全文获取类型
收费全文 | 69篇 |
免费 | 1篇 |
专业分类
大气科学 | 2篇 |
地球物理 | 6篇 |
地质学 | 49篇 |
海洋学 | 5篇 |
天文学 | 5篇 |
自然地理 | 3篇 |
出版年
2021年 | 1篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1989年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有70条查询结果,搜索用时 15 毫秒
31.
Oxygen Isotope Geochemistry of Oceanic-Arc Lavas 总被引:19,自引:11,他引:8
EILER JOHN M.; CRAWFORD ANTHONY; ELLIOTT TIM; FARLEY KENNETH A.; VALLEY JOHN W.; STOLPER EDWARD M. 《Journal of Petrology》2000,41(2):229-256
Variations of oxygen isotope ratios in arc-related lavas canconstrain the contributions of subducted crustal igneous rocks,sediments, and fluids to the sub-arc mantle. We have measuredoxygen isotope ratios in 72 arc and back-arc lavas from fiveoceanocean subduction zone systems using laser-fluorinationanalyses of olivine and other phenocrysts and glass. Eightypercent of our samples have 相似文献
32.
Serial variation between Micraster populations from successive zones in the Upper Cretaceous Chalk of Europe is widely cited as evidence for evolution at the species level, whether changes between species are interpreted as gradual or punctuational. That these changes were adaptive and represent an improved functional efficiency with time is also now widely agreed, if not whether the changes were independent of environmental change or a response to it. Dead specimens of Micraster were commonly encrusted by a wide variety of small invertebrates, presumably because they provided islands of hard substrate on an otherwise soft, muddy sea floor. Less commonly, there is evidence that living specimens of Micraster were susceptible to predation by gastropods and other organisms, one of the natural selection pressures favouring adaptation to a burrowing mode of life. 相似文献
33.
ABSTRACT. Meteorological tsunamis, or meteo‐tsunamis, are long‐period waves that possess tsunami characteristics but are meteorological in origin, although they are not storm surges. In this article we investigate the coast of southern Britain‐the English Channel, the Bristol Channel, and the Severn Estuary‐for the occurrence of tsunami‐like waves that, in the absence of associated seismic activity, we recognize as meteo‐tsunamis. The passage of squall lines over the sea apparently generated three of these events, and two seem to have been far‐traveled, long‐period waves from mid‐North Atlantic atmospheric low‐pressure systems. The remaining three wave events appear to have been associated with storms that, among possible explanations, may have induced large‐amplitude standing waves‐such as seiches‐or created long‐period waves through the opposition of onshore gale‐force winds and swells with high ebb tidal current velocities. This coastal hazard has resulted in damage and loss of life and should be considered in future coastal defense strategies and in beachuser risk assessments. 相似文献
34.
An Experimental Study of Water and Carbon Dioxide Solubilities in Mid-Ocean Ridge Basaltic Liquids. Part I: Calibration and Solubility Models 总被引:14,自引:7,他引:7
DIXON JACQUELINE EABY; STOLPER EDWARD M.; HOLLOWAY JOHN R. 《Journal of Petrology》1995,36(6):1607-1631
Experiments were conducted to determine the solubilities ofH2O and CO2 and the nature of their mixing behavior in basalticliquid at pressures and temperature relevant to seqfloor eruption.Mid-ocean ridge basaltic (MORB) liquid was equilibrated at 1200°Cwith pure H2O at pressures of 176717 bar and H2OCO2vapor at pressures up to 980 bar. Concentrations and speciationof H2O and CO2 dissolved in the quenched glasses were measuredusing IR spectroscopy. Molar absorptivities for the 4500 cm1band of hydroxyl groups and the 5200 and 1630 cm1 bandsof molecular water are 067±003, 062±007,and 25±3 l/mol-cm, respectively. These and previouslydetermined molar absorptivities for a range of silicate meltcompositions correlate positively and linearly with the concentrationof tetrahedral cations (Si+Al). The speciation of water in glass quenched from vapor-saturatedbasaltic melt is similar to that determined by Silver &Stolper (Journal of Petrology 30, 667709, 1989) in albiticglass and can be fitted by their regular ternary solution modelusing the coefficients for albitic glasses. Concentrations ofmolecular water measured in the quenched basaltic glasses areproportional to f H2O in all samples regardless of the compositionof the vapor, demonstrating that the activity of molecular waterin basaltic melts follows Henry's law at these pressures. Abest fit to our data and existing higher-pressure water solubilitydata (Khitarov et al., Geochemistry 5, 479492, 1959;Hamilton et al., Journal of Petrology 5, 2139, 1964),assuming Henrian behavior for molecular water and that the dependenceof molecular water content on total water content can be describedby the regular solution model, gives estimates for the Vo, mH2Oof 12±1 cm3/mol and for the 1-bar water solubility of011 wt%. Concentrations of CO2 dissolved as carbonate in the melt forpure CO2-saturated and mixed H2O-CO2-saturated experiments area simple function of fCO2 These results suggest Henrian behaviorfor the activity of carbonate in basaltic melt and do not supportthe widely held view that water significantly enhances the solutionof carbon dioxide in basaltic melts. Using a Vo, mr of 23 cm3/mol(Pan et al., Geochimica et Cosmochimica Acta 55, 15871595,1991), the solubility of carbonate in the melt at 1 bar and1200°C is 05 p.p.m. Our revised determination of CO2solubility is 20% higher than that reported by Stolper &Holloway (Earth and Planetary Science Letters 87, 397408,1988). KEY WORDS: mid-ocean ridge basalts; water and carbon dioxide solubility; experimental petrology 相似文献
35.
CLIFFORD TOM N.; BARTON ERIKA S.; RETIEF EDWARD A.; REX DAVID C.; FANNING C. MARK 《Journal of Petrology》1995,36(1):231-258
The Koperberg Suite comprises some 1700 small bodies of intrusiverocks largely composed of andesine anorthosite, biotite diorite,and leuconorite, norite and melanorite-hypersthenite; 30 mineshave been established in the O'okiep District in the cupriferousrocks of this anorthosite-charnockite kindred. The suite isintrusive into a sequence of granite gneiss and metavolcanicand metasedimentary rocks, and intrusive granite, that wereelevated to the granulite fades of regional metamorphism.TheSm-Nd model ages for the country rocks and the Koperberg Suiteare all 1700 Ma (TCHUR) and 2000 Ma (TDM) supporting a majorcrustforming event in this portion of Namaqualand at the endof Lower Proterozoic times. The granulite fades metamorphismin the O'okiep District is recorded by a Rb-Sr isochron ageof 1223 48 Ma on the Nababeep Granite Gneiss, and by (1197 15)-Ma-old inherited cores of zircons in the Koperberg Suite.The time of intrusion of the Concordia and Rietberg Granitesis believed to be reflected by their Rb-Sr whole-rock age of1105 24 Ma. The mean U-Pb age of 1029 10 Ma on individualzircon grains and zircon rims from the Koperberg Suite recordsthe time of its intrusion, and this is supported by the Sm-Ndwhole-rock age of 1022 42 Ma for the suite. Subsequent coolingand reheating events are recorded by the Ar-Ar ages of 800850Ma for the Koperberg Suite, and of 500550 Ma for thesuite and certain country rocks, respectively.An Nd value of-7,and its volume and composition, suggest a crustal-melt sourcefor the intrusive Concordia Granite. Moreover, the age-correctedhigh lSr (07061-07272) and low Nd (-9), and the high µ2(101), that characterize the Koperberg Suite also imply a crustalsource, and a model is presented for the generation of the majorpart of the suite by partial melting of granulites of overallintermediate (diorite) composition in the lower crust.
Corresponding author 相似文献
36.
GREW EDWARD S.; PERTSEV NIKOLAY N.; YATES MARTIN G.; CHRISTY ANDREW G.; MARQUEZ NICHOLAS; CHERNOSKY JOSEPH V. 《Journal of Petrology》1994,35(5):1275-1293
Sapphirine occurs with humite-group minerals and forsteritein Precambrian amphibole-facies rocks at Kuhi-lal, SW PamirMountains, Tajikistan, a locality also for talc+kyanite magnesiohornblendewhiteschist. Most of these sapphirine-bearing rocks are graphiticand sulfidic (pyrite and pyrrhotite) and contain enstatite,clinohumite or chondrodite, spinel, rutile, gedrite, and phlogopite.A phlogopite schist has the assemblage with XFe = Fe/(Fe+Mg)increasing as follows: chlorite (0-003)<phlogopite (0.0040.005)sapphirine (0.0040.006) enstatite (0-006)forsterite (0-0060-007)<spinel (0-014). This assemblage includes the incompatiblepair sapphirine+forsterite, but there is no textural evidencefor reaction. In one rock with clinohumite, XFe increases asfollows: clinohumite (0-002) <sapphirine (0-003) <enstatite(0-0040-006) <spinel (0-010). Ion microprobe and wet-chemicalanalyses give 0-570-73 wt.% F in phlogopite and 0-27wt.% F in chlorite in the phlogopite schist; 0-04, 1.51.9,and 4.4 wt.% F in forsterite, clinohumite, and chondrodite,respectively; and 0-0-09 wt.% BeO and 0-050-21 wt.% B2O3in sapphirine. Stabilization of sapphirine+clinohumite or sapphirine+chondroditeinstead of sapphirine+phlogopite is possible at high F contentsin K-poor rocks, but minor element contents appear to be toolow to stabilize sapphirine as an additional phase with forsterite+enstatite+spinel.Although sapphirine+forsterite is metastable relative to spinel+enstatitein experiments conducted at aH2O=1 in the MgO-Al2O3-SiO2-H2Osystem, it might be stabilized at aH2O0.5, P4 kbar, T650700C.Textures in the Kuhi-lal whiteschists suggest a polymetamorphicevolution in which the rocks were originally metamorphosed atT650C, P 7 kbar, conditions under which sapphirine+clinohumiteand sapphirine+chondrodite are inferred to have formed, andsubsequently affected by a later event at lower P, similar T,and lower aH2O. The latter conditions were favorable for sapphirine+forsteriteto form in a rock originally containing chlorite+forsterite+spinel+enstatite. 相似文献
37.
38.
Geology and the liberation of Normandy, France, 1944 总被引:1,自引:0,他引:1
The Allied victory in Europe in May 1945 marked the end of an 11-month campaign which began with the invasion of Normandy on 6 June 1944 - D-Day. Geologists participated in both the planning and operational phases of the campaign. Geological factors influenced the trafficability of the Normandy beaches, site selection for temporary airfields, quarrying for road metal and development of potable water supplies, and were also involved in ground response to aerial bombardment, vehicular movement cross-country and characteristics of both sea floor and river beds. Little-known applications of geology thus contributed to the final victory. 相似文献
39.
碳质球粒陨石是太阳系中最原始的物质之一.通过对碳质球粒陨石的光谱分析,可以建立其与母体小行星之间的联系,有助于探测小行星表面物质成分、研究太阳系早期的演化历史.研究了6个CM2型碳质球粒陨石和11个煤炭样品(碳质球粒陨石所含有机质的地球类比物)可见-远红外谱段反射光谱特征,并分析了它们与有机组分的关系.结果表明,对于不... 相似文献
40.
Observation bias correction with an ensemble Kalman filter 总被引:1,自引:0,他引:1
ELANA J. FERTIG SEUNG-JONG BAEK BRIAN R. HUNT EDWARD OTT ISTVAN SZUNYOGH JOSÉ A. ARAVÉQUIA EUGENIA KALNAY HONG LI JUNJIE LIU 《地球,A辑:动力气象学与海洋学》2009,61(2):210-226
This paper considers the use of an ensemble Kalman filter to correct satellite radiance observations for state dependent biases. Our approach is to use state-space augmentation to estimate satellite biases as part of the ensemble data assimilation procedure. We illustrate our approach by applying it to a particular ensemble scheme—the local ensemble transform Kalman filter (LETKF)—to assimilate simulated biased atmospheric infrared sounder brightness temperature observations from 15 channels on the simplified parameterizations, primitive-equation dynamics (SPEEDY) model. The scheme we present successfully reduces both the observation bias and analysis error in perfect-model simulations. 相似文献