Uranium and Thorium Concentration and Isotopic Composition in Five Glass (BHVO‐2G,BCR‐2G,NKT‐1G,T1‐G,ATHO‐G) and Two Powder (BHVO‐2, BCR‐2) Reference Materials

Here we report uranium and thorium isotopic ratios and elemental concentrations measured in solid reference materials from the USGS (BHVO‐2G, BCR‐2G, NKT‐1G), as well as those from the MPI‐DING series (T1‐G, ATHO‐G). Specifically created for microanalysis, these naturally‐sourced glasses were fused from rock powders. They cover a range of compositions, elemental concentrations and expected isotopic ratios. The U‐Th isotopic ratios of two powdered source materials (BCR‐2, BHVO‐2) were also characterised. These new measurements via multi‐collector thermal ionisation mass spectrometry and multi‐collector inductively coupled plasma‐mass spectrometry can now be used to assess the relative performance of techniques and facilitate comparison of U‐Th data amongst laboratories in the geoscience community for in situ and bulk analyses.     

合肥盆地磨墩水库石墨片岩变形变质分析及构造意义探讨

合肥盆地中南部肥西县磨墩水库南岸防虎山组侏罗系砾岩下发育一套石墨片岩系,两者之间呈断层接触.该石墨片岩不同于钻井揭示的合肥盆地石炭纪一二叠纪沉积岩,亦不同于河南固始县杨山煤系.经分析认为该石墨片岩应属于北淮阳佛子岭群岩系,原岩为炭质泥岩或炭质粉砂岩.石墨为有机成因,石墨化程度较低,但变形强烈,部分已糜棱岩—超糜棱岩,反映出俯冲—碰撞带变形变质特征.通过对白云母、石墨XRD衍射和电子探针测试分析,认为石墨片岩为绿片岩相,估算其变质温度为450～ 500℃,压力0.55 ～0.8GPa.根据显微构造特征和变形—变质条件推断,该石墨片岩为扬子板块北缘的沉积盖层(佛子岭群部分),在扬子板块与华北板块碰撞过程中受到强烈挤压,变形—变质成糜棱岩、石墨构造片岩.该变形带暗示了扬子板块向华北板块缝合带的位置,即石墨片岩出露区及其附近,部分被新生代沉积所覆盖.     

阿尔金北缘喀腊大湾地区早古生代中酸性火山熔岩岩石地球化学特征及其构造环境

阿尔金北缘喀腊大湾地区早古生代的中酸性火山岩为一套英安岩—流纹岩—粗面英安岩(少量)组合,在岩石地球化学上高SiO2、富碱(Na2O/K2O =0.4 ～22.2,Na2O+ K2O =2.49％ ～9.74％)、低钛,里特曼指数(δ)为0.20～5.52,铝饱和指数A/CNK为0.8～1.4,指示这是一套低钾—中钾钙碱性—碱性钾玄质(少量)火山岩,自北向南具有从准铝质Ⅰ型向弱过铝质—强过铝质S型花岗质岩浆过渡的特征.LREE、K、Ba、Th(U)、Pb、Zr富集以及Nb(Ta)、P、Ti的亏损指示其形成于与俯冲消减作用有关的活动大陆边缘环境.岩石地球化学研究表明,英安岩和流纹岩不存在分异演化关系,其源岩分别为变质(基性)火山岩和变质泥质岩.结合区域地质特征,认为该套中酸性火山岩形成于活动大陆边缘洋壳俯冲消减后期同碰撞—碰撞后的环境,是俯冲碰撞过程中陆壳巨量增厚,碰撞后伸展阶段中下地壳(或岩石圈)拆沉,幔源岩浆底侵,诱发趋于成熟的大陆边缘弧地壳在不同深度位置上发生部分熔融的产物.这一地质过程是对同一时期阿尔金北缘地区古大洋自北向南俯冲消减到米兰—金雁山地块之下的动力学机制的响应,也为判断阿尔金北缘红柳沟—拉配泉地区蛇绿混杂岩带早古生代的俯冲极性提供了佐证.     

北秦岭瓦穴子—乔端断裂带的构造特征及形成温度—压力条件探讨

瓦乔(瓦穴子—乔端)断裂带是北秦岭尤为重要的断裂带之一,该带经历了长期的变质变形作用,记录了二郎坪弧后盆地向华北板块南缘俯冲消亡的信息。本文运用多种方法,对瓦乔断裂带几何学、运动学及形成温压条件进行研究和探讨,得出以下几点认识:①瓦乔断裂带产状基本倾向NNE,带内线理发育,表现为由N向S逆冲的运动学特征,且存在左旋剪切的分量;②瓦乔断裂带变形岩石显微构造特征明显,反映了挤压应力下塑性流变的特征;③运用角闪石全铝压力计,得到瓦乔断裂带形成压力为0.64GPa。越靠近瓦乔断裂带中心,压力逐渐变大,位于断裂带中心压力达到0.68GPa,已达到中压相系环境;④运用角闪石—斜长石地质温压计算得瓦乔断裂带形成温度范围500～550℃,属中温环境。     

The timing behavior of magnetar Swift J1822.3—1606： timing noise or a decreasing period derivative？

The different timing results of the magnetar Swift J1822.3—1606 are analyzed and understood theoretically.It is noted that different timing solutions are caused not only by timing noise,but also because the period derivative is decreasing after the outburst.Both the decreasing period derivative and the large timing noise may originate from wind braking associated with the magnetar.Future timing of Swift J1822.3—1606 will help clarify whether or not its period derivative is decreasing with time.     

A Method to Calculate Inclination Function with Jacobi Polynomials

In this paper, a method to calculate the inclination function with Jacobi polynomials is studied, the formulation of this method is very simple, it needs not to concern about whether k and l have the same parity, and to calcu- late the non-integral factorials, nor to concern about the conversion between the case of k < 0 and the case of k ≥ 0, and the recurrent formula can be the stan- dard recurrent formula for Jacobi polynomials. In addition, its computational accuracy and applicable order-numbers are equivalent to those of the Gooding method, but its calculating time is shorter than that of the Gooding method for 9%.     

TECTONIC EVOLUTION OF THE YANGTZE PASSIVE MARGIN AND SONGPAN GARZ? FOLD BELT, CHINA

TECTONIC EVOLUTION OF THE YANGTZE PASSIVE MARGIN AND SONGPAN GARZ? FOLD BELT, CHINA     

DISCUSSION ABOUT THE PETROGENESIS OF THE CENOZOIC VOLCANIC ROCKS FROM YUMEN AND HOH XIL AREA, QINGHAI-TIBET PLATEAU

DISCUSSION ABOUT THE PETROGENESIS OF THE CENOZOIC VOLCANIC ROCKS FROM YUMEN AND HOH XIL AREA, QINGHAI-TIBET PLATEAU     

THE PERMIAN SYSTEM OF THE NUJIANG—LANCANGJIANG—JINSHAJIANG AREA, SOUTHWESTERN CHINA

THE PERMIAN SYSTEM OF THE NUJIANG—LANCANGJIANG—JINSHAJIANG AREA, SOUTHWESTERN CHINA     

THE LATE QUATERNARY RIGHT LATERAL STRIKE-SLIPPING OF ZHONGDIAN—DAJU FAULT IN NORTHWEST YUNNAN, CHINA

THE LATE QUATERNARY RIGHT LATERAL STRIKE-SLIPPING OF ZHONGDIAN—DAJU FAULT IN NORTHWEST YUNNAN, CHINAthesubject“TherecentdisplacementandDynamicsoflithosphereintheQinghai XizangPlateau”ofnation alclimbingproject“Therecentdisp