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71.
Ricardo Arevalo Jr William F. McDonough Philip M. Piccoli 《Geostandards and Geoanalytical Research》2011,35(2):253-273
An in situ, medium‐resolution LA‐ICP‐MS method was developed to measure the abundances of the first‐row transition metals, Ga and Ge in a suite of geological materials, namely the MPI‐DING reference glasses. The analytical protocol established here hinged on maximising the ablation rate of the ultraviolet (UV) laser system and the sensitivity of the ICP‐MS, as well minimising the production of diatomic oxides and argides, which serve as the dominant sources of isobaric interferences. Non‐spectral matrix effects were accounted for by using multiple external calibrators, including NIST SRM 610 and the USGS basaltic glasses BHVO‐2G, BIR‐1G and BCR‐2G, and utilising 43Ca as an internal standard. Analyses of the MPI‐DING reference glasses, which represent geological matrices ranging from basaltic to rhyolitic in composition, included measurements of concentrations as low as < 100 μg g?1 and as high as > 104 μg g?1. The new data reported here were found to statistically correlate with the ‘preferred’ reference values for these materials at the 95% confidence level, though with significantly better precision, typically on the order of ≤ 3% (2sm). This analytical method may be extended to any matrix‐matched geological sample, particularly oceanic basalts, silicate minerals and meteoritic materials. 相似文献
72.
Kathryn A. Matthews Michael T. Murrell Steven J. Goldstein Andrew J. Nunn Deborah E. Norman 《Geostandards and Geoanalytical Research》2011,35(2):227-234
Here we report uranium and thorium isotopic ratios and elemental concentrations measured in solid reference materials from the USGS (BHVO‐2G, BCR‐2G, NKT‐1G), as well as those from the MPI‐DING series (T1‐G, ATHO‐G). Specifically created for microanalysis, these naturally‐sourced glasses were fused from rock powders. They cover a range of compositions, elemental concentrations and expected isotopic ratios. The U‐Th isotopic ratios of two powdered source materials (BCR‐2, BHVO‐2) were also characterised. These new measurements via multi‐collector thermal ionisation mass spectrometry and multi‐collector inductively coupled plasma‐mass spectrometry can now be used to assess the relative performance of techniques and facilitate comparison of U‐Th data amongst laboratories in the geoscience community for in situ and bulk analyses. 相似文献
73.
琼东南盆地长昌凹陷三维地震区中新统微观构造成因探讨 总被引:1,自引:0,他引:1
基于高精度三维地震资料的精细解释和方差体顺层切片技术,在琼东南盆地长昌凹陷中新统首次发现高密度小断裂,它们近SN走向,断距6~28m,长0.5~4km,倾角约60°.这些小断裂既不是渐新统继承性断裂,也不是近期热点讨论的多边形断层,而是在中新世特定地质条件下由局部引张形成的微观构造.其成因为:1)中新世琼东南盆地处于坳... 相似文献
74.
Occurrence and exploration of gas hydrate in the marginal seas and continental margin of the Asia and Oceania region 总被引:5,自引:0,他引:5
Ryo Matsumoto Byong-Jae Ryu Sung-Rock Lee Saulwood Lin Shiguo Wu Kalachand Sain Ingo Pecher Michael Riedel 《Marine and Petroleum Geology》2011,28(10):1751-1767
Supplies of conventional natural gas and oil are declining fast worldwide, and therefore new, unconventional forms of energy resources are needed to meet the ever-increasing demand. Amongst the many different unconventional natural resources are gas hydrates, a solid, ice-like crystalline compound of methane and water formed under specific low temperature and high pressure conditions. Gas hydrates are believed to exist in large quantities worldwide in oceanic regions of continental margins, as well as associated with permafrost regions in the Arctic. Some studies to estimate the global abundance of gas hydrate suggest that the total volume of natural gas locked up in form of gas hydrates may exceed all known conventional natural gas reserves, although large uncertainties exist in these assessments. Gas hydrates have been intensively studied in the last two decades also due to connections between climate forcing (natural and/or anthropogenic) and the potential large volumes of methane trapped in gas hydrate accumulations. The presence of gas hydrate within unconsolidated sediments of the upper few hundred meters below seafloor may also pose a geo-hazard to conventional oil and gas production. Additionally, climate variability and associated changes in pressure-temperature regimes and thus shifts in the gas hydrate stability zone may cause the occurrence of submarine slope failures.Several large-scale national gas hydrate programs exist especially in countries such as Japan, Korea, Taiwan, China, India, and New Zealand, where large demands of energy cannot be met by domestic supplies from natural resources. The past five years have seen several dedicated deep drilling expeditions and other scientific studies conducted throughout Asia and Oceania to understand gas hydrates off India, China, and Korea. This thematic set of publications is dedicated to summarize the most recent findings and results of geo-scientific studies of gas hydrates in the marginal seas and continental margin of the Asia, and Oceania region. 相似文献
75.
D. Franke U. BarckhausenN. Baristeas M. EngelsS. Ladage R. LutzJ. Montano N. PellejeraE.G. Ramos M. Schnabel 《Marine and Petroleum Geology》2011,28(6):1187-1204
The South China Sea formed by magma-poor, or intermediate volcanic rifting in the Paleogene. We investigate the structure of the continent-ocean transition (COT) at its southern margin, off NW Palawan between the continental blocks of Reed Bank and the islands of Palawan and Calamian. Several surveys, recorded by the BGR from 1979 to 2008, established a comprehensive database of regional seismic lines, accompanied with magnetic and gravity profiles.We interpret two major rifted basins, extending in the NE direction across the shelf and slope, separated by a structural high of non volcanic origin.The continent-ocean transition is interpreted at the seaward limit of the continental crust, when magnetic spreading anomalies terminate some 80-100 km farther north. The area in between displays extensive volcanism - as manifest by extrusions that occasionally reach and cut the seafloor, by dykes, and by presumed basaltic lava flows - occurring after break-up.The COT is highly variable along the NW Palawan slope: One type shows a distinct outer ridge at the COT with a steep modern seafloor relief. The other type is characterised by rotated fault blocks, bounded by listric normal faults ramping down to a common detachment surface. Half-grabens developed above a strongly eroded pre-rift basement. The seafloor relief is smooth across this other type of COT.We suggest the pre-rift lithospheric configuration had major influence on the formation of the COT, besides transfer zones. Volcanic domains, confined to the north of competent crustal blocks correlate with the style of the COT.Gravity modelling revealed an extremely thinned crust across the shelf. We propose a depth-dependent extension model with crust being decoupled from mantle lithosphere, explaining the discrepancy of subsidence observed across the South China Sea region. 相似文献
76.
David C. Mosher 《Marine and Petroleum Geology》2011,28(8):1540-1553
It is the intent of this paper to explore a significant extent of an entire passive continental margin for hydrate occurrence to understand hydrate modes of occurrence, preferred geologic settings and estimate potential volumes of methane. The presence of gas hydrates offshore of eastern Canada has long been inferred from estimated stability zone calculations, but little physical evidence has been offered. An extensive set of 2-D and 3-D, single and multi-channel seismic reflection data comprising in excess of 140,000 line-km was analyzed. Bottom simulating reflections (BSR) were unequivocally identified at seven sites, ranging between 250 and 445 m below the seafloor and in water depths of 620-2850 m. The combined area of the BSRs is 9311 km2, which comprises a small proportion of the entire theoretical stability zone along the Canadian Atlantic margin (∼715,165 km2). The BSR within at least six of these sites lies in a sedimentary drift deposit or sediment wave field, indicating the likelihood of grain sorting and potential porosity and permeability (reservoir) development. Although there are a variety of conditions required to generate and recognize a BSR, one might assume that these sites offer the most potential for highest hydrate concentration and exploitation. Total hydrate in formation at the sites of recognized BSR’s is estimated at 17 to 190 × 109 m3 or 0.28 to 3.12 × 1013 m3 of methane gas at STP. Although it has been shown that hydrate can exist without a BSR, the results from this regional study argue that conservative estimates of the global reserve of hydrate along continental margins are necessary. 相似文献
77.
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79.
利用可实例化的智能线程池技术,通过两个线程池分别实现了前兆数据的并行数据采集与数据的多目标入库,可自动实现对最近巧天内的数据进行检测与采集,采集仪器的数量由原来的几台、十几台提高到上千台,大大提高了地震前兆数据的采集效率;通过数据的多目标入库,数据由台站到区域中心以及国家台网中心的同步速度也得到很大提高. 相似文献
80.
安徽省地震会商地理信息系统的研制与实现 总被引:3,自引:1,他引:2
文章结合安徽省现有分析预报手段和数学模型,以Visual Studio2005.net作为开发语言,利用GIS技术对地震地质和基础地理等数据进行管理、分析,通过快速访问前兆数据库,对前兆数据进行查询和曲线调用出图,最终研制实现了一套满足日常及紧急会商需要,集"基础数据查询""前兆数据管理""前兆数据注释""应急会商报告... 相似文献