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1.
ChangLiang Yin TanDong Yao LiDe Tian DongNian Liu WuSheng Yu DongMei Qu 《中国科学D辑(英文版)》2008,51(7):966-975
Oxygen stable isotope of atmospheric water vapor is widely used to study the modern process of climate. Atmospheric water
vapor samples were collected at Dlingha, northeast of Tibetan Plateau during the period from July 2005 to February 2006. The
variation of δ
18O and the relationships between δ
18O and both the temperature and specific humidity are analyzed in this paper. Results show that the seasonal variation of δ
18O of atmospheric water vapor at Delingha is remarkable with higher δ
18O in summer and lower δ
18O in winter. The temporal variation of vapor δ
18O shows obvious fluctuations, with magnitude of over 37‰ The daily variation of the δ
18O is highly correlated with air temperature. The relationship between δ
18O and atmospheric water vapor content is complex. Study shows that δ
18O of atmospheric water vapor is positively correlated with specific humidity in winter in seasonal scale and inversely correlated
with specific humidity in summer rainy period. The δ
18O values of atmospheric water vapor are lower than those of precipitation at Delingha, and the average difference is 10.7‰
Variations of δ
18O of atmospheric water vapor is also found to be affected by precipitation events, The model results show that the precipitation
effect could have caused the vapor δ
18O in the raining season to lower by 7% in average in July and August.
Supported by the National Natural Science Foundation of China (Grant Nos. 40671043, 40571039 and 40771048) and National Basic
Research Program of China (Grant No. 2005CB422002) 相似文献
2.
The occurrence of γ-phase, a high-pressure polymorph of olivine (α-phase), in the shock veins of Sixiangkou chondrite was
due to a greater cooling rate (> 10 000°C·s-1) in the veins. Because γ-phase partially reverted to β-phase and no back-transformation from β-phase to α-phase took place,
the shock veins of Peace River chondrite with a cooling rate of 1 000–2 000δC·s-1 contain a great amount of β-phase. In the shock veins of Mbale chondrite with a cooling rate of <500°C·s-1, the majority of γ-phase reverted to α-phase. The heat dissipation in shock veins took place after a stage of shock compression
of chondrite parent body, and the parent body was broken into fragmental pieces. Cooling rate in the shock veins constrained
the back-transformations of (Mg, Fe)2SiO4 high-pressure polymorphs.
Project of Chen and Xie supported by the National Natural Science Foundation of China (Grant No. 496720981, Natural Science
Foundation of Guangdong Province (Grant No. 960500), and the Science Foundation of Academia Sinica for the returned scholars. 相似文献
3.
Oxygen and carbon isotope composition from the UHP Shuanghe marbles, Dabie Mountains, China 总被引:5,自引:0,他引:5
Investigations on the oxygen and carbon isotope compositions from the ultrahigh-pressure (UHP)-metamorphosed Shuanghe marbles,
that occur as a member of a UHP slab, show that the δ18 O values range from +11.1% to+20.5% SMOW, and δ13 C from+1.0% to+5.7% PDB, respectively. The variations in isotope compositions show a centimeter scale of homogeneity and
a heterogeneity of regional scale larger than 1 meter.
In contrast to the eclogite marbles from Norway, the Shuanghe marbles have inherited the carbon isotope compositions from
their sedimentary precursor. The δ13C shows positive correlation to the content of dolomite. The depletion in18O, compared with the pmtolithic carbonate strata, might result from three possible geological processes: 1) exchanging oxygen
isotope with meteoric water before the UHP metamorphism, 2) decarbonation during the UHP metamorphism, and 3) exchanging oxygen
isotope with country gneiss at local scale during retrograde metamorphism.
It seems that the advection of fluid in the orogenic belt was very limited during subduction and exhumation of UHP rocks.
Project supported by a U. S. -China cooperative project led by Prof. Cong Bolin of the Institute of Geology. Chinese Acade-my
of Sciences, and Prof. J. G. Liou of the Department of Geological and Environmental Sciences, Stanford University and by the
National Natural Science Foundation of china (Grant No. 49794042). Chinese Academy of Sciences (Grant No. KZ951-A1-401r, and
National Science Foundation (Grant No. EAR-95-26700). 相似文献
4.
During the 22nd Chinese Antarctic Research Expedition (CHINARE-22), the atmospheric gas samples above the oceanic surface
and near the surface were collected on the track for the scientific ship “Xuelong” and on Millor Peninsula of eastern Antarctica, respectively, using the Tedlar gas bags. Every day the sampling times were
10:00 and 22:00 (local time), respectively. In the laboratory, high-precision measurement of the isotopic compositions for
N2O in these gas samples was conducted using Thermo Finnigan MAT-253 Isotopic Mass Spectrometer with a fully automated interface
for the pre-GC concentration (PreCon) of trace gases. The temporal and spatial variations of δ
15N and δ
18O in atmospheric N2O were analyzed. The mean δ
15N and δ
18O-N2O values above the oceanic surface were (7.21±0.50)‰ and (44.52±0.52)‰, respectively. From 30°N to Antarctica, the δ
15N (6.05‰–7.88‰) linearly increased with the rate of about 0.01‰ with the latitude while the δ
18O (43.05‰–48.78‰) showed a large fluctuation. The δ
15N negatively correlated with air temperature and N2O concentration, and slightly positively correlated with δ
18O. The summertime variations of δ
15N and δ
18O-N2O appeared the same trend on Millor Peninsula of eastern Antarctica. They significantly positively correlated with each other
and negatively with N2O concentration. The δ
15N and δ
18O-N2O at different sites averaged (7.42±0.35)‰ and (44.69±0.49)‰, respectively, slightly higher than those above the oceanic surface,
significantly higher than those of atmospheric N2O in the low-latitude regions of Northern Hemisphere. The predominant factors affecting the spatial variations of δ
15N and δ
18O values were also discussed. The isotopic data given in this study can help to investigate the global and regional N2O budgets.
Supported by the National Natural Science Foundation of China (Grant Nos. 40676005 and 40406001) 相似文献
5.
Leping Zheng 《中国科学D辑(英文版)》1999,42(6):588-594
The δ13c values of soil CO2 are less than that of atmosphere CO2 in the karst area. On the soil-air interface, the δ13c vlaues of soil CO2 decrease with the increase in soil depth; below the soil-air interface, the δ13c values of soil CO2 are invariable. The type of vegetation on the land surface has an influence on the δ13C values of soil CO2. Due to the activity of soil microbes, the δ13C values of soil CO2 are variable with seasonal change in ps. Isotopic tracer indicates that atmosphere CO2 has a great deal of contribution to soil CO2 at the lower parts of soil proflie.
Project supported by the National Natural Science Foundation of China (Grant Nos. 49703048 and 49833002) 相似文献
6.
Modern hot spring geochemistry at the Tanlu fault and Jiaoliao block in eastern China 总被引:1,自引:0,他引:1
Zhiguan Shangguan Jikui Du Wei Zang Jihua Wang Lingchang Kong Songsheng Gao 《中国科学D辑(英文版)》1998,41(1):87-94
The δD, δ18O values of the hot springs are always more negative than those of the local cold springs. The main cause for the ocrurrence
is physically isotope fractionation during the deep circulating process of the groundwater. The relational expression between
the δD, δ18O values and the maximum circulating depths of the groundwaters is given. The gases escaped from the geothermal fluid are
mostly crust-derived gases in the studied area. The compressive structure of the Tanlu fault could extend to the deep crust,
and basically stop the ascent of deep-seated gases towards the surface.
Project supported by the National Natural Science Foundation of China (Grant No. 49373165) 相似文献
7.
Eight favorable ore-forming conditions for the Shizhuyuan W-multimetal deposit are proposed. They are: (i) the geochemistry
background special enriching the volatile and W and Sn ore-forming elements; (ii) the existence of melt-fluid system very
rich in volatile and ore-forming elements; (iii) supply of sufficient ore-forming material and volatile multi-source; (iv)
the infiltration and convection water source and driving force partly supplied by the Jurassic reservoir basin; (v) favorable
tectonic conditions; (vi) ore-bearing greisen and vein superimposed in the pre-existing skarn rocks; (vii) favorable ore-transport
and ore-concentration strata condition; (viii) there were a set of favorable ore-forming structures in Shizuyuan area; (ix)
the orebody has good ore-reserve condition. Finally, ore-forming models are proposed.
The paper is one of the achievements on the research related to the Climbing Project “The basic related to searching for the
superlarge deposits supported by the State Science and Technology Commission. This research is also granted by the National
Natural Science Foundation of China (Grant No. 49572134). 相似文献
8.
The sorption of AuCl4
−,AuCl2
− and Au(S2O3)3- on δ-MnO2 was investigated at pH2–11.6, 0.01 mol/L and 0.1 mol/L NaNO3 solutions. At pH 4 in two electrolyte strength solutions, Au sorption densities on δ-MnO2 are 0.18–0.21 and 0.28μmoL/m2 for AuCl4
− and Au(S2O3)2
3-, respectively, and the Au surface coverage is approximate to or lower than 1%. This adsorption of the two Au complexes decreases
as the solution pH increases, which conforms to the sorption regularity of the anion on δ-MnO2. The Au sorption decreases in the sequence of Au(S2O3)2
3- >AuCl4
− >AuC12
−. The intrinsic equilibrium constants (logK
int) of the three Au complexes are 1.17–2.7, much higher than those of Cu and Cd. The hydrolysis products of AuCl4
- are preferentially adsorbed by δ-MnO2 and the inner-sphere Au-surface complexes are formed on the surface.
Project supported by the National Studying-abroad Foundation, the National Natural Science Foundation of China (Grant No.
49573200) and the Australian Mining Industry. 相似文献
9.
Conduit system and formation mechanism of heat fluids in diapiric belt of Yinggehai basin, China 总被引:3,自引:0,他引:3
The conduit system of heat fluids in diapiric belt of Yinggehai basin is dominantly vertical faults and fractures. Detailed
research on the formation mechanism and their occurrence features shows that the faults and fractures can be classified into
three types: intrastratal dispersive hydrofracture, puncturing fault and upwarping-extensional fault. The development of the
fault and fracture system not only resulted in the changes of the temperature and pressure fields in the basin, but also affected
the hydrocarbon migration in the overpressured system. These faults and fractures constituted the main pathways for vertical
hydrocarbon migration, and opening and closing intermittently led to episodic expulsion of overpressured fluid compartment.
Thus there formed the pool-forming model of multi-source mixing and ploy-stage migration and accumulation for hydrocarbons
in the Yinggehai basin.
Project jointly supported by the Ministry of Science and Technology of China (Grant No.95-Pre-39) and the National Natural
Science Foundation of China (Grant No. 49732005), and A Hundred Excellent Researchers Foundation from the Ministry of Land
and Resources. 相似文献
10.
Chemocline instability and isotope variations of the Ediacaran Doushantuo basin in South China 总被引:4,自引:1,他引:3
Stable isotope analyses in sections across a shelf to basinal transect of the Ediacaran Doushantuo basin show substantial isotope variabilities. In Songlin section where sediments were deposited in an intrashelf basin, δ 13C values are persistently negative (_3‰ to _5‰, VPDB) through the entire Doushantuo Formation, similar to those obtained from the slope section in Wuhe (_5‰ to _10‰, VPDB). Shallow water sections in Weng'an and Duoding show two broad δ 13C anomalies overprinted with significant meter-scale variations, but none of the curves has similar absolute δ 13C values compared to the Yangtze Gorges areas in South China and other sections globally. Such isotope variations, if partially recording ancient seawater signature, imply spatial and temporal chemocline instability in the Doushantuo basin. In combination with available δ 13C records from other Ediacaran successions globally, the data from the Doushantuo basin are consistent, in first order, with the existence and oxidation of a large dissolved organic carbon (DOC) reservoir in Ediacaran oceans, but imply local environmental controls on Neoproterozoic isotope values and call attentions for using δ 13C anomalies as time lines in stratigraphic correlation. 相似文献
11.
Crude oil as carrier of gold: petrological and geochemical evidence from Lannigou gold deposit in southwestern Guizhou, China 总被引:1,自引:0,他引:1
Organic matter is related closely to mineralization of Lannigou gold deposit in southwestern Guizhou, China. Regionally, the
distribution of organic carbon agrees well with that of faults within which gold deposits are hosted. Studies on organic petrology
show that pyrobitumen, which is related most closely to mineralization, adheres to quartz vein or fills quartz veinlet. Proton-induced
X-ray emission (PIXE) analysis shows an evident abundance of Au in pyrobitumen. Pyrobitumen paragenetically associates with
pyrite and arsenopyrite which are the main carrier minerals of Au. The thermal simulation experiment indicates that about
99% of Au will be concentrated in oil phase in the coexisting system of oil and brine and rock. The role of crude oil in ore-forming
process is: as carrier of Au, crude oil moves upwards, and undergoes thermal decomposition and thermochemical reduction when
it encounters the oxidizing fluid within the Trassic turbidity; Au is thus released from crude oil, reduced and precipitated.
Project supported by the Climbing Project (No. PA30) and the National Natural Science Foundation of China (Grant No. 49673190). 相似文献
12.
The study results of He and Ar isotopes from fluid inclusions in pyrites formed during mineralization stage of Jinding superlarge
Pb-Zn deposit in west Yunnan, China are reported. The data show that the40Ar/36Ar and3He/4He ratios of fluid inclusions are respectively in the range of 301. 7–385. 7 and 0. 03–0.06Ra, suggesting the oreforming fluid
is a kind of air saturated meteoric groundwater. On the basis of research on coupled relationships among He, Ar, S and Pb
isotopes, the evolution history of ore-forming fluid of the deposit can be summarized as (i) air saturated meteogenic groundwater
infiltrated down and was heated→ (ii) leached S, C and radiogenic He, Ar from the basinal strata → (iii) leached Pb and Zn
from mantle-derived igneous rocks located in the bottom of the basin→ (iv) ore-forming fluid ascended and formed the deposit.
Due to this process, the isotope signatures of crustal radiogenic He, atmospheric Ar (with partial radiogenic40Ar), crustal S and mantle-derived Pb remained in the ore-forming fluid.
Project supported by A30 Project of the National Climbing Program of China and University of Manchester. 相似文献
13.
Wu GuangHai Zhou HuaiYang Zhang HaiSheng Ling HongFei Ma Weilin Zhao HongQiao Chen JianLin Liu JieHong 《中国科学D辑(英文版)》2007,50(3):371-384
Ferromanganese crusts (hereinafter crusts) form in aerobic environment and the environmental oxida-tion degree is recorded by the redox sensitive element Co in the crusts. The ages of the layers from the surface to bottom of the crusts are determined, and main element contents at high resolution along the depth sections of three crusts from the Pacific Ocean are analyzed by an electron microprobe. Thus the variations of Co/(Fe Mn) and Co/(Ni Cu) with age/depth of the crust layers are obtained. By comparing the ratios of Co/(Fe Mn) and Co/(Ni Cu) with the δ 18O curves of the Pacific benthic foraminifera, we find that these two ratios can reflect the variation of the environmental oxidation state under which the crust layers deposit. The evolution of the oxidation degree reflected by the two indexes resembles the evo-lution of temperature since the Oligocene reflected by the δ 18O curves of the Pacific benthic foraminif-era. This suggests that the crust-forming environment after the Oligocene is controlled mainly by the oxygen-rich bottom water originated from the Antarctic bottom water (AABW). However it is not the case prior to the Oligocene. Furthermore it suggests that the environmental oxidation degree controls the formation of the crusts and the Co contents in the crusts. This explains why the Co contents in the crusts increase with time up to now. 相似文献
14.
The Xiaoxinancha Au-rich copper deposit is one of important Au-Cu deposits along the continental margin in Eastern China. The deposit consists of two sections: the Beishan mine (North), composed of altered rocks with veinlet-dissemination sulfides and melnicovite-dominated sulfide-quartz veins, and the Nanshan mine (South), composed of pyrrhotite-dominated sulfide-quartz veins and pure sulfide veins. The isotope compositions of noble gases extracted from fluid inclusions in ore minerals, i.e. ratios of 3He/4He, 20Ne/22Ne and40Ar/36Ar are in the ranges of 4.45―0.08 Ra, 10.2―8.8 and 306―430, respectively. Fluid inclusions in minerals from the Nanshan mine have higher 3He/4He and 20Ne/22Ne ratios whereas those from the Beishan mine have lower 3He/4He ratios. The analysis of origin, and evolution of the ore fluids and its relations with the ore-forming stages and the ages of mineralization suggests that the initial hydrothermal fluids probably come from the melts generated by partial melting of oceanic crust with the participation of fluids from the mantle (mantle-plume type)/aesthenosphere. This also corresponds to the continental margin settings during the subduction of Izanagi ocaneic plate towards the palaeo-Asian continent (123―102 Ma). The veinlet-dissemination ore bodies of the Beishan mine were formed through replacement and crystallization of the mixed fluids generated by mixing of the ascending high-temperature boiling fluid with young crustal fluid whereas the melnicovite-dominated sulfide-quartz veins were formed subsequently by filling of the high-temperature ore fluid in fissures. Pyrrhotite-dominated sulfide-quartz veins in the Nanshan mine were formed by filling-deposition-crystallization of the moderate-temperature ore fluids and the pure sulfide veins were formed later by filling-deposition-crystallization of ore substance-rich fluids after boiling of the moderate-temperature ore fluids. The metallogenic dynamic processes can be summarized as: (1) formation of fluidand ore substance-bearing Adakitic magma by degassing, dewatering and partial melting during subduction of the Izanagi plate; (2) separation and formation of ore fluids from the Adakitic magma; and (3) success-sive ascending of the ore fluids and final formation of the Au-rich Cu deposit of veinlet-dissemination and vein types by secondary boiling. 相似文献
15.
The secular variations (SV) ing
1
0
of geomagnetic field, caused by the interaction between the geomagnetic field and the radial fluid-flow of the outer-core,
are discussed with both statistical and analytic methods. When the value ofg
1
0
s
2
0
is relatively high compared with other terms, SV ing
1
0
is characterized by exponential change. When the effect of non-dipole field is notable, SV ing
1
0
shows complex features. Especially when the value of g
1
0
is close to zero, SV ing
1
0
is completely determined by the random process of non-dipole fields.
Project supported by the National Natural Science Foundation of China (Grant No. 49429405) and by the Chinese Academy of Sciences. 相似文献
16.
Organic carbon isotopes of the Sinian and Early Cambrian black shales on Yangtze Platform, China 总被引:5,自引:0,他引:5
Organic matter of the Sinian and early Cambrian black shales on the Yangtze Platform belongs to the light carhon group of
isotopes with the δ13C values from - 27% to - 35 %, which are lower than those of the contempomneously deposited carbonates and phosphorites. A carbon isotope-stratified
paleooceanographic model caused by upwelling is proposed, which can be used not only to interpret the characteristies of organic
carbon isotopic compositions of the black shales, but also to interpret the paleogeographic difference in the organic carbon
isotope compositions of various types of sedimentary rocks.
Project supported by the National Natural Science Foundation of China (Grant No. 49472114) and the Open Laboratory of Organic
Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. 相似文献
17.
We have selected 171 near-field records from 391 aftershock records of the Lulong, Hebei Province, earthquake in October 1982
and relocated the hypocenter of 45 aftershocks using the program Hypoinverse. The distribution of aftershocks reveals a set
of earthquake faults: a WNW stretching fault truncates two NNE stretching faults. The two branches of faults show the conjugate
structure which is often seen in brittle fracture. The NNE stretching faults are connected together. The Luanhe river valley
near Lulong developed to a rudiment rift basin surrounded by a series of faults. The fault of Lulong earthquake is a strike-slip
fault with tension component. This fault type matches with the activity of Zhangjiakou-Bohai seismic belt (Zhang-Bo belt)
and also shows the action of Zhang-Bo belt as a boundary of two secondary active blocks that truncates the NNE fault.
Foundation item: National Natural Science Foundation of China (40234038).
Contribution No. 05FE3016, Institute of Geophysics, China Earthquake Administration. 相似文献
18.
Sliding-window cross-correlation method is firstly adopted to identify sPn phase, and to constrain focal depth from regional
seismograms, by measuring the time separation between sPn and Pn phases. We present the focal depths of the 17 moderate-sized
aftershocks (M
S⩾5.0) of the Wenchuan M
S8.0 earthquake, using the data recorded by the regional seismic broadband networks of Shaanxi, Qinghai, Gansu, Yunnan and
Sichuan. Our results show focal depths of aftershocks range from 8 to 20 km, and tend to cluster at two average depths, separate
at 32.5°N, i.e., 11 km to the south and 17 km to the north, indicating that these aftershocks are origin of upper-to-middle
crust. Combined with other results, we suggest that the Longmenshan fault is not a through-going crustal fault and the Pingwu-Qingchuan
fault may be not the northward extension of the Longmenshan thrust fault.
Supported by the National Natural Science Foundation of China (Grant Nos. 40604009 and 40574040) and Special Project for the
Fundamental R & D of Institute of Geophysics, China Earthquake Administration (Grant No.DQJB08B20) 相似文献
19.
Geology and isotopic composition of helium,neon, xenon and metallogenic age of the Jinding and Baiyangping ore deposits,northwest Yunnan,China 总被引:23,自引:0,他引:23
TheJindingoredeposit,locatedinthenorthwestYunnanProvince,isthelargestPb-Zndeposit(Pb Zn>15Mt1),averagingZn=6.08%andPb/Zn=1/4.7)inChinaatpresent.Toitsnorth,alargeCu-Co-AgdeposithasbeenfoundatBaiyangpingrecently1).TheJindingPb-Zndepositishostedinsandstonesa… 相似文献
20.
Ping Ding ChengDe Shen Ning Wang WeiXi Yi KeXin Liu XingFang Ding DongPo Fu 《中国科学D辑(英文版)》2009,52(5):638-646
We present the carbon isotopic composition of the total organic carbon (TOC) and fine roots in the sedimentary profile from
the underground ancient forest in Sihui to study the climatic and environmental changes from 4.5 ka BP to 0.6 ka BP. Results
show that C3 plant was the main vegetation from 4.5 ka BP to 0.6 ka BP in this region. The ancient forest began to develop in the wetland
at around 4 ka BP and disappeared together with the wetland at about 3.0 ka BP, implying that the climate had changed greatly
at around 3.0 ka BP. As indicated by the simulation results, the content of atmospheric CO2 increased slightly during 3.5 ka BP to 3.0 ka BP, implying climate warming during that period. The interval of radiocarbon
age between 3.0 ka BP to 1.2 ka BP was possibly caused by the strong erosion when the block was lifted in the neotectonic
movement. From 1.2 ka BP to 0.6 ka BP, the region remained in terrestrial sedimentary environment, and the surface plant biomass
declined gradually. Drought caused by the climate change was the likely cause for the disappearance of the ancient forest.
South transition of Intertropical Convergence Zone (ITCZ) was probably the main mechanism for the climate change.
Supported by National Natural Science Foundation of China (Grant Nos. 40231015 and 40473002), National Basic Research Program
of China (Grant No. 2005CB422004), the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KSCX2-SW-133)
and Open Funds of State Key Laboratory of Organic Geochemistry (Grant No. OGL-200607) 相似文献