Identification of Hercynian shoshonitic intrusive rocks in central Hainan Island and its geotectonic implications

Hercynian (Variscan) orogenic belts, including the European-NW African orogen, the Appalachian orogen of North America and the central Asia-Mongolia- Hinggan orogen, etc., are widely distributed in the world. Their extensions are often several thousand ki…     

科技期刊亮点

胸腔接种间充质干细胞为胸膜疾病治疗提供新的方法复旦大学附属华东医院瞿介明、秦朝辉等在《中国药理学报》2011年第5期上提出了一种间充质干细胞(MSCs)移植的新途径——经胸腔接种。该途径的建立为MSCs用于胸膜疾病治疗提供了新的方法。同时,以胸腔接种为模型,将有利于探讨MSCs基本生物学特性及其在体内与机体细胞间的相互作用。     

地幔柱学说的发展

随着板块构造的发展和成熟,人们对地球表层的认识已经逐渐清晰起来,地球深层的动力机制还在进一步的认识中,地幔柱是个很值得研究的理论,从热点学说到地幔柱再到超级地幔柱和地幔柱构造,尽管地幔柱在解释地球现象的时候还有很多不尽人意的地方．更需要我们积极的去怀疑或者证实。峨眉山玄武岩被认为是地幔柱头的结果,它的喷发持续时间,物质来源,和古地磁的关系,和生物灭绝的关系以及潘基亚大陆的演化还在进一步的研究中。     

Mantle olivine xenocrysts entrained in Mesozoic basalts from the North China craton：Implication for replacement process of lithospheric mantle

Mesozoic (125 Ma) Fangcheng basalts fromShandong Province contain clearly zoned olivines that arerare in terrestrial samples and provide first evidence for thereplacement of lithospheric mantle from high-Mg peridotitesto Iow-Mg peridotites through peridotite-melt reaction.Zoned olivines have compositions in the core (Mg# = 87.2--90.7) similar to those olivines from the mantle peridotiticxenoliths entrained in Cenozoic basalts from the NorthChina craton and in the rim (Mg# = 76.8--83.9) close to oli-vine phenocrysts of the host basalts (75.7--79.0). Thesecompositional features as well as rounded crystal shapes andsmaller grain sizes (300—800 μm) demonstrate that thesezoned olivines are mantle xenocrysts, i.e. disaggregates ofmantle peridotites. Their core compositions can representthose of olivines of mantle peridotites. The zoned texture ofolivines was formed through rapid reaction between the oli-vine xenocryst and the host basalt. This olivine-basaltic meltreaction could have been ubiquitous in the Mesozoic litho-spheric mantle beneath the North China craton, i.e. an im-portant type of the replacement of lithospheric mantle. Thereaction resulted in the transformation of the Paleozoic re-fractory (high-Mg) peridotites to the late Mesozoic fertile(Iow-Mg) and radiogenic isotope-enriched peridotites, lead-ing to the loss of old lithospheric mantle.     

辽河裂谷玄武岩成因机理与盆地演化

认为辽河裂谷第三系玄武岩由两类原生玄武岩浆喷发形成，一是形成于地下７０～８５ｋｍ的碱性橄榄玄武岩浆，二是形成于地下３５～５０ｋｍ的拉斑玄武岩浆。两者分别为源区岩石局部熔融３．８８％和１０．１１％的产物。下辽河平原处于中国北方大陆地幔热柱、亚热柱之上。随着热柱的形成、拱起和岩石圈的飘移，火山活动由强而弱，由碱性趋向亚碱性，岩浆熔出位置由深而浅，源区岩石熔融程度由低而高。与此相应，下辽河裂谷盆地经历了裂前成穹、张裂破碎、拉张沉陷及拗陷４个阶段，裂谷由张裂而拗陷，直至消亡。     

关于（MgFe）2SiO4物性参数计算公式的讨论

(MgFe)_2SiO_4是上地幔介质的主要成分,计算其物性参数有助于了解地球内部的物理状态和物理过程,是地学的基础性研究工作。Goto等曾给出(MgFe)_2SiO_4的物性参数,但其所用公式尚需作适当修正。本文在对Birch状态方程作进一步讨论的基础上,修正了Goto等的公式,并重新计算了(MgFe)_2SiO_4的密度、热膨胀系数和定压比热,在综述目前工作的基础上给出了热传导系数的计算结果。     

The low-velocity layer at the depth of 620 km beneath Northeast China

Based on the 3-D Earth model, the common convert points-phase weighted stacks （CCP-PWS） migration method is used to image the upper mantle discontinuities beneath Northeast China （longitude 120°―132°; latitude 38°―40°） with 802 observed receiver functions. Teleseismic records are obtained from 4 stations belonging to CCDSN and 19 stations belonging to PASSCAL. A low-velocity layer has been detected at the depth of 620 km. This low-velocity layer rises to 600 km in the east of the study region close to the subducted slab. We consider that this low-velocity layer might be the accumulated oceanic crustal material delaminated from the western Pacific subducted slab. Additionally, we detect the obvious depression of 660 km discontinuity which was attributed to the interaction between the upper mantle and subducted slab. The maximum depth of 660 km discontinuity approaches 700 km, and 660 km discontinuity splits into multiple discontinuities in the northeast of the study region.     

贵州泥堡金矿床成矿地质条件研究

泥堡金矿是黔西南卡林型金矿矿集区的重要组成部分,但在赋矿岩石、含金建造和岩相古地理位置方面,泥堡金矿具有显著的特殊性。本文通过对贵州泥堡金矿床成矿地质条件的研究,分析认为峨眉山地幔热柱的活动为泥堡金矿的形成提供了物质来源和热能来源,为含矿热液的形成和活动创造了前提条件,燕山期大规模的构造造山运动最终决定了泥堡金矿的定位和形成。     

中条山西南地区基性岩墙群的地球化学特征及其地质意义

根据岩石学和地球化学组成分析, 分3组讨论了中条山西南地区辉绿岩岩墙群的成因。结果表明: 它们都是富集地幔源区源岩部分熔融的产物。第1组岩墙是初始岩浆经历少量的铁镁质矿物分离结晶作用的产物; 第2组和第3组岩墙是玄武质岩浆又经历壳幔岩浆混合和斜长石、钛磁铁矿等分离结晶作用的产物; 第3组岩墙可能受地壳混染和后期热液蚀变的影响较大。它们都形成于板内伸展环境, 可能与熊耳?中条拗拉谷的发育有关。