摘要:1 Introduction Toothless pterosaurs are much less abundant than toothed forms and most of them come from the Late Cretaceous (Wellnhofer, 1991). Toothless forms from the Early Cretaceous of western Liaoning are Tapejaridae including Sinopterus dongi (Wang and Zhou, 2002), Sinopterus gui (Li et al., 2003) and a new genus (Lü and Yuan, in review); Chaoyangopterus (Wang and Zhou, 2003); Jidapterus (Dong et al., 2003) and a new pterosaur (Lü and Zhang, in review). The long and toothless …

摘要:1 Introduction The ophiolitic and slightly metamorphic complexes in northeastern Jiangxi have been traditionally considered to be related to the Proterozoic “Banxi (=Penhsi) Group” of the Jiangnan Uplift in South China and have become a classic area for the study of pre-Sinian stratigraphy. However, since Zhao et al. (1995, 1996) and He et al. (1996, 2000) (the Zhao-He research group) reported their discoveries of Paleozoic Radiolaria from the siliceous rocks in the ophiolitic and meta…

摘要:1 Introduction Besides the applications in traditional stratigraphy and paleoenvironment analysis, ecostratigraphy has been applied in other geological fields. For example, it has been applied in the high-resolution dating of terrestrial sections (Rull and Lorente, 1999), geological mapping (Zhao et al., 2000; Zhao and Wang, 2004), and interpreting depositional dynamics (Oloriz et al., 2002). It is also a useful tool to reconstruct paleoceanography by planktonic microfossil paleocommunity an…

摘要:1 Introduction Recently, nominally anhydrous minerals (NAMs), such as olivine, pyroxene and garnet, have been found to contain trace amounts of hydrogen as OH? in their crystal lattice (Bell and Rossman, 1992; Rossman, 1996; Beran, 1999; Ingrin and Skogby, 2000; Williams and Hemley, 2001; Luth, 2003). Because of the importance of volume and mass in the mantle, NAMs probably represent the largest reservoir of hydrogen (Bell and Rossman, 1992; Ingrin and Skogby, 2000). Although the signi…

摘要:The geometry of the Dabie Mountains is manifested in terms of the distribution of petro-tectonic units in three dimensions. It is identified into three segments from east to west, four horizons in vertical profiles and eight petro- tectonic units from north to south. Three segments are the east, middle and west segments. Four horizons, from top to bottom, are two different meta-tectonic mélange in the uppermost part, underthrust basement and cover below them, and mantle at the bottom of the profiles. Eight petro-tectonic units from north to south are: (1) the hinterland basin, (2) the meta -flysch, (3) the ultramafic rock belt (UM) + Sujiahe eclogite belt (SH), (4) eclogite belt 2 (Ec2) with most eclogites of continental affinity, (5) eclogite belt 1 (Ecl1) with some eclogite of oceanic affinity, (6) the Dabie complex or underthrust basement of the Yangtze continent, (7) the Susong and Zhangbaling Groups or underthrust cover of the Yangtze continent and (8) the foreland belt. The (3), (4) and (5) units belong to meta-tectonic mélange. Some ultrahigh pressure metamorphic minerals such as coesite and micro-diamonds have been found in (3) and (4) units; a possible ultrahigh pressure mineral, clinozoisite aggregate pseudomorph after lawsonite, was found in unit (5). The three tectonic units are speculated to be coherent initially; the UM and SH units are suggested to be the root belt in the east, middle and west segments respectively. The kinematics of the Dabie orogen is divided into three stages: top-to-south thrusting during the eclogite-granulite facies metamorphism, top-to-north extension during the amphibolite metamorphic stage, and faults or shear bands of brittle deformation and greenschist facies metamorphism were formed in the post-orogenic stage since the Late Jurassic and the movement pictures of these faults is different from each other.

摘要:1 Introduction Much research has been carried out on the Upper Cambrian of the northern part of the North China Platform, including that on stratigraphy by Lu et al. (1994) and Xiang et al. (1981, 2000) as well as that on sedimentology by Wang et al. (1989), Meng et al. (1986) and Feng et al. (1990). In recent years, a great deal of fruitful research on sequence stratigraphy has been made, such as the chronostratigraphic studies of Shi et al. (1997) and Mei et al. (1996), and those on plat…

摘要:1 Introduction As the most prominent geological event since the Cenozoic, the uplift of the Qinghai-Tibet Plateau plays an important role in the formation and evolution of global atmospheric circulation pattern and climate changes. This has been verified by more and more geological facts; especially when the plateau had uplifted to some key heights, it could exert a great influence on the global environment. The Tibetan area has already become a natural experiment field of scientific researc…

摘要:1 Introduction The concept of the Oceanic Anoxic Event (OAE) was introduced by Schlanger and Jenkyns (1976) to delineate a period of time characterized by abnormally high depositional and preservational rates of organic carbon in favorable marine environments in many parts of the globe. This concept, with particular respect to the Cretaceous, has since been discussed, elucidated, and refined by many researchers (e.g. Schlanger et al., 1987; Jenkyns, 1985). The signatures, causes and models…

摘要:1 Introduction There have been a lot of studies on the Upper Pleistocene-Holocene Series and the paleoclimate vicissitude in the Salawusu River valley on the southeastern border of the Mu Us Desert on the Ordos Plateau, China (Fig. 1) (de Chardin and Licent, 1924a, b; de Chardin and Young, 1930; de Chardin, 1941; Pei and Li, 1964; Kozlovski, 1971; Yuan, 1978; Dong et al., 1983, 1989, 1998; Gao et al., 1985; Lu, 1985; Guan et al., 1986; Shao, 1987; Li et al., 1988, 1993; Sun and Zhao…

摘要:1 Introduction The region of the middle-lower reach of the Yangtze River is an important mineralized belt of Fe, Cu, Au, S and other elements, with a series of sedimentary-hydrothermal diplogenetic mineral deposits (Xu and Zhu, 1978; Liu et al., 1984; Gu and Xu, 1986; Gu et al., 1993, 2000; Zhai et al., 1992). Some geologists thought that the Carboniferous massive sulfide exhalative sediment was the basis of the late diplogenetic mineralization (Gu and Xu, 1986; Gu et al., 1993, 2000); o…

摘要:1 Introduction Metallogenic chronology is one of the keys in the research of mineral deposits. Determination of metallogenetic epoch is very important for understanding the relationships between mineralization and regional tectonomagmatic events, in studying the origin of mineral deposits, and for summarizing regional mineralization and instructing regional prospecting. The eastern Liaoning region hosts the main concentration of boron resources in China. The boron reserve in eastern Liaoning…

摘要:1 Introduction It is difficult to identify carbon dioxide origin merely by C isotopic compositions in the C-H-O system near surface environments due to possible contamination of crustal components and ambiguous information provided by carbon isotopic compositions. However, analysis of MORB basalts, xenoliths, volcanic gas, hot-spring gas, etc., has shown that CO2 gas is the principal carrier phase of mantle-derived He (Gerlach, 1989; Javoy and Pineau, 1991; Trull et al., 1993). 3He is th…

摘要:Geochemical Characteristics of Fossil Ginkgo huttonii Cuticles from the Jurassic in Gansu, ChinaSHI Yajun, SUN Bainian, ZHANG Chengjun and YAN Defei (Key Laboratory of Western China's Environmental Systems of the Ministry of Education, College of Earth and Environmental Science, Lanzhou University, Lanzhou, Gansu 730000)A comparison analysis of geochemical characteristics was made on cuticles of Jurassic fossil Ginkgo huttonii from the Minhe Basin in Gansu and extant Ginkgo b…

摘要:1 Introduction Coherent element pairs (Y3+-Ho3+, Zr4+-Hf4+, Nb5+-Ta5+ and Sr2+-Eu2+) have the same valences and very similar ionic radii. They are seldom fractionated during silicate mineral/melt interaction systems because the partitioning of these element pairs between melts and minerals is tightly controlled by charge valence and crystal structure (lattice site size) or ionic radius. The concentration ratios of these pairs in igneous rocks are close to the chondritic values (Y/Ho=28, Zr…

摘要:1 Introduction Co-rich ferromanganese crusts occurring on submarine guyots have received much attention from scientists since the beginning of the 1980’s because they are enriched in Co, Mn, Pt, and rare earth elements (REEs), and have large potential mineral resources, occurring as they do on topographic highs relative to polymetallic nodules in the C-C (Clarion-Clipperton) zone (Halbach et al., 1982, 1989; Hein et al., 1992, 1999; Usui and Someya, 1997; Yamazaki and Sharma, 1998, 2000…

摘要:1 Introduction Chevkinite groups can be assigned to the chevkinite-(Ce) subgroup and perrierite-(Ce) subgroup in accord with the angle β : β ≈ 100o for the chevkinite subgroup and β ≈ 113o for the perrierite subgroup. Chevkinite-(Ce), polykovite-(Ce) and Maoniupingite (new mineral No. 017 of 2003) belong to the former subgroup, while renjeite and matsubaraite belong to the latter group. As strontio-chevkinite is a Sr-analogue of perrierite, usually the natural chevkinite-(Ce) group min…

摘要:1 Introduction Micas are a series of layer silicates (phyllosilicates). Many clay minerals, such as muscovite, celadonite, illite, phengite, belong to the mica series and possess the same basic crystallographic symmetries. Illite is a kind of micas whose unit structure consists of one octahedral sheet in between two opposing tetrahedral sheets. These sheets form a basic 2:1 layer that is linked by interlayer cations. Mica twinnings and twin laws (Donnay et al., 1964; Rieder, 1970) have been …

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