Oil and Gas Distribution in Hailar Basin,Northeast China

1IntroductionHailar Basin is located in the eastern part of In-ner Mongolia Autonomous Region, China, with the area of 44 210 km2 (Fig.1).Fig.1SketchmapshowingthelocationofHailarBasinThe Hailar Basin is neither different from the foreland basin of west pa…     

Stable carbon isotope evidence for tracing the diet of the host Hepialus larva of Cordyceps sinensis in the Tibetan Plateau

Two types of Hepialus larvae with different diets were distinguished in the Sejila Mountain,Tibetan Plateau based on the stable carbon isotope data of the host Hepialus larva of Cordyceps sinensis and its closely adjacent tender plant roots and humus fractions.Type I is the larva chiefly fed by soil humus,and characterized by the δ 13C values of -22.6‰ to-23.4‰,and more than -23.4‰ in its heads.Type II is the larva chiefly fed by tender plant roots,and characterized by the δ 13C values of-24.6‰ to -27.6‰,an...     

饱水粘性土主固结理论(续): 主固结过程粘性土含水量与时间的关系

论文的前文(饱水粘性土主固结理论) 已从理论上导出粘性土“主固结比(η) ”、“极限主固结量(S_η) ”及其主固结度U_η的计算方法, 它们取决于粘性土的初始含水量和液限(W_t、W_L) 而与固结应力p无关.作为前文的续篇, 主要是探求一维主固结过程含水量和时间(t) 的变化关系(W_t=f(t, z)).根据一维固结物理模型及假设条件建立的含水量为因变量的主固结二阶偏微分方程并通过特定的边界条件和初始条件, 利用分离变量法和三角函数正交原理解得主固结过程含水量和时间的关系式, 并获得主固结系数Θ及其时间因数Δ的新表达式, 它们在形式上与太沙基固结方程相似, 但实质内容上不一致, 前者是探索粘性土含水量变化, 后者是超静孔压u的变化, 利用新的一维主固结方程进一步导出主固结量(S_t), 平均主固结度(U_t) 及主固结剩余量(ΔS) 等新一组表达式, 利用工程实际数据分别计算表明新的主固结系数Θ所含的相关物理量除含水量外, 其他的物理量如渗透系数(K), 超静孔压水头高度(h₁), 粘性土比重(G_s) 等都不具实质的影响.      

Abiogenic hydrocarbons in commercial gases from the Songliao Basin, China

This paper discusses the kinetic fractionation, composition and distribution characteristics of carbon and hydrogen isotopes for various alkane gases formed in different environments, by different mecha- nisms and from different sources in nature. It is demonstrated that the biodegradation or thermode- gradation of complex high-molecule sedimentary organic material can form microbial gas or thermogenic gas. The δ 13C1 value ranges from -110‰ to -50‰ for microbial gases but from -50‰ to -35‰ (even heavier) f...     

Impending HRT wave precursors to the Wenchuan M_s8.0 earthquake and methods of earthquake impending prediction by using HRT wave

We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wenchuan Ms8.0 earthquake, we recorded the HRT wave precursor at the only operating station in Hongge (HG, Δ=465 km) and found that significant impending signal had been recorded at the station in the early morning ( 0―5 am) of 12th of May, 2008. The precursor for this earthquake is consistent wit...     

Glass and Mineral Chemistry of Northern Central Indian Ridge Basalts:Compositional Diversity and Petrogenetic Significance

Abstract: The glass and mineral chemistry of basalts examined from the northern central Indian ridge (NCIR) provides an insight into magma genesis around the vicinity of two transform faults: Vityaz (VT) and Vema (VM). The studied mid-ocean ridge basalts (MORBs) from the outer ridge flank (VT area) and a near-ridge seamount (VM area) reveal that they are moderately phyric plagioclase basalts composed of plagioclase (phenocryst [An60–90] and groundmass [An35–79]), olivine (Fo81–88), diopside (Wo45–51, En25–37, Fs14–24), and titanomagnetite (FeOt ~63.75 wt% and TiO2 ~22.69 wt%). The whole-rock composition of these basalts has similar Mg# [mole Mg/mole(Mg+Fe2+)] (VT basalt: ~0.56–0.58; VM basalt: ~0.57), but differ in their total alkali content (VT basalt: ~2.65; VM basalt: ~3.24). The bulk composition of the magma was gradually depleted in MgO and enriched in FeOt, TiO2, P2O5, and Na2O with progressive fractionation, the basalts were gradually enriched in Y and Zr and depleted in Ni and Cr. In addition, the SREE of magma also increased with fractionation, without any change in the (La/Yb)N value. Glass from the VM seamount shows more fractionated characters (Mg#: 0.56–0.57) compared to the outer ridge flank lava of the VT area (Mg#: 0.63–0.65). This study concludes that present basalts experienced low-pressure crystallization at a relatively shallow depth. The geochemical changes in the NCIR magmas resulted from fractional crystallization at a shallow depth. As a consequence, spinel was the first mineral to crystallize at a pressure >10 kbar, followed by Fe-rich olivine at <10 kbar pressure.     

黑龙江汤原断陷第三纪地层层序及时代

依据黑龙江汤原断陷30口井的岩性及古生物资料,建立了汤原断陷古近纪、新近纪地层层序。依据孢粉、藻类、植物和介形类化石建立19个生物化石组合,讨论了各组的时代及其与邻区的对比。依据汤参3井(25.0-100.0m)和互6井(138.5-237.5m)岩性及孢粉组合将道台桥组引入汤原断陷。汤原断陷地层层序为古新统乌云组,始新统新安村组、达连河组,渐新统宝泉岭组,中新统富锦组,上新统道台桥组。     

Carbonate Sequence Stratigraphy of a Back-Arc Basin： A Case Study of the Qom Formation in the Kashan Area, Central Iran

The Qom Formation comprises Oligo-Miocene deposits from a marine succession distributed in the Central Basin of Iran. It is composed of five members designated as A-F. Little previous work exists on the sequence stratigraphy. Based on an integrated study of sequence stratigraphy with outcrop data, wells and regional seismic profiles, the Qom Formation is interpreted as a carbonate succession deposited in a mid-Tertiary back-arc basin. There are two second-order sequences (designated as SS1 and SS2) and five third-order sequences (designated as S1-S5). Five distinct systems tracts including transgressive, highstand, forced regressive, slope margin and lowstand have been recognized. The relationship between the sequences and lithologic sub-units has been collated and defined (S1 to S5 individually corresponding to A-C1, C2-C4, D-E, the lower and upper portions of F); a relative sea level change curve and the sequence stratigraphic framework have been established and described in detail. The coincidence of relative sea level change between that of the determined back-arc basin and the world indicates that the sedimentary cycles of the Qom Formation are mainly controlled by eustatic cycles. The variable combination of the systems tracts and special tectonic-depositional setting causally underpin multiple sequence stratigraphic framework styles seen in the carbonates of the back-arc basin revealing: (1) a continental margin basin that developed some form of barrier, characterized by the development of multiple cycles of carbonate-evaporites; (2) a flat carbonate ramp, which occurred on the southern shelf formed by the lack of clastic supply from nearby magmatic islands plus mixed siliciclastics and carbonates that occurred on the northern shelf due to a sufficient clastics supply from the land; and (3) a forced regressive stratigraphic stacking pattern that occured on the southern shelf and in basin lows due to the uplifting of the southern shelf. Thick and widespread aggradational framework limestone usually occurs in the initial sequences (S1 and S3) of the supersequence, which led to preferential oil reservoir deposition but a lack of source and cap rocks, whereas the retrogradational and progradational framework limestone usually occurs in the later sequences (S2 and S4-S5) of the supersequence, which results in two perfect sets of source, reservoir and cap rock assemblies, so that the limestone in sub-member C2-C4 and the F-Member can be predicted as important objects for oil exploration.     

Late-Pleistocene tidewater glaciers and glaciomarine sequences from north County Mayo,Republic of Ireland

Late-Pleistocene deposits in north County Mayo were deposited in three main glacigenic environments. 1. Drumlins and basal tills were formed when ice moved from the Irish lowlands and local mountain catchments into Donegal Bay. 2. Gilbert-type deltas accumulated up to 80m I.O.D. on the lowlands and subaqueous moraines formed across minor valleys when marine-based ice grounded inland. 3. A thick drape of fossiliferous glaciomarine mud along the coastal fringe was deposited from meltwater plumes and by ice-rafting immediately outside of these ice limits. The muds contain an Elphidium clavatum-dominated, low-diversity microfauna which is characteristic of cold-water conditions adjacent to glacier termini. Valves of Macoma calcarea from the mud have been ¹⁴C dated at 16940 ± 120 and 17300 ± 100 BP. The high-level delta complex was deposited from tidewater glaciers in a peripheral depression adjacent to the drumlin ice limits of north County Mayo. Although the field evidence cannot be used to determine former sea level history with any accuracy, it poses general problems for sea level history and isostatic effects of the last major ice sheet in the west of Ireland. Raised glaciomarine sequences commonly occur in close association with drumlin ice limits elsewhere in Ireland and represent marine transgressions prior to glacial unloading. It is suggested that the magnitudes and patterns of crustal depression are greater and geometrically more complex at the margins of ice sheets in Ireland than hitherto realised.