共查询到20条相似文献，搜索用时 78 毫秒
1.
吉木萨尔凹陷芦草沟组碳酸盐岩碳氧同位素特征及其古湖泊学意义 总被引：2，自引：0，他引：2
吉木萨尔凹陷芦草沟组是准噶尔盆地重要的湖相碳酸盐岩致密油富集区,为明确其沉积时期古湖泊的环境特征,利用磷酸法对吉木萨尔凹陷芦草沟组碳酸盐岩样品进行了测试。测试结果表明,芦草沟组碳酸盐岩δ~(13)C值介于6.80‰~9.70‰之间,平均值为8.30‰;δ~(18)O值介于-11.90‰~-3.50‰之间,平均值为-6.20‰。δ~(18)O和δ~(13)C的特征及变化规律表明,早期古湖泊为淡水短期注入的畅流湖泊环境,后期古湖泊为水体长时间滞留、封闭性强的咸化湖泊体系。由于火山物质带来大量营养物质,有机生物十分繁盛,致使湖相碳酸盐岩δ~(13)C较重,富含低值氧同位素的大气降雨周期性输入引起湖相碳酸盐岩δ~(18)O显著降低。芦草沟组沉积时期古湖水具有咸化程度较高、变化频繁的特点,受大气降雨和强烈蒸发作用的影响,湖泊水位具有高—低—高或高—低的变化规律,受其影响湖泊盐度随之表现为低—高—低或低—高的变化规律。 相似文献
2.
江陵凹陷古新世盐湖沉积碳酸盐碳氧同位素组成及其环境意义 总被引：4，自引：0，他引：4
江陵凹陷位于江汉裂谷盆地西部, 古新世是该区富钾卤水形成的主要时期, 研究该时期古气候的演化, 对下一步找钾有重要的理论和实际意义。古新统沙市组和新沟嘴组湖相碳酸盐岩分析结果显示, 沙市组沉积碳酸盐岩δ13CPDB值介于–4.8‰ ~ –1.0‰之间, 平均值为–3.4‰; δ18OPDB值介于–5.6‰ ~ –0.6‰之间, 平均值为–3.3‰; 新沟嘴组碳酸盐岩δ13CPDB值介于–10.8‰ ~ –8.8‰之间, 平均值为–9.3‰; δ18OPDB值介于–10.2‰ ~ –6.7‰之间, 平均值为–8.6‰。沙市组碳酸盐岩样品的δ13CPDB和δ18OPDB之间具有良好的正相关性, 表明它们发育在蒸发作用明显的相对封闭的咸水湖泊体系中; 而新沟嘴组δ13CPDB和δ18OPDB之间相关性差, 指示该时期是水体滞留时间较短的开放型湖泊系统。碳氧同位素, Sr/Ba值和Mg/Ca值均说明沙市组沉积时期古盐度和蒸发/降雨大于新沟嘴组沉积时期; 古新世的岩相古地理演化说明了沙市组沉积时期古湖水面小于新沟嘴组沉积时期。江陵凹陷古新统湖泊沉积碳酸盐碳氧同位素组成的变化指示了区域古气候条件由沙市期的干热向新沟嘴期的湿润转变。显示古新统沙市组到新沟嘴组江陵凹陷古气候格局发生了重大变化, 这一变化对于沙市组时期古盐湖演化和成钾十分有利。 相似文献
3.
长阳锰矿位于扬子陆块北缘,赋存于南华系大塘坡组含锰黑色岩系中,含锰矿物主要是菱锰矿。通过对含锰岩系C、O同位素及黄铁矿单矿物S同位素的分析表明:δ13C、δ18O值分布范围和平均值分别为﹣6.2‰～﹣2.1‰、﹣2.9‰和﹣7.9‰～﹣5.3‰、﹣6.8‰,δ34S介于38.41‰～66.85‰,平均值为60.95‰。研究认为:长阳锰矿炭质主要来源于无机碳,在沉积过程中有有机质碳的加入。通过O同位素反演的古温度一般在39.4℃～58.2℃,均值为48.9℃,古温度偏高说明其沉积时水体较深。研究区古盐度Z值大部分大于120,为古盐度较高的海相沉积环境,有部分降水和陆源淡水进入沉积区。长阳锰矿含锰层位中黄铁矿具有异常高的δ34S值,δ34S介于38.41‰～66.85‰,平均值为60.95‰,沉积盆地的封闭性和冰川事件使海水浓度降低并富集重硫同位素,随着海水硫酸盐和硫化物之间的硫同位素分馏的减小,使黄铁矿的δ34S达到异常高值。 相似文献
4.
对塔里木盆地西南依格孜牙组和卡拉塔尔组灰岩碳、氧同位素特征研究结果表明,上白垩统依格孜牙组δ13C(PDB标准)平均值为3.79‰,δ18O(PDB标准)平均值为-3.49‰;古近系卡拉塔尔组灰岩δ13C(PDB标准)平均值为2.09‰,δ18O(PDB标准)平均值为-4.54‰.与前人和世界其他剖面数据对比认为,碳同位素比较稳定,能够反映其沉积时的特征,而氧同位素变化较大,可能受沉积后作用的影响.依格孜牙组与卡拉塔尔组灰岩碳同位素具较大差异,主要受陆源环境(？)物质的注入,海水盐度、生物作用和古大气CO2含量等因素的影响. 相似文献
5.
依据实测的塔里木盆地麦盖提斜坡玉北地区41个碳酸盐岩碳氧同位素数据,结合岩石学方法,研究了碳氧同位素的组成、演化及其地质意义。数据显示,δ~(13) C值主要分布在-2.6‰~0.7‰,均值为-1.0‰;δ~(18) O值分布在-9.4‰~-3.5‰,均值为-6.9‰。玉北地区古盐度为118.39~126.34,平均为121.94。奥陶系碳酸盐岩淡水改造作用明显。碳氧同位素的组成和演化不但可以指示沉积环境,而且还与生物生产率以及古海平面变化呈正相关性:δ~(13) C的低值对应于局限台地台内滩亚相沉积环境;δ~(13) C的高值对应于开阔台地滩间海、台内滩亚相沉积环境。碳氧同位素组成还对成岩环境有明显响应:鹰山组δ~(13) C与δ~(18) O均向高负值偏移,表明经历过强烈的表生岩溶作用;蓬莱坝组δ~(13) C低—中负值,δ~(18) O表现为高负值,在白云岩储层中可见鞍状白云石及燧石,主要为深埋藏成岩环境;良里塔格组同位素特征为δ~(18) O高负值,δ~(13) C低正值,并且在进入埋藏岩溶阶段之前还经历过风化壳岩溶作用。 相似文献
6.
湘中地区有中奥陶世和早震旦世两个重要的锰碳酸盐层。安化县附近的湘锰组含锰泥灰岩和锰白云岩的碳和氧同位素值分别为—2.69～—4.00‰PDB和—6.87～—14.04‰PDB。湘锰组MnCO_3有δ~(12)C值—7.44～—13‰PDB和δ~(18)O值—2.65～—13.03‰。磨刀溪组黑色页岩(中奥陶世)中的Mn-泥灰岩显示负的δ~(13)C值(—1.7～—6.56‰PDB)和δ~(18)O值(—11.67～—14‰PDB)。但结晶锰矿石有更高的负δ~(13)C(—4.70％～—17.79‰PDB)和δ~(18)O(—11.67～17.27‰)。本区存在三种锰碳酸盐岩C和O同位素演化趋势:(1)安化地区的锰灰岩为稳定的δ~(13)C趋势;(2)湘锰组黑色页岩中的MnCO_3具有同步趋势:(3)中奥陶世黑色页岩中的锰矿石具有强烈反向趋势。碳成岩作用对锰碳酸盐形成过程中C和O同位素组成影响很大。湘锰组碳酸盐来源为非生物成因的海洋CO_2和SR至Me带的有机碳加入有关。磨刀溪组结晶锰碳酸盐的主要来源是热解脱羧基带(D)。δ~(34)S也为生物来源(—8～—27.49‰CDT)。Mn(％)品位与δ~(13)C呈负相关关系。证据表明锰碳酸盐成因与海盆地缺氧事件和海底热水(喷气)沉积有关。 相似文献
7.
白云鄂博赋矿白云岩与微晶丘和碳酸岩墙的碳氧同位素对比研究 总被引：26，自引：7，他引：19
本文通过方解石和白云石的碳和氧同位素分析,对比研究了白云鄂博赋矿白云岩、黑脑包微晶丘、北京西山微晶丘、宽沟北正常沉积灰岩和白云鄂博碳酸岩墙,从而探讨了赋矿白云岩的成因及其与超大型Fe-Nb-REE矿床的成因关系。结果为:①黑脑包腮林忽洞群顶部微晶丘和北京西山寒武系顶部微晶丘碳酸盐的δ~(13)C值都在0±2‰左右,δ~(18)O值为18.3‰～25.1‰,均具有典型海相沉积碳酸盐岩的特点;②白云鄂博东矿采场δ~(13)C值为-7.9‰～-1.1‰,δ~(18)O值为9.1‰～20.9‰;矿区东西两端δ~(13)C值-7.9‰～-0.6‰,δ~(18)O值8.6‰～25.7‰;均介于地幔流体与典型沉积碳酸盐岩之间。部分赋矿白云岩样品中白云石与方解石之间的碳氧同位素分馏△~(13)C和△~(18)O值均小于0‰,表明其受到过次生蚀变作用,低δ~(18)O值白云石样品所对应的负△~(18)O值反映了地幔镁质流体对沉积碳酸盐岩的强烈交代作用;③矿区—富稀土碳酸岩墙的δ~(13)C值为-7.2‰～-4.7‰,δ~(18)O价值为11.9‰～16.4‰,表明其碳酸岩岩浆并非原始地幔来源,而可能与俯冲板块携带的沉积碳酸盐岩与地幔流体在深部的高温混合熔融有关。碳酸岩墙中白云石与方解石之间的碳和氧同位素分馏均小于0‰,说明该碳酸岩墙中的白云石与方解石并非同成因矿物,至少其中之一为 相似文献
8.
9.
辽北辽河群碳酸盐岩碳-氧同位素特征及其地质意义 总被引：13，自引：10，他引：3
辽宁省关门山地区辽河群形成时代限于2.3～1.85Ga之间,辽河群关门山组白云岩的42件样品的δ~(13)C介于3.5～5.9‰之间,具有明显的正异常特征,δ~(18)O值为15.4‰～24.8‰,指示了对Jatulian事件的响应。其中,未遭受后期流体作用的35件样品的δ~(18)O和δ~(13)C明显高于受到流体作用的7件样品,表明流体作用使碳酸盐岩δ~(18)O和δ~(13)C降低。在地质历史中,以2.33～2.06Ga时期的全球性δ~(13)C_(carb)正漂移最强烈,而辽河群强烈的δ~(13)C_(carb)正漂移现象指示辽河群沉积于2.33～2.06Ca之间。 相似文献
10.
研究了若尔盖铀矿田中灰岩、硅灰岩及方解石脉的碳氧同位素组成,结果表明产于地层中的灰岩、硅灰岩及方解石脉的δ13C值为-1.48‰～3.18‰,平均为1.51‰,为海洋沉积碳酸盐岩的碳同位素组成特征;δ18O值为-12.81‰～-3.71‰,平均为-9.92‰,在铀矿田中δ18O值最高.与成矿作用关系最为密切的含矿方解石脉δ13C值为-2.78‰～-4.81‰,平均为-3.93‰,明显表现为地幔来源的特点;δ18O值为-13.14‰～-15.05‰,平均为-13.87‰,其值在铀矿田中介于地层中岩石(脉)与矿区方解石脉之间.矿区方解石脉的δ13C值为-3.53‰～-6.35‰,平均为-4.93‰,与含矿方解石脉的碳同位素组成相近,表明其亦是成矿作用的产物;δ18O值为-16.00‰～-24.75‰,平均为-19.36‰,在铀矿田中δ18O值最低,明显表现为深部来源特征.综合若尔盖铀矿田的碳氧同位素组成特征,暗示其成矿流体应当来源于地幔. 相似文献
11.
东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。 相似文献
12.
The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads 总被引：3，自引：1，他引：2
Clemente Irigaray Francisco Lamas Rachid El Hamdouni Tomás Fernández José Chacón 《Natural Hazards》2000,21(1):65-81
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning. 相似文献
13.
郯庐断裂南段研究进展与断裂性质讨论 总被引：13，自引：3，他引：13
据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。 相似文献
14.
Guboglo M. N. 《GeoJournal》1980,4(1):53-58
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen. 相似文献
15.
某高速公路下伏煤矿采空区稳定性分析 总被引：10，自引：0，他引：10
在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。 相似文献
16.
17.
Jiayu Rong Michael Melchin S. Henry Williams Tatyana N. Koren Jacques Verniers 《《幕》》2008,31(3):315-318
The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs. 相似文献
18.
Dean S. Oliver 《Mathematical Geology》1998,30(7):911-933
In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix. 相似文献
19.
Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth
B. P. Kondratyev 《Astronomy Reports》2017,61(8):709-714
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″. 相似文献
20.
正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the 相似文献