103～82m)冷湿和暖干交替变化;阶段Ⅲ(深度82～67m)气候相对暖干;阶段Ⅳ(深度67～57m)气候冷湿;阶段Ⅴ(深度57～46m.)气候温暖且偏干;阶段Ⅵ(深度46～18m)气候主要在冷湿背景下夹有3次暖干的气候波动;阶段Ⅶ(深度18～0m)气候干旱化加剧。该研究表明,中更新世时期罗布泊地区沉积环境以浅湖相—滨湖相为主,并在晚更新世发展为以风成相堆积为主;气候变化的水热组合形式主要遵循着"冷湿—暖干"的变化模式。     

北部湾X1钻孔岩芯沉积物的Ⅹ射线衍射分析研究

X射线技术在结晶矿物学上已得到广泛的应用,它测量精度较高,快速简便,对样品无破坏作用,是地质研究中的重要手段之一,它还广泛地用于大陆架地区的沉积物研究(俞旭等,1982; Devine,1972)。本文将对北部湾东北部x1钻孔近百米的沉积物岩芯全样进行X射线衍射定量分析研究,并根据矿物组合特征,探讨北部湾沉积区的沉积环境及演化过程。     

南黄海中部沉积岩芯的微体古生物组合特征及古环境演化

本文分析测定南黄海中部两个沉积物柱状样中的有孔虫、介形虫和“C年代，对其微体古生物组合特征、沉积环境和地层年代进行了初步的探讨。有孔虫组合表明研究海域为近岸一浅海环境，其含量从下到上由缺失到出现近岸、浅海有孔虫，反映了沉积环境由陆相到滨岸相、浅海相环境的变迁；孢粉组合反映的古气候也同样经历了针、阔叶混交林一草原，到阔叶林或以阔叶树为主的针、落叶混交林的变化，反映出气候由冷干到暖干的特点。研究结果表明，所研究的柱状样沉积物下部形成于晚更新世晚期，上部属于全新世。     

南沙群岛永暑礁90多万年以来的海平面变化

于１９９０年５－６月在永暑礁坪上打一全采芯的地质研究钻井，编号为南永１总进尺为１５２．０７ｍ，对岩芯详细的地质年代学，地层学，相学和岩石学等进行多学科的分析研究，结果表明，永暑礁地区的海平面自早更新世晚期以及经历了４次上升和间隔的３次下降，形成了４个沉积旋回及其间的３个沉积间断。海平面呈波动式上升趋势。     

晚更新世末期南黄海中部埋藏古三角洲的研究

１９９２－１９９３年用浅地层剖面仪对南黄海中部浅地层进行测量在,７０－８０ｍ左在的深水区发现了埋藏三角洲堆积体,结合实测海底地形图及岩芯沉积相资料对浅地层剖面进行了综合分析,结果表明,该区域是距今２．７万ａ左右的黄河河口三角洲,这说明,晚更新世末期黄河已经流入南黄海陆架区,水深７０－８０ｍ附近曾经发育一期古海岸线。     

黄海南部陆区冰后期沉积环境的演变

研究区内全新统与上更新统间普遍发现沉积间断。晚更新世古地形呈东个完南向西北逐渐抬高的掀斜状。本文以李堡孔为例,讨论了全新统垂向层序,自下而上由滨海,河口海湾,近岸浅海和潮坪相组成,为一个完整的海浸海退层序。全新世海侵层受古地形及三角洲进积、主河道南偏影响,表现明显的水平相变。通过对区内十几个钻孔剖面的对比分析,揭示了垂向演替及水平相变的规律及其两者间的关系,恢复了全世以来沉积环境的演化过程。     

辽东湾北部晚更新世中期以来的地层结构及环境演化

晚更新世中期以来，辽东湾是一个在海侵一海退旋回中连续接受沉积的沉降盆地。在对岩心和高分辨率地层剖面记录分析的基础上，得到了本地区的地层结构和地震反射资料。从海底往下120．4m的岩芯可划分为16个沉积层，沉积物以粗粒物质为主。根据地震反射资料，本区地层可分为6个地震单元，分别属于3个海相层和3个陆相层。与Bcl孔相同，研究区沉积地层与冰期旋回具有明显的对应关系，冰期时形成陆相地层，间冰期时形成海相地层。冰期时河流作用较为发育。并且绝大多数河流沉积被风力作用所改造。     

杭州湾地区末次冰盛期第一硬质黏土层粒度特征及其环境意义

对于沉积物粒度分布特征的研究是衡量沉积介质能量,判别沉积地理环境和水动力条件的最基本方法之一。对杭州湾地区河姆渡钻孔的末次冰盛期第一硬质黏土层样品进行系统的粒度分析,并与典型黄土、古土壤、下蜀土及河流相、湖相样品进行对比后发现,该层位样品所显示的粒度分布特征与湖相沉积物极为相似,而与下蜀土及河流相沉积物有所差别。从粒度分布的角度推断,该区第一硬质黏土层的沉积环境为河湖相。     

PALYNOLOGICAL ASSEMBLAGES FROM THE QUATERNARY SEDIMENTS OF THE CHANGJIANG RIVER DELTA AND THE AGE OF STRATA AND PALEOGEOGRAPHY

Through the palynological research of Quaternary sediments in Changjiang River Delta, 14 spores and - pollen zones might be distinguished, reflecting the vegetation succession and climate fluctuation of Quaternary, which conforms to the climate of the world.Zones 1-9 are thought of as Pleistocene and Zones 10-14 as Holocene based on the climatic fluctuation reflected by these zones and the comparison with the climatic stage at home and abroad.The marine facies sediments of Quaternary in the Changjiang River Delta contain abundant fossil spores and pollen and have obvious characters. Because the warm and humid climate reflected by the palynological assemblages of marine facies sediments often fittes with the transgression, the curve line of the climate fluctuation of Quaternary in the Delta coincides with that of sea level changes.     

QUATERNARY SEA LEVEL CHANGES IN CHINA

Many transgressions on the plains along the Eastern China Sea had occurred in the Quaternary. They are named Beijing, Bohai, Haixing, Huanghua, Qingxian, Baiyangdian, Haizhou Bay. Cangxi, Xianxian and Candong transgressions. Their beds of marine facies have been buried in the Hebei Province, or on the shelf of China. The greatest transgressions occurred in the Early Pleistocene, while the smallest in the Middle Pleistocene, and the transgressions in the Late Pleistocene and Holocene were larger than that in the Middle Pleistocene. In accordance with the 14C dating and the paleomagnetic stratigraphy, they may be compared with the transgressions in the Late pleistocene with the δ18O stages of the core V28-232 at Equatorial Pacific.     

Offshore Atlas Project: Methodology and Results

The Offshore Atlas Project (OAP) grouped 4,325 Miocene and older and 5,622 Pliocene and Pleistocene productive sands in the Gulf of Mexico into 91 chronostratigraphic hydrocarbon plays to aid the oil and gas industry with regional hydrocarbon exploration and field development. OAP has produced a two-volume atlas series entitled Atlas of Northern Gulf of Mexico Gas and Oil Reservoirs. Volume 1 comprises Miocene and older reservoirs, while volume 2 comprises Pliocene and Pleistocene reservoirs. Chronozones (Reed et al., 1987) were used to define geologic ages in the Gulf of Mexico. A chronozone is a time-stratigraphic unit defined by a particular benthic foraminifera biostratigraphic zone. The 26 chronozones identified by Reed et al. (1987) were further grouped into 14 Cenozoic and 2 Mesozoic chronozones for OAP. A composite type log (CTL), which shows the chronostratigraphic relationship of all productive sands in a field, was constructed for each of the 876 proved federal fields in the Gulf of Mexico. Depositional facies (retrogradational, aggradational, progradational, and submarine fan)were next identified on each CTL. The four facies were identified primarily according to characteristic SP-curve shapes, paleoecozones, and sand content. The chronozones and depositional facies identified on each CTL were then correlated among fields across the Gulf of Mexico. All productive sands correlated to the same chronozone and depositional facies were then identified as a unique play. Both federal and state fields in the Gulf of Mexico contain original proved reserves (sum of cumulative production and remaining proved reserves) estimated at 12.481 Bbbl of oil and condensate and 156.466 Tcf of gas (40.322 Bboe [sum of liquids and energy equivalent gas]). Of this, 9.943 Bbbl of oil and condensate and 122.263 Tcf of gas (31.698 Bboe) have been produced. Miocene plays contain the most total original proved reserves with 41.9 %, followed by Pleistocene plays (36.2 %), Pliocene plays (18.6 %), Mesozoic plays (2.9 %), and Oligocene plays (0.4 %). Miocene plays have produced the largest amount of total hydrocarbons, as well, at 43.5 % followed by Pleistocene plays (36.5 %), Pliocene plays (19.1 %), Oligocene plays (0.5 %), and Mesozoic plays (0.4 %). Just over two-thirds of the Gulf of Mexico's total original proved reserves are contained in progradational facies (67.4 %),with the remainder comprising submarine-fan facies (18.5 %), aggradational facies (9.9 %), retrogradationalfacies (2.4 %), combination facies (1.7 %), and caprock and reef reservoirs (0.1 %). Total cumulative production from the different facies closely mimics the distribution of original proved reserves. Of the 91 plays, the lower Pleistocene progradational play (LPL P.1) contains the most original proved gas reserves (10.5 %) and has produced the most gas (11.4 %). However, the upper upper Miocene eastern progradational play (UM3 P.1B) contains the most original proved oil and condensate reserves (18.9 %) and has produced the most oil and condensate (21.4%). Several technical studies resulting from OAP have been published. Hunt and Burgess (1995) described the distribution of OAP plays deposited by the ancestral Mississippi River delta system in the north-central Gulf of Mexico over the past 24 million years. The lower Miocene plays are restricted to the westernmost portion of the Louisiana shelf. In the late middle Miocene, the depocenter migrated east of the present-day Mississippi River delta. During the late upper Miocene, the depocenter began migrating back to the west and prograded basinward, and it continued to do so throughout the Pliocene and Pleistocene. Lore and Batchelder (1995) discussed how OAP plays can be used to find exploration targets and assess undiscovered resources. As an exploration tool, OAP play maps can be used to identify conceptual submarine-fan plays downdip of established shallow water producing facies, and to identify wells where a known producing facies or chronozone has not yet been reached. As an assessment tool, the extensive data sets associated with each OAP play can be used to infer statistically the size of undiscovered resources in a play to determine if exploration in that play is economically justifiable. Lore et al. (1995) estimated the amount of undiscovered conventionally recoverable resources in the Gulf of Mexico, basing their assessment on previous work performed for OAP. Mean level estimates show that, by far, submarine-fan plays have the greatest potential for additional oil and gas in the Gulf of Mexico, with 75.1 % and 70.4 % of the total oil and gas resources, respectively. Mean level estimates for the 13 OAP Miocene, Pliocene, and Pleistocene chronozones show that upper Pleistocene plays have the most oil resource potential (24.3 %), while lower Pleistocene plays have the most gas resource potential (20.6 %).