贵州黔西煤田白岩脚矿区煤中硫的分布规律

通过对黔西煤田白岩脚矿区龙潭组主要煤层进行化验分析,认为矿区煤中硫含量从低到高均有分布,垂向上自下而上逐渐降低,平面上9、14及15煤总体呈现东北部高西南部低的趋势,4煤层则表现为西南部相对较高;硫的赋存形态以硫化物硫为主,沉积环境控制了煤中硫的含量及各种形态硫的分布;9、14煤层以硫化物硫为主,脱硫效果良好,15煤层以有机硫为主,脱硫效果一般。建议在矿山开发过程中对低硫煤和高硫煤进行配采。     

Geochemistry and geochronology of the mafic dikes in the Taipusi area,northern margin of North China Craton: Implications for Silurian tectonic evolution of the Central Asian Orogen

The Taipusi area in the Bainaimiao Arc Belt is located in the northern margin of the North China Craton, at the southern margin of the middle Central Asian Orogenic Belt. It is characterized by large exposures of mafic dikes. In this contribution, we present first-hand whole-rock major and trace elements, zircon U–Pb geochronology and in situ trace element geochemistry data for these mafic rocks, which reveal their petrogenesis and tectonic evolution. These mafic dikes display varied compositions of \(\hbox {SiO}_{2}\) (49.42–54.29%), \(\hbox {TiO}_{2}\) (0.63–1.08%), \(\hbox {Al}_{2}\hbox {O}_{3}\) (13.94–17.60%), MgO (4.66–10.51%), \(\hbox {Fe}_{2}\hbox {O}_{3}\) (1.59–3.07%), FeO (4.60–6.90%), CaO (4.57–8.91%), \(\hbox {Na}_{2}\hbox {O}\) (1.61–4.26%), \(\hbox {K}_{2}\hbox {O}\) (0.92–2.54%) and \(\hbox {P}_{2}\hbox {O}_{5}\) (0.11–0.29%). They are mainly of high-K calc-alkaline series with indistinct Eu anomalies, enriched in large ion lithophile elements (e.g., Rb, Ba, K and Sr) but depleted in high field strength elements (e.g., Nb, P and Ti). These suggest that the crystallizing magma was derived from enriched mantle altered by metasomatic fluids in a subduction setting with imprints of active continental margin features. The high concentrations of Hf, U, Th, Pb and Y, pronounced positive Ce but slightly negative Eu anomalies in zircons indicating that the magma underwent a fractional crystallization and crustal contamination process, with medium to high \(f\hbox {O}_{2}\). Zircon LA–ICP–MS U–Pb dating yielded concordant ages of 437–442 Ma for these mafic dikes, which is consistent with the early Paleozoic volcanic arc magmatic activity in the Bainaimiao area. Hence, we conclude that the Bainaimiao Arc Belt is a continental arc formed by the southward subduction of the Paleo-Asian ocean during early Paleozoic.     

波阻抗反演在东胜煤田勘探中的应用

东胜煤田为陆相沉积煤田,具有含煤层数多、厚度不均、层间距不稳定等特点,勘探区内地震反射波追踪对比存在多解性,严重影响了煤层的追踪对比。为破解该难题,对东胜煤田地震勘探资料进行了以模型为基础的多井约束岩性宽带反演,即:利用该勘探区的地震数据资料、对煤层反射波解释层位、断层数据,结合测井数据、岩性柱状数据及其它地质资料,进行多井约束下的二维叠后反演,对所得到的反演数据体再依据反演原理,结合已知测井数据进行地震属性反演,最终得到能够反映岩性变化的波阻抗数据。对波阻抗反演数据进行煤层追踪对比解释,准确圈定出区内煤层的赋存范围,并合理解释了煤层分叉、合并、尖灭及厚度变化等地质现象,取得了较为可靠的地质成果。     

信息整合是地震政务网站建设的基础和关键——中国地震局门户网站建设的几点思考

电子政务是国民经济和社会信息化的重要内容,也是当前和今后一个时期我国信息化工作的重点。本文从信息整合的概念及面临的形势阐述了地震政务网站信息整合分类体系构架和面向公共服务的构成,提出了地震政务网站信息整合的新思路。     

亚洲-大洋州地球科学协会(AOGS)第五届年会在韩国釜山召开

2008年6月16日,亚洲-大洋州地球科学协会(Asia Oceania Geosciences Society,AOGS)第五届年会在韩国第二大城市釜山市的展览会议中心(BEXCO)召开。本次会议是继去年在曼谷之后第二次在新加坡以外的城市召开。在开幕式上,大会主席N ishida博士首先致辞,釜山市长致欢迎辞。随后韩     

研究地下水中HCO_3~－来源的稳定碳同位素法

自然界中ＣＯ＿２主要来自有机质、大气和碳酸盐岩石，因同位素分馏作用，其稳定碳同位素组成在这三种物质中的分配不尽相同。本文根据地下水实测ＨＣ，的δ￣（１３）Ｃ￣２值，利用热力学及同位素平衡计算与之相平衡的ＣＯ＿２气体的δ￣（１３）Ｃ值，确定了ＣＯ＿２气体来源，进而确定了的有机来源。     

Tectono-chronologic constraints on a Mesozoic slip and thrust belt in the eastern Jiaodong Peninsula

A major slip and thrust belt within the eastern Jiaodong Peninsula is located at the eastern terminal of the Qinling-Dabie-Sulu orogenic belt between the Sino-Korea Block and Yangtze Block. Although a lot of isotope chronologic data have been obtained regionally, little structural chronological research has been conducted in this region and this paper corrects that. Syn-deformational minerals were system-atically selected from samples of the NE-ENE trending transpressional shear zones and transpres-sional nappes and carefully analysed using 40Ar/39Ar methods. Two tectonic events were defined with the first event resulting from early movement of transpressional nappes around 190 Ma ago. This ac-cords with the period of syn-orogenic sinistral slip of the Tan-Lu faults and clockwise shear in the Eastern Qinling-Tongbaishan part of the Qinling-Dabie-Sulu orogenic belt. The second event involved strikeslip thrust movement of deep shear zones between 130Ma and 120Ma. This resulted from the onset of Mesozoic tectonic conversion in the eastern Jiaodong Peninsula. The sinistral strikeslip-thrusting in Jiaodong Peninsula and the extensional tectonism (toward ESE) in Liaodong Peninsula probably resulted in the clockwise rotation of Korea Peninsula in late Mesozoic.     

胶州湾潮汐潮流的数值计算

自从1952年Hansen提出用数值计算的方法求解潮汐方程以来,数值计算方法在国外已有了长足的进展,国内也得到了越来越多的应用。1969-1978年,在潮流大面预报工作中,我所与国家海洋局科技情报研究所等单位合作,对黄海东部、东海、朝鲜海峽、台湾海峡等海区进行了潮汐潮流的数值计算。在这些计算中,略去了非线性平流加速度的影响,这在水较深的中型海区是完全允许的;但在浅海,当未扰动水位之上的水表面高度可与平均水深相比拟时,平流项就不能省略。一九七九年,山东海洋学院王化桐等人采用Leendertse的差分格式对胶州湾进行了数值计算,考虑了非线性平流加速度的影响,但该格式以海图0米等深线作为固定的水-陆边界,没有考虑到潮间带。为了计算近岸浅水海区的潮汐潮流,本文采用R.A. Flather和N.S. Heaps的格式,编制了在108-乙机上计算任意形状近岸浅水海区潮汐潮流的手编程序,并以胶州湾为例进行了试算。 在试算时,我们用四组计算对非线性平流加速度的影响和潮间带的影响进行了比较，得出了在胶州湾这样的潮间带约占四分之一的近岸浅水海区,潮间带的影响比非线性平流加速度的影响更加明显的结论。 这四组计算是： I.不考虑潮间带(以平均水深0米作为固定的水-陆边界,并略去了平流项)； Ⅱ.不考虑潮间带,但考虑平流项； Ⅲ.考虑潮间带(海陆边界沿网格移动),但略宏平流项; IV.考虑潮间带,又考虑平流项.     

Pseudosection modelling and garnet Lu–Hf geochronology of HP amphibole schists constrain the closure of an ocean basin between the northern and southern Lhasa blocks,central Tibet

The P–T–t path of high‐P metamorphic rocks in subduction zones may reveal valuable information regarding the tectonic processes along convergent plate boundaries. Herein, we present a detailed petrological, pseudosection modelling and radiometric dating study of several amphibole schists of oceanic affinity from the Lhasa Block, Tibet. The amphibole schists experienced an overall clockwise P–T path that was marked by post‐P_max heating–decompression and subsequent isothermal decompression following the attainment of peak high‐P and low‐T conditions (~490°C and 1.6 GPa). Pseudosection modelling shows that the amphibole schists underwent water‐unsaturated conditions during prograde metamorphism, and the stability field of the assemblage extends to lower temperatures and higher pressures within the water‐unsaturated condition relative to water‐saturated model along the prograde path. The high‐P amphibole schists were highly reduced during retrograde metamorphism. Precise evaluation of the ferric iron conditions determined from the different compositions of epidote inclusions in garnet and matrix epidote is crucial for a true P–T estimate by garnet isopleth thermobarometry. Lu–Hf isotope analyses on garnet size separates from a garnet‐bearing amphibole schist yield four two‐point garnet–whole‐rock isochron ages from 228.2 ± 1.2 Ma to 224.3 ± 1.2 Ma. These Lu–Hf dates are interpreted to constrain the period of garnet growth and approximate the timing of prograde metamorphism because of the low peak metamorphic temperature of the rock and the well‐preserved Mn/Lu growth zoning in garnet. The majority of zircon U–Pb dates provide no constraints on the timing of metamorphism; however, two concordant U–Pb dates of 222.4 ± 3.9 Ma and 223.3 ± 4.2 Ma were obtained from narrow and uncommon metamorphic rims. Coexistence of zircon and sphene in the samples implies that the metamorphic zircon growth was likely assisted by retrogression of rutile to sphene during exhumation. The near coincident radiometric dates of zircon U–Pb and garnet Lu–Hf indicate rapid burial and exhumation of the amphibole schists, suggesting a closure time of c. 224–223 Ma for the fossil ocean basin between the northern and southern Lhasa blocks.