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1.
Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule upli  相似文献   

2.
Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule upli  相似文献   

3.
Since the coexistence of the Cretaceous and Palaeocene was ascertained in the Hengyang Basin of Hunan in the middle of the 1960's, the Cretaceous and Tertiary boundary has been discussed in several papers, but it still remains controversal. The points at issue are the connotation, stratigraphical position and lateral correlation of the Dongtang (or Chejiang) Formation.  相似文献   

4.
Past workers have used rare-earth element patterns recorded in biogenic apatite as proxies for original seawater chemistry. To explore the potency of this approach, we analyzed Pennsylvanian conodonts from limestones, gray shales, and black shales of the Fort Scott and Pawnee formations (Desmoinesian) and Swope and Dennis formations (Missourian) in Kansas, Missouri, and Iowa, U.S.A. Analysis of individual platform conodonts from seven taxa using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) revealed a consistent enrichment in the middle rare-earth elements (MREE). Analogous MREE enrichment has been observed in authigenic apatite and bulk samples of phosphate-rich black shales from the same formations. Importantly, however, phosphate-depleted shales intimately associated with the P-rich intervals are relatively depleted in MREE. These antithetic patterns argue convincingly for secondary migration from the bulk sediment into the phosphate, and the extent of MREE enrichment in the conodonts is correlated positively with the total REE content. MREE enrichment in conodonts does not vary systematically as a function of lithology, stratigraphic level, conodont genus, geographic location, or with independent estimates of paleoredox conditions in the bottom waters. Collectively, these results argue for postmortem (diagenetic) REE uptake resulting in a pronounced (and progressive) MREE enrichment. Any cerium anomalies, if initially present, were masked by diagenetic uptake of REE. Paleoenvironmental interpretations of conodont REE, particularly for samples exhibiting MREE enrichment, should therefore be viewed with caution.  相似文献   

5.
Arsenic is the 20th most abundant element in the Earth crust. Humans are exposed to naturally occurring and anthropogenic sources of arsenic compounds in the environment. A wide variety of adverse health effects have been attributed to chronic exposure to high levels of arsenic. More than two-dozen arsenic compounds （species） are present in the environment and in biological systems. The various arsenic species have dramatically different behavior and toxicity. This presentation briefly describes arsenic speciation analysis, human exposure to and metabolism of arsenic species. Environmental issues on arsenic in Canada are briefly discussed. These include （1） the arsenic waste left from previous gold mining and smelting activities; （2） the domestic use of wood treated with chromated copper arsenate; and （3） use of well water as the source of drinking water by approximately one third of the Canadian population.  相似文献   

6.
Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gaswater interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule uplift and the Tahe Oilfield are assemblages of various types of reservoirs, which have an overall oH-bearing potential and obvious uneven distribution. Testing and producing tests are the major means to evaluate this type of reservoirs and acid fracturing improvement is a key link in petroleum exploration and development.  相似文献   

7.
International Journal of Earth Sciences - When and how the Bangong–Nujiang Tethyan Ocean closed is a highly controversial subject. In this paper, we present a detailed study and review of the...  相似文献   

8.
This study focused on the geochemical distribution patterns and ecological effects of Cd and other heavy metals such as As, Hg, Cr, Cu, Ni, Pb, and Zn in rock, soil, water, sediment and crops in the area of the Three-Gorges Reservoir within Chongqing, and aimed at the protection of ecological environment and rational application of the local lands. This study found that the metals of Cd, Hg and Pb presented pollution in the surface environment along the Yangtze River, that is Cd〉Hg〉Pb （Cu）〉Zn〉As〉Ni〉Cr. The pollution of Cd in sediment was mainly attributable to the regional black shales, and partly to the urban sewage and garbage. The geochemical modes of metals in the sediment varied. Cr, Hg, Ni, and Pb mainly existed as residues, and Cd as carbonate. Cd exited as a high proportion in the modes of ion-exchange, carbonate, and iron-manganese oxidation, up to 63 percent. The contents of heavy metals in soiland sediment were correlated to the host clay minerals, such as illite, montmorillonite, kaolinite and chlorite. It is shown that Cd was transported with clay minerals in the Yangtze River over long distance and formed the regional anomaly. In the abnormal area of Jianping in Wushan County, higher Cd contents are reported in the local crops and local villagers＇ hairs than from the background areas.  相似文献   

9.
A simple mechanical model explaining the long-period (about 100-year) variations in the Earth’s rotational velocity is proposed. This model takes into account the gravitational interaction of the mantle with the solid core of the Earth and the fact that the core rotation leads that of the mantle. Well-known Earth parameters provide estimates of the gravitational torque that support the proposed model. The mathematical problem involved reduces to the classical problem of a nonlinear oscillator exposed to a constant torque. The well-known parameters of the core-mantle system result in a stable equilibrium and a stable limiting cycle on the phase cylinder of this oscillator. This equilibrium corresponds to a single angular velocity for the mantle and solid core, with no long-period oscillations in the length of the day. The limiting cycle corresponds to the core rotation leading the mantle rotation. In this case, the ellipsoidality of the gravitationally interacting bodies provides a periodic interchange of kinetic angular momentum between the mantle and solid core that results in long-period variations in the length of the day. The proposed model does not support the formerly widespread opinion that the core rotates more slowly than the mantle.  相似文献   

10.
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11.
This is a 4-year longitudinal study to evaluate changes to the environment and exposure of young children associated with the introduction of methylcyclopentadienyl manganese tricarbonyl （MMT） into Australia in 2000. The cohort includes 57 females and 56 males; age range of 0.29 to 3.9 years. Samples are collected every 6 months from children in residences located at varying distances from major traffic thoroughfares in Sydney. Environmental samples： air, house and day care dustfall, soil, dust sweepings and gasoline. Samples from children： blood, urine, handwipes prior to and after playing outdoors, and a 6-day duplicate diet. All samples are analyzed for a suite of 20 elements using ICP-MS. Results are presented for the first three 6-month sampling periods for Pb and Mn. For dustfall accumulation, there was no significant change over the 3 sampling periods （time） for Pb or Mn, and a positive relationship between ‘traffic exposure＇ （traffic volume and proximity to the road） and Pb but not Mn. For handwipes, Pb and Mn in wipes taken from children after playing outdoors were usually significantly greater than for wipes taken prior to playing. There was no significant association between Pb or Mn in handwipes with traffic exposure. Dustfall accumulation was a significant predictor for Pb in the handwipes, and dust sweepings were a significant predictor of Mn in handwipes.  相似文献   

12.
Characteristics of deformation in the thrust belt and sequence stratigraphic framework in the foreland basin, structural features of the basin margin, and the episodic thrusting are studied in this paper by combining the eastern Qilian thrust belt and the Late Triassic foreland basin on the southwestern margin of Ordos. On this basis, a geological model and a mechanical model of coupling mechanism were established for the pair of thrust belt and foreland basin, and the subsidence and deposition process of the foreland basin were simulated on given parameters.  相似文献   

13.
Extensive volcanism is one of the important features of Cenozoic geology in China.Based on temporal-spatial distribution,the volcanism was associated with three major different geological settings:1)the continental rift basalts in Northeast and North China;2)the tension-fault basalts on the continental margins of Southeast China; and 3) the collision-zone high-K volcanics in the Qinghai-Xizang Plateau and its vicinities.The characteristics of “depletion in the south and enrichment in the north“of the China continental mantle are strongly supported by isotopic evidence.The Cenozoic continental cal characters,into the following geochemical provinces:1)the depleted mantle in South China;2)the primary mantle in Northeast and NorthChina; 3)the hybrid and transi-tional mantle in the region of Shandong ,Anhui,Jiangsu and northern Zhejiang;4)the depleted mantle around the Bohai Bay and the Lower Liaohe River;5)the K-metasomatic enriched mantle in the northern part of Northeast China;and 6)the re-cycled enriched mantle in the ancient subduction zone in the Qinghai-Xizang Plateau and its surround-ings.These geochemical characteristics on a regional scale must be a reflection of the nature of lithosphere evolution.  相似文献   

14.
The Ordovician Changtu Fauna is recently discovered in the Xia' ertai and Hulan Groups in northernLiaoning-central Jilin. The fauna, containing 10 genera and 14 species (including 3 new genera, 9 new speciesand an unidentified species), is closely related in evolution with the Early Cambrian Qinghezhen Fauna. Thediscovery of this fauna is significant to the study on the age of the strata, Ordovician biostratigraphy and geo-logical evolution of the tectonostratigraphical terrane on the northern margin of the Sino-Korean plate.  相似文献   

15.
The paper deals with the background features, formation and distribution of the chemical el-ements K, Na, Ca, Mg, Si, Fe, Mn, Cr, Ni,V, Co, Ti, Mo, Cu, Pb, Zn, As, Hg, Cd, Be, Li, Sr, B,F, Cl, Br and I in the groundwater in the region of the middle and lower reaches of the YangtzeRiver and their relations to the composition of the water-bearing media, properties of the overly-ing rocks and soils, redox environment, and groundwater flow condition, mineralization and pHof groundwater.  相似文献   

16.
F, Cl, S and P were determined, using electron microprobe, in magmatic inclusions trapped within minerals and glass mesostasis from Wudalianchi volcanic rocks. The initial volcanic magma from Wudalianchi corresponds to the basanitic magma crystallized near the surface ( pressure < 91 Mpa ). The potential H2O content of this magma is in the range 2 — 4 wt. %. The initial composition of volcanic magmas varies regularly from early to late volcanic events. From the Middle Pleistocene to the recent eruptions (1719 – 1721 yr.), the basicity of volcanic magma tends to increase, as reflected by an increase in MgO and CaO contents and by a progressive decrease in SiO2 and K2O contents. Meanwhile. from early (Q2 ) to late (Q3) episodic eruptions of the Middle Pleistocene, the initial concentrations of chlorine in volcanic magmas range from 1430 – 1930 ppm to 1700 ppm and decrease to 700 — 970 ppm for the first episodic eruption during the Holocene (Q 4 1 ). The chlorine concentrations of volcanic magmas of recent eruption (Q 4 2 ) are increased again to 2600 – 2870 ppm. A parallel evolution trend for phosphorus and chlorine concentrations in magmas has been certified: 1500 – 5970 ppm (Q2)→ 3500 – 4210 ppm (Q3)→ 1100– 3500 ppm (Q 4 1 )→ 6800– 7900 ppm (Q 4 2 ). The fluorine contents of volcanic magmas, from early to late volcanic events, show the same trend: 770 – 2470 ppm → 200–700 ppm → 700 – 800 ppm. During the crystallization-evolution of volcanic magmas, fluorine and phosphorus tend to be enriched in residual magmas as a result of crystal-melt differentiation. for example. the fluorine contents reach 5000– 6800 ppm and the phosphorus contents, 2.93wt.% in residual magmas. An appreciable amount of chlorine may be lost from water rich volcanic magmas prior to eruption as a result of degassing. Apparently, water serves as a gas carrier for the chlorine. The chlorine contents of residual magmas may decrease to 100 – 300 ppm. The volcanic magmas from Wudalianchi are poor in sulfur, normally ranging from 200 to 400ppm. On account of the behavior of sulfur in magmas and the strontium and oxygen isotopic analyses ((87Sr /86Sr)i=0.70503– 0.70589; δ18O = + 5.50 – + 6.89 ‰ ), it can be considered that the basanitic magmas in the Wudalianchi volcanic area came from the upper mantle and have not yet been contaminated probably by continental crust materials.  相似文献   

17.
We present an analysis of spectrophotometric observations of the latest cycle of activity of the symbiotic binary Z And from 2006 to 2010. We estimate the temperature of the hot component of Z And to be ≈150 000−170 000 K at minimum brightness, decreasing to ≈90 000 K at the brightness maximum. Our estimate of the electron density in the gaseous nebula is N e = 1010−1012 cm−3 in the region of formation of lines of neutral helium and N e = 106−107 cm−3 in the region of formation of the [OIII] and [NeIII] nebular lines. A trend for the gas density derived from helium lines to increase and the gas density derived from [OIII] and [NeIII] lines to simultaneously decrease with increasing brightness of the system was observed. Our estimates show that the ratios of the theoretical and observed fluxes in the [OIII] and [NeIII] lines agree best when the O/Ne ratio is similar to its value for planetary nebulae. The model spectral energy distribution showed that, in addition to a cool component and gaseous nebula, a relatively cool pseudophotosphere (5250–11 500 K) is present in the system. The simultaneous presence of a relatively cool pseudophotosphere and high-ionization spectral lines is probably related to a disk-like structure of the pseudophotosphere. The pseudophotosphere formed very rapidly—over several weeks—during a period of increasing brightness of Z And. We infer that in 2009, as in 2006, the activity of the system was accompanied by a collimated bipolar ejection of matter (jets). In contrast to the situation in 2006, the jets were detected even before the system reached its maximum brightness. Moreover, components with velocities close to 1200 km/s disappeared at the maximum, while those with velocities close to 1800 km/s appeared.  相似文献   

18.
Apatite is a common U- and Th-bearing accessory mineral in igneous and metamorphic rocks, and a minor but widespread detrital component in clastic sedimentary rocks. U–Pb and Th–Pb dating of apatite has potential application in sedimentary provenance studies, as it likely represents first cycle detritus compared to the polycyclic behavior of zircon. However, low U, Th and radiogenic Pb concentrations, elevated common Pb and the lack of a U–Th–Pb apatite standard remain significant challenges in dating apatite by LA-ICPMS, and consequently in developing the chronometer as a provenance tool.This study has determined U–Pb and Th–Pb ages for seven well known apatite occurrences (Durango, Emerald Lake, Kovdor, Mineville, Mud Tank, Otter Lake and Slyudyanka) by LA-ICPMS. Analytical procedures involved rastering a 10 μm spot over a 40 × 40 μm square to a depth of 10 μm using a Geolas 193 nm ArF excimer laser coupled to a Thermo ElementXR single-collector ICPMS. These raster conditions minimized laser-induced inter-element fractionation, which was corrected for using the back-calculated intercept of the time-resolved signal. A Tl–U–Bi–Np tracer solution was aspirated with the sample into the plasma to correct for instrument mass bias. External standards (Ple?ovice and 91500 zircon, NIST SRM 610 and 612 silicate glasses and STDP5 phosphate glass) along with Kovdor apatite were analyzed to monitor U–Pb, Th–Pb, U–Th and Pb–Pb ratiosCommon Pb correction employed the 207Pb method, and also a 208Pb correction method for samples with low Th/U. The 207Pb and 208Pb corrections employed either the initial Pb isotopic composition or the Stacey and Kramers model and propagated conservative uncertainties in the initial Pb isotopic composition. Common Pb correction using the Stacey and Kramers (1975) model employed an initial Pb isotopic composition calculated from either the estimated U–Pb age of the sample or an iterative approach. The age difference between these two methods is typically less than 2%, suggesting that the iterative approach works well for samples where there are no constraints on the initial Pb composition, such as a detrital sample. No 204Pb correction was undertaken because of low 204Pb counts on single collector instruments and 204Pb interference by 204Hg in the argon gas supply.Age calculations employed between 11 and 33 analyses per sample and used a weighted average of the common Pb-corrected ages, a Tera–Wasserburg Concordia intercept age and a Tera–Wasserburg Concordia intercept age anchored through common Pb. The samples in general yield ages consistent (at the 2σ level) with independent estimates of the U–Pb apatite age, which demonstrates the suitability of the analytical protocol employed. Weighted mean age uncertainties are as low as 1–2% for U- and/or Th-rich Palaeozoic–Neoproterozoic samples; the uncertainty on the youngest sample, the Cenozoic (31.44 Ma) Durango apatite, ranges from 3.7–7.6% according to the common Pb correction method employed. The accurate and relatively precise common Pb-corrected ages demonstrate the U–Pb and Th–Pb apatite chronometers are suitable as sedimentary provenance tools. The Kovdor carbonatite apatite is recommended as a potential U–Pb and Th–Pb apatite standard as it yields precise and reproducible 207Pb-corrected, 232Th–208Pb, and common Pb-anchored Tera–Wasserburg Concordia intercept ages.  相似文献   

19.
The results of electromagnetic sounding of the Earth??s crust in the vicinities of the SG-6 and SG-7 superdeep boreholes (Yamal-Nenets Autonomous Okrug) are presented. The studies were conducted in the fields of natural sources (AMT-MTS) and in the field of the Zevs ULF antenna located at a distance of more than 2000 km from the receiver points. In the vicinity of the SG-7 superdeep borehole, where the small industrial noise was observed, the results of inverse problem solution are completely consistent with the electric logging data. The conducting layers have been identified at the depths of 150 m and 1.1 km. The roof of rocks having small electrical conductivity and belonging to the Permian-Triassic trappean complex has been found at the depth of about 7 km. The response of the Zevs signal (the frequency range of 44?C182 Hz) has indicated the properties of the upper part of the geoelectrical section better than audiomagnetotelluric sounding for both boreholes. Based on the sounding in the vicinity of the SG-6 superdeep borehole, with the data of the Novosobirsk observatory taken into account, the distribution of resistivity down to about 800 km depth has been obtained. This distribution can serve as additional information in calculation of the temperature and rheological regime of the lithosphere and the upper mantle in the region of Western Siberia.  相似文献   

20.
Geotectonics - The geological and sedimentological interpretation of several time and deep seismic profiles within junction zone of the Volga‒Ural area of the East European Platform,...  相似文献   

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