～4.1 Ga xenocrystal zircon from Ordovician volcanic rocks in western part of North Qinling Orogenic Belt

High-precision U-Pb dating by in situ LA-ICP-MS yields an age of 4079±5 Ma for a xenocrystal zircon from Ordovician volcanics of the Caotangou Group in western part of the North Qinling Orogenic Belt. As a result, the North Qinling Orogenic Belt becomes one of a few localities in the world that contain Hadean age records (4276±6 Ma and 4404±8 Ma detrital zircons from Jack Hill of the Yilgarn craton, 4016 Ma Acasta gneisses of the Wopmay Orogeny and Burang quartzite with detrital zircon of 4103 Ma in Tibet). It is also the first report of the Hadean age in Phanerozoic volcanics. The finding of the 4.1 Ga xenocrystal zircon provides not only the geochronological record of the oldest crustal materials in China, but also the condition for further search for rocks forming in the region during the early time of the Earth’s evolution. Thirty-six zircon U-Pb dates from the Ordovician volcanic rocks are subgrouped into seven generations that represent different tectono-magmatic events in the North Qinling Orogenic Belt. Among them, two periods of 0.9-1.5 Ga and 0.4-0.5 Ga are consistent with Mesoproterozoic and Early Paleozoic orogenies, respectively.     

喀斯特洞穴叠层石及其沉积模式

在研究喀斯特洞穴有光及黑暗环境中的洞穴叠层及其沉积作用的基础上,总结出喀斯特洞穴叠层石的沉积模式,进一步确定了喀斯特洞穴石灰华沉积物的生物成因观点。     

Discovery of ∼4.0 Ga detrital zircons in the Changdu Block,North Qiangtang,Tibetan Plateau

Using in situ zircon dating by LA-ICP-MS and MC-ICP-MS, detrital zircon of 3981±9 Ma age was found in metamorphic rocks of the Ningduo Rock Group, Changdu Block of Northern Qiangtang. This is the oldest age record that has been found in the Qiangtang area. This finding also constitutes the third zircon locality in China with an age older than 3.9 Ga. Thus, the discovery provides new information for the study of Hadean crust. In addition, we found 3.51–3.13 Ga, ∼2440 Ma, ∼1532 Ma, ∼982 Ma and ∼618 Ma age peaks from 100 test spots. The younger ages of ∼982 Ma and ∼618 Ma correspond to the formation of the Rodinian super-continent and the Pan-African event, respectively. These findings suggest a close relationship between these zircons and the Gondwanan super-continent. The age of ∼618 Ma defines the lower limit on the deposit time of the protolith for the garnet-mica-quartz schist in the Ningduo Rock Group. Zircons with an age of ∼982 Ma generally display a negative ɛ_Hf(t) and a two-stage Hf model with concentrated ages around 1933–2553 Ma. This pattern indicates that the source area of the Ningduo Rock Group underwent a significant separation of depleted mantle into the crust during the Paleoproterozoic Era. However, zircons with ages of 2854–3505 Ma also show a negative ɛ_Hf(t) and a two-stage Hf model with a concentration of ages around 3784–4316 Ma. These results demonstrate that the source area of the Ningduo Rock Group contains a residual amount of ancient (Hadean) crustal materials. This paper provides new information on the relationship between the basement of the Qiangtang area and the Paleoproterozoic basements of the Gangdese and Himalayan regions, which constrains the northern boundary of Gondwana.     

青藏高原当雄错晚更新世末期-全新世早期叠层石新发现

 在青藏高原首次发现当雄错第四纪晚期叠层石群,其发现对于阐明高原第四纪晚期古环境演化有重要意义。通过对当雄错第四纪晚期发育的3层叠层石的地球化学特征以及14C年龄研究发现：叠层石发育最佳温度20~30℃,当温度低于12~15℃时,蓝藻停止生长。目前,当雄错湖水年均温度为4.8℃,可知当时水温高于现代10℃;这3层叠层石的¹⁴C年龄分别与同布林（Bölling）和阿路罗德（Allevöd）两次暖期事件,及10.5 ka~9 kaBP全新世早期转暖期一致,并且叠层石中δ¹⁸O均值在-7.23~-6.6之间,δ¹³C均值在4.75~5.65之间,两者均较高,可知当雄错当时气温较高。该时段3个暖期的发现,对详细建立划分青藏高原第四纪晚期气候-年代学标尺有重要价值。     

～4.1 Ga xenocrystal zircon from Ordovician volcanic rocks in western part of North Qinlin80rosenic Belt

High-precision U-Pb dating by in situ LA-ICP-MS yields an age of 4079±5 Ma for a xenocrystal zircon from Ordovician volcanics of the Caotangou Group in western part of the North Qinling Orogenic Belt. As a result, the North Qinling Orogenic Belt becomes one of a few localities in the world that contain Hadean age records （4276±6 Ma and 4404±8 Ma detrital zircons from Jack Hill of the Yilgarn craton, 4016 Ma Acasta gneisses of the Wopmay Orogeny and Burang quartzite with detrital zircon of 4103 Ma in Tibet）. It is also the first report of the Hadean age in Phanerozoic volcanics. The finding of the 4.1 Ga xenocrystal zircon provides not only the geochronological record of the oldest crustal materials in China, but also the condition for further search for rocks forming in the region during the early time of the Earth＇s evolution. Thirty-six zircon U-Pb dates from the Ordovician volcanic rocks are subgrouped into seven generations that represent different tectono-magmatic events in the North Qinling Orogenic Belt. Among them, two periods of 0.9--1.5 Ga and 0.4--0.5 Ga are consistent with Mesoproterozoic and Early Paleozoic orogenies, respectively.     

鄂东X区8#煤层构造演化及控藏作用分析

鄂尔多斯盆地东部X区本溪组煤层气区域性富集,生产资料显示其成因与构造有一定关联,但其缺乏明确的富集规律与地质理论。鉴于此,分析X区煤层构造演化历程,对比井上热演化史及生烃史分析成果,以期明确构造演化对深部煤层气富集的控制作用。结果表明:（1）本溪组煤层生烃主要发生在晚二叠-早三叠世与晚侏罗-早白垩世两个阶段,其中晚侏罗-早白垩世大量生烃。两次生烃期煤层顶部古构造对于煤层气的富集、高产均具有一定的控制作用,且第二次生烃期古构造控藏作用明显,煤层气主要在煤层顶部古构造低洼处富集、高产;（2）工区受多期构造运动影响,8#煤层气主要富集在煤层顶部现今构造缓坡段,陡坡段极少或者不富藏,且煤层顶部现今构造高度相对越低,产气量表现为上升趋势;（3）综合构造演化史认为深部煤层气的富集、高产主要受第二次生烃期古构造洼地和后期抬升作用控制。研究结果为古构造源内控藏理论及深层煤层气富集、高产成因提供了一定的地质理论依据。     

西北地区构造活动对煤层气成藏的控制作用

从西北地区构造背景、构造演化及构造类型等几方面探讨了构造作用对煤层气的控制。构造作用直接或间接控制着从含煤地层形成至煤层气生成聚集全过程,是煤层气控制地质因素中最重要的因素。聚煤期构造控制煤系地层和煤层发育特征。聚煤期后构造控制着生、储、盖层性能及组合,并影响煤层气运、聚、保特征,从而影响煤层气勘探开发潜力。     

冀东南堡凹陷高尚堡潜山深层花岗质基岩的特征及成因

通过对高参１井岩石化学、地球化学（含微量元素地球化学）及年代学的研究,确定本区花岗质基岩及其包体形成于地壳深部,并被上部地壳同化混杂。其原岩形成年代为２８．９Ｍａ,花岗质岩石为２５～２４Ｍａ;在２２～２０Ｍａ,１７～１５Ｍａ,１０～９Ｍａ间,由于受华北造台运动影响,本区花岗质岩石中发生过几次构造—热事件并遭受过强烈改造。     

不良学风的成因分析及其基本对策的探讨

在对目前高校大学生学风状况调查的基础上,指出了存在的不良学风现象,并从社会、学校、家庭及个人的角度分析了产生这些现象的原因,对当前不良学风的基本对策作了进一步的探讨．     

太古宙的生命起源信息及研究评述

太古宙生命起源研究是地学领域争议激烈的热点研究方向，已报道发现太古宙生命遗迹的地区集中在格陵兰岛istu绿岩带，澳大利亚西部Pilbara克拉通和南非Kaapvaal克拉通等三处。判别太古宙岩石中关于生命存在指示信息的可靠性是探讨生命起源的首要内容，当前微组构分析技术、生物标志物测试以及古生物学形态类比法的融合大大推动了对太古宙生命鉴别研究的深度，但现有认识或推论均带有不同程度的间接性和不确定性，如δ^13C指标的有效性、形态类比法的局限性、化石的微构造等诸多科学问题依然存在争论。今后多学科思想和技术的交叉融合是研究太古宙生命起源领域的发展趋势，在研究对象上要重视对化石母岩的深入研究。     

采用空气阻力修正的火箭残骸落点算法

针对火箭分离后残骸落点计算问题,分析了火箭残骸在下落过程中的动力学特性,重点就空气阻力对残骸落点产生的影响进行研究,提出了带空气阻力修正的火箭残骸落点算法。与传统落点计算方法不同之处在于,该算法充分考虑落点地区的大气分层空气密度的影响,并根据下落过程空气动力学方程,估计空气阻力因子,采用积分法计算残骸在空中的运动轨迹并得到最终的落点数据。最后计算分析了4次卫星发射任务（对应4种火箭型号）一级残骸的落点,对算法的有效性进行了验证。     

全球麻粒岩相地体与大陆下地壳成分模型

在出露地表的中、高压相麻粒岩地体代表下陆壳的认识基础上,建成全球麻粒岩相地体地球化学成分数据库（共１６８５套分析数据）。利用ＩＢＭ４３８１大型计算机对全部数据进行了多元变量统计分析,成功地建立了迄今为止精度最高的太古代、后太古代和全球大陆下地壳化学成分模型。     

阿中地块南缘晚元古代火山岩地质特征及构造环境分析

阿中地块南缘晚元古代索尔库里群基性火山岩与滨浅海相细粒陆源碎屑岩、成熟度较高的石英砾岩和碳酸盐岩共生,这套火山-沉积岩发生浅变质强变形作用改造,其形成于大陆裂谷构造环境,基性火山岩为大陆裂谷拉斑玄武岩,火山岩-火山碎屑岩上覆岩系--碳酸盐岩中含大量小型叠层石,通过区域对比证明该套地层时代为晚元古代青白口纪,其沉积建造、岩相古地理环境与塔里木北缘库鲁克塔格地区同时代地层特征相似,说明青白口纪时南、北塔里木就有了统一的盖层.     

卸压瓦斯抽取及煤与瓦斯共采技术研究

强调指出瓦斯不只是煤矿的一大危害 ,而且它还是一种宝贵的清洁能源。提出了基于采动影响下煤层瓦斯产生“卸压增流效应”的煤与瓦斯共采的理论认识 ,并依此提出了几种井下抽取卸压瓦斯的方法 ,最后分析了煤与瓦斯共采产生的社会经济效益     

大学文化氛围的内涵、作用及其建设

大学的文化氛围指的是校园内的环境、气氛、传统、人际关系乃至一草一木间的一种意识层面的东西及其物化形态,它对师生员工的成长发展具有教育、引导、陶冶、凝聚与约束的功能。大学文化氛围的营造应从良好的精神文化氛围与制度行为文化氛围、物质文化氛围几方面着手。     

Methane seeps, methane hydrate destabilization, and the late Neoproterozoic postglacial cap carbonates

Natural gas (methane) hydrates, the crystalline solids composed mainly of methane and water, are present in marine sediments of the continental margins and polar permafrost under a delicate balance of temperature (< 7℃) and hydrostatic pressure (> 50×10…