潜江凹陷潜江组油气成藏期次及时间分析

基于圈闭形成时间法推测潜江凹陷潜江组油气藏形成的最早时间为上始新统潜二段沉积初期,利用烃源岩生排烃史法分析潜江凹陷潜江组油气成藏的最早时间为晚始新世,应用流体包裹体资料揭示潜江凹陷潜江组共经历了晚始新世-早渐新世(37~32 Ma)、早渐新世-中中新世(32~14 Ma)及中上新世-现今(3~0 Ma)共3期油气充注过程,并以第2期早渐新世-中中新世油气充注最为重要,且自蚌湖向斜带和潜北陡坡带至周矶向斜带再至斜坡带,油气充注时间有逐渐变晚的趋势。由此得出,综合应用流体包裹体法、圈闭形成时间法、烃源岩生排烃史法等多种方法可较为有效地确定具有复杂构造-沉积背景与演化历史的含油气盆地(凹陷)的油气成藏期次与时间。     

南海南北共轭边缘伸展模型探讨

通过对南海南北边缘地震剖面的对比,结合周边构造分析,提出南海大陆边缘的裂离经历了两期伸展作用,即早期的简单剪切和晚期的纯剪切伸展作用。简单剪切发生在晚白垩世-早始新世,其动力与太平洋板块俯冲带的后撤、太平洋板块与欧亚板块之间汇聚速率的降低、以及先存北倾缝合带等密切相关。纯剪切发生在中始新世－渐新世－早中新世,剪切作用的转变与古南海的南向俯冲板块拖曳有关。     

太平洋海山富钴结壳钙质超微化石生物地层学及生长过程

正确判断富钴结壳生长年代及过程有助于研究结壳形成地质历史和重建古海洋环境.利用生物地层学方法(生物遗留印痕)对太平洋不同海山结壳样品进行生长时代和阶段研究,发现麦哲伦海山CM3D06结壳和中太平洋海山CB14结壳最初形成年代和富集特征差异显著: 前者为白垩纪(或更古老)、晚古新世-早始新世、中-晚始新世、中-晚中新世、上新世-更新世等5个阶段;后者为晚古新世-早始新世、中-晚始新世、中中新世、上新世-更新世等4个阶段.两座海山结壳层内部超微化石组合具有极强的区域性特征,反映了大洋环境对生物的影响以及生物对环境的适应.结壳层间的不整合和结构构造的变化指示在渐新世其生长存在间断期,与成矿作用的间断有关.      

墨西哥中新生代岩浆活动规律及成矿研究

墨西哥中新生代岩浆作用与太平洋板块向东俯冲消减作用及晚白垩-始新世的拉腊米期造山运动有关,岩浆作用控制了矿床的分布规律。文章通过综合分析大量墨西哥中新生代岩浆岩和矿床资料,讨论了岩浆活动规律及构造活动和成矿作用的关系。墨西哥主要有5个岩浆活动时期,分别为晚古生代岩浆作用、早-中侏罗世岩浆作用、白垩世岩浆作用、古近纪岩浆作用、中新世岩浆作用。墨西哥的成矿作用主要与拉腊米期岩浆活动有关(约80 Ma—40 Ma),中新生代的矿床明显分成晚侏罗世(J3)、早白垩世(K1)、晚白垩世(K2)、古新世(E1)、始新世(E2)、渐新世(E3)、中新世(N1)等地质时期。古太平洋板块、法拉隆板块和科科斯板块等三大板块俯冲消减形成3个俯冲成矿系列,即从沿海到内陆依次发育有IOCG型铁铜金成矿带→斑岩型铜钼金成矿带→浅成低温热液型银金多金属成矿带,分别代表太平洋古板块、法拉隆板块和科科斯板块向北美板块从俯冲挤压到碰撞后伸展的岩浆成矿环境。     

富钴结壳中的磷酸盐岩及其古环境指示意义

磷酸盐岩是富钴结壳老壳层的主要组分之一。本文对来自中太平洋海山的三块富钴结壳样品中的磷酸盐岩进行了研究,以期对富钻结壳形成环境的变化有所了解。通过扫描电镜发现结壳中磷酸盐岩的形态有六种,磷酸盐岩主要分布在老壳层,新壳层中偶见。结壳中的磷酸盐岩为碳氟磷灰石(CFA),经成分分析及电镜中反射色的差异可以区分出两种成因的CFA：一种为交代碳酸盐岩型的,相对富Si、Al、Fe;另一种为从结壳孔隙水中直接沉淀而成的,基本不含Si、Al、Fe。对CB12样品中磷酸盐岩脉进行生物地层学鉴定,得出其老壳层下部火焰状磷酸盐岩的形成年代为晚渐新世一早中新世(23.2-29．9Ma),而其上部充填脉状磷酸盐岩的形成年代为中中新世(10.8-16Ma)。老壳层中富集磷酸盐岩说明在结壳形成早期,结壳形成环境条件尚不够稳定,底部存在富磷深层储库,当底流突然增强时,可携带磷在海山上交代结壳中的碳酸盐岩或在结壳内部合适条件下直接沉淀形成磷酸盐岩充填脉。新壳层形成时底流已相对髂定,富磷深层储库已消失,不再有广泛磷酸盐化形成。     

江南东段地区NE-SW向断裂带断层滑移矢量反演及其大地构造意义

华南中-新生代构造演化受太平洋构造域和特提斯洋构造域的联合控制.以江南东段NE-SW向景德镇-歙县剪切带和球川-萧山断裂中发育的脆性断层为研究对象,利用野外交切关系和断层滑移矢量反演方法厘定了7期构造变形序列并反演了各期古构造应力场,讨论了断层活动的时代及其动力学.白垩纪至新生代研究区7期古构造应力场分别为:(1)早白垩世早期(136～125Ma)NW-SE向伸展;(2)早白垩世晚期(125～107Ma)N-S向挤压和E-W向伸展;(3)早白垩世末期至晚白垩世早期(105～86Ma)NW-SE向伸展;(4)白垩世中期(86～80Ma)NW-SE向挤压和NE-SW向伸展;(5)晚白垩世晚期至始新世末期(80～36Ma)N-S向伸展;(6)始新世末期至渐新世早期(36～30Ma)NE-SW向挤压和NW-SE向伸展;(7)渐新世早期至中新世中期(30～17Ma)NE-SW向伸展.结合区域地质研究表明,第1期至第4期古构造应力场与古太平洋构造域的板片后撤、俯冲以及微块体(菲律宾地块)间的碰撞作用有关;第5期伸展作用受控于新特提斯构造域俯冲板片后撤,而第6期和第7期古构造应力场主要与印-亚碰撞的远程效应有关.白垩纪至新生代,华南东部受伸展构造体制和走滑构造体制的交替控制.先存断裂的发育可能是导致华南晚中生代走滑构造体制的主要控制因素.     

四川攀西地区晚新生代构造变形历史与隆升过程初步研究

基于TM遥感图像解译和野外调研，分析了攀西地区大渡河、安宁河深切河谷地貌特征和断裂带构造变形特征，建立了安宁河断裂带晚新生代5阶段变形历史。研究表明，中新世晚期—上新世早期，安宁河断裂以挤压走滑活动为主；上新世晚期至早更新世时期，断裂以斜张走滑活动为主，活动强度较弱；早中更新世之间发生的元谋运动使昔格达组湖相地层褶皱变形；中晚更新世时期发生断陷作用，形成安宁河两堑夹—垒的构造格局；晚更新世—全新世时期又以左旋走滑活动为主。综合安宁河、大渡河河谷地貌和晚新生代地层记录和变形特征，提出了攀西高原晚新生代4阶段隆升模式：中新世早中期(12Ma之前)以缓慢隆升与区域夷平化作用为主，中新世晚期—上新世早期(12～3．4Ma)是高原快速隆升与河流强烈下切的时期，上新世晚期—早更新世(3．4～1.1Ma)为昔格达湖盆发育时期，中晚更新世—全新世(1．1Ma以来)是高原快速隆升与河谷阶地发育时期。最后指出，至上新世晚期(3．4Ma以前)，攀西高原海拔高度可能超过了3000m。     

南海西南部曾母盆地早中新世以来沉降史分析

采用回剥法和局部均衡模式研究曾母盆地早中新世以来的沉降史，并探讨了该盆地构造演化特征。曾母盆地自早中新世以来经历了17．5-11．6Ma、11．6-5．5Ma、5．5-3．0Ma和3．0-0Ma的4次快速沉降作用，其构造演化受控于曾母地块与南沙地块及婆罗洲地块的碰撞和盆地两侧的万安-卢帕尔断裂与廷贾走滑断裂的综合作用，可划分为南北双向挤压（晚始新世-早中新世）、走滑改造（中中新世-晚中新世）和区域沉降（上新世-第四纪）3个演化阶段。     

南海晚渐新世滑塌沉积指示的地质构造事件

南海北部ODP1148站晚渐新世至早中新世沉积以滑塌堆积和长时间沉积缺失为主要特征.由构造活动引起的沉积间断始于渐新世中期28.5 Ma至早中新世23 Ma左右结束.主间断面位于25 Ma, 亦即滑塌沉积层的底界.4次沉积间断总共造成至少3 Ma沉积记录的缺失.综合岩性、古生物年代测定、地球化学等分析结果, 表明南海晚渐新世的海底扩张模式呈多次跳跃式, 并以“25 Ma事件”为型变高峰.这一系列构造活动是欧亚、澳大利亚、菲律宾-太平洋板块相互作用的结果, 直接导致南海向前期裂谷更发育, 红河大断裂左擦拉张更强的南部扩张的转型.1148站的滑塌沉积为此次南海扩张转型提供了直接的证据.      

菲律宾海盆东北部晚始新世以来放射虫及其古海洋学意义

研究了菲律宾海盆东北部“大洋钻探工程”１２５航次７８２Ａ孔晚始新世以来的放射虫化石。根据Ｓａｎｆｉｌｉｐｐｏ等１９８５年的分带,将研究区自下而上划分为１０个带。讨论了始新世与渐新世、渐新世与中新世、中中新世与晚中新世、中新世与上新世以及上新世与第四纪的界线。研究区存在两个沉积间断,分别位于晚渐新世与早中新世晚期之间和中中新世与晚中新世之间。研究区第四纪放射虫化石仍以暖水分子为主,冷水分子分布较浅。依据放射虫化石分异度曲线得出,晚第三纪以来本区存在５个相对暖水期和５个相对较凉期,渐新世时处于冷水期,这与钙质超微化石复合分异度和碳酸钙含量曲线的变化是一致的。晚渐新世与早中新世晚期之间的沉积间断是由于中新世南极冰盖扩展造成大洋底层洋流活动加剧而形成的。     

内蒙古阿拉善地区的第三系

依据丰富翔实的地层古生物资料,首次在内蒙古西部建立了比较完整的第三纪地层层序：命名或厘订了中始新统乌兰乌珠尔组、上始新统查干布拉格组、下渐新统乌兰塔塔尔组、上渐新统、下中新统乌尔图组、上中新统呼和好来组和上新统昂冈浩特组等７个地层单元;区分出了中始新世乌兰乌珠尔、晚始新世查干布拉格、早渐新世早期克克阿木、早渐新世晚期乌兰塔塔尔、晚渐新世因德里沟、早中新世乌尔图、晚中新世呼和好来和上新世昂冈浩特等８个动物群（组合）。     

Geological structure of the submarine Vityaz Ridge within the <Emphasis Type="Italic">Seismic Gap</Emphasis> area (Pacific slope of the Kurile island arc)

Results of geological research conducted by the Pacific Oceanological Institute of the Far East Division of the Russian Academy of Sciences and the Institute of Oceanology of the Russian Academy of Sciences on the submarine Vityaz Ridge during Cruise 37 of R/V Akademik M.A. Lavrentyev in 2005 are discussed. Various rocks constituting the basement and sedimentary cover of the ridge were dredged in three areas of the ridge. Based on isotope geochronology, petrogeochemical, petrographic, and paleontological data and comparison with similar rocks available from the adjacent land and Sea of Okhotsk, they are subdivided into several age complexes. Late Cretaceous, Eocene, Late Oligocene, Miocene, and Pliocene-Pleistocene complexes are defined among the igneous rocks, while volcanogenic-sedimentary rocks are united into Late Cretaceous-Early Paleocene (late Campanian-Danian), undivided Paleogene (Paleocene-Eocene?), Oligocene-early Miocene, and Pliocene-Pleistocene complexes. The obtained data on the age and formation settings of the defined complexes made it possible to reconstruct the geological evolution of the central Pacific slope of the Kurile island arc.     

太平洋水下海山磷酸盐的成因及形成环境

笔者首次对太平洋与大洋富钴结壳密切相关的海山磷酸盐的成因及形成环境进行了比较深入的研究。研究发现 ,各种产出形态的磷酸盐都不同程度地交代碳酸盐等含钙物质 ,而呈现出交代生物结构、交代凝灰结构、交代角砾状结构及交代填间结构等各种交代结构 ,反映了磷酸盐的交代成因。此外 ,其δ13 C值 (变化于 0 .7‰～ 2 .0‰之间 )也证实其属于交代成因。磷酸盐中Na、Mg、Sr、F、P2 O5含量以及Na/P2 O5、Mg/P2 O5、Sr/P2 O5、F/P2 O5的比值 ,特别是晶格中结构CO2 的含量 (变化于 5 .7%～ 6 .2 %之间 ) ,与形成于氧化环境下的Blakeplateau、ChathamRise、AgulhasBank等处的磷酸盐相近 ,表明调查区磷酸盐亦形成于氧化环境。氧同位素测定结果表明 ,磷酸盐的形成温度为 5 .8～ 14 .8℃ ,平均为 11.5℃ ,显示其形成于正常的海水温度环境。西、中太平洋海山磷酸盐形成环境十分接近的事实暗示 ,西、中太平洋广大区域内的成磷事件存在着时间上和成因上的统一性和相似性。     

西太平洋782A钻孔新生代的有孔虫

大洋钻探工程” 1 2 5航次的 782 A钻孔位于西太平洋菲律宾海东北部 ,井深 4 76.8m。基底为安山岩 ,上覆盖层为中始新统—更新统的沉积层 ,其中保存有低丰度的有孔虫。自下而上可划分出 8个浮游有孔虫带。由于出现 Catapsydrax dissimilis,C.stainforthi为 N5 、N6 带的带化石 ,表明本钻孔存在早中新世的地层。同时由于缺失浮游有孔虫带 P1 5 — P1 6 下部 ,N3上部—N4,N7—N1 1 带的带化石 ,说明在中始新世与晚始新世之间、晚渐新世与早中新世之间、早中新世与中中新世之间存在 3个沉积间断。钻孔中的有孔虫标志本区当时处于温暖亚热带环境。根据不同时期温度的变化 ,可划分出 5个阶段 ,包括 3个偏暖时期和 2个温凉时期。     

南海北部陆缘盆地形成的构造动力学背景

摘要：南海北部陆缘盆地处于印度板块与太平洋及菲律宾海板块之间,但三大板块对南海北部陆缘盆地的影响是不同的。通过对三大板块及古南海演化的研究,可知南海北部陆缘地区应力环境于晚白垩世发生改变。早白垩世处于挤压环境,晚白垩世以来转变为伸展环境并且不同时期的成因不同。晚白垩世-始新世,华南陆缘早期造山带的应力松弛、古南海向南俯冲及太平洋俯冲板块的滚动后退导致其处于张应力环境。始新世时南海北部陆缘裂陷盆地开始产生,伸展环境没有变,但因其是由太平洋板块向西俯冲速率的持续降低及古南海向南俯冲引起的,南海北部陆缘盆地继续裂陷。渐新世-早中新世,地幔物质向南运动及古南海向南俯冲导致南海北部陆缘地区处于持续的张应力环境;渐新世早期南海海底扩张;中中新世开始,三大板块开始共同影响着南海北部陆缘盆地的发展演化。     

新疆乌伦古河地区第三纪哺乳动物群初析及地层年代确定

新疆准噶尔盆地北缘乌伦古河地区第三纪含有 7个哺乳动物群 :可可买登动物群 ,哈拉玛盖动物群 ,索索泉组顶部动物群 ,索索泉动物群 ,索索泉组底部 990 0 5动物群 ,铁尔斯哈巴合动物群和乌伦古河动物群。依据动物群分析初步确定 5个岩石地层单元的地质时代分别为 :可可买登组——中中新世晚期 ;哈拉玛盖组——中中新世早期 ,索索泉组——最早中新世至早中新世最晚期或中中新世最早期 ;铁尔斯哈巴合组——晚渐新世 ;乌伦古河组——早始新世至早渐新世。     

Sea-level fluctuations on the northern shelf of the Eastern Paratethys in the Oligocene-Neogene

Sea-level fluctuations in the terminal Eocene, Oligocene, and Neogene of the Eastern Paratethys are quantitatively assessed on the basis of facies and old coastlines traced on the northern platform shelf, levels of river valley incisions, and the study of seismic profiles. The first data massif allows the characterization and correlation of transgression stages in the history of the Eastern Paratethys. The greatest transgressions fall within the first half of the Late Eocene, mid-Early Oligocene, initial Late Oligocene, initial Early Miocene, the initial Tchokrakian, Karaganian and Sarmatian in the Middle Miocene, the middle and late Sarmatian and early Pontian in the Late Miocene, and the Akchagylian in the Caspian basin of the Pliocene. In contrast, the greatest incisions of northern rivers running from the platform allow us to establish the time and extent of the main declines in the base levels of the erosion. Maximal incisions date back to the terminal Eocene-initial Oligocene, terminal Solenovian time in the terminal Rupelian, the terminal Maikop in the Early Miocene, the terminal Sarmatian and middle Pontian in the Late Miocene, and the Early Pliocene in the Caspian basin. Large regressions also formed unconformity surfaces, traced on seismic profiles as erosion boundaries of several orders. The surfaces are confined to the Eocene/Oligocene boundary, middle and late Maikop, Sarmatian/Meotian boundary, middle Pontian, and terminal Miocene-initial Pliocene, as well as being traced even in the most deep-water basins. The synthesis of these data suggests a preliminary version for the curve of transgression-regression cyclicity. Its correlation with the eustatic curve shows their similarity only in the lower part-prior to the initial Middle Miocene, when Paratethys became a semi-closed basin.     

An ancient submarine canyon in the Oligocene-Miocene of the western Niger Delta

ABSTRACT
An anomalous sequence of thick fossiliferous marine shale of late Oligocene-early Miocene age, here termed the Opuama Shale Member, occurs within the paralic Agbada Formation in the subsurface of the western Niger Delta. The Opuama Shale fills a deep palaeochannel which was cut into Eocene-early Oligocene paralic beds. Planktonic and benthic foraminifera suggest that deposition in the channel began in the late Oligocene-early Miocene at outer shelf-slope depths, and that by the late early Miocene the channel had filled to shallow neritic depths. The channel, which is believed to be of submarine origin, is termed the Opuama canyon. The Opuama canyon originated during the pronounced early-Middle Oligocene drop in sea-level, and was cut by turbidity currents. It was filled, during the major late Oligocene-early Miocene rise of sea-level.
The location of the Opuama canyon in the western re-entrant of the Niger Delta supports Burke's (1972) conclusion that the western and eastern (where ancient submarine canyon fills are known) re-entrants of the delta are potential sites for ancient submarine canyons. Burke based his conclusion on the observation that the eastern and western re-entrants of the modern delta are areas where opposing longshore drifts converge and generate turbidity currents which cut submarine canyons.     

Long-lived,stationary magmatism and pulsed porphyry systems during Tethyan subduction to post-collision evolution in the southernmost Lesser Caucasus,Armenia and Nakhitchevan

The composite Meghri–Ordubad and Bargushat plutons of the Zangezur–Ordubad region in the southernmost Lesser Caucasus consist of successive Eocene to Pliocene magmatic pulses, and host two stages of porphyry Cu–Mo deposits. New high-precision TIMS U–Pb zircon ages confirm the magmatic sequence recognized by previous Rb–Sr isochron and whole-rock K–Ar dating. A 44.03 ± 0.02 Ma-old granite and a 48.99 ± 0.07 Ma-old granodiorite belong to an initial Eocene magmatic pulse, which is coeval with the first stage of porphyry Cu–Mo formation at Agarak, Hanqasar, Aygedzor and Dastakert. A subsequent Oligocene magmatic pulse was constrained by U–Pb zircon ages at 31.82 ± 0.02 Ma and 33.49 ± 0.02 Ma for a monzonite and a gabbro, and a late Miocene porphyritic granodioritic and granitic pulse yielded ages between 22.46 ± 0.02 Ma and 22.22 ± 0.01 Ma, respectively. The Oligo-Miocene magmatic evolution broadly coincides with the second porphyry-Cu–Mo ore deposit stage, including the major Kadjaran deposit at 26–27 Ma.Primitive mantle-normalized spider diagrams with negative Nb, Ta and Ti anomalies support a subduction-like nature for all Cenozoic magmatic rocks. Eocene magmatic rocks have a normal arc, calc-alkaline to high-K calc-alkaline composition, early Oligocene magmatic rocks a high-K calc-alkaline to shoshonitic composition, and late Oligocene to Mio-Pliocene rocks are adakitic and have a calc-alkaline to high-K calc-alkaline composition. Radiogenic isotopes reveal a mantle-dominated magmatic source, with the mantle component becoming more predominant during the Neogene. Trace element ratio and concentration patterns (Dy/Yb, Sr/Y, La/Yb, Eu/Eu*, Y contents) correlate with the age of the magmatic rocks. They reveal combined amphibole and plagioclase fractionation during the Eocene and the early Oligocene, and amphibole fractionation in the absence of plagioclase during the late Oligocene and the Mio-Pliocene, consistent with Eocene to Pliocene progressive thickening of the crust or increasing pressure of magma differentiation. Characteristic trace element and isotope systematics (Ba vs. Nb/Y, Th/Yb vs. Ba/La, ²⁰⁶Pb/²⁰⁴Pb vs. Th/Nb, Th/Nb vs. δ¹⁸O, REE) indicate that Eocene magmatism was dominated by fluid-mobile components, whereas Oligocene and Mio-Pliocene magmatism was dominated by a depleted mantle, compositionally modified by subducted sediments.A two-stage magmatic and metallogenic evolution is proposed for the Zangezur–Ordubad region. Eocene normal arc, calc-alkaline to high-K calc-alkaline magmatism was coeval with extensive Eocene magmatism in Iran attributed to Neotethys subduction. Eocene subduction resulted in the emplacement of small tonnage porphyry Cu–Mo deposits. Subsequent Oligocene and Miocene high-K calc-alkaline and shoshonitic to adakitic magmatism, and the second porphyry Cu–Mo deposit stage coincided with Arabia–Eurasia collision to post-collision tectonics. Magmatism and ore formation are linked to asthenospheric upwelling along translithospheric, transpressional regional faults between the Gondwana-derived South Armenian block and the Eurasian margin, resulting in decompression melting of lithospheric mantle, metasomatised by sediment components added to the mantle during the previous Eocene subduction event.     

内蒙古阿拉善地区的第三系及其动物群

笔者依据丰富翔实的资料,论述了该区第三地层的分布,区划,地层划分沿革,岩性,岩相古地理特征及地质演化史;在地层方面,首次在内蒙古西部建立了比较完整的第三纪地层序列;命名和划分了中始新统乌兰乌珠尔组,上始新统查干布拉格组。下渐新统乌兰塔塔尔组,上渐新统,下中新统乌尔较组,上中新统呼和好来组和上新统昂冈浩特组等６个地层单元,补充界定了查干布拉格组并将其时代厘定为晚始新世;在动物群方面,发现和命名了中始