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胶南造山带榴辉岩中的高压、超高压变质矿物主要有绿辉石、镁铝榴石、柯石英、金刚石、金红石等。柯石英、金刚石均呈微晶状包裹于石榴子石、绿辉石中。柯石英多已转化为石英聚晶,并使包裹它的矿物产生放射状胀裂纹;金刚石呈近等轴八面体等,其形成压力达3.5GPa以上。榴辉岩围岩中的高压、超高压变质矿物主要有辉石类(透辉石、霓石、暗硬玉)、钠钙质钠质角闪石(钠闪石、镁钠闪石)、多硅白云母(3T型)、钠长石、绿帘石等。高压、超高压变质矿物的广泛出现指示区内存在两期高压变质作用:早期为超高压榴辉岩相变质作用;晚期为高压绿片岩相榴辉岩相变质作用。华北板块与扬子板块的多次碰撞是区内高压、超高压变质作用产生的主要原因。 相似文献
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中国旅游业发展灰色关联动态分析 总被引:10,自引:0,他引:10
随着国民经济的快速发展、人口数最的不断增长和消费水平的逐步提高,人们对旅游的体验需求越来越大。如何实现中国旅游业的持续发展,是摆在全国人民面前一个严峻的问题。通过对近24年中国旅游国内总收入变化趋势的分析,运用灰色系统理论对影响中国旅游业发展诸因素进行关联分析,量化了旅游业产值与诸因子的关联程度,为中国旅游业制定发展规划、促进旅游业的可持续发展提供了参考依据。 相似文献
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内蒙额尔古纳在矿带中生代火山岩浆活动与金属成矿的关系 总被引:1,自引:0,他引:1
在岩石学和微量元素地球化学研究的基础上,通过对不同类型矿床的成矿岩体及围岩条件的分析,探讨了中生代火山岩浆活动与金属成矿的关系。认为晚侏罗世火山岩浆活动为成矿提供了有利的围岩的构造空间;早白垩世岩浆活动提供了成矿岩体及热力学条件,该期次火山岩浆的侵入并作用于不同的围岩、形成了由斑岩型Cu、Mo矿,浅成熟液型Ag、Pb、Zn矿等组成的一系列矿床组合。 相似文献
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The Kos Plateau Tuff consists of pyroclastic deposits from a major Quaternary explosive rhyolitic eruption, centred about 10 km south of the island of Kos in the eastern Aegean, Greece. Five main units are present, the first two (units A and B) were the product of a phreatoplinian eruption. The eruption style then changed to `dry' explosive style as the eruption intensity increased forming a sequence of ignimbrites and initiating caldera collapse. The final waning phase returned to phreatomagmatic eruptive conditions (unit F). The phreatomagmatic units are fine grained, poorly sorted, and dominated by blocky vitric ash, thickly ash-coated lapilli and accretionary lapilli. They are non-welded and were probably deposited at temperatures below 100°C. All existing exposures occur at distances between 10 km and 40 km from the inferred source. Unit A is a widespread (>42 km from source), thin (upwind on Kos) to very thick (downwind), internally laminated, dominantly ash bed with mantling, sheet-like form. Upwind unit A and the lower and middle part of downwind unit A are ash-rich (ash-rich facies) whereas the upper part of downwind unit A includes thin beds of well sorted fine pumice lapilli (pumice-rich facies). Unit A is interpreted to be a phreatoplinian fall deposit. Although locally the bedforms were influenced by wind, surface water and topography. The nature and position of the pumice-rich facies suggests that the eruption style alternated between `wet' phreatoplinian and `dry' plinian during the final stages of unit A deposition.Unit B is exposed 10–19 km north of the inferred source on Kos, overlying unit A. It is a thick to very thick, internally stratified bed, dominated by ash-coated, medium and fine pumice lapilli in an ash matrix. Unit B shows a decrease in thickness and grain size and variations in bedforms downcurrent that allow definition of several different facies and laterally equivalent facies associations. Unit B ranges from being very thick, coarse and massive or wavy bedded in the closest outcrops to source, to being partly massive and partly diffusely stratified or cross-bedded in medial locations. Pinch and swell, clast-supported pumice layers are also present in medial locations. In the most distal sections, unit B is stratified or massive, and thinner and finer grained than elsewhere and dominated by thickly armoured lapilli. Unit B is interpreted to have been deposited from an unsteady, density stratified, pyroclastic density current which decelerated and progressively decreased its particle load with distance from source. Condensation of steam during outflow of the current promoted the early deposition of ash and resulted in the coarser pyroclasts being thickly ash-coated. The distribution, texture and stratigraphic position of unit B suggest that the pyroclastic density current was generated from collapse of the phreatoplinian column following a period of fluctuating discharge when the eruptive activity alternated between `wet' and `dry'. The pyroclastic density current was transitional in particle concentration between a dilute pyroclastic surge and a high particle concentration pyroclastic flow. Unidirectional bedforms in unit B suggest that the depositional boundary was commonly turbulent and in this respect did not resemble conventional pyroclastic flows. However, unit B is relatively thick and poorly sorted, and was deposited more than 19 km from source, implying that the current comprised a relatively high particle concentration and in this respect, did not resemble a typical pyroclastic surge. 相似文献
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灰色系统理论在二连洪浩尔舒特凹陷储层评价中的应用 总被引:2,自引:0,他引:2
本文利用测井资料,依据测井地质评价油气储层的分析准则,提出灰色理论精细评价油气储层的处理方法和解释系统。通过二连洪浩尔舒特凹陷储层的精细评价和综合解释,取得了明显的效果。文中介绍了这一分析方法处理过程及实用效果。 相似文献
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