The lithostratigraphy of the English Chalk Rock

The Upper Turonian Chalk Rock occurs within a nodular unit within the otherwise generally soft, white chalk that dominates the English Upper Cretaceous. The nodular unit is condensed, and contains a number of hardgrounds that are designated here as the Chalk Rock Formation. The Chalk Rock contains some seven or eight hardgrounds, most of which are lithologically distinctive and can be traced over distances of up to 250 km. Nine beds within the Chalk Rock are named, comprising six hardgrounds and three marl seams. The lowermost widespread hardground appears to be more or less equivalent to the “Spurious Chalk Rock” of the south coast of England. In two areas the thickness of the Chalk Rock is greatly diminished. The most marked area, in west Wiltshire, is located close to the Palaeozoic Mendip Hills and indicates that the Mendip structure has influenced Turonian sedimentation. The other region of thinning is a platform-like area in the eastern Chiltern Hills WNW of London.     

西天山阿吾拉勒二叠纪陆相长英质火山岩铜银矿矿床模式

通过对西天山二叠纪陆相火山岩及成矿作用的研究,指出铜银矿床与长英质火山岩一石英钠长斑岩有直接关系,并从成矿构造背景、产出地质环境、矿床地质特征等方面总结出二叠纪陆相长英质火山岩铜银矿床矿床模式。     

Middle Permian palaeobiogeography study in East Kunlun,A’nyêmaqên and Bayan Har

Three regions can easily be identified in the study area according to the Middle Permian palaeobiogeographic distribution of biota, they are the southern slope of East Kunlun, A'nyêmaqên and Bayan Har. Biotic constitution and ecology in the southern slope of East Kunlun and Bayan Har are very similar. Both the diversity and abundance of organisms in these two areas are very high and reefs are widely developed. However, biotic diversity and abundance in A'nyêmaqên which is between the above two areas are obviously low. Differentiation of palaeobiogeographic distribution in these areas should be due to the baring of A'nyêmaqên ocean in the time of Middle Permian. Middle Permian radiolarian chert and thick abyssal red ooze are widely spread in A'nyêmaqên, implying that the A'nyêmaqên ocean had a great scale in size. Vast scale of deep ocean basin became an impassable gulf for some of the benthos, and as a result, only part of the organisms could have the chance to get to the isolated islands situated in ocean basin. Small living space and hard conditions in the islands further limited the abundance and diversity of biota. Tectonic background reflected by the geochemical study of basalt in the three areas is coupling well enough with the palaeobiogeographic division.     

广西高龙孤立碳酸盐台地的生长发育模式

在二叠纪的南盘江盆地中发育着许多大大小小的孤立碳酸盐台地,高龙碳酸盐孤立台地是其中一个小型的孤立碳酸盐台地。在该孤立台地上,马平组珊瑚生物礁和茅口组海绵生物礁呈一种滑动面的形式接触,意味着高龙孤立台地具有极为独特的生长发育历史。横穿高龙孤立台地的区域性同生断裂———八渡—那棉断裂,把高龙孤立台地分割为南北两个不同的块体,该断层的南翼和北翼形成差异极大的地层系统。该同生断裂以及与其倾向相反的滑动面的共同作用使高龙孤立台地呈现出一个"地垒"的形态。构造作用以及沉积作用等方面呈现出独特的现象,表明高龙孤立台地的生长过程可能代表了一个特别的孤立碳酸盐台地的生长发育模式。     

滇东Pt-Pd-Cu含矿建造地球化学特征及其含矿性分析

滇东Pt-Pd-Cu含矿建造包括黑色页岩建造和玄武岩建造,黑色页岩建造由不同层位的黑色岩系组成.作者重点对元古宙昆阳群、下寒武统黑色岩系和二叠纪峨眉山玄武岩的地球化学特征进行了系统研究.研究表明昆阳群黑色岩系以As、B(K≥5)显著富集,Sb、Pd、Mo、Ag、U、Pt、V、Zn、W、Cu(K≥1.2)富集为特征;滇东下寒武统黑色岩系以Mo、Ag、U、As、V、B、Pd、Sb(K≥5)显著富集,Pt、Pb、Zn、W、Cu、Ni(K≥1.2)富集为特征;峨眉山玄武岩则以Pt、Pd(K≥5)显著富集,Au、Ag、Cu、Zn、Sb、B、U、V(K≥1.2)富集为特征.总之,分布于研究区不同层位的黑色岩系和二叠纪峨眉山玄武岩建造构成了该区贵金属(Pt、Pd、Ag、Au等)和有色金属(Cu、Mo、V等)元素成矿的初始矿源层,上述区域成矿要素最佳匹配地段是可能产出非传统贵金属(pt、Pd、Ag、Au等)和有色金属(Cu、Mo、V等)矿床的潜在地段.     

Les monchiquites de Tchircotché, vallée de la haute Bénoué (Nord du Cameroun)

Dykes of monchiquites of Cainozoic age (37.5±2.3 Ma) are intrusive in Cretaceous sandstones in the Tchircotché area, Upper Benue valley (northern Cameroon). The differentiation of the monchiquites is explained by crystal fractionation of olivine, clinopyroxene, magnetite, ilmenite and apatite. A studied rock has low Sr-isotope ratio $\text{(0.703}\text{69±10)}$, which is similar to those of the alkali basalts of the Cameroon Line. Therefore the continental crust appears to have no significant role in the genesis of the monchiquites.     

Devonian to Triassic Successions of the Changning-Menglian Belt, Western Yunnan, China

Phanerozoic strata are distributed in several north-south trending zones in the central part of the Changning-Menglian Belt. Four types of Devonian to Triassic stratigraphic successions can be identified: (1) elastics with limestone lenses in the mid-section, changing up-section into alternations of fine elastics and cherts; (2) elastics with chert intercalations and limestone lenses, and topped by Permian basic volcanics; (3) elastics-basic volcanics-carbonates-clastics; and (4) limestones, dolomitic limestones-dark gray thin-bedded limestones, argillaceous limestones, mudstones and siliceous mudstones. Devonian to Triassic cherts occur in different horizons and different zones from east to west. These cherts are usually transitional to their neighboring elastics. There is no continuous Devonian to Middle Triassic chert sequence in the central zone of the Changning-Menglian Belt as Liu et al. (1991,1993) reported. Volcanics and the overlying carbonates described by some workers as "seamount" sequences     

四川宣汉盘龙洞晚二叠世生物礁古油藏剖面序列

盘龙洞生物礁发育于上二叠统长兴组的中上部,厚度约80m。生物礁主要为浅灰色块状海绵障积岩、海绵骨架岩。造礁生物主要为房室海绵、水螅、苔藓虫等;附礁生物主要为腕足、瓣鳃及腹足等;造架生物含量约为38％～50％;充填物为泥晶方解石,含量为50％～70％;孔洞丰富,多被方解石晶体充填,孔洞间连通性好。该生物礁及其上下地层均有大量的沥青,揭示着有过油气的运移过程。沥青充填可以分为两期：第一期充填于生物骨架孔隙、粒间孔隙、海绵体腔和都分其他生物体腔孔隙中;第二期主要充填于后期裂骧和次生孔隙中,该期的沥青广泛分布于生物礁和整个礁的盖层之中（包括亮晶砂屑灰岩和白云岩）,规模较大,含沥青的地层总厚度达120m左右。     

"涵化"与岷江上游民族文化多样性

岷江上游不仅是中国的一条重要生态过渡带,同时也是历史上一条民族迁移的“走廊”和交汇地带。该地区的生物多样性研究已引起了国内外科学家的重视,但在具有同样保护意义的文化多样性方面,研究工作才刚刚起步。本文从文化的涵化概念出发,以岷江上游的民族迁移为线索,分析了该地区民族文化的涵化现象。并将涵化作为文化多样性形成的驱动因素,分析了涵化在文化多样性形成中的作用与机理,以及涵化与民族地理分布的关系,指出了民族地理分布与自然生态条件和文化传统的关联性。     

Reaction of OH Radicals with Acetone: Determination of the Branching Ratio for the Abstraction Pathway at 298 K and 1 Torr

We have determined the 2-oxo-propyl CH₃C(O)CH₂ (sometimes called 1-methylvinoxy or acetonyl) radical yield for the reaction of acetone with OH radical relative to the 2-oxo-propyl yields for the reactions of F- and Cl atoms with acetone using the Discharge Flow technique. The 2-oxo-propyl radical has been monitored by Laser Induced Fluorescence LIF at short reaction times in the systems: OH + acetone (R1), F + acetone (R2), and Cl + acetone (R3). From these measurements we have deduced the branching ratio for the 2-oxo-propyl radical formation in the title reaction to be in the range 0.8 R 1.