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91.
C1相干算法是计算每道的横测线和相邻纵测线的互相关,依据相干值来判断地层和岩性的横向不均匀性。根据互相关原理,提出了相干体算法中二维和三维C1算法的内容及其具体实现。通过对实际三维地震资料的处理,结合已知地质资料,证明C1相干技术在三维地震资料的断层解释方面有着明显的效果。  相似文献   
92.
刘桥一矿陷落柱发育规律及含水性研究   总被引:3,自引:0,他引:3  
根据刘桥一矿1971年建井至今发现的8个陷落柱实际资料,通过对揭露陷落柱的地质、水文地质及分布特征的分析,阐述了陷落柱发育的根基所在,对陷落柱发育规律及成因进行了探讨,对于含水陷落柱的注浆封堵、留设保护煤岩柱,以及本矿矿井的深部开采都具有借鉴意义。  相似文献   
93.
岩石边坡系统是一典型灰色系统,其变形发展过程可以用灰色预测模型完成。尽管传统GM(1,1)模型预测有很多成功的实例,但是也存在一些预测偏差过大的情况,必须对其进行优化。逐步迭代法GM(1,1)模型不仅收敛速度快,而且与原始数据库序列的凹凸性保护一致。利用自编的计算程序对马步坎边坡预测测点G1沉降和开裂进行预测分析,结果表明逐步迭代法GM(1,1)优化模型计算精度较传统GM(1,1)模型和背景构造法GM(1,1)优化模型高,较好地反映了岩石边坡的变形趋势。  相似文献   
94.
A new geochemical reference material, coral Porites sp. JCp-1 has been prepared by the Geological Survey of Japan (GSJ). Provisional values for twenty one major, minor and trace elements are presented. The homogeneity tests showed that all elements studied are considered to be homogeneously distributed.  相似文献   
95.
Results are presented for round one of a new international proficiency testing programme designed for microprobe laboratories involved in the routine analysis of silicate minerals. The sample used for this round was TB-1, a basaltic glass fused and prepared by the USGS. Thirty nine laboratories contributed data to this round, the majority of major element results being undertaken by EPMA and the majority of trace elements by LA-ICP-MS. Assigned values were derived from the median of results produced by nine selected laboratories that analysed powdered material by conventional ICP-MS, INAA and XRF techniques using bulk powders of the sample. Submitted microprobe results were evaluated using a target precision calculated using the Horwitz function, adopting the same criteria as those used for "applied" geochemistry laboratories in the companion GeoPT proficiency testing programme for laboratories involved in the routine bulk analysis of silicate rocks. An evaluation of results from participating microprobe laboratories indicated that overall, data were compatible with this precision function. A comparison between the performance of bulk and microprobe techniques used in the analysis of the basaltic glass showed remarkably good agreement, with significant bias only observed for the major oxide MgO.  相似文献   
96.
Two ordination techniques (Romaniszyn diagram, RD, and Canonical correspondence analysis, CCA) were applied to the same data set (fish assemblage composition along two Paraná river tributaries and associated environmental variables), to identify spatial community patterns and further to evaluate the performance of RD. The major patterns in these Brazilian streams were successfully revealed by both methods (i.e. clear separation of both tributaries on the basis of fish assemblage composition and environmental factors), but more complex situations may limit the application of RD in comparison with CCA.  相似文献   
97.
2001年11月14日新疆-青海交界8.1级地震   总被引:3,自引:0,他引:3  
简要介绍了2001年11月14日新疆-青海交界8.1级地震的预测情况,给出了中、美、日等对此次地震的震源参数测定和震源机制,以及余震的分布和加卸载响应比随时间的变化。进而对震区近期地震趋势进行预测。  相似文献   
98.
The Hercynian basement of the Iberian Peninsula was uplifted by the Alpine orogeny during the Tertiary. It gave rise to a set of block mountains and tectonic grabens, one of which is the Ciudad Rodrigo Basin. It is located in Western Spain and forms a westward extension of the great Tertiary Duero Basin. The sediments filling this graben are of continental origin, their ages ranging from Palaeogene to Quaternary. Morphologically, the southern part of this basin forms a set of piedmont surfaces (the “Raña” surfaces) appearing above the terrace system of the present rivers. This paper examines the weathering processes developed over these old piedmont surfaces using micromorphological, XR diffraction, scanning electron microscopy (SEM) and microporosity techniques.The Raña sediments are rich in quartzite pebbles and gravel within a clayey matrix. Once deposited, these materials underwent important in situ weathering processes under somewhat hydromorphic conditions, of which hydrolysis, ferrolysis and xerolysis were the most important. All these processes gave rise to: (1) transformation of most of the clasts of shists and slates into a matrix causing the destruction of the original sedimentary structures and a relative concentration of the resistant lithologies (quartzites and quartz); (2) important changes in the clay fraction, leading to a predominance of kaolinite in the upper levels of the profiles, (3) release of elements from primary minerals, Fe being one of the most important, and (4) redistribution of matter, mainly clay and Fe oxyhydroxides, within the profiles.The coexistence of seasonal periods with pF higher than 4.2 repeated over a long time, together with poor internal and external drainage conditions, are the cause of the special features displayed by Raña deposits.  相似文献   
99.
The columnar cactus Polaskia chende, endemic to Central Mexico, occurs in the wild and in silviculturally managed populations where artificial selection for better edible fruits operates by sparing and favouring desirable phenotypes during vegetation clearance. Wild and managed populations were compared in morphology and reproductive biology to analyse if human selection has influenced phenotypic divergence, if it has modified breeding systems and if reproductive isolation exists between them. Fruits from managed populations were larger (6·36±0·17 cm3), heavier (19·62±1·32), sweeter (9·07±0·25 °Brix), and with thinner peel (2·09±0·13 mm) than those from wild populations (5·77±0·18 cm3, 15·73±0·85 g, 8·23±0·31 °Brix, and 2·58±0·14 mm, respectively). Both population types bloom synchronically, show diurnal anthesis, with bees as the most likely pollinators, and have breeding system predominantly self-incompatible. Spatial and temporal barriers to pollen exchange between wild and managed populations are unlikely, and morphological differences would be related with an ongoing process of artificial selection.  相似文献   
100.
Snow accumulation is responsible for geomorphic and biogeographic processes taking place in the southern sector of the Peñalara massif in central Spain (40°51′N, 3°57′W; max. altitude 2428 m at Pico de Peñalara). This work compares the intensity of nivation on the eastern slope, leeward of the prevailing westerly winds and heavily eroded by glacial activity during the Pleistocene, to that of the western slope on the windward side, unaffected by glacial erosion and completely covered by a thick weathering mantle. On the eastern slope, nivation is effective only where the weathering mantle is exposed or on morainic formations. It does not occur on the landforms derived from glacial erosion. In contrast, the western side shows almost no evidence of snow action except where catastrophic mass movements have altered the regularity of the slope. During the post-glacial epoch, nivation cirques formed in the scars left by mass wasting. In the last 30 years, spring temperatures have increased and this activity has diminished. The pattern of evolution observed at Peñalara can be extrapolated to other Mediterranean mountains with similar characteristics such as marginal glacial activity during the Pleistocene, unconsolidated formations on the summits caused by chemical weathering, and dry, hot summers that can increase the effectiveness of nivation.  相似文献   
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