苏北箕状断陷形成的动力学机制

苏北盆地由多个小型箕状盆地组成,过去一直用“拉线作用”和“裂谷盆地”理论解释其成因,但大量地震资料显示,新生界地层“楔状实体”的形成除沉积因素外,更主要的是因为多次不均衡抬升削蚀所造成,实际是一个早第三纪残留盆地。新生代构造现象既是中生代时期构造作用的延续,也是始新世以来复杂应力环境作用的结果。印支－燕山中期,中国东部只受到太平洋－库拉板块一种力源作用,地层形变强烈,受力方向单一,以NW,NWW向挤压或左行剪切为主,发育了大量逆冲推覆构造,始新世,由印度板块向欧亚大陆冲撞引发的NE向挤压力加入到本区,使苏北盆地从此处在因两大板块非均速推进而产生的二元交变动力环境：印度板块力源占主导时,产生“右旋扭动”力偶,使燕山早－中期逆断层复活反转的同时,由于中国西部大陆的不断抬升,本区总的以沉积作用为主,而太洋板块力源占主导时又产生“左行剪切挤压”,在整体抬升基础上,斜坡－凸起处的过多蚀进一步加强了箕状盆地结构。两种力源的时空交替实际形成了一个完整的“断－坳－隆”沉降－抬升构造旋回,利用裂变途径迹资料探讨了不同方向构的形成年代。     

瘤状软骨凹顶藻化学成分研究

采用硅胶柱色谱以及Sephadex LH-20凝胶色谱手段,对海洋红藻瘤状软骨凹顶藻(Chondrophycus papillous Garbary et Harper)进行化学成分研究,分离得到5个化合物.通过MS、NMR等方法对得到的化合物进行结构确证,分别鉴定为邻苯二甲酸二丁酯(Ⅰ),邻苯二甲酸二异辛酯(Ⅱ),胆甾醇(Ⅲ),植醇(Ⅳ)和4-羟基苯甲醛(Ⅴ).所有化合物均为首次从该种海藻中分离得到.通过MTT法对得到的单体化合物进行细胞毒活性筛选,结果显示所有化合物在10 mg/L浓度下均无明显活性.     

Carbon isotopic change at the base of the upper permian zechstein sequence

Fluctuation of the carbon isotope composition of marine carbonates has recently been developed as a powerful tool for the identification of ocean-wide anoxic conditions and changes in the world budget of carbon and oxygen. A change in δ¹³ from the normal marine values (0 to + 2%) to values highly enriched in ¹³C (+3·5 to 4·5%) is recorded at the base of the Zechstein sequence both in central Germany and northeastern England. The change occurred over a relatively short period of time indicating a rapid and pronounced change in the organic carbon/carbonate budget. Evidence from other Permian basins show similar highly enriched δ¹³C values. This change may correspond to that in carbon balance distinguished by the Garrels and Perry (1975) model and based on the change in sulphur isotopic composition during the Permian.     

Zur Geologie der Danakil-Senke

Geological and geophysical investigations in the Northern part of Afar-Region were carried out by a group of scientists in 1967 and 1968. The Afar-structure is framed by the Ethiopian Highland in the West, the Somali Plateau in the South and the Danakil horst in the E. Its northern part is occupied by the NNW trending Danakil Depression (Danakil Graben), a branch of the NW trending Red Sea-Graben. The block mosaic border land in the West as well as the Danakil Alps consist of basement overlain by unfolded Mesozoic strata. Within the Afar Depression the pre-Tertiary formations are covered by limnic-fluviatile — in upper portions marine — sediments, Miocene and Pliocene in age, thickening towards the centre of the Depression. These basin fillings indicate a major phase of rift faulting prior to and during their deposition. Marginal extensions of these “Danakil-Formation” on both flanks of the Depression accompany the structural borders of the Danakil Graben, coinciding with the “outer rift structural margin” (Mohr 1967). Evaporites occupy the deepest part of the structure, “the inner Danakil Graben”, downfaulted or opened by major rift movements during Pliocene. A NW trending fault zone cutting through the flat plain north of Dallol covered by gypsum beds, seems to form the Eastern margin of the inner Danakil Graben. In its southeastern prolongation the fault and fissure system of the Amarti Volcanic Range is situated. Still active rift faulting during Quaternary caused the present topographic form of the region. These movements were followed by a marine ingression. Its sediments (Zariga-Formation, 14 C Modell ages 25 000–34 000 y) ring the depression and pass into gypsum beds towards the centre of the basin. The deepest parts of the Depression are hidden beneath the Afrera-Formation (14 C Modell ages 5800 y) framing the Lake Assale/Bakili and the Lake Afrera (soft limestones, clay and gypsum beds). The rift-forming movements in the northern Afar were accompanied by strong volcanic activity. Besides different igneous rocks intruding the pre-Tertiary and Tertiary strata of the rift margin, extensive basaltic lava flows intercalate and locally underly the Danakil-Formation. Potassium-argon age determinations on these “Afar Basalts” yielded Miocene to Pliocene age. In the southern area of the Danakil Graben the Upper Tertiary sedimentary basin fillings are replaced by “Afar Basalts” (plateau-forming flood basalt) flows. They are succeeded by scoriaceous fissure alkali-olivine-basalts and their differentiated lavas forming huge volcanoes aligned parallel to the rift structures. The Central Volcanic Range (Erta Ale volcanic chain) marking the central part of the Danakil Graben, remains active today. Besides the basaltic activity, numerous huge volcanoes display rhyolitic rocks with strong alkaline affinity.     

苏皖地块构造演化、苏鲁造山带形成及其耦合的盆地发育

郯庐断裂带一度是古特提斯洋域中的转换断层,其东的苏皖地块和胶辽克拉通分别是曾经独立于扬子克拉通和华北克拉通之外的构造单元。苏皖地块原属中朝构造域,因中元古代时苏鲁洋的张开而向南漂移,震旦纪起归入华南构造域。受北东东-近东西向的江南断裂和江绍断裂右行走滑活动控制,苏皖地块及怀玉地块在石炭纪末-三叠纪时脱离华南构造域,成为古特提斯洋域中的中间地块。中国东部地区东亚燕山期山系的形成受两个地球动力学系统制约:一是苏鲁洋的消减及闭合后苏皖地块与胶辽克拉通的碰撞,二是江南断裂和江绍断裂的先剪后压,苏皖地块与拼合了的扬子-华北克拉通间发生斜向会聚和剪切造山,怀玉地块仰冲超叠在苏皖地块上。分5个阶段(印支期消减,早-中侏罗世斜向会聚,晚侏罗-早白垩世消减,早白垩世碰撞和燕山造山带坍塌)叙述了中生代造山作用的表现和特点,探讨了与各阶段造山作用耦合的盆地类型和时空分布。因燕山造山带的坍塌而燕山运动构建的“盆”“山”关系解脱,中国东部第三纪的伸展盆地直接叠加在燕山造山带的坍塌裂谷上。     

雄关漫道真如铁——论中国油气二次创业

半个多世纪以来,中国经历了油气资源的第一次创业,在祖国大陆和近海大陆架地区的新生代陆相碎屑岩沉积盆地中,发现了一批油气田,使原油年产量达1．67亿吨,位居世界第五,天然气疸这241亿立方米,居世界第十五位,成绩是巨大的,但是,1993年开始进口原油3000万吨,2000年进口原油7200万吨,严重影响国家经济建设,而且这种趋势还在不断发展,预测2010年将进口原油1亿吨,天然气200亿立方米,那么,中国油气资源的出路何在？作者指出,从中国大地构造演化来看,前新生代海相残留盆地还有巨大的油气潜力,尽管其勘探的难度是世界级的,但是,只要我们切实地依靠科学技术,进行油气资源的二次创业,困难上,在实践中克服困难,就可以发现更多的石油天然气,支持国家经济建设的持续发展。     

秦岭造山带金矿床类型与构造背景

独具特色的秦岭复合型大陆造山带位于中国南北大陆中央,由古生代盆－岛兼杂的小型陆块及其南北缝合构造带组成,并与华北和扬子大陆碰撞镶嵌,中一新生代陆内造山形成山盆耦合,构成独特的地质构造格局,造成了闻名于世的秦岭成矿带,形成贵金属,有色与黑色金属为特色的丰富矿产资源,根据秦岭造山带的组成与结构,阐述本区造山－成矿作用机制下在不同构造单元中形成的复杂的金矿床类型,分析了秦岭造山带金矿类型产出的地质背景,分布规律及成矿潜力。     

汶川县生物多样性保育与区域发展的综合地域划分

依据生物多样性和社会经济发展方面的 2 0个指标 ,应用模糊聚类算法对汶川县的综合地域划分研究表明 ,汶川县可以划分为 4个综合地域类型 :发展主导型 (Ⅰ ) ,占县域面积的4 3% ;特色开发型 (Ⅱ ) ,占县域面积的 2 3 5 % ;发展支持型 (Ⅲ ) ,占县域面积的 6 5 % ;生态保育和限制性开发型 (Ⅳ ) ,占县域面积的 6 5 7%。县域水平上协调生物多样性保育和区域发展关系的空间策略是东西分治 ,东部 (Ⅰ、Ⅱ、Ⅲ )以社会经济发展为主 ,西部 (Ⅳ )以生态保育为主。在区域发展的产业选择上应重视产业的生态化 ,突出地域优势与特色。     

潼关小秦岭地区金的热穹窿成矿地质模型

根据对小秦岭地区大地构造位置的最新认识,在对一系列野外地质矿产信息综合研究的基础上,提出了“板内Ａ型俯机制下变质核杂岩内岩浆热穹窿金成矿地质模型”。认为小秦岭地区金矿的矿质来源于华北陆块南缘上地慢,成矿介质为下渗的地表水,成矿机制是以燕山斯花岗岩基熔体为中心的热穹窿所形成的热力系统。热穹窿的成生、演化,消亡过程不仅从时间上决定了矿化发生的有序性及叠加规律。并且通过对变质核杂岩构造的改造,利用,决定     

天山乌鲁木齐河融雪和河川径流的水文化学过程

研究结果表明, 含 Ｃａ Ｃ Ｏ３矿物的溶解作用在乌鲁木齐河源区居主导地位 尽管融雪径流的 “离子脉冲”作用可以释放峰值强度达 ３～４ 倍的 Ｓ Ｏ２４ 和 Ｎ Ｏ－３ 流, 并且引起了总控断面河川径流与之相像的“离子脉冲”现象,但河川径流仍然呈现弱碱性;河源区强烈的含 Ｓ矿物的氧化溶解作用,产生大量的 Ｈ＋ ,被含 Ｃａ Ｃ Ｏ３矿物的溶解作用所缓冲, 未引起河川径流的酸化乌鲁木齐河以冰川站为界, 以上地区的水文化学过程为矿物的侵蚀－ 溶解过程,以下则发生部分矿物的沉淀,如 Ｃａ Ｃ Ｏ３的沉淀 Ｃａ Ｃ Ｏ３ 的沉淀作用一定程度上又增强了河流的酸缓冲力 