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1.
国际埃迪卡拉系年代地层学研究进展与发展趋势 总被引：2，自引：0，他引：2
埃迪卡拉系为国际地层表新增的新元古界最上部的系级年代地层单位，层型剖面被确定为南澳大利亚弗林德斯山脉依诺拉马河剖面，其底界点位（GSSP）选定为埃拉逖那冰成杂砾岩（Elatina diamictite）之上盖帽碳酸盐岩努卡利那组（Nuccaleena Formation）的下界（Gradstein et al．，2004；Knoll et al．，2004）。我国修定后的震旦系与埃迪卡拉系完全相当，底界以南沱冰碛岩之上盖帽碳酸盐岩的下界为界。本文综合国际地层委员会新元古代地层分会以及相关国家和地区近年来在埃迪卡拉系年代地层学领域研究的新进展、存在问题以及未来发展趋势作一概要介绍，以期引起国内晚前寒武纪地层古生物学者的广泛关注。 相似文献
2.
塔里木盆地奥陶系层序地层格架 总被引：15，自引：1，他引：14
在不同沉积相区典型露头、钻井及地震层序综合分析基础上,将塔里木盆地奥陶系海相地层划分出8个可全盆地对比的三级层序(OSQ1～OSQ8),首次建立了综合露头层序、钻井层序及地震层序划分的层序地层格架,建立了年代地层、牙形石生物地层、岩石地层与层序地层之间的相互关系(表1)。首次提出海相碳酸盐岩全岩或生物化石壳的碳同位素值可作为全球海平面变化的良好指标。在相似气候带及沉积环境具备相近的碳酸盐沉积速率的假设条件下,当沉积相分析所得到的相对海平面变化趋势与全岩碳同位素分析反映的全球海平面变化趋势总体一致时,说明碳酸盐层序的发育主要受控于全球海平面变化,反之则主要受控于区域构造沉降运动。鉴于这样的分析原理,我们认为塔里木盆地下奥陶统层序OSQ1及层序OSQ2属于主要受控于全球海平面变化的稳定加积型层序,而中、上奥陶统层序OSQ3～层序OSQ8则属于全球海平面总体上升背景下主要受区域构造运动控制形成的构造淹没型层序。 相似文献
3.
通过2 0 0 4年度各相关图幅的大力工作,在基础地质、矿产和资源等方面取得了大量实际材料,综合研究区域构造地层格架、青藏高原地质图和青藏高原南部火山岩及其地球动力学意义等,取得重要进展和新认识,在矿产资源、旅游和人文景观等方面也取得重要阶段性成果。 相似文献
4.
Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated. 相似文献
5.
综合运用钻井、测井、地震等资料,将黄骅坳陷目前的勘探热点地区——歧北次凹的主要勘探目的层段,即沙一下亚段划分为4个四级层序和8个五级层序,建立了沙一下亚段高精度层序地层格架。结合属性提取和测井约束反演等地球物理方法技术,在高精度层序地层格架约束下对歧北次凹目标层内单个地质体进行多层次多角度的精细刻画,研究其空间展布,并剖析其内部结构特征,分析地质体的控制因素。研究发现:物源供给、断裂陡坡带及断裂转换带对地质体的发育具有重要的控制作用,最后提炼出地质体发育模式,为研究区隐蔽油气藏的勘探和开发提供科学依据。 相似文献
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The significant role of the drainage area’s geological background in the formation of the groundwater runoff in the active
water-exchange zone was revealed for the first time on the basis of long-term observations of streams of the Upper Kolyma
River region during the autumn-winter low-water period, when the rivers are fed only by the groundwater recharge. The analysis
of all the available data made it possible to define the characteristic periods in the autumn-winter low-water season. The
waters of the seasonally thawed layer play the dominant role in the river’s recharge in September; the suprapermafrost water,
in January; and the subgelisol water (nonfreezing water streams) during the 30-day-long period of the minimal flow. The quantitative
parameters of the groundwater runoff corresponding to its module during this period reflect the water influx to the active
water-exchange zone. It is established that the latter is minimal in the In’yali-Debin synclinorium, which consists of sedimentary
rocks formed in deepwater trough environments. Their subsequent transformation proceeded under the action of subduction-accretionary
and shear strains. The water availability in the active water-exchange in the Ayan-Yuryakh anticlinorium zone is substantially
higher, although the Late Paleozoic and Early Mesozoic sedimentary formations of this area were also deposited in deepwater
trough settings, but their subsequent evolution was related to the uplift of the anticlinorium. The maximal watering is observed
in the active water-exchange zone of the Omulevka terrane, which is composed of Paleozoic terrigenous-carbonate and carbonate
formations. The differences in the hydrogeological regimes of the terranes may be significant with respect to their geoecology. 相似文献
9.
《Comptes Rendus Geoscience》2005,337(1-2):97-106
This paper reports on glacier variations in two mountainous regions of the world, the Alps and the tropical Andes. Available records of snout position and glacier mass balance are compared and interpreted on a climatological basis. In both regions, there is a long-term decreasing trend over the 20th century. The yield of this trend is different from one glacier to the other, depending on geographic and geometric characteristics. Analysing the surface energy balance, net all wave radiation is the main energy flux at the glacier surface. The turbulent fluxes represent an important term with strong positive sensible heat flux in the Alps and strong negative latent heat flux (sublimation) in the Andes. Tropical glaciers are sensitive to inter-annual variations in solid precipitation that affects the albedo, whereas Alpine glaciers are strongly influenced by air temperature changes in the Alps. To cite this article: C. Vincent et al., C. R. Geoscience 337 (2005). 相似文献
10.
环境中硒形态分析方法的研究进展 总被引：2，自引：0，他引：2
硒的形态研究是了解环境中硒的毒性、生物可利用性、迁移和生物地球化学循环等方面的基础,其研究方法一般分为直接和间接法。本文总结了环境中硒形态的研究方法,特别是对环境样品中常用的硒形态分析技术——连续化学浸提技术作了全面详细的讨论,并综述了其它硒形态分析方法的最新动态。 相似文献
11.
燕山地区中元古代常州沟组潜穴化石 总被引：2，自引：4，他引：2
在燕山地区中元古代常州沟组中发育有大量的潜穴化石，潜穴产于常州沟组中部的泥质粉砂岩中。潜穴呈个体较大的直管状，垂直层面保存。这是我国迄今为止发现的最古老的遗迹化石，表明在距今近1800Ma前就已出现古老的后生动物，这对于研究后生动物的起源及演化具有重要意义。 相似文献
12.
金湖凹陷是苏北盆地的主要含油气凹陷,阜宁组二段沉积时期广泛发育陆源碎屑与湖相碳酸盐的混合沉积,结合研究区内岩芯、录井、测井等资料对金湖凹陷阜二段的混合沉积进行了系统研究。其中,金湖凹陷阜二段沉积时期,混合沉积微观上表现为陆源碎屑组分与碳酸盐组分混合沉积形成混积岩,宏观上表现为陆源碎屑岩—碳酸盐岩层系、陆源碎屑岩—混积岩层系、碳酸盐岩—混积岩层系和混积岩层系;混积类型主要发育渐变式和复合式混合沉积,少量发育突变式混合沉积。通过对比分析区域地质背景、岩石学特征、沉积环境等,建立了阜二段混合沉积相模式。对研究区的混合沉积控制因素进行了讨论,认为其主控因素为阜二段沉积时期的海侵作用,同时构造作用、气候条件、湖平面变化、物源等也对研究区混合沉积有重要的影响。 相似文献
13.
松辽盆地三肇地区榆树林油田葡萄花油层储层沉积模式 总被引：6，自引：0，他引：6
葡萄花油层是大庆外围榆树林油田刚刚投入开发的一个主要产油层。本文从取心井出发，通过储层层次划分及单井相分析，利用大量地质，测井资料详细研究了榆树林油田葡萄花油层储层沉积微相特征，确定葡萄花油层属于河控三角洲沉积，发育三种亚相:三角洲水上平原亚相，三角洲外前缘亚相，三角洲内前缘亚相，进一步划分为八种微相:水上分流河道，河间洼地，河间沼泽，水下分流河道，河口坝，支流间湾，席状砂和三角洲前缘泥。在此基础上，编制了各小层沉积微相平面展布图，结合区域地质特征，首次建立了榆树林油田葡萄花油层储层沉积模式。 相似文献
14.
V. Yu. Zabrodin 《Russian Journal of Pacific Geology》2007,1(5):473-481
Using the standard methods of paleogeographic analysis, small-scale paleogeographic sketch maps of the Verkhnyaya Bureya and Gudzhik depressions of the Bureya Foredeep are compiled for the Pliensbachian, Bajocian-Bathonian, Callovian, and Tithonian ages of the Jurassic. Marine sedimentation settings that existed during the Late Triassic and the major part of the Jurassic are characterized. 相似文献
15.
南海北部陆坡构造坡折带中的天然气水合物 总被引：2，自引：0，他引：2
构造坡折带是由同沉积构造长期活动引起的沉积斜坡明显突变的地带,对盆地充填的可容纳空间和沉积作用可产生重要的影响,构造坡折带和油气资源分布有着较为密切的关系。本文首次把“构造坡折带”概念引入到天然气水合物调查研究中,认为:构造坡折带是天然气水合物发育和赋存的重要构造单元。论文从海底坡降、断层发育以及温压场环境等角度讨论了构造坡折带对天然气水合物的控制作用,发现BSR发育位置的海底坡降一般在10×10-2～30×10-2之间;利用论文中设计的相对构造强度的算法计算了南海北部陆坡D区的相对构造强度,发现相对构造强度的次高值区有利于水合物赋存;根据高分辨率地震数据计算的构造坡折带的温压场环境,发现构造坡折带中连续变化的温压场环境能够使游离气运移到适宜的温压场中并形成水合物。在对上述研究进行总结归纳的基础上,初步提出了南海北部陆坡构造坡折带中天然气水合物的成藏模式。 相似文献
16.
近百年来西居延海湖泊水位变化的湖岸林树轮记录 总被引：7，自引：1，他引：6
通过对西居延海柽柳树轮年表与气象、水文要素进行相关分析,结果表明:标准年表和西河下游5～8月平均地下水位变化呈显著正相关,而且这一相关具有明确的生物学意义.利用标准化年表和地下水位的相关关系,重建了西居延海近100a以来5～8月的水位变化,检验表明重建结果是可靠的.结合西居延海在1960—1962年干涸的史实和重建水位变化曲线,将湖岸林柽柳树轮年表涵盖的近百年分为湖水水位和地下水水位变化两个时期.其中湖水水位上升阶段为1932—1952、1956—1958年,下降阶段为1920—1932、1952—1956、1958—1960年,持续时间分别为20a、2a、12a、5a和2a;地下水水位上升阶段为1974—1981、1996—1997年,下降阶段为1961—1973、1981—1995、1997—2002年,持续时间分别为8a、1a、13a、15a和5a. 相似文献
17.
北羌塘盆地中部上侏罗统研究新进展 总被引：8，自引：1，他引：7
北羌塘盆地腹地自然条件恶劣 ,地层研究难度极大。经在北羌塘盆地腹地东湖、河湾山、长水河及半岛湖等地进行了详细的岩石地层及生物地层研究工作 ,依据岩石特征和生物化石特征 ,将上侏罗统二分 :下部灰岩层为索瓦组 ,含 L acunosella triobatiformis- Pentithyris vulgaris、Radulopecten fibrosus- Gervillella aviculoides组合 ,其时限为牛津期 ;上部灰岩、碎屑岩互层为白龙冰河组 ,具 Radulopecten scarburgensis、R.moondanensis、Cladophylliaqeibulaensis、Stylosmilia chaputi化石 ,其主体时限为基默里奇期—提塘期 ,顶部可能跨入早白垩世。白龙冰河组的确立 ,是北羌塘盆地上侏罗统岩石地层与生物地层研究上一个新进展 相似文献
18.
黑河流域近两千年人—水—生态演变研究进展 总被引：2，自引：0，他引：2
理解流域历史时期的人—水—生态演变过程和规律,对其当前和未来的管理规划极为重要。通过梳理近几十年来有关学者对西北干旱区典型内陆河流域——黑河流域过去2 000年的水环境、人类活动、生态环境演变及其耦合研究等方面的成果,发现单个方面的研究均已较为普遍和成熟,并且积累了大量的素材和数据,但是缺乏以流域为单元,从长时间尺度综合考虑人—水—生态相互作用,定量分析人—水—生态协同演化过程的研究成果。今后的研究,一是应当着重于数据挖掘方法的探索,对已有成果进一步挖掘并进行对比和校正,构建一套长时间序列的可靠的人类活动、水文和生态数据集;二是应当着重于动力学模型的构建,增加生态—水文系统与人类活动的互馈机制描述,刻画人—水—生态的协同演化过程,从而达到通过揭示流域过去2 000年的人—水—生态协同演化过程,为流域当前和未来的管理提供历史镜鉴,为国内外的其他类似流域提供参考。社会水文学的提出无疑将极大地促进流域人—水—生态演变研究的发展。 相似文献
19.
The Mesoproterozoic successions in the North China Craton (NCC) and the Qinling–Qilian–Kunlun Orogens have been revised using the new and highly reliable age data. Many Proterozoic strata in the Qinling–Qilian–Kunlun Orogens, such as the Qinling, Jinshuikou and Beidahe groups that have been ascribed to be Paleoproterozoic are actually of Mesoproterozoic Era. The most significant advances are recent geochronological studies on the Mesoproterozoic stratigraphy and magmatic events in the NCC. The boundary age between the Dahongyu Formation and the overlying Gaoyuzhuang Formation is well constrained to be ∼1600 Ma, corresponding to the boundary age between Statherian and Calymmian. The boundary between the Tieling Formation and the overlying Xiamaling Formation is best positioned at ∼1400 Ma, which is coeval with the boundary between Calymmian and Ectasian, and is about 400 Myrs older than the conventional value of 1000 Ma originally defined by the All China Commission of Stratigraphy. Hence the Jixianian System, including the Gaoyuzhuang, Yangzhuang, Wumishan, Hongshuizhuang and Tieling formations in ascending order, is comparable with the Calymmian System in the International Stratigraphic Chart. The lower boundary of the Changchengian System, the first system of the Mesoproterozoic in China Regional Stratigraphic Chart, also needs revision from the conventional 1800 Ma to ∼1650 Ma well constrained by the zircon U–Pb ages 1673 ± 10 Ma (LA-MC-ICP-MS) and 1669 ± 20 Ma (SHRIMP) of a granite-porphyry dike that was overlain unconformably by the basal conglomerate of the Changzhougou Formation, the first formation of the Changchengian System. Therefore, the earliest Mesoproterozoic sequence in the NCC represented by the Changchengian and Jixianian Systems in the Yanliao Aulacogen is identical to that of the Vindhyan Supergroup in Central Indian and the Riphean Series in Russia. On the other hand, a series of 1.8–1.6 Ga anorogenic magmatic records were well-preserved around the NCC, which marked the initial rifting of the Columbia Supercontinent in the NCC. The magmatic events can thus be subdivided into three phases with peaks at ca 1.77 Ga, ca 1.70 Ga and ca 1.63 Ga, respectively. In addition to 1.8–1.6 Ga magmatic events, some minor volcanic eruptions at ca 1.56 Ga and 1.44 Ga, and wide-spread bi-modal magmatic intrusions at 1.35–1.32 Ga have been recognized in the northern NCC, marking the continued rifting of the Columbia Supercontinent since ∼1.8 Ga. 相似文献
20.
Kozlov V. I. 《GeoJournal》1980,4(1):23-30
The paper deals with the processes of ethnic consolidation, ethnic and linguistic assimilation and inter-ethnic integration taking place in the USSR. The author shows the influence of consolidation and assimilation processes over the trends in the numerical strength of individual peoples and the resulting change in the country's ethnic composition as this is reflected in the Soviet population censuses of 1926, 1959, 1970, and 1979. 相似文献