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辽北吉中晚中生代地层发育,植物化石丰富,并赋存重要煤层。笔者在前人工作的基础上,着重分析了本区晚中生代植物群的性质及组合序列特征。辽北吉中晚中生代植物群与Ruffordia-Onychiopsis植物群相一致。由于辽北吉中在地理位置上的重要性,本区可能成为华北、西北的陆相中生代地层与黑龙江东部海相或海陆交互相地层对比的纽带。辽北吉中晚中生代植物群具有明显的晚侏罗-早白垩世色彩。本区Ruffordia-Onychiopsis植物群可以划分为早、中、晚三期组合,早期组合大体相当于晚侏罗世;中期组合为早白垩世早期;晚期组合可能相当于早白垩世中晚期。根据植物化石组合特征,笔者将辽北吉中侏罗—白垩系界线暂置于火石岭组与沙河子纽之间。 相似文献
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本文利用综合地层学理论,在研究过程中选用了多门类生物地层学、同位素年龄地层学和火山地层学、生态地层学和岩石地层学及沉积地层学、地震地层学和测井地层学等手段,对鲁北区、鲁西南区、鲁中区和鲁东区中生代地层进行了划分和对比,即把沂沭断裂带以西的坊子组归为中、下侏罗统,三台组归为中侏罗统,分水岭组归为上侏罗统至下白垩统,西洼组归为下白垩统,“王氏组”归为上白垩统;把沂沭断裂带以东的莱阳组主要归为下白垩统中、下部,青山组归为下白垩统上部,王氏组归为上白垩统。 相似文献
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中侏罗统在鄂东盆地零星散布,应用现代沉积学理论和陆相层序地层学原理,结合露头、薄片、古生物等资料,分析沉积相、物源、构造背景等.结果表明:中侏罗统主要为辫状河、辫状河三角洲及滨浅湖-半深湖沉积体系,可划分为4个三级层序,而整个中侏罗统大致相当于1个二级层序;成因层序的形成受控于秦岭-大别山造山带与中扬子前陆盆地强构造运... 相似文献
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本文综合应用生物地层学，同位素年代学、磁性地层学方面的资料，论述了浙江白垩系顶、底界的位置。指出浙江白垩系的最高层为发育于桐乡凹陷中的桐乡组．其层位与江苏的泰州组相当；对白垩系底界进行了较详细的讨论，指出建德群古生物组合的总面貌显示早白垩世的色彩。劳村组同位素年龄测定值小于130Ma，属于白恶纪范畴。磁性地层学研究发现M0R负极性超时出现在横山组，层位相当于阿普第阶的底部。因此，古地磁资料也不支持将建德群归入侏罗系。浙江白垩系的底界应划在劳村组的底部。 相似文献
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本文从现代理论地层学的概念出发，对华北二叠纪地层划分对比中的几个重要问题，进行了探讨：①岩石地层、生物地层与年代地层的含义；②岩石地层基本单元一组的划分；③岩石地层对比与年代地层对比；④重要标志层在区域对比中的作用；⑤华北二叠系上、下统分界线的划分。通过对这些问题的探讨，暴露了在地层划分对比中，因长期受传统地层学与统一地层划分某些观点的影响所产生的问题，今后应该注意什么和如何处理。 相似文献
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塔里木盆地喀什北地区白垩系层序岩相古地理特征 总被引：1，自引：0，他引：1
根据天山南麓露头剖面和钻井层序地层研究,结合地震资料分析,将塔里木盆地喀什北地区白垩系划分为2个巨旋回层序、4个超长期旋回层序和8个长期旋回层序。其层序-岩相古地理特征自下而上表现为海平面持续上升过程中,由陆相河-湖三角洲过渡到海相三角洲,再到局限台地的沉积相变。利用泥岩微量元素分析,确定古特提斯洋在下白垩统克孜勒苏群上亚旋回就已经影响到喀什北地区,在海侵过程中,形成了连片叠置的退积型三角洲前缘沉积,并造成了该段砂岩中富含碳酸盐胶结物。下白垩统上亚旋回厚层砂岩与上白垩统及古近系的膏泥岩层构成良好的储盖组合,是喀什北地区最重要的油气储集层。 相似文献
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《东北石油大学学报》2015,(3)
以南黄海盆地为研究区,以海相中—古生代地层为研究目的层,采用地震地层学研究方法,综合解释采集处理的地震剖面,结合地层发育特征,划分地震层序.结果表明:研究区可识别T8、T9、T10、T11、T12、T13、Tg等7个反射界面;自上而下将基底反射界面以上的海相地层划分为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ等6个地震层序.根据地震反射特征、地层速度、重磁震联合反演和区域地质,确定地层属性分别为震旦系、寒武系—奥陶系、志留系—泥盆系、石炭系—下二叠统、上二叠统和下三叠统.根据研究区石油地质条件,南黄海盆地海相地层分布稳定,残留厚度较大,存在4套生储盖组合,具备形成大型油气藏的油气地质条件.该研究成果可为分析南黄海盆地地层结构和地质演化特征提供基础资料,对其油气勘探和资源评价具有指导意义. 相似文献
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东北区域水汽收支的变化及其与降水的关系 总被引：2，自引：0，他引：2
为了明确东北区域水汽收支变化及其与降水的关系,利用1970～2010年NCEP/NCAR逐月平均分析资料、国家气象信息中心提供同期的气象站逐日降水实况资料,对东北区域夏半年（5～9月）区域水汽收支的年（年代）际变化及其与降水的关系、降水偏多（少）年的水汽输送特征进行研究.研究结果表明：（1） 1970年代水汽异常输送主要来自华北地区;1980年代,水汽异常输送主要来自蒙古东部和日本海;1990年代,水汽异常输送主要来自鄂霍次克海;2000年以后,水汽异常自东北区域向西南方向输送.总体而言,1970～1990年代区域内的水汽增加,2000年以后区域内水汽明显大幅度减少.（2）东北区域水汽总收支与夏季降水相关性较好,相关系数可达0.79,通过99％的信度检验,南、北边界的水汽输送对该区域的夏季降水有显著影响.（3）东北地区降水偏多年,西北太平洋上的水汽明显增强;降水偏少年,西风带和西北太平洋的水汽输送明显减弱. 相似文献
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Liaodong Bay is one of the largest semi-enclosed bays located in Bohai Sea, in northeast China. It is an important feeding and spawning place, even wintering and breeding migration base for many marine organisms. The size structure of phytoplankton communities is a key feature of marine ecosystems and can be used as an indicator for algae disaster, but the methods to evalute is still challenging. Here, we compared the size-fractionated chlorophyll-a method with a high-throughout sequencing method in an evaluation of the size structure of phytoplankton assemblages in Liaodong Bay, China, in 2014. The proportion of picophytoplankton was estimated at just 19% according to the results based on size-fractionated chlorophyll-a, which likely represents a severe underestimation. The sequencing method confirmed that many kinds of phytoplankton species appeared in more than one size-fractionated filter membrane, with some even dominating where the filter membrane pore size was greater than the individual phytoplankton size. According to the sequencing method, the phytoplankton assemblages in Liaodong Bay were dominated by picophytoplankton(average proportion = 44%), followed by the nanophytoplankton(average 32%), a composition that is more consistent with other studies. The sequencing method provides a more robust way to assess the size structure and taxonomic diversity of marine phytoplankton communities. 相似文献
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Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages,and the sediment sources and depositional dynamics of the environment reconstructed.The assemblages were taken from marine sediments from the late Pleistocene to the Holocene in Core Q43 situated on the outer shelf of the East China Sea.Based on the variable boundaries of the mineral assemblage at 63 and 228 cmbsf (cm below sea floor),the core might have previously been divided into th... 相似文献
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干旱灾害给整个自然灾害体系带来的经济损失最为严重,也是目前检测难度较高的自然灾害之一。SaTScan在灾害时空聚集区的识别中已有应用,但其存在参数设定困难、识别区域不够精确等问题。本文对Moran散点图和局部空间关联指标（Local Indicators of Spatial Association, LISA）进行时空扩展,提出了一种时空Moran散点图的方法,根据研究者对关注现象阈值及置信程度的要求,筛选出符合条件的点,并将其绘制在对应的时空坐标系上,从而得到时空聚集区。以2009—2014年中国干旱时空聚集区识别为例,结果表明：① 时空Moran散点图识别到的干旱时空聚集区与实际基本相符,验证了方法的有效性;同时,与时空扫描法相比,该方法具有识别结果边界清晰、精确,参数设置容易等优点;② 2009年和2011年呈现大范围、较强的干旱时空聚集区,2010年和2014年出现局部、较强的干旱时空聚集,而2012年和2013年的干旱时空聚集情况较轻。综合来看,2009—2014年干旱时空聚集区主要出现在云贵川、东北、黄淮地区和长江中下游等地区。 相似文献
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Early Cretaceous flora from coal-bearing strata of Markovsky Peninsula in South Primorye，Russia 总被引：1，自引：0，他引：1
The Early Cretaceous flora from the coal-bearing strata(Ussuri and Lipovtsy formations)in the Markovsky peninsula of South Primorye,Far East Russia,is reported in some detail in this paper.The flora containing over 80 species of about 50 genera can be divided into two assemblages.The paleofloristic characteristics and the comparisons of this flora with its coeval floras from the adjacent region of the eastern Heilongjiang of Northeast China,indicate the flora and its coal-bearing strata of the Markovsky peninsula can be compared to those of the Chengzihe and Muling formations of the Jixi area of Heilongjiang,representing probably the late Barremian and Aptian age,respectively. 相似文献
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《中国地理科学(英文版)》2019,(6)
Adjacent intensive agriculture disturbs the natural condition of wetlands.However, to assess the effect of this agriculture on wetlands, few studies have used indices based on aquatic invertebrates.Multi-metric indices(MMIs) have been successfully used to assess freshwater ecosystems worldwide and are an important management tool, but little is known about their applicability in the Sanjiang Plain, Northeast China.In this study, we developed a MMIs for aquatic invertebrates to assess freshwater wetlands in this region.The aquatic invertebrate assemblages were sampled in 27 wetlands in the Sanjiang Plain that included those in natural reserves and those affected by adjacent, intensive agriculture.Twenty-four candidate metrics were initially reviewed and screened before four core metrics were selected: total number of taxa, number of Hemiptera taxa, proportion of Gastropoda, and proportion of predators.Mann-Whitney U tests, Box and Whisker plots, correlation analyses, and redundant metric tests were used to assess the ability of metrics to distinguish among reference and impaired wetlands.Four ordinal rating categories for wetland were defined: poor, fair, good, and excellent.Of the impaired freshwater wetlands, 76.2% were in poor or fair categories.The MMIs was robust in discriminating reference wetlands from impaired wetlands and therefore have potential as a biomonitoring tool to assess the condition and to guide the restoration efforts of freshwater wetlands in Northeast China. 相似文献
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The Jiayin area along the Heilongjiang River in Northeast China has attracted stratigraphic and sedimentological interests recently because the Cretaceous--Tertiary (K/T) boundary should be located in this non-marine succession.Dinosaur remains disappear suddenly at the upper part of the Maastrichtian,whereas plants gradually evolved throughout the succession.Analysis of sedimentary facies has been carried out and paleo-environments through Upper Cretaceous to lower Paleocene sections are reconstructed.Fluvial to lacustrine sedimentary environments are inferred from the facies.Several debris flow events have been identified,and it is in these deposits that the dinosaur fossils are concentrated. 相似文献
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Weiwei Chen Shichun Zhang Quansong Tong Xuelei Zhang Hongmei Zhao Siqi Ma Aijun Xiu Yuexin He 《中国地理科学(英文版)》2018,28(5):836-850
Northeast China experiences severe atmospheric pollution, with an increasing occurrence of heavy haze episodes. However, the underlying forces driving haze formation during different seasons are poorly understood. In this study, we explored the spatio-temporal characteristics and causes of haze events in Northeast China by combining a range of data sources(i.e., ground monitoring, satellite-based products, and meteorological products). It was found that the ‘Shenyang-Changchun-Harbin(SCH)'city belt was the most polluted area in the region on an annual scale. The spatial distribution of air quality index(AQI) values had a clear seasonality, with the worst pollution occurring in winter, an approximately oval-shaped polluted area around western Jilin Province in spring, and the best air quality occurring in summer and most of the autumn. The three periods that typically experienced intense haze events were Period I from mid-October to mid-November(i.e., late autumn and early winter), Period II from late-December to February(i.e., the coldest time in winter), and Period III from April to mid-May(i.e., spring). During Period I, strong PM_(2.5) emissions from seasonal crop residue burning and coal burning for winter heating were the dominant reasons for the occurrence of extreme haze events(AQI 300). Period II had frequent heavy haze events(200 AQI 300) in the coldest months of January and February, which were due to high PM_(2.5) emissions from coal burning and vehicle fuel consumption, a lower atmospheric boundary layer, and stagnant atmospheric conditions. Haze events in Period III, with high PM_(10) concentrations, were primarily caused by the regional transportation of windblown dust from degraded grassland in central Inner Mongolia and bare soil in western Jilin Province. Local agricultural tilling could also release PM_(10) and enhance the levels of windblown dust from tilled soil. Better control of coal burning, fuel consumption, and crop residue burning in winter and autumn is urgently needed to address the haze problem in Northeast China. 相似文献