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101.
102.
A 3-D coupled ice sheet model, GLIMMER model is introduced, and an idealized ice sheet experiment under the EISMINT-1 criterion of moving boundary condition is presented. The results of the experiment reveal that for a steady-state ice sheet profile the characteristic curves describe the process of evolution which are accordant with theoretical estimates. By solving the coupled thermodynamics equations of ice sheet, one may find the characteristic curves which derived from the conservation of the mass, energy and momentum to the ice flow profile. At the same time, an agreement, approximate to the GLIMMER case and the confirmed theoretical results, is found. Present study is explorihg work to introduce and discuss the handicaps of EISMINT criterion and GLIMMER, and prospect a few directions of the GLIMMER model. 相似文献
103.
矿产资源是工业的粮食,矿业是国民经济的基础产业,是现代工业和工业文明的基石。实行两个具有全局意义的根本性转变和可持续发展战略,我国矿业经济的发展和矿产资源的行政管理面临新的挑战和机遇。文章运用社会主义市场经济理论和行政管理原理,阐述了当前矿业经济和矿政管理的严峻形势和突出问题,分析了体制转轨和增长转型期的矿业实际,从开展理论研究,提高对矿产资源重要性、紧迫性的认识;健全矿产资源管理新体制,完善矿业市场机制;强化矿业法制,切实依法管矿;适时调整矿产资源政策,改善矿业经济宏观调控等4个方面,就强化和完善矿产资源的政府职能,推进矿业经济可持续发展提出建议。 相似文献
104.
Due to the bird's eye view of remote sensing sensors, the orientational information of an object is a key factor that has to be considered in object detection. ... 相似文献
105.
Seismic tomography is one of the main tools to explore the interior of the earth.In this study,the quasi-waveform seismic tomographic method is used for the first time to reveal the crustal structures in the capital region of China.3-D highresolution V_P,V_S and the Poisson’s ratio models are generated by inverting 29839 direct P-and 29972 direct S-wave traveltimes selected from 3231 local earthquakes.The results reveal strong crustal heterogeneities.The velocity anomalies at shallow depths are well consistent with surface geologic structures.The relatively low-velocity anomaly layer in the middle crust may be the result of multiple phases of tectonic activity.Earthquakes generally occurred on the boundaries of high-and low-velocity and Poisson’s ratio anomalies.There are obvious low-velocity anomalies below the hypocenters of the Tangshan earthquake and the historical Sanhe-Pinggu earthquake,implying the existence of fluids.The similar velocity structures around the hypocenters of the two earthquakes indicate that the occurrences of the two earthquakes may be related to the same mechanism.The highresolution velocity models provide important observational constraints on the small-scale heterogeneities and dynamic mechanism of the crust in the capital region of China. 相似文献
106.
107.
东秦岭商丹地区蛇绿岩中的角闪石研究 总被引:1,自引:0,他引:1
东秦岭蛇绿岩主要分布在北秦岭南缘、商丹断裂带以北的狭窄地带,断续逶迤呈带状作近东西向展布。分布于商丹地区的蛇绿岩是东秦岭蛇绿岩带的重要组成部分并具有代表性。 本文着重论述了商丹地区蛇绿岩中广泛分布的主要造岩矿物之一,角闪石的主要特征组份、微量元素、晶胞参数、阳离子占位度等成因矿物学特点。并据此说明了该蛇绿岩中的角闪石属于区域正变质的产物;形成的物质来源具有同源性,原岩为超镁铁质-镁铁质的岩浆岩和火山熔岩;形成的热力学条件基本相同,变质程度为绿帘角闪岩相或角闪岩相,变质温度为610℃左右,压力大于5×10~8Pa。 此外,根据商丹地区蛇绿岩中角闪石成因矿物学特征之相同性所提供的信息表明,东秦岭蛇绿岩带是华北和扬子两个板块俯冲、碰撞的构造边界变质带。 相似文献
108.
天山乌鲁木齐河源冰川与空冰斗辐射气候的计算结果 总被引:3,自引:0,他引:3
提要 在朝向、坡度和山体遮蔽度影响下,与水平面相比朝北冰川和朝南空冰斗在太阳偏角为15°,0°和-10°时的平均太阳辐射能量损失分别是40.6%和21.0%。1号冰川东支夏季消融期内自然冰雪面辐射场内辐射平衡各分量平均日总量值受地形因素和反射性能的控制而显示出由西北侧向东南侧逐渐降低的带状分布规律。晴朗少云天气下的总辐射和有效辐射的垂直梯度分别是14.52Wm~(-2)/100m和2.77Wm~(-2)/100m。 相似文献
109.
Types and distribution of silver ore deposits in China 总被引:2,自引:0,他引:2
Silver is generally recovered as a by- and co-product along with Au, Pb, Zn, Cu, Sb, Bi, Hg, Sn and W from polymetallic and
gold mines in China. Chinese silver deposits can be classified into five principal types according to host rocks. These types
and their host rocks are: (1) marine volcanic-sedimentary rocks hosting (la) massive sulfide Pb-Zn-(Cu)-Ag ores and (1b) stratiform
Ag-(Au) ores; (2) continental volcanic-sedimentary rocks containing (2a) various polymetallic-silver veins and/or stockworks,
and (2b) Ag-(Au) veins in pyroclastic rocks; (3) rocks affected by metasomatic processes including (3a) complex Sn-polymetallic-Ag
ores, (3b) Pb-Zn-(Cu)-Ag skarns, (3c) associated W-Ag quartz veins and/or skarns, and (3d) Ag-(Au) zones and veins in altered
carbonate rocks; (4) metamorphic-intrusive rocks, principally Ag-(Au) veins in sheared and brecciated metamorphic rocks; and
(5) sedimentary rocks including (5a) stratiform Pb-Zn-Ag ores in carbonate rocks, (5b) Ag-V mantos in black shales, and (5c)
Cu-(Ag) layers in red sandstones. A sixth grouping includes gossans. The tectonic settings, geological features, and temporal
and spatial distribution of these different types of silver occurrences indicate that silver mineralization reflects to a
great extent the evolution of tectonic environments in China throughout geological time. Type 1 is generally developed in
association with several fold belts from the Caledonian to Yanshanian orogens, while types 2, 3 and 4 correlate with rejuvenation
of the eastern China continent during the Mesozoic period. The three subgroups of type 5 are recognized in different stages
and various sedimentry and diagenetic environments during the development of paraplatforms and fold belts. Type 6 results
from recent weathering of existing sulfide ores or protores.
Editorial handling: DR 相似文献
110.
敖瑙达巴斑岩型铜银锡乡金属矿床既不同于大多数由幔源岩浆衍生物所形成的斑岩铜矿,也不同于大多由地壳重熔岩浆衍生物形成的斑岩型锡(钨钼)矿床。它是分布于过渡性地壳上的、由起源于下地壳-上地幔的过渡性岩浆的衍生物形成的斑岩型铜银锡矿床。根据已取得的资料,在矿区内磁法、电法、化探异常的展布与已知矿化蚀变带一致。凡磁、电、化探异常吻合一致的综合异常,经验证都已见到了矿体。 相似文献