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1.
为了恢复兰坪盆地古近系云龙组的沉积环境,采用电感耦合等离子体质谱(ICP-MS)方法对兰坪盆地古近系云龙组的石膏、灰岩、膏泥、泥岩和砂岩共计13件样品进行微量元素分析。根据各岩性中微量元素的蛛网图和m(Cu)/m(Zn)、m(Sr)/m(Cu)和m(Sr)/m(Ba)比值特征及Sr元素含量等恢复沉积环境及古气候。结果表明:石膏、灰岩、膏泥、泥岩和砂岩均有富集Rb、Pb、Zr的特征;石膏和膏泥形成于干热海相咸水的贫氧弱还原环境;砂岩和泥岩形成于温湿陆相淡水的富氧氧化环境;灰岩形成于干热海相咸水的富氧氧化环境。据此建立研究区沉积环境演化模式,并将其划分为2个阶段,第一阶段为气候干热的弱还原海相咸水湖沉积,沉积出石膏、灰岩和膏泥;第二阶段为温暖湿润的富氧氧化环境,沉积出砂岩、泥岩。这种沉积环境变化与古近纪云龙期气候环境周期性变化密切相关,同时也为盆地的矿产资源勘探提供依据。   相似文献   

2.
Two deep cores (SSDP 102 and SSDP 105) from the southeastern inner shelves of Korea were examined in order to reconstruct the paleoenvironmental history of the Korea Strait during postglacial sea-level fluctuations. The results of the lithofaces, organic geochemical components, foraminiferal assemblages, and stable isotopes show that the Korea Strait was influenced in different ways by river discharges and open-ocean currents, according to their temporal and spatial variability.The results of core SSDP 105 indicate that the southeastern coast of Korea was probably a shallow coastal environment, such as a shoreface or beach, by about 17.5 cal ka. The area remained a coastal environment that was affected by high energy conditions and partly by freshwater input during the transgressive period of 17.5–8.1 cal ka. The area has changed to a modern-type shelf environment influenced by the inflow of the Tsushima Current and by the high supply of fine-grained sediments derived from the Nakdong River since 8.1 cal ka.Meanwhile, the results of core SSDP 102 taken from the Nakdong River mouth reveal that the river mouth area was most likely a terrestrial or fluvial environment at least before 13.9 cal ka. It then changed to the estuarine (deltaic) environment that was directly affected by the Nakdong River between 13.9 and 7.0 cal ka, and established a modern-type shelf (prodeltaic) environment, which is similar in many respects to the southeastern coast of Korea after temporarily undergoing erosion between 7.0 and 6.1 cal ka.  相似文献   

3.
本文将探讨采用环境系统分析方法,从保护地下水环境出发,把极其复杂的环境系统的结构、功能、影响和效益结合起来作为一个整体,通过由于城市发展、农业开发、以及自然环境的变迁等,对地下水环境系统的影响效应及其发展趋势,进行系统分析和评价,从而提出最有效、最经济、最优化的环境对策。对区域性地下水系统环境影响评价理论和实践方法进行了探讨。  相似文献   

4.
The formation environment of the main coal seam in Shengli coal mine is analyzed, and the effect of coal ash parameters on the coal-forming environment is mainly discussed according to gray component parameters combined with other coal quality test analysis data. Results show that the hydrodynamic conditions of the main coal during coal accumulation have a general pattern of strong northeast and weak southwest, and lakeside swamp is generally in the retrograde process from south to north. The No.5 coal seam is a water entry cycle, and the No.5lower coal is a water withdrawal cycle. The No.6 thick coal seam is formed in the peat swamp environment where the water is shallow and the groundwater activity is weak. The input of terrestrial debris material was most abundant in the formation period of No.5lower coal, followed by No.5 coal, and that in No.6 coal is the least. Vertically, the peat swamp environment changed from weak reduction to weak oxidation to strong reducing environment. The ash yield was low to high to low from bottom to top. The organic sulfur is the main type of sulfur in the main coal seam. The weaker the hydrodynamic condition, the higher the organic sulfur content in the reduction environment, while lower organic sulfur content in the oxidation environment. The peat swamp water of No.5lower coal is medium alkaline, and the peat swamp water of No.5 and No. 6 coals is weakly alkaline or acidic.  相似文献   

5.
本文通过XRF和ICP-MS测试方法对油页岩样品进行测试,根据常量元素和微量元素特征、组分含量及某些元素的比值,探讨了研究区油页岩样品的地球化学特征,进一步阐述了其沉积环境的指示意义.结果表明,P和B元素强烈富集,相当硼及古盐度值都表明属于半咸水沉积环境,B/Ga、Sr/Ba值也说明受到海水影响或间歇性受海水影响,沉积环境以半咸水湖泊为主;Fe2+/Fe3+、V/(V+Ni)、V/Ni、Cu/Zn、Ni/Co和U/Th值及Ni的含量说明沉积环境为咸化的弱还原—还原环境;Mn/Fe和Mn/Ti值也较小,反映近岸的沉积环境;Sr/Cu表明主力油页岩形成时期处于温湿—干热气候.总体上反映出,研究区油页岩的沉积介质环境的显著特征是半咸水状态的弱还原—还原环境.  相似文献   

6.
Any mankind engineering projects will have effect of various degrees and properties on the soil and water environment (water amount, water quality, aquatic organisms and bottom sediment). With a pipe transport engineering as example, analysis was made on the factors influencing geological environment and optimized calculation by genetic algorithms was done on soil pollution factors (oil pollutant and its annual accumulation amount in soil). Controlling pollution factors’ total amount, so that decreasing soil pollution intensity, extending service years for soil environment capacity, saving waters and decreasing production cost, so as to control the geological environment change caused by the mankind development and construction activities. It is a new way that the mankind development projects will have effect on the earth environment.  相似文献   

7.
This article examines Holocene environmental change in Zhuye Lake in the marginal area of the Asian monsoon, NW China. Holocene environment records were obtained for the QTH01 and QTH02 sections in Zhuye Lake. The fluctuations in grain size, pollen, total organic carbon content and C/N ratios record notable environmental variation. The early Holocene (11.0 to 7.4 cal. kyr BP) was relatively arid, while vegetation coverage was sparse and primary productivity low. The optimal environment prevailed during the mid-Holocene (7.4 to 4.7 cal. kyr BP). Vegetation coverage was the densest and primary productivity the highest during the mid-Holocene. During the late Holocene (4.7 to 0 cal. kyr BP), the environment became arid, as shown by low lake level and sparse vegetation coverage. After 1.6 cal. kyr BP another strong aridification occurred. In this area, the environment was likely to have been influenced by both the Westerlies and the East Asian monsoon during the Holocene. During the early Holocene, the relatively arid environment lay in the background of the increasing East Asian monsoon and dry westerly wind. During the mid-Holocene, central Asia was controlled by the humid Westerlies, while a strong East Asian monsoon prevailed in Central China. The mid-Holocene optimum in this area benefited from an expanded East Asian monsoon and the humid Westerlies. Weakening of the East Asian monsoon caused aridification of the environment during the late Holocene. Intensification of this aridification after 1.6 cal. kyr BP might be correlated with appearance of the arid environments in the Westerly domain after ∼1.5 cal. kyr BP. These arid conditions might be affected by the decreased moisture content of the Westerlies.  相似文献   

8.
重庆綦江莲花保寨保存有大量以莲花卡利尔足迹为主的恐龙足迹,研究其沉积环境对恢复当时恐龙动物群的生活环境有着十分重要的意义。运用岩石学、沉积学和古生物学方法,通过岩石学特征、沉积构造特征、粒度分布特征等分析重庆綦江莲花保寨恐龙足迹群的沉积环境,认为当时的沉积环境为曲流河沉积,恐龙足迹的赋存层位为曲流河边滩和河漫滩环境。  相似文献   

9.
青海黄河源盆地早更新世以来环境演变   总被引:2,自引:0,他引:2  
黄河源盆地位于青藏高原东北部,是黄河的源头地区,对环境和气候变化非常敏感。对黄河源盆地中的河湖相沉积物进行了孢粉分析,获得丰富的孢粉数据,结果显示孢粉组合以菊科、蒿科、藜科、禾本科、松、桦等草本和木本植物花粉为主。通过对各类植物的孢粉组合特征分析,揭示了黄河源地区早更新世以来古植被、古气候的演替和变化。其演变经历了4个阶段:第一阶段223.9~90.1万年,为森林草原环境,反映了温暖潮湿的气候;第二阶段90.1~35万年,为灌丛草原环境,反映了总体干冷的气候;第三阶段35~2.8万年,为稀树草甸草原环境,属湿润寒冷的气候;第四阶段2.8~0.8万年,为荒漠草原环境,反应干冷的气候。  相似文献   

10.
把影响农用土地环境质量的所有环境要素综合起来,分解量化指标,重建评价体系,提出宏观指标分等、微观指标定级的新观点,并就县市级农用土地环境质量进行全要素整合评价和等级评定进行了探讨。结果表明,保证评价精度和把握等级评定的关键步骤是正确选择和划分评价单元;土地农业综合生产能力和清洁度指标是农用土地环境质量的综合反映和集中体现,是所有被整合调查要素和评价因素中最重要的两个刚性指标,在评价中必须加大权重;全要素整合评价可以弥补农业或土地部门多指标评价的不足,能够比较全面和客观地反映农用土地环境质量状况。农用土地环境质量的全要素整合评价为新一轮土地利用规划修编、基本农田保护区准确划定、农用土地分等定级和建设用地的区划调整以及土地基准定价能提供有力技术支持。  相似文献   

11.
将土壤和潜水作为一个相互作用的系统,提出了研究区土壤酸化及地下水碱化、土地沙化、湿地退化、土地盐渍化等主要水土地质环境问题。系统地研究了海河平原北部地区土壤、潜水等地质环境的影响因素。以土壤剖面实测数据为基础,认为土壤环境主要受自然因素的控制,人类活动的影响也不容忽视;以地下水监测数据为基础,认为潜水环境受自然因素和人类活动双重作用的控制。为研究区水土地质环境保护提供了重要的依据。  相似文献   

12.
人类活动是加剧矿山地质环境演化的“催化剂”。矿产资源开采对环境的破坏具有必然性、综合性,对环境的影响有链式放大效应和滞后效应。从项目需求出发,利用遥感技术对湖北省东部矿山开发占地、矿山地质灾害和矿山地质环境恢复治理进行了遥感调查,查明了2013年湖北省东部矿山开发总占地面积为7339.29hm2,2014年较2013年总占地面积增加了1065.44hm2。矿山地质灾害61处,矿山塌陷地质灾害分布具有地理空间差异性,主要分布在鄂城、铁山、金山店、灵乡、殷祖和阳新6大岩体边缘地带。从生态文明建设的角度看,迫切要求人们树立“绿水青山也是金山银山”的理念,转变发展思路,保护好矿山地质环境。遥感调查结果表明:矿山地质环境治理及矿山复绿工程执行时存在区域不平衡性;武汉市、黄石市矿山地质环境的恢复治理与矿山复绿的强度、速度明显高于其他地区,且其近城区的矿区治理力度大、复绿效果好。  相似文献   

13.
利用锆石裂变径迹研究漠河盆地隆升过程   总被引:1,自引:1,他引:0  
通过对漠河盆地内32件样品的锆石裂变径迹进行详细分析,锆石单颗粒径迹年龄最大值为143.9±18.7Ma,最小年龄为58±12.1Ma,峰值年龄为92~98Ma和132~138Ma。结合盆地断裂展布及大地构造背景,认为漠河盆地在95Ma和135Ma发生了2次强隆升过程。结合盆地断裂系统、构造特征及区域地质背景,认为自晚侏罗世以来盆地形成受到蒙古-鄂霍次克海碰撞关闭和古太平洋板块俯冲碰撞双重作用的影响,盆地中晚侏罗世(135Ma左右)处于南北向挤压背景,形成东西向展布的前陆盆地;白垩纪中期,盆地处于伸展构造背景,属东北(同)大陆裂谷系的一部分。白垩纪中晚期(95Ma左右),漠河盆地由拉张环境再一次变为挤压环境,盆地形成了又一次的强隆升过程。  相似文献   

14.
水对岩石亚临界裂纹扩展及门槛值的影响研究   总被引:2,自引:0,他引:2  
万琳辉  曹平  黄永恒  汪亦显 《岩土力学》2010,31(9):2737-2742
亚临界裂纹扩展是岩体工程时间相依性的主要原因之一。采用常位移松弛法,对饱水和干燥两种状态下的大理岩、花岗岩双扭试件进行了亚临界裂纹扩展试验研究,获得了两种岩石在两种状态下的亚临界裂纹扩展速率V与应力强度因子 的关系,分析了两种岩石在两种状态下亚临界裂纹扩展的规律,并确定了两种岩石在两种状态下的门槛值(干燥状态):大理岩 为1.365,花岗岩 为2.305;(饱水状态):大理岩 为1.118,花岗岩 为1.490。研究表明,两种岩石的 与 关系有较好的线性规律, 但由于岩石本身矿物成分等的不均匀性,同种岩石的 与 关系离散性较大,饱水状态下离散性更大;水能加速岩石亚临界裂纹的扩展,且对不同的岩石,其影响程度也不一样;水可以使岩石亚临界裂纹扩展的门槛值有较大幅度降低,不同岩石其降低的程度也不一样。  相似文献   

15.
柴西地区上干柴沟组上段(N12)烃源岩的沉积水体环境为咸水湖相。其烃源岩的有机质总体丰度不高;有机质类型主要有腐殖腐泥型和腐殖型,具体分布受烃源岩所处位置及沉积环境控制;有机质成熟度多为未成熟-低成熟;有机质的烃转化率较高,反映其大部分有机质已经进入生烃门限,少量已经进入生烃高峰期。其烃源岩具有咸化湖泊相未熟-低熟有机质生烃的特点,而其生烃机理很可能是藻类生物类脂物和细菌的早期成烃。柴西地区上干柴沟组上段(N12)烃源岩作为该区未熟-低熟石油主要源岩之一,具有非常大的勘探潜力。  相似文献   

16.
本研究选取天然红壤作为研究对象,分析其中的含铁半导体矿物光催化作用对本源微生物群落结构的影响。采用聚 合酶链式反应/变性梯度凝胶电泳(PCR-DGGE),研究了不同原始光照条件的红壤中微生物群落在外源电子作用下群落结 构的改变。DGGE图谱的主成分分析表明,两个不同原始光照环境的土壤样品的微生物群落结构由于原始环境的差异而不同: 原始环境为强光照的样品中微生物群落结构受外源电子影响较小;原始环境为弱光照的样品中微生物群落结构受外源电子 影响较大。这一群落结构改变的差异可能由于原始环境为强光照时半导体矿物光催化作用产生光生电子传递到环境中持续 影响周围的微生物群落,而原始弱光照环境中则缺少光生电子的作用。  相似文献   

17.
Different sedimentary settings can influence preservation of pollens, which would lead to misinterpretation of fossil pollen spectrum. This study investigates the influence on the preservation of Pinus tabulaeformis pollen by simulating alkaline and oxidative environment in the laboratory. There was no obvious change in the content of Pinus tabulaeformis pollen while comparing the original with the ones that were immersed with 10% NaOH liquor for ten days, or boiled for five hours, and or boiled with 20%–30% NaOH for one hour, respectively. However, the pollen fossils were obviously corroded and eroded after being boiled with 40% NaOH for one hour and were seriously corroded after five hours. The result indicates that Pinus tabulaeformis pollen is quite durable in alkaline environment and heating condition within a shorter period of time, although alkaline environment has a disadvantage for its preservation. We also tested the influence of oxidation on Pinus tabulaeformis pollen preservation with KMnO4 as oxidant. The result presents that the number of remaining Pinus tabulaeformis pollen grains decreased quickly after being dipped in KMnO4 along with extending the reaction time and reinforcing oxidant. The rate of remnant pollen grains was less than 1% after being dipped with 2% KMnO4 for one hour. It is suggested that oxidative environment has stronger influence on Pinus tabulaeformis pollen preservation than alkaline environment.  相似文献   

18.
运用层次分析和全局主成分分析结合的综合统计评价模型(AHP-GPCA模型),以县域和流域为评价单元,以气温、降水、归一化差异植被指数(NDVI)、冰川密度、湿地密度、湖泊率、人口密度、荒漠化率等数据为评价指标基础,基于GS/GIS对20世纪70年代末期至2000年青藏高原生态环境变迁进行综合评价,并探讨了研究区生态环境总体变化和空间分异特征。结果表明:从20世纪70年代末期到2000年,青藏高原生态环境变迁较为剧烈,重度中度恶化面积占青藏高原总面积的31.8%,轻度恶化面积占14.5%,好转的地区面积占13.5%,反映青藏高原地区生态环境自20世纪70年代末期以来总体恶化,仅有部分县域生态环境好转;依据全局主成分分析得到的三个主成分分别是荒漠化、冰川密度和NDVI,其累计贡献率超过70%,基本能够代表最初获取的8个指标;生态环境退化程度最为严重的流域主要在青藏高原腹地、柴达木盆地以及环青海湖地带,恶化最为严重的流域为格尔木地区,生态环境好转程度最大的流域为藏东南地区;青藏高原环境变迁呈现由边缘地区向腹地恶化的多层次结构,并呈现向两个极端方向发展的特征,其中生态环境转好的县域多分布在冰川较为集中的地区,反映了从20世纪70年代末期到2000年在冰川变迁影响下部分县域的局地气候、生态环境、水资源变化的复杂性。最后探讨了Rs/GIS和AHP_GPcA模型进行综合评价的优势,认为该方法兼顾了评估主客观权重,减少了信息重复,使结果具有直观化的特点。  相似文献   

19.
新嘎果矿床是西藏冈底斯成矿带北缘矽卡岩多金属成矿带的一个典型矽卡岩型铅锌矿床。矽卡岩矿体主要呈层状、似层状产于下白垩统塔克那组地层中。电子探针测试结果表明,矽卡岩矿物主要为钙铝榴石、钙铁辉石和绿帘石,少量的硅灰石、密绿泥石等,构成典型的钙质矽卡岩。金属矿物主要为闪锌矿、方铅矿、磁黄铁矿、黄铜矿、黄铁矿,少量的白铁矿、毒砂、自然铋、斜方辉铅铋矿、辉砷镍矿等。该矿床中石榴子石成分特征指示成矿环境是变化的,在早期进变质阶段由氧化环境向还原环境转变,而晚期退变质阶段由氧化环境向还原环境转变。金属矿物中闪锌矿主要为铁闪锌矿,表明其形成于中高温环境。而含铋的矿物主要为自然铋、斜方辉铅铋矿和方铅矿,并且在这些矿物中Ag和Bi的含量呈正相关性,指示铋对银的富集可能起着重要的作用;此外,铋也是新嘎果矿床重要的伴生有用元素,具有较高的综合利用价值。  相似文献   

20.
The Ordovician System, cropping out in southern and west-central Jordan, consists entirely of a 750 m thick clastic sequence that can be subdivided into six formations. The lower Disi Formation starts conformably above the Late Cambrian Umm Ishrin Formation. According to Cruziana furcifera occurring in the upper third of the Disi Formation, an Early Ordovician age is confirmed. The Disi Formation, consisting mainly of downstream accretion (DA) fluvial architectural element, was deposited in a proximal braidplain flowing N–NE from the southerly-located Arabian–Nubian Shield towards the Tethys Seaway. The braidplain depositional environment evolved into a braidplain-dominated delta through the middle and upper parts of the Disi Formation and the lower part of the overlying Um Saham Formation. The delta was replaced by siliciclastic tidal flats, that in turn evolved into an upper to lower shoreface environment through the upper part of the Um Saham Formation. The depositional environment attained the maximum bathymetric depth during the deposition of the lower and central parts of the third unit, the Hiswa Formation, where offshore graptolite-rich mudstone with intercalated hummocky cross-stratified tempestites were deposited. The Tethys Seaway regressed back through the upper part of the Hiswa Formation promoting a resumption of the lower–upper shoreface sedimentation. Oscillation between the lower to upper shoreface depositional environment characterized the entire fourth unit, the Dubaydib Formation, as well as the Tubeiylliat Sandstone Member of the fifth unit, the Mudawwara Formation. The depositional history of the Ordovician sequence was terminated by a glaciofluvial regime that finally was gradually replaced by a shoreface depositional environment throughout the last unit, the Ammar Formation.  相似文献   

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