浙江省船山组的划分与对比

桐庐沈村船山组深灰色灰岩 ,厚 12 6 .35 m ,与下伏地层黄龙组、上覆地层梁山组均为整合关系。船山组可划分为 3个化石带 ,上部为 Eoparafusulina pseudosimplex带 ,归属隆林阶 ;中部为 Sphaeroschwagerina subrotunda带 ,归属紫松阶 ;下部为 Triticites subcrassulus带 ,归属逍遥阶。     

浙江桐庐阳新统栖霞组的■类化石及多重地层划分

浙江桐庐栖霞组可划分为二个带:上部为Cancelli naneoschwagerinoides-Verbeekina grabaui带,归属祥播阶;下部为Misellinaclaudiae带,归属罗甸阶。栖霞组被划分出3个正层序和6个四级层序。高频旋回层研究表明:栖霞组主要的成岩环境有台地相、浅海陆棚相和盆地相三种类型,从下至上总体反映为台地向盆地的演化环境。     

浙江桐庐阳新统栖霞组的(竹蜓)类化石及多重地层划分

浙江桐庐栖霞组可划分为二个(竹蜓)带:上部为Cancellina neoschwagerinoides-Verbeekina grabaui带,归属祥播阶;下部为Misellina claudiae带,归属罗甸阶.栖霞组被划分出3个正层序和6个四级层序.高频旋回层研究表明:栖霞组主要的成岩环境有台地相、浅海陆棚相和盆地相三种类型,从下至上总体反映为台地向盆地的演化环境.     

桂林泥盆纪碳酸盐台地礁组合的层序地层研究

桂林的泥盆系以发育碳酸盐台地和礁组合沉积为特征，岩相多样，地层对比和时代确定的难度较大。本文应用层序地层学原理，结合生物地层和岩石地层特征，研究桂林泥盆系露头的相结构及碳酸盐台地礁组合不同亚相的９个剖面中的不整合界面，识别出该区中、晚泥盆世地层的５个层序界面：（１）牙形刺下ｖａｒｃｕｓ亚带和中ｖａｒｃｕｓ亚带之间；（２）牙形刺ｈｅｒｍｍａｎｉ－ｃｒｉｓｔａｔｕｓ带和ｄｉｓｐａｒｉｌｉｓ带之间；（３）牙形刺下ｒｈｅｎａｎｅ亚带和上ｒｈｅｎａｎｅ亚带之间；（４）牙形刺ｅｘｐａｎｓａ带内部；（５）牙形刺ｐｒａｅｓｕｌｃａｔａ带和ｓｕｌｃａｔａ带之间。这些层序界面在岩石学上的特征为具有生物铸模溶孔的白云岩和不同规模的暴露溶蚀面。比较明显的大的海泛面有２次：（１）牙形刺ｅｎｓｅｎｓｉｓ带和ｖａｒｃｕｓ带之间；（２）牙形刺ｌｉｎｇｕｉｆｏｒｍｉｓ带和下ｔｒｉａｎｇｕｌａｒｉｓ亚带之间。     

中下扬子区二叠系露头层序地层研究

按新近国际年代地层划分方案（ICS，2000），下扬子区二叠纪地层自下向上分为3统，9阶和相对应的华南传统6阶划分。二叠系从阿瑟尔阶至长兴阶（44Ma)共划分出14个三级层序，每个三级层序平均时限约为3.14Ma，其中“紫松阶”）相当阿瑟尔＋2／3萨克马尔阶）1个（船山组中上部）、“隆林阶、（相当1／3萨克马尔阶＋阿丁斯克阶）2个（分别对应船山组上部和梁山组或镇江组）、“栖霞阶”（相当库班甘德阶＋1／3罗德阶）3个（栖霞组），“茅口阶”（相当于2／3罗德阶＋沃德阶＋卡皮丹阶）4个（孤峰组，茅口组，堰桥组，银屏组和武穴组），吴家坪阶2个（龙潭组或吴家坪组），长兴阶2个（长兴组或大隆组）；共归并为4个层序组（sequence set)。     

浙江桐庐地区上石炭统—中二叠统层序地层学研究

在生物地层及年代地层研究的基础上,对本区上石炭统至中二叠统进行了层序地层学研究,从船山组至孤峰组下部共划分了5个三级层序、13个四级层序。通过五百多个米级旋回层序的研究,认为本区海盆有台地、台盆相间及盆地3个发展阶段,并得出4—6个米级旋回层序组成一个更高级别旋回的结论。     

辽宁大连地区震旦系甘井子组层序地层研究

大连地区甘井子组是辽宁重要的新元古界层位,发育大量的碳酸盐岩.运用经典层序地层学理论,通过对野外实测剖面的综合分析,对大连地区新元古界震旦系甘井子组进行层序地层学研究,共识别出5个层序界面,划分了4个三级层序,15个准层序组和55个准层序.甘井子组碳酸盐岩沉积可划分为局限台地亚相和开阔台地亚相,进一步划分为潟湖、潮坪、潮下低能和浅滩微相.运用区域大地构造和天文旋回方法对甘井子组环境演化进行探讨,认为其经历了局限台地→开阔台地→局限台地的演化过程.受扬子旋回末期低幅度的构造升降作用影响,大连地区南关岭期末期—甘井子期出现了5次短暂暴露,形成了5个层序界面.同时受周期性天文旋回的影响形成了准层序、层对等高频旋回.通过对大连地区甘井子组进行层序地层和沉积演化研究,为探索辽东南地区的油气资源提供依据.     

泥盆系弗拉阶／法门阶之交米兰柯维奇旋回及高分辨率地层对比

在广西泥盆系弗拉阶－法门阶（F－F）之交盆地相－斜坡相碳酸盐地层（桂林杨堤剖面，阳朔龙门剖面，德保都安剖面和横县六景剖面）中识别出超层序组、层序组、层序和纹层4级旋回层，它们在牙形石带内的级序结构、数量关系和排列顺序在时间上持续、稳定，在空间上可进行跨相、跨盆地的远距离对比。我们的资料表明，超层序组、层序组、层序和纹层旋回分别相当于长偏心率、偏心率、斜度或岁差和亚米兰柯维奇旋回。泥盆纪时它们的周期值分别为400，000年100，000年、33，333年或16，667年和8，000－17，000年。长偏心率与偏心率、偏心率与斜度、偏心率与岁差的比例关系分别为1：4、1：3和1：6。与第四纪相比，泥盆纪时斜度和岁差周期变短，偏心率周期基本保持恒定，表明地球自转至少自泥盆纪以来变慢。在研究剖面上，F－F事件前后超层序组与层序组间的级序结构存在明显的差别，即F－F事件前为1：4，F－F事件后为1：3。造成这种变化的原因可能与F－F事件期间多次陨击事件对地球长偏心率周期的影响有关。利用米兰柯维奇旋回的研究结果可使弗拉阶－法门阶之交年代地层的划分对比达到十万年级和万年级的分辨率，并可对上泥盆统国际通用的标准牙形石带进行数字标定，即上rhenana带、linguiformis带、下、中、上triangularis带的时间延续分别为0．6Ma、0．8Ma、0．3Ma、0．3Ma和0．3Ma。在十万年级和万年级分辨率基础上弗拉期－法门期之交的海平面变化不具一致性和同步性。     

芙蓉统和排碧阶底界全球层型剖面的牙形刺生物地层

寒武系芙蓉统和排碧阶全球层型剖面——湖南花垣排碧剖面底界界线层的牙形刺生物地层,由下至上划分为Westergaardodina tetragonia带、Westergaardodina matsushitai带和Westergaardodina bicuspidate 3个牙形刺带,可与该界线层的三叶虫带进行很好对比;同时讨论了芙蓉统和排碧阶底界划在牙形刺Westergaardodina mat-sushitai带和Westergaardodina bicuspidata带之间的合理性;此外,还将该牙形刺分带与华北和东北地区寒武系牙形刺带进行了对比。     

陕西镇巴火焰溪法门阶牙形刺研究

陕西镇巴火焰溪剖面部于大巴山西段，临近川陕交界，交通便利。那里晚泥盆世地层出露完好，层序清楚，化石丰富。本文就该剖面法门阶牙形刺动物群、泥盆系石炭系的界线进行了研讨，建立了该区法门阶的两个浅水相牙形刺生物组合带。     

Police, politics, and the right to the city

Space and spatiality have recently been at the core of debates concerning the political possibilities of the city. The arguments advanced in this paper might be seen as an attempt to contribute to these debates through a reflection on the spatiality of (in) justice, politics, and the right to the city. The case of French urban policy, with its focus on distressed urban areas, and the `suburban problem' in France are used as examples to make arguments more concrete.     

Isotopic systematics of He,Ar, S,Cu, Ni,Re, Os,Pb, U,Sm, Nd,Rb, Sr,Lu, and Hf in the rocks and ores of the Norilsk deposits

This paper reports the first results of a study of 11 isotope systems (³He/⁴He, ⁴⁰Ar/³⁶Ar, ³⁴S/³²S, ⁶⁵Cu/⁶³Cu, ⁶²Ni/⁶⁰Ni, ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, ^206–208Pb/²⁰⁴Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others.     

Influences of the unsaturated,saturated, and riparian zones on the transport of nitrate near the Merced River,California, USA

Transport and transformation of nitrate was evaluated along a 1-km groundwater transect from an almond orchard to the Merced River, California, USA, within an irrigated agricultural setting. As indicated by measurements of pore-water nitrate and modeling using the root zone water quality model, about 63% of the applied nitrogen was transported through a 6.5-m unsaturated zone. Transport times from recharge locations to the edge of a riparian zone ranged from approximately 6 months to greater than 100 years. This allowed for partial denitrification in horizons having mildly reducing conditions, and essentially no denitrification in horizons with oxidizing conditions. Transport times across a 50–100-m-wide riparian zone of less than a year to over 6 years and more strongly reducing conditions resulted in greater rates of denitrification. Isotopic measurements and concentrations of excess N₂ in water were indicative of denitrification with the highest rates below the Merced River. Discharge of water and nitrate into the river was dependent on gradients driven by irrigation or river stage. The results suggest that the assimilative capacity for nitrate of the groundwater system, and particularly the riverbed, is limiting the nitrate load to the Merced River in the study area.     

扬子北缘马元铅锌矿床闪锌矿微量元素及S-Pb-He-Ar-C同位素地球化学研究

马元铅锌矿床是近年扬子陆块北缘铅锌找矿的新突破。矿体呈层状、似层状产于碑坝隆起翼部震旦系灯影组角砾状白云岩层间构造带中,围岩蚀变很弱。矿石中硫化物以闪锌矿、方铅矿为主,中粗粒晶质结构,充填于白云岩角砾间。闪锌矿富集Cd、Ge、Ag,贫In、Tl、Se,Ga/In为6~132,Ge/In多1000,成矿温度以中-低温为主。金属硫化物ε~(34)S值相对集中,为12.9‰~19.4‰,平均为17.4‰,来自于海相硫酸盐的还原。铅同位素组成稳定,~(206)Pb/~(204)Pb为17.858~17.918:~(207)Pb/~(204)Pb为15.603~15.694;~(208)Pb/~(204)Pb为37.756~38.046,具有造山带和上地壳铅的特征,震旦系可能提供了金属成矿物质。闪锌矿中流体包裹体的~3He/~4He为0.03Ra~1.05Ra,~(40)Ar/~(36)Ar为326.1~765.1,~(38)Ar/~(36)Ar为0.183~0.204,表明成矿流体主要为地壳流体和饱和大气水(大气降水或海水)的混合。闪锌矿内流体包裹体挥发分δ~(13)C_(CH_4)值为-36.01‰~-28.80‰,δ~(13)C_(C_2H_6)值为-27.72‰~-22.44‰,δ~(13)C_(CO_2)值为-23.24‰~-9.68‰,表明有机流体参与了成矿作用。石英、方解石的H-O同位素结果表明具有海水和有机水混合的特征。可见,成矿流体具有两种流体混合的特征,一为蒸发海水与围岩反应所形成的盆地卤水,二为有机流体。推测矿区可能存在一个古油气藏,由于TSR生成一高硫气藏,为区内还原性有机流体的主要来源。当富含Pb、Zn等成矿物质的成矿流体运移至富含CH_4和H_2S的还原性流体的矿区角砾岩带时,两种流体混合,Pb、Zn等遇到H_2S发生反应而沉淀成矿,并伴生热液白云石等,形成了马元铅锌矿床。综上所述,我们认为马元矿床属MVT型铅锌矿床。     

Rb-Sr, K-Ar, H-and O-Isotope systematics of the Middle Riphean shales from the Debengda Formation, the Olenek Uplift, North Sibera

Clay subfractions (SFs) of <0.1, 0.1–0.2, 0.2–0.3, 0.3–0.6, 0.6–2 and 2–5 μm separated from Middle Riphean shales of the Debengda Formation are studied using the TEM, XRD, K-Ar and Rb-Sr isotopic methods. The oxygen and hydrogen isotope compositions in the SFs are studied as well. The low-temperature illite-smectite is dominant mineral in all the SFs except for the coarsest ones. The XRD, chemical and isotopic data imply that two generations of authigenic illite-smectite different in age are mixed in the SFs. The illite crystallinity index decreases in parallel with size diminishing of clay particles. As compared to coarser SFs, illite of fine-grained subfractions is enriched in Al relative to Fe and Mg, contains more K, and reveals higher K/Rb and Rb/Sr ratios. The Rb-Sr age calculated by means of the leachochron (“inner isochron”) method declines gradually from 1254-1272 Ma in the coarsest SFs to 1038-1044 Ma in finest ones, while the K-Ar age decreases simultaneously from 1225–1240 to 1080 Ma. The established positive correlation of δ¹⁸O and δD values with dimensions of clay particles in the SFs seems to be also consistent with the mixing systematics. The isotopic systematics along with data on mineral composition and morphology lead to the conclusion that mixedlayer illite-smectite was formed in the Debengda shales during two periods 1211–1272 and 1038–1080 Ma ago. The first period is likely close to the deposition time of sediments and corresponds to events of burial catagenesis, whereas the second one is correlative with the regional uplift and changes in hydrological regime during the pre-Khaipakh break in sedimentation.     

Delivery of Trace Metals (Al,Fe, Mn,V, Co,Ni, Cu,Cd, Ag,Pb) from the Trinity River Watershed Towards the Ocean

The Trinity River (Texas, USA) contains in its watershed 23 different reservoir lakes, the largest one being Lake Livingston situated in the lower Trinity River watershed and two potentially polluting metroplexes, Dallas and Houston. In order to determine fluxes of nutrients and trace metals to Galveston Bay, a survey that included 24 discreet samples collected over a year and at various stages of discharge was carried out during 2000–2001. Geochemical (i.e., sorption by Fe oxyhydroxides), biological (i.e., seasonal uptake by sinking algae in Lake Livingston), and hydrological (i.e., dilution effects by increasing flow rates) controls were found to be mainly responsible for variations in dissolved trace metal concentrations rather than pollution sources. The Trinity River loads of suspended sediments and pollutant trace metals entering Galveston Bay at Anahuac were <20% of those reaching Lake Livingston, and only a few percent of the total upstream trace metal load is entering the Gulf of Mexico. Thus, during the transit through the 23 man-made lakes and an estuary, >96% of the pollutant trace metal load is lost to sediments.     

海南长塘岭矿区大坡岩体岩石学、地球化学特征及其含矿性初探

海南大坡岩体位于五指山褶皱带内,主要受昌江—琼海构造带、琼西构造带与潭爷断陷构造带控制.岩石地球化学及岩石学研究表明,大坡岩体形成于海西-印支晚期,岩性单一,主要为中细粒似斑状黑云母二长花岗岩.岩体显示为Ⅰ型花岗岩与S型花岗岩的混合,主体以地壳物质部分熔融为主,形成过程有少量地幔物质加入.元素对的比值及稀土元素配分特征说明岩体钨锡等多金属含矿性可能较差.     

贵州岑巩羊桥罗家塘杷榔动物群的发现及其后生动物早期演化的意义

岑巩县羊桥乡罗家塘杷榔组仅出露中-上部地层,岩性单一,均为青灰、灰绿色粉砂质泥、页岩.在其上部层位发现了俞氏贵州始海百合(Guizhoueocrinus yui Zhao,Parsley et Peng,2007),计有棘皮动物始海百合、腕足动物、软体动物-软舌螺、节肢动物-三叶虫等8属9种,包括了2个未定名的新种和1...     

Breakthroughs in the biodiversity, biogeography, biostratigraphy, and basin analysis of the Beaufort group

Over the past decade researchers working on the rocks of the Beaufort Group in the main Karoo Basin of South Africa have vastly increased our understanding of this important Permo-Triassic sequence. Many new fossil forms have been discovered, allowing for breakthroughs into the biodiversity, biogeography and biostratigraphy of the group. Taxonomic and phylogenetic advances are many and varied, and cover most of the vertebrate taxa, but with emphasis placed on the temnospondyl amphibians, archosauriforms and non-mammalian synapsids, in particular the anomodontia. Biostratigraphic breakthroughs have centered on the Middle Permian Eodicynodon and Tapinocephalus assemblage zones, the Late Permian Dicynodon Assemblage Zone, and the Triassic Lystrosaurus and Cynognathus assemblage zones. Correlation of these biozones with better dated sequences in Europe, Russia and China has allowed for many chronostratigraphic refinements, which are in turn vital for sequence stratigraphical analysis of the basin fill. Based on fossil data, both the lower (Ecca–Beaufort) and upper (Beaufort–Molteno) contacts of the group have been proved to be highly diachronous. The refined chronostratigraphic framework has also allowed for a better analysis of the basin evolution through time, particularly in terms of the correlation of external stimuli that affect basin sedimentation patterns.