排序方式: 共有36条查询结果,搜索用时 171 毫秒
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本文利用地表露头、岩芯、测井、三维地震和微观分析资料,根据多尺度裂缝的发育特征及不同资料的精度,探讨了多尺度裂缝的表征方法。致密低渗透砂岩储层发育多尺度天然裂缝,根据天然裂缝规模以及限制天然裂缝扩展延伸的岩石力学层界面,将天然裂缝分为大尺度裂缝、中尺度裂缝、小尺度裂缝和微尺度裂缝4级,不同尺度裂缝的发育特征存在较大差异。其中大尺度裂缝主要应用三维地震资料的叠后属性进行检测和表征;中小尺度裂缝在单井上可以应用岩芯、成像测井和常规测井相结合的方法进行表征,在平面上采用基于地质和测井约束的三维地震叠前各向异性分析以及储层地质力学相结合的方法进行综合预测和评价;微尺度裂缝一般应用铸体薄片、普通薄片、扫描电镜和三维CT扫描等微观分析方法进行观察描述,通过主控因素约束的方法进行预测。利用本文提出的多尺度裂缝表征方法实现了对鄂尔多斯盆地西南部致密砂岩储层多尺度裂缝表征,可为其它致密低渗透砂岩储层多尺度裂缝表征提供借鉴。 相似文献
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Origin of a Mesozoic granite with A-type characteristics from the North China craton: highly fractionated from I-type magmas? 总被引:2,自引:0,他引:2
Neng Jiang Shuangquan Zhang Wenge Zhou Yongsheng Liu 《Contributions to Mineralogy and Petrology》2009,158(1):113-130
We report geochronological, geochemical and isotopic data for the Mesozoic Shangshuiquan granite from the northern margin
of the North China craton. The granite is highly fractionated, with SiO2 > 74%. Occurrence of annitic biotite, high contents of alkalis (K2O + Na2O), Rb, Y, Nb and heavy rare earth elements, high FeOt/MgO, low contents of CaO, Al2O3, Ba, and Sr, and large negative Eu anomalies, makes it indistinguishable from typical A-type granites. A mantle-derived origin
for the rocks of the granite is not favored because their high initial 87Sr/86Sr (≥0.706) and low εNd (t) (<−15) are completely different from either those of the lithospheric or asthenospheric mantle. In fact, their Sr–Nd isotopes
fall within the range of Sr–Nd isotopic compositions of the Archean granulite terrains and are comparable to those of Mesozoic
crustal-derived I-type granitoids in the region. Therefore, the Shangshuiquan granite is considered to be dominantly derived
from partial melting of the ancient lower crust. Its parental magmas prove to be similar to I-type magmas and to have undergone
extensive fractionation during its ascent. This is supported by the fact that some of the nearby Hannuoba feldspar-rich granulite
xenoliths can be indeed regarded as the early cumulates in terms of their mineralogy, chemistry, Sr–Nd isotopes and zircon
U–Pb ages and Hf isotopes. It is furthermore argued that some of highly fractionated granites worldwide, especially those
with A-type characteristics and lacking close relationship with unfractionated rocks, may in fact be fractionated I-type granites.
This suggestion can explain their close temporal and spatial associations as well as similar Sr–Nd isotopes with I-type granites.
Our study also sheds new light on the petrogenesis of deep crustal xenoliths. 相似文献
33.
基于一元线性回归函数模型,利用计算机程序实现建筑沉降数据处理,根据误差理论和概率统计原理,建立数学计算与分析模型,对沉降观测各要点进行误差分析,提高沉降观测数据分析的精准性与快捷性。该方法在望京高层沉降工程中得到有效验证。 相似文献
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周口店遗址是中国古人类学的发源地 ,在很长的时期内一直是我国古人类学、旧石器时代考古学和第四纪地质学的科研基地。该遗址丰富的人类化石、文化遗物和动物化石都是宝贵的科学资源 ,而过去对这些材料整理与研究的局限性为未来系统而深入的研究工作和产生新的成果预留了空间。遗址区仍然埋藏着丰厚的科学资源 ,新的发现、发掘和研究势必在探索东亚地区古人类体质与行为特点、演化过程以及生存环境背景的重建诸方面取得新的突破。 相似文献
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文章从考古学角度对遗址周围潜在原料产地进行调查,并以遗址出土文化遗物最为丰富的第4~5层为例对其原料采集策略进行初步分析.调查显示,遗址以北、周口河两岸的石炭-二叠系地层和花岗岩侵入体中多有石英脉出露,而遗址以南多为灰岩、白云岩山地,少见石英脉出露.遗址第4~5层石制品的原料分析显示,距今30万年左右的“北京人”既从河流砾石层也从岩脉露头或风化处采集脉石英进行石器生产;古人类可能对不同类型脉石英采取多种开发策略;对石英脉的利用具有一定的技术组织性,表现出一副多样的原料开发图景. 相似文献