Search

Late Hercynian-early Indosinian (Triassic) granite is widely distributed around the Taer region of the northern margin of West Kunlun. The rock mass is mainly composed of calcalkaline porphyroid biotite adamellite and characterized by SiO2-rich, high-Ca, moderate-alkaline, and strongly peraluminous attributes, and relatively low ΣREE with LREE enrichment and a moderate Eu anomaly. As shown in the trace element spider web diagram, distinct peaks appear for Th, La, Nd, and Zr and clearly low values appear for Ba, Nb, Sr, P, and Ti. Further, compared with the primitive mantle, Rb/Sr and Rb/Ba are considerably higher and Nd/Th and Nb/Ta are relative low, all falling into the scope of the crust-origin rocks, indicating the characteristics of the crust-origin S-type granite. The rock mass's zircon U-Pb isotopic age is determined to be 235.7 ± 3.9 Ma. On the basis of the age data, spatio-temporal location, lithology, and geochemistry of the rock mass, we conclude that the formation of the rock mass is closely related to the strong compressional orogenic movement (240 Ma) of the Tianshuihai terrane and the South Kunlun terrane. The rock mass is the product of the collision orogenic movement. However, distinct differences are observed between the studied rock mass and the synorogenic Bulunkou rock mass, which may be caused by the different collision strength and different positions with respect to the collision zone.

The molybdenum-nickel deposits in Shuidong District of Nayong County (Guizhou Province, Southwest China) are found mainly in black shale series of Lower Cambrian Niutitang Formation, which is another Mo-Ni-rich region besides Zunyi District (Guizhou province). Our systematic study on the Mo-Ni deposits in Tangjiaba of Nayong reveals that layered coarse-grained limestones, spherical beaded limestones concretions are hosted at the lower seam of the Mo-Ni deposits. Its strong negative carbon isotope anomaly (the carbon isotope value of the coarse-grained limestones varies from –2.148‰ to 8.223‰) is similar to that in the modern submarine black smoker chimney. The carbon in the coarse-grained limestones from black rock series of Nayong County might be deep source inorganic carbon. The seams, coarse-grained limestones, ore-bearing coarse-grained limestones and the roof and floor of the deposits are characterized by co-variation on the trace element spider diagram, showing good homology. The extraordinary enrichment of Ag, As and Sb resembles hydrothermal sedimentation. Pro-Earth's core elements Se is strongly enriched in Ni-Mo ore-bearing coarse-grained limestones. The ore-bearing rock series has an extremely low Th/U value (0.012–0.19); in the logU-logTh Cartesian Coordinates, the samples of the roof and floor of the deposits and ore-bearing coarse-grained limestones are found in the East Pacific tise; and the samples of coarse-grained limestones are found between the paleo-hydrothermal dedimentary area and the East Pacific tise. The chondrite-normalized rare earth element patterns of the Ni-Mo deposits show LREE enrichment, Ce negative anomaly, and Eu negative anomaly (which is supposed to be influenced by the deep magmatic processes in an extensional environment) resembles the rare earth element distribution patterns of the fluid and its sediments in modern submarine hydrothermal system. It proves that coarse-grained limestones is characterized by typical hydrothermal limestones, being closely related with the genesis of Mo-Ni deposits in Nayong County, which provides new evidence for hydrothermal sedimentary genesis of Mo-Ni deposit and negative carbon anomaly in the basal Cambrian on a global scale.

As viewed from space remote-sensing images (e.g. Google Earth images) of South Guizhou and North Guangxi, the authors found that macroscopic karst landscape on the Earth's surface is strongly controlled by the Conjugated shear joint of “X” type. Joints of this kind constitute a huge infiltration network and act as channel-ways for the permeation of meteoric waters from the surface, thus, leading to the dissolution of carbonate rocks nearby. As a result, the karst landscape is formed, which is dominated by linear karst valleys. An “X” karst valley network structure appears in the area where horizontal strata are distributed, and a feather-like network structure appears in the area where vertical strata are distributed, respectively. When the water permeates downwards to the underground-water level, it will flow horizontally along the strike of “X” joints toward the local base level of erosion to form an “X” network system of underground conduits in the area where horizontal strata are distributed, but it is relatively complex, because of the joining of other joints. This is the first time we have made use of Google Earth images to study the karst environment. Therefore, it has been successful in research on the Earth's geomorphology, which could only rely on aerial photos and satellite photos in the past. Google Earth images provide low-cost and applicable imaging materials for the study of Earth's geomorphology and karst rocky desertification and its control.

Recently a rich and well—preserved crinoid community including Traumatocrinus and Encrinus has been found in the Late Triassic Zhuganpo Formation in Guanling and Xingyi, Guizhou province, China. Among the fossils Traumatocrinus is the richest, and most of it occurs as clusters, with each cluster containing 3–42 crinoid branches. Study of the stem and calyx of Traumatocrinus shows that the number of stem-joints (columnals) is equal to the total stem length × K (5.85 per cm × stem—diameter). There are about 376 first- and second—order columnals on the whole stem. This number seems to coincide with the number of days in a year at that time. According to the present study of the palaeoecological environment of the crinoid community, it is considered that the reproduction and preservation of the crinoid community were controlled by the Late Triassic regression and the restricted bay of an interior sea behind the S—shaped shoal zone.

Large amounts of vermicular fossils and a minor amount of sponge animal fossils have been found in the Early Cambrian Xidashan Formation in the region of Quruqtagh, Xinjiang. Vermicular fossils are generally more than 50 mm long and 0.3-1.4 mm wide; their wrinkled lamellae are microfine with 3-10 pieces within the length of every each millimeter. The fossils are considered to be Sabellidites cambriensis Sokolov (1965). The Xidashan Formation is the highest stratum in which Sabellidites occur, as has been so far reported. * Supported by the Major Stage Basic Research Development Program of China (Grant No. 2002CCC02600), National Natural Science Foundation of China (Grant Nos. 400462001, 40062001), Guizhou Provincial Excellent Talent Foundation (2002-013), the Postdoctoral Scientific Foundation of China (20033209) and Guizhou Provincial President’s Funds (2004-233)

The early Early Cambrian strata within the bounds of Guizhou Province are almost predominated by black shale deposition. Recently, however, the authors have found a section consisting of a set of mudstones interbedded with limestones at the basement of the Cambrian at Yingping, Fuquan County, Guizhou Province, which provides favorable conditions for the study of marine geochemical characteristics of the early Early Cambrian. The characteristics of intense negative carbon isotopic anomalies near the Precambrian/Cambrian boundary at Yingping, Fuquan County, Guizhou Province, can be correlated with those of global carbon isotopic anomalies at the same time on a global scale, corresponding to the intense negative carbon isotopic anomalies near the Neoproterozoic/Cambrian boundaries at the bottom of the Xiaowaitoushan Member, Huize, Yunnan Province, at the top of the Tsagaan Oloom Formation of Mongolia and at the top of the Salarmy Gol Formation of Siberia, as well as those observed in southwestern United States, Iran, Amman, Poland, Newfoundland, the Great Britain, Canada, etc. Negative carbon isotopic anomalies can be used as the important basis for the division of the Precambrian/Cambrian boundaries. There have been found 8 m-thick black shales and cherts below the intense negative carbon isotopic anomalies in this profile. In the black shales there have been found large amounts of fossils such asBradorida, gernusArchotuba, indicating that during the period of sedimentation of black shales under anaerobic conditions there would be large quantities of organic species living in the sea. But in the section of grayish-green mudstones interbedded with limestones with intense negative carbon isotopic anomalies almost no organic fossil has been found. This may imply that the anaerobic event seems to have little bearing on the mass extinction near the Precambrian/Cambrian boundary, whereas the intense negative carbon isotopic anomaly event appears to be more closely related to the mass extinction occurring near the Precambrian/Cambrian boundary.

Phosphorites occurring at the bottom of the Cambrian system contain abundant small shelly fossils, which are the product of the first episode of life explosion in the Cambrian. It was previously reported that the small shelly fossils are dominated by hyolithids, olivooids, zhijinitids, conodontomorphs, yubelichitids, camenitids and algae, with minor amounts of sponge fossils. Large amounts of sponge spicules, diverse in form, have been found for the first time in the Gezhongwu Formation phosphorites at Shixing, Zhijin County, Guizhou Province, of which such spicules as diaxon-triactins, diaxon-tetractins, pentaxon-pentactins and hexon-hexactins account for 30%. These spicules constitute the sponge clastic phosphorites made up of sponge clastics. Meanwhile, it is also expected that the radiation and diversity of sponge animals started as early as in the earliest Early Cambrian. Habit and burying environment of sponge animal are discussed in the paper.

A global-scale glaciation occurred at about 600 Ma ago. As a result, the Earth became the “Snowball Earth”. The glaciation came to the end abruptly when atmospheric carbon dioxide increased to such an extent as to be about 350 times the modern level because of subaerial volcanic degassing. The rapid termination of glaciation would have led to warming of the Snowball Earth and extreme greenhouse conditions would have been created. The transfer of atmospheric carbon dioxide to oceans would give rise to the rapid precipitation of calcium carbonate in warm surface seawaters, thus forming the cap carbonate rocks as observed worldwide today.

Yangtze platform Doushantuoian is the first large-scale phosphorous forming peak period of China, and the sedimentary phosphorite is widely distributed in south China, at same time, this area have phosphorous deposits with abundant iodine element. Especially, the phosphorite occurred in the Doushantuo formation in the Late Ediacaran in Central Guizhou features the highest iodine, with the content achieving 76 mg kg -1 (Zhou 1984; Zhang et al., 2003). In 20 th century many countries extract the iodine from the phosphorite, hovever, the process flow was complicated the production cost was too high and the industrialized production was not realized (Zhang et al., 2011; Reich et al., 2013). In 2007, Wengfu (Group) Co., Ltd. extracted the iodine from the processing of the phosphorite successfully. The proved phosphate ore reserve of the whole Guizhou Province is 2.7 billion tons. There is a large reserve of associated iodine resource, for instance, the Yingping ore block of Wengfu phosphate ore has associated iodine reserve of almost 7,000 t (Zhang et al., 2011). However, the previous researches all focus on the mineral processing technology, only few of them related to the enriching reasons and rules, occurrence states and control factors of the iodine in the phosphorite, which becomes as a point of departure and priority to this research work.