山东块断构造特征与地震带的初步划分

前言地质与地球物理调查研究的深入开展表明地球的岩石圈具有明显的板块构造特征,大陆可随板块运动破裂而漂移,又可随漂移而并合。这一假说推动了人们对大陆地质历史时期的地台和地槽发展的深入理解。     

全球气候的演化和成因

地球气候历史的特征具有多变性。地球上冰川作用的时期是发生在温暖时期之后的.而寒冷和温暖时期的延续时间相差极大。关于这种变化的发生和某些周期性的产生巳知有几种原因,其它的分布是任意的,甚至在时间上是特殊的事件。本文试图根据可用资料阐述过去的气候,现代全球的平均温度,同时总结这种趋势的已知原因。     

地球物质演变的能源问题

地球发展历史是地球物质运动的过程。核转变更新着地球的化学元素与同位素组成;它影响着地球发展过程中各特殊矛盾的发展与转化。地球的能源有外来能与内生能,这两种近于相互独立而又统一的能源体系组成了地球的演化能源。我们研究和计算了各种外来能与内生能的产生方式、能量大小及对地球演化的影响,而地球演化的主要内能源是核转变能。天然核转变有两种,一种是在地球发展过程中自发产生的(核衰变、自发裂变等),一种是受外因条件所激发而产生的(诱发裂变,核反应等)。     

人类从哪里来？——（4）人类演化与古地理、古环境和古气候变化

详细介绍了8 Ma以来全球气候变化的规律,研究表明地球上主要发生过3次冷气候事件：第一次冷气候事件大约发生在距今7 Ma,一股强烈的干冷气流刮过欧洲大陆,穿越赤道地区直达非洲大陆,使得原始森林开始萎缩,面积的缩小导致古猿与人类发生演化分异;第二次冷气候事件大约发生在距今4.2 Ma,那时干冷气候持续发展,非洲大陆的原始森林进一步萎缩,并逐渐演化为稀树草原,出现了南方猿人和傍人;第三次冷气候事件大约发生在距今2.3 Ma,全球气候变化波动较大,冷-暖气候交替发育,地球上出现了真正意义上的人（人属）,并逐渐演化成现代人。根据目前的研究,人类的起源和演化与古地理、古环境和古气候变化密切相关,人类演化历史大致可分为7个时期：撒海尔猿人—原初猿人时期、地居猿人时期、南方猿人—傍人时期、能人—鲁道夫人时期、匠人—直立人时期、先驱人—海德堡人时期和智人时期。     

深时古气候对未来气候变化的启示

当前人类活动引起大气中二氧化碳(CO_2)的浓度逐渐升高,地球气候可能将发生不可逆的变化,从目前的冰室气候进入温室气候状态。文中通过对现在地球气候系统与深时温室气候时期的大气CO_2浓度与气候变化临界点、温度与温度梯度、海平面变化与水循环、大洋水体氧化还原状态几个方面进行对比和分析,提出对地球在这种温室气候状态中的气候动力系统的认识亟待提高。尽管深时温室气候并不严格等同于未来地球的气候,但深时时期形成的地质记录为我们提供了全尺度洞察在温室气候状态下地球系统是如何运行的一个天然实验室。     

河北夏家沟震旦纪页岩中可提取有机质的研究

前寒武纪占了地球地质历史的八分之七,其地层中有机质的研究,是一个十分重要的领域。它主要包括两个方面的意义:一方面在于追踪地球早期历史的生物演化,企图为了解地球上生命起源和早期生命的特点提供信息;另外在于对前寒武纪、特别是晚前寒武纪地层中石油的兴趣。六十年代,G. Eglinton和M. Calvin提出了“化学化石”的概念。“化学化石”也叫做分子化石或“地球化学化石”。     

东营凹陷沙四下亚段沉积环境特征及沉积充填模式

沉积盆地中沉积环境特征控制了砂体沉积成因类型及盆地沉积充填模式。通过对东营凹陷丰深2井、官112井及梁120井沙四下亚段泥质沉积物系统取样,进行全岩X衍射分析和常量及微量地球化学元素分析,在此基础上对东营凹陷沙四下亚段古气候和古盐度指标进行分析。结果表明,古气候指标Rb/Sr比值与石英+长石含量、Cr元素含量及P元素含量呈正比,含量增加反映了气候相对潮湿,与古盐度指标碳酸盐+硫酸盐含量呈反比,其含量增加反映了气候相对干旱。东营凹陷沙四下亚段沉积时期气候干湿交替频繁,气候潮湿时期相对湖平面上升,湖水盐度降低;气候干旱时期相对湖平面下降,湖水盐度升高,使得此时期湖泊呈现为高频振荡性盐湖特征。气候潮湿时期以沉积碎屑沉积物为主,包括冲积扇、浅水型三角洲、滨湖滩坝及近岸水下扇沉积,由于湖水盐度较低,洼陷带主要沉积泥岩、灰质泥岩、含膏泥岩和少量泥质膏岩;气候干旱时期相对湖平面下降,湖泊水体盐度升高,洼陷带以沉积膏盐岩为特征,垂向上具有含膏泥岩、泥质膏岩、膏岩和盐岩的演化序列,平面上表现为由湖泊边缘向湖泊中心发育灰质泥岩、含膏泥岩、泥质膏岩、膏岩和盐岩的环带状结构特征。     

走进神农架,探寻远古冰川的奥秘

正全球变暖等气候问题日益引起世界的关注和重视,在地质历史过程中,也发生过极端的气候现象。现代冰川作为寒冷气候的产物分布于极地或高海拔地区,在地质历史时期,地球曾多次被冰雪覆盖,陆地、海洋到处分布有巨厚的冰川。据地质学家研究,在距今654-635百万年之间[1-2]的新元古代成冰纪,发生了极端的冰川事件,地球被冰雪完全覆盖,就连赤道地区都不能幸免,这被称之为"雪球地球"[2-3]。在这次极端寒冷事件期间,地表温度降     

乌尔禾-风城地区二叠系白云质岩类岩石学特征及成因分析

为了探讨准噶尔盆地西北缘乌尔禾-风城地区二叠系风城组白云质岩类的成因, 利用岩矿鉴定技术,地球化学分析技术等手段, 系统分析该套云质岩类的地球化学特征。研究表明,该区云质岩类有别于海相碳酸盐岩,受外物源的影响较大,成份复杂,多为过渡性岩类。以泥质白云岩和白云质泥岩和白云质粉砂岩为主,含有少量的凝灰质白云岩和白云质凝灰岩。岩石矿物学特征和地球化学分析数据均表明,研究区的云质岩类主要形成于水体安静、深度较大、盐度偏高的半封闭陆源近海湖湾环境。二叠系时期气候炎热,蒸发作用强烈与火山活动频繁,加之淡水补给相对匮乏,为该区的云质岩类形成提供了良好的镁离子来源和水动力条件。这时湖湾中沉积的富含文石或高镁方解石的泥岩或凝灰岩,在早成岩阶段经过渗透回流白云石化作用形成了大量泥质白云岩、白云质泥岩和白云质粉砂岩。在中晚成岩阶段,经过埋藏作用生成自形或半自形的细晶-中晶白云石。     

地震地质的一般知识

地震现象地震俗说地动,就是我们居住的地方忽然摇晃起来了。它与日蚀、月蚀、台风、暴雨、洪水、冰雹、寒流、霜冻……等一样,是一种经常发生的自然现象。地球上每年约发生地震五百万次,其中大部分是轻微震动,人感觉不出来,用仪器才能记录到。从历史记载看,人能感觉到的有五万次左右,破坏性大地震全世界每年只有十几次,而且大部分发生在大洋里或人烟稀少的山区,发生在陆地上人口稠密的地方就更少。     

黔中红粘土的物质来源与成因研究——以平坝剖面为例

以黔中平坝剖面为具体对象,从矿物、元素地球化学、元素质量平衡等多方面对黔中白云岩上覆红粘土剖面进行了详细研究。结果显示该剖面是下伏基岩白云岩风化成土并累积的结果,无其他外来物源,是原位风化壳;成土过程具有两阶段模式特征,即白云石、方解石的溶蚀-酸不溶物累积和酸不溶物进一步风化两个阶段;长时期的构造稳定和白云岩整体溶蚀作用是黔中地区白云岩风化壳土层厚度大、分布连续的主要制约因素。     

热带地区碳酸盐岩上覆红色风化壳的成因机理及元素演化

开展热带岩溶地区红色风化壳元素地球化学演化规律研究,有助于丰富碳酸盐岩风化成土理论的认识。在越南北部选取典型的碳酸盐岩风化剖面,分析热带气候条件下碳酸盐岩上覆红色风化壳中主量元素的物质来源和演化特征。结果表明:无论Ti/Zr的元素比值分析,Hf-Zr、Nb-Ta及Sm-Nd的元素对协变分析,还是上地壳元素平均值(UCC)标准化分析,两个剖面的上覆风化壳均显示原地残积的特征,即两个剖面是碳酸盐岩的原位风化产物。碳酸盐岩风化成土过程中,CaO、MgO淋失明显,Al_2O_3和Fe_2O_3发生富集,显示两个剖面均经历较强的风化过程,但是白云岩和灰岩剖面有一定的分异特征。越南北部白云岩风化剖面从基岩到上部土层显示出稳定的Ti-Fe元素共富集特征,而灰岩剖面中Fe的增长速率明显超过Ti。白云岩上覆风化壳经历了强烈的风化作用,其脱硅作用弱于灰岩风化剖面,而富集铝的作用强于灰岩。迁移系数的演化规律说明两个剖面中长石成分(钾长石、钠长石等)或次生矿物(伊利石等)在风化成土过程中逐渐分解,同时Al、Fe、Si等稳定元素的在风化剖面中不断富集。     

广西桂林石灰土元素迁移特征及影响因素——以会仙峰丛谷地石灰土为例

碳酸盐岩的化学风化是岩溶关键带各圈层相互作用的主要形式,风化壳中蕴含重要气候环境和物质循环信息。通过对广西桂林会仙峰丛谷地石灰土的化学风化强度及元素迁移特征的研究,并与滇黔湘和青藏高原的岩溶风化壳的对比分析,结果表明:（1）会仙石灰土化学蚀变指数（CIA）均值为92.14,与贵州兴义岩溶风化壳相当,反映炎热潮湿气候下的强烈化学风化;白云岩风化壳CIA与灰岩风化壳相当,CIA值主要受“不溶物”含量的影响;地形上,从上坡到下坡,从坡地到谷地,垂向剖面从浅部到深部,碳酸盐岩风化壳的CIA值呈减小趋势;（2）包括会仙石灰土在内的中国南方碳酸盐岩风化壳的CIA值与纬度成负相关,青藏高原地区和北方地区碳酸盐岩风化壳的CIA值与纬度不存在相关性,可能受晚第三纪以来印度板块俯冲推挤,青藏高原地区构造抬升和夷平面变形的影响;（3）与硅酸盐风化壳、黄土剖面不同,碳酸盐岩风化壳CIA和Na/K（摩尔比值）不存在相关性,但CIA和K/Al（摩尔比值）则存在显著负相关,可采用K/Al来表征碳酸盐岩剖面的风化程度,其主要是受可溶成分的快速淋失影响;会仙石灰土、贵州兴义风化壳较其他风化壳更接近Al端,化学风化程度更高;（4）会仙石灰土的化学成分与中国其他地区碳酸盐岩风化壳基本一致,剖面上分布均匀;与上陆壳相比,Na、K、Ca、Mg表现为亏损,其他元素为富集;和下伏碳酸盐岩的稳定元素Ti相比,除了Cr、Fe、P、Al富集或不变外,其他元素都发生明显的迁移淋失;会仙风化壳元素的迁移性由强到弱为:Ca ? Mg ? B ? Na ? N ? Cd ? Zn ? As ? K ? Pb ? Si ? Mn ? Al ? Cr ? Fe ? P,高含量Ca、Mg的快速溶失对其他元素的迁移性有重要影响。      

黔西北地区二叠纪玄武岩古风化壳常量元素的地球化学特征

通过对峨眉山玄武岩古风化壳进行野外调查、取样和分析测试工作,认为: ①贵州西部广泛出露峨眉山玄武岩,晚二叠世古气候温润潮湿,利于峨眉山玄武岩风化形成含Fe、Ti的黏土矿物和铝质黏土矿物的古风化壳,该风化壳受古地理环境和峨眉山玄武岩控制。②相对玄武岩而言,铝质黏土岩主量元素含量特征表现为富TiO₂、Al₂O₃,轻度亏损SiO₂,明显亏损TFe,其他主量元素大量流失; 铁质黏土岩主量元素含量特征表现为富TFe、TiO₂, 轻度富Al₂O₃,但相对于铝质黏土岩,TiO₂的富集程度偏低,SiO₂亏损明显,其他元素亦大量流失。③由于晚二叠世频繁的海侵作用,水位较高的区域,风化壳下部处于较还原的条件下,Fe被还原成易溶的二价状态或在有机质的作用下迁出风化壳,而Ti由于存在形式较为稳定,继续保存在黏土矿物中,与Fe发生分异; 局部水位较浅的氧化环境及重力分异作用下,黏土矿物与铁矿物由于比重差异而分选开来,形成Fe与Al、Ti的分异,并伴随铁矿、钛矿和铝土矿的富集。该富集规律的发现对寻找该区铁、钛和铝土矿有一定的理论指导意义。     

喜马拉雅和冈底斯弧形山系中的岩浆岩带及其成因模式

国内外广泛地认为,处于喜马拉雅和冈底斯弧形山系之间的雅鲁藏布江-噶尔河谷地是一条印度板块和欧亚板块之间的缝合线带。由于印度板块自中生代以来的向北漂移,及其与欧亚板块的接近和相互之间的碰撞,先后造成了冈底斯和喜马拉雅弧形山系。     

白云岩风化剖面元素地球化学特征:对黔中九架炉组“三稀金属”富集机制的启示

黔中早石炭世九架炉组铝土矿含矿岩系富集Ti、Li、Sc、V、Ga、Nb、Ta、Zr、Hf、Th和稀土(REEs)等"三稀金属",具有成为独立矿床或伴生资源的潜力。这些元素大部分与九架炉组共有同一母岩,且富集程度受母岩的成分和风化作用控制。本研究选取九架炉组母岩乌当娄山关群白云岩和纳雍牛蹄塘组泥质白云岩的现代风化剖面为研究对象,研究元素在风化作用过程中的迁移特征及分布规律,进而为九架炉组微量元素的富集机制提供启示。研究获得以下认识:1)依据剖面结构、ZrHf、Nb-Ta、Y-Ho二元图特征及REE配分曲线和Eu/Eu*值的相似性表明研究区土层主要来源于基底或母岩的风化; 2)白云岩风化成土过程中Si、Fe、Cr、As、Sb、Ti、Nb、Ta、Zr、Hf、Th、REEs等元素化学性质相对稳定,富集程度较高,而Ca、Mg、Na、K、Sr、P、Mo、Cd等元素化学性质活泼,容易淋失亏损; 3)纳雍剖面REEs~(3+)和Ca~(2+)半径差与REEs富集系数相关性良好,表明碳酸盐岩风化过程中,含钙矿物磷灰石是稀土元素分配的重要控制因素; 4)九架炉组的母岩也是Ti、Li、Sc、V、Ga、Nb、Ta、Zr、Hf、Th等微量元素的主要物质来源,母岩风化过程中,这些微量元素首先在副矿物、黏土矿物、铝矿物及磷灰石等矿物相中初步富集,之后随风化碎屑物一起沉积形成微量元素超常富集地层; 5)纳雍剖面地表和地下水提供了部分P、Be、Zn、Sb、Pb、Y及REEs来源,指示水体迁入作用也是九架炉组REEs富集的重要原因。研究表明黔中九架炉组微量元素的来源较复杂,风化-沉积过程中,化学性质稳定的元素残留在风化碎屑物中并被搬运-沉积在负地形中,而化学性质活泼的元素首先被带入水体,在沉积-成岩过程中特定条件下发生二次富集作用(例如次生矿物的形成及吸附)形成微量元素富集的地层。     

Geochemistry of approximately 1.9 Ga sedimentary rocks from northeastern Labrador, Canada

Fifty-eight rock chips from fifteen samples of sedimentary rocks from the Ramah Group (approximately 1.9 Ga) in northeastern Labrador, Canada, were analyzed for major and minor elements, including C and S, to elucidate weathering processes on the Earth's surface about 1.9 Ga ago. The samples come from the Rowsell Harbour, Reddick Bight, and Nullataktok Formations. Two rock series, graywackes-gray shales of the Rowsell Harbour, Reddick Bight and Nullataktok Formations, and black shales of the Nullataktok Formation, are distinguishable on the basis of lithology, mineralogy, and major and trace element chemistry. The black shales show lower concentrations than the graywackes-gray shales in TiO2 (0.3-0.7 wt% vs. 0.7-1.8 wt%), Al2O3 (9.5-20.1 wt% vs. 13.0-25.0 wt%), and sigma Fe (<1 wt% vs. 3.8-13.9 wt% as FeO). Contents of Zr, Th, U, Nb, Ce, Y, Rb, Y, Co, and Ni are also lower in the black shales. The source rocks for the Ramah Group sediments were probably Archean gneisses with compositions similar to those in Labrador and western Greenland. The major element chemistry of source rocks for the Ramah Group sedimentary rocks was estimated from the Al2O3/TiO2 ratios of the sedimentary rocks and the relationship between the major element contents (e.g., SiO2 wt%) and Al2O3/TiO2 ratios of the Archean gneisses. This approach is justified, because the Al/Ti ratios of shales generally retain their source rock values; however, the Zr/Al, Zr/Ti, and Cr/Ni ratios fractionate during the transport of sediments. The measured SiO2 contents of shales in the Ramah Group are generally higher than the estimated SiO2 contents of source rocks by approximately 5 wt%. This correction may also have to be applied when estimating average crustal compositions from shales. Two provenances were recognized for the Ramah Group sediments. Provenance I was comprised mostly of rocks of bimodal compositions, one with SiO2 contents approximately 45 wt% and the other approximately 65 wt%, and was the source for most sedimentary rocks of the Ramah Group, except for black shales of the Nullataktok Formation. The black shales were apparently derived from Provenance II that was comprised mostly of felsic rocks with SiO2 contents approximately 65 wt%. Comparing the compositions of the Ramah Group sedimentary rocks and their source rocks, we have recognized that several major elements, especially Ca and Mg, were lost almost entirely from the source rocks during weathering and sedimentation. Sodium and potassium were also leached almost entirely during the weathering of the source rocks. However, significant amounts of Na were added to the black shales and K to all the rock types during diagenesis and/or regional metamorphism. The intensity of weathering of source rocks for the Ramah Group sediments was much higher than that of typical Phanerozoic sediments, possibly because of a higher PCO2 in the Proterozoic atmosphere. Compared to the source rock values, the Fe3+/Ti ratios of many of the graywackes and gray shales of the Ramah Group are higher, the Fe2+/Ti ratios are lower, and the sigma Fe/Ti ratios are the same. Such characteristics of the Fe geochemistry indicate that these sedimentary rocks are comprised of soils formed by weathering of source rocks under an oxygen-rich atmosphere. The atmosphere about 1.9 Ga was, therefore, oxygen rich. Typical black shales of Phanerozoic age exhibit positive correlations between the organic C contents and the concentrations of S, U, and Mo, because these elements are enriched in oxygenated seawater and are removed from seawater by organic matter in sediments. However, such correlations are not found in the Ramah Group sediments. Black shales of the Ramah Group contain 1.7-2.8 wt% organic C, but are extremely depleted in sigma Fe (<1 wt% as FeO), S (<0.3 wt%), U (approximately l ppm), Mo (<5 ppm), Ni (<2 ppm), and Co (approximately 0 ppm). This lack of correlation, however, does not imply that the approximately 1.9 Ga atmosphere-ocean system was anoxic. Depletion of these elements from the Ramah Group sediments may have occurred during diagenesis.     

黔北白云岩红色风化壳元素地球化学特征

选取贵州高原喀斯特地区典型白云岩风化剖面作为研究对象,探讨了红土剖面元素迁移特征及其影响因素,为进一步认识红色风化壳元素地球化学特征提供依据。结果表明:（1）红土剖面中土壤样品（XPS-4~XPS-25）Fe、K、Mn常量元素及Co、Pb、Zn微量元素的分布曲线相对于其他元素靠近 UCC,元素Mg、Ca、Na、Ti和 Li、Cr、Ba、V 的数据点则显著偏离了上部陆壳的平均组成。（2）元素对协变分析得出Ti与Fe、Ba和V的积累特征一致,呈增加趋势;Ti与Mg呈反向变化特征。（3）以Ti为参比元素的剖面迁移特征表明,绝大部分元素的地球化学行为表现为迁移淋失,仅 Fe 、Cr和V 富集。K、Ba总体上呈迁出趋势,个别层段有轻微富集;Na和Co在风化原岩处有一个富集端点。元素在风化过程中的迁移聚集与土壤剖面的pH值和剖面结构变化、粘土矿物和有机质等的吸附有关。      

Major Element, REE, and Other Trace Element Behavior in Amphibolite Weathering under Semiarid Conditions in Southern India

A body of komatiitic amphibolite, an enclave within the Archean high-grade orthogneisses in southern India, shows mild chemical weathering under semiarid conditions. Along fractures, chemical weathering has advanced (Chemical Index of Alteration &sqbl0;CIA&sqbr0;=53; CIA of fresh rock approximately 26) to the extent that secondary Mg-Fe-Al clay minerals have formed and the rock has turned brownish red, soft, and fine grained. The weathering process has resulted in the mobilization and redistribution of the so-called immobile elements Fe, Al, Ti, and REE effected by the nature of secondary mineral formation (talc vs. aluminous clay minerals) and also possibly by soil microbes. In the initial stages of secondary mineral formation, there is a small loss of Fe, Al, and REE (noticeably Eu). However, in the fracture zone as well as in the incipiently altered zone, there is significant REE enrichment, probably affected by a different precipitation mechanism. Mobilized REE may have come from a minor alteration of clinopyroxene.     

Geochemistry and origin of ferruginous nodules in weathered granodioritic gneisses, Mysore Plateau, Southern India

Fe-nodules occur within saprolites formed from weathering of granodioritic gneisses in the rain-shadow region of the Mysore Plateau adjacent to the Sahyadri Mountains in Southern India. These nodules and their host saprolites were studied for their geochemistry, including chemical speciation, to understand nodule formation and chemical redistribution processes during rock weathering. From their mode of occurrence, and mineralogical and geochemical data, we infer that the nodules originated by a two-stage process in which the initial extensive weathering of gneisses likely facilitated subsequent ferrolysis weathering and nodule formation. Nodules originated by precipitation of goethite, hematite and gibbsite along with several amorphous phases within the matrix of weathered gneisses. This is possible only under hydromorphic conditions, suggesting that parts of the plateau must have gone through a humid phase prior to the present aridity. In the saprolites, Al, Fe, and Ti become enriched because of the removal of Si, Ca, Na, and K. However within the nodule, Fe, Ti, Cr, and Ni are deposited after their chemical transport from the saprolite. Titanium, known for its immobile nature, was also mobilized and concentrated under the conditions of nodule formation. The most important elements in the nodule constitution are Fe, Al, Ti, and Mn, each having both crystalline and amorphous phases. Fe-Ti and Mn oxyhydroxides grain coatings in the saprolites and discrete amorphous Mn and Ti phases in the nodules seem to have scavenged trace elements from the weathering profile. REE were mobilized during weathering and nodule genesis in which Ce and Ti show a strong geochemical coherence. The enrichment of only HREE in saprolite, and both HREE and LREE with significant Ce in the nodule, indicate the control of evolving secondary minerals in the REE redistribution during rock weathering. Strong enrichment of Ce in the weathering profile and in nodules has important implications to the REE chemistry of river waters.