共查询到18条相似文献，搜索用时 93 毫秒
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道县地区泥盆纪地层存在不同的3个沉积相区,各相区岩石组合特征具明显差异,在该区125万区调工作的基础上,总结了泥盆纪地层的沉积相变规律,建立了岩石地层格架,划分出7个岩石层序,并对层序地层进行了浅析. 相似文献
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根据湖南地层发育情况,依国际地层划分标准和中国地层指南要求,将湖南省境内原震旦纪早世划归新元古代南华纪,地层系统可分为3个相区.综合已有同位素测年数据,初步建立起南华纪年代构造格架,确立南华纪底界年龄为800Ma左右,顶界年龄为700Ma左右. 相似文献
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本文系统地总结了百色盆地的第三纪地层,运用多重地层学的理论和方法进行了新的研究和对比,初步提出了划分依据。对古生物七个门类27个组合(带)进行了对比和厘定,重新研究洞均组古脊椎动物化石确定时代为中始新世晚期;在原定更新世长蛇岭组中新发现植物和孢粉,确定地层时代为上新世;研究物性地层解决六吜组与那读组的对比;研究地震地层序列4个,对深部地层划分和构造特征和演化取得了一些新的资料。分析年代地层,提出盆地主干断裂—南伍断裂的初始活动时间为29Ma。为油田开发和油层对比提供了可靠的基础资料。 相似文献
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关中盆地巨厚的新生代沉积为研究区域构造、沉积环境演变与古气候变化研究提供了良好的地质记录，但目前对新生界地层划分和第四纪下限问题仍存在争论。基于钻孔和剖面资料，结合古地磁和生物地层，对关中盆地新生界地层进行了梳理和修订，就第四纪下限和新生界地层划分与对比问题进行了探讨。岩性地层、磁性地层、生物地层证据以及气候变化特征等都支持将第四纪下限定在传统三门组的黄三门与绿三门的交界处或风成黄土与红黏土的界线之处，即松山负极性向高斯正极性转换处(M/G)，古地磁年龄为2.6 Ma。基于关中盆地钻孔和剖面的古地磁数据及前人资料，划分了新生界地层，重新厘定了各沉积地层的沉积年代，将新近纪和第四纪沉积分为风成相和河湖相两套同期异相沉积地层序列，风成红黏土的年代延伸到中中新世，建议将中新世的风成堆积命名为段家坡组。这对关中盆地沉积环境形成演化与古气候变化研究、盆地资源开发以及地质工程建设具有重要意义。 相似文献
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四川盆地寒武系洗象池群发育大套白云岩,由于岩性、电性差异小,化石稀少,地层厚度变化大,层序划分与演化特征一直存在很大争议。基于层序地层学及沉积学相关理论研究,通过对露头剖面、钻井岩心的观察及测井资料的研究,结合测井曲线频谱趋势分析技术及碳氧同位素相关数据,开展对洗象池群层序地层的划分及建立全盆地统一的层序地层格架研究。盆地内虽然基本都是一套白云岩,各分区命名差异大,但依然具有全盆范围内可对比的不整合界面和最大海泛面。研究认为四川盆地洗象池群可划分为4个三级层序,并且厘定了盆地内各分区间的层序地层对应关系。在建立全盆地层序地层格架的基础上,发现洗象池群地层分布呈西薄东厚的楔形体,其中遂宁-乐至-资阳以西缺乏洗象池群沉积。层序格架内有利储集层的分布明显受控于层序界面,其中颗粒滩相主要发育在高位体系域。 相似文献
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通过山西省寿阳测区1:5万区域地质调查工作,在华北板块中部太行山中段地区西部的小方山地区内,发现了下古生界寒武系下统馒头组地层,增补了该区寒武系馒头组地层的空白.通过多重划分对比,建立起了小方山寒武系馒头组沉积地层在岩石、生物、时间等多维空间中的立体形态,为今后在该区域上馒头组地层划分并与邻区进行多重地层对比提供了可靠的资料. 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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Seismic stratigraphic analysis of 150 km of high-resolution seismic profiles (GEO-PULSE and 3.5 kHz) obtained along the muddy coast off Taishan, Guangdong provided valuable information on the offshore Quaternary stratigraphy, tectonics, sedimentary evolution, and environmental and engineering geology of this area. The following late Quaternary stratigraphic sequences were mapped. (1) Pleistocene alluvial silty sand and shallow marine clay; (2) coarse fluvial channel sand; (3) nearshore and bay clayey sediments. The incision of fluvial channels occurred in two stages: dttring the Late Pleistocene and at the beginning of the Holocene. The Pleistocene fluvial channels have been filled by coarses and overlain by more than 10 m of late Pleistocene clay and 20 - 30 m of Holocene clay. The coastal area is dissected by two major fault systems: the first group strikes ENE-WSW and controls the evolution of the adjacent Quaternary basin, while the second one trends NNE-SSW. These fault systems must be taken into account in any coastal engineering considerations. In addition, both granitic and metamorphic basements were recognized. 相似文献
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Regular distribution patterns of elements Ca, Sr, K, Na, Mg, Fe, Mn, Ti, Cu, Co, Ni, Zn, Pb, Cr, Rb, Ba, Cd, and U in Late
Quaternary strata have been studied in detail. The regional variation patterns of elements in these strata are similar to
those in recent surface sediments, showing that the sedimentary environment has been relatively stable since Late Quaternary.
Element distribution changes with the variations of lithological characters. Contents of Ca and Sr increase in coarse sediments,
while those of other elements decrease. Na content increases in the pumice layer. Mn, content tends to increase sharply towards
the surface layer. Ca content decreases sharply in strata where water depth is more than 2,000 m. The strata can be divided
based on the distribution curves of element assemblages. The variations in contents of most elements in Holocene Series are
smaller than those in Late Pleistocene Series, which might be related to the factors of glacial and interglacial changes,
sea level fluctuations and material source differences.
Contribution No. 1488 from Institute of Oceanology, Academia Sinica 相似文献
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Late Paleozoic strata in northeastern China are distributed in a zonal pattern around the old-land on the Jiamusi-Mongolia Block.They are composed of active deposits in the regular distributed tectonic lithofacies zones.This indicates that the late Paleozoic strata belong to continental margin deposits.According to the strong conformability of the sedimentary strata in the same continental margin and distinct differences among the three continental margins,three stratigraphical regions of the Jiamusi-Mongolia Stratigraphical Province are recognized along the northern,southern and eastern margins of the Jiamusi-Mongolia Block,named respectively as Xing’an Stratigraphical Region,Inner Mongolia grass--Songhua River Stratigraphical Region and Baoqing--Hunchun Stratigraphical Region.Due to the characteristics of continental margin deposits and active sediments,the strata can be correlated on the level of formation by the methods of analysing the rock association in the same stratigraphic region.Therefore,some revisions of the lithological formations of the late Paleozoic strata in northeastern China have been made,and a new chart of lithostratigraphic correlation has been proposed.Furthermore,the present stratigraphic framework is setting on the International Stratigraphic Chart on the level of stage,after comprehensive researches to lithostratigraphy,biostratigraphy and chronostratigraphy,especially the conodont biostratigraphy and isotopic ages of volcanic rocks obtained in recent years. 相似文献
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ESR dating of aragonitic and calcitic corals , eolianite , calcrete , and corallineae from coral reefs in the South China Sea was applied to study of Quaternary reef geology . The ESR ages of calcitic corals correlated with the biostratigraphy , lithostratigraphy and geochemistry of Well Xi-Chen-1 and the oxygen-isotope stratigraphy of deep sea sediments, were reliable and up to 1.26 Ma. The selection of signals for dating and other related problems are discussed . 相似文献
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自释光现象被用于沉积物测年的半个多世纪以来,释光测年技术已被广泛应用于各类海洋沉积物的年代测定,为古环境古气候和构造活动及地形地貌演变等研究提供了高精度年代学约束的同时,释光测年技术的精度和准确性也取得了长足发展。在系统回顾和总结海洋沉积物释光测年的发展历史基础上,详细讨论了释光测年技术在海洋沉积物测年中的研究现状,总结了全球海洋沉积物释光测年研究的特点。海洋沉积物的沉积埋藏过程相对复杂,部分晒退现象普遍存在,饱和含水的沉积环境导致环境剂量精确测定存在一定困难。因此在海洋沉积物年代测定和计算过程中需要根据实际情况对样品的释光性质进行分析,选择合适的等效剂量测试方法,并使用合适的环境剂量校正方法进行年代计算。释光测年方法在晚更新世以来海洋沉积物测年中表现出了独特的优势,释光测年目标矿物在海洋沉积物中普遍存在,并且随着近年来研究的不断深入,测年精度也得到了明显的提高,可以为晚更新世以来的海洋沉积物研究提供高精度的绝对年代地层格架。 相似文献
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Jian-hui Jin Zhi-zhong Li Yan Cheng Xiao-lin Xu Zhi-xing Li Xiao-ju Liu 《山地科学学报》2018,15(8):1777-1788
The 'Old Red Sand' is a type of semicemented medium-fine sandy sediment that is red (10R4/8) or brown red (2.5YR4/8) in colour and is found in late Quaternary deposits. The sediments have distinctive characteristics and are a critical archive for understanding climatic changes in the coastal areas of East Asia. The ages of the late Quaternary aeolian sand dunes from Haitan Island in the coastal area of South China are still in debate. In this study, three sets of marine terraces were identified in the northern region of Haitan Island. Aeolian dune sands are well preserved on the top of these terraces. Quartz Optically Stimulated Luminescence dating and the distribution of the formation ages demonstrated that the palaeo-dunes are deposits from the middle-late period of the Late Pleistocene (Q 3 2-3 ). The period may be divided into three stages, 100–90 ka, 70–60 ka, and 40–20 ka, in which the palaeo-dunes of the first two stages are more widespread and were formed separately during a low-sea level period of the Marine Isotope Stages 5b and 4. Several depositional palaeo-flood event records were preserved during the last stage due to the increasing gradient of mountain gullies formed during the Last Glacial Maximum. 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 three sediment strata marked with units I, II and III, which would be consistent with the divided sediment
stratum of the core using minor element geochemistry. The downcore distribution of heavy minerals divided the sedimentary
sequence into three major units, which were further subdivided into four subunits. The interval between 0 and 63 cmbsf of
the core (unit I), which spans the Holocene and the uppermost late Pleistocene, is characterized by a hornblende-epidote-pyroxene
assemblage, and contains relatively a smaller amount of schistic mineral and authigenic pyrite. In comparison, the interval
between 63 and 228 cmbsf (unit II), is representative of the Last Glacial Maximum (LGM), and features a hornblende-epidote-magnetite-ilmenite
assemblage containing the highest concentrations of heavy minerals and opaque minerals. However, the interval between 228
and 309 cmbsf (unit III), which spans the subinterglacial period, is characterized by a hornblende-authigenic-pyrite-mica
assemblage. Relative ratios of some heavy minerals can be used as tracers of clastic sediment sources. The lower part of the
sediment core shows the highest magnetite/ilmenite ratio and relatively high hornblende/augite and hornblende/epidote ratios.
The middle core shows the highest hornblende/augite and hornblende/epidote ratios, and the lowest magnetite/ilmenite ratio.
The upper part exhibits a slightly higher magnetite/ilmenite ratio, and also the lowest hornblende/augite and hornblende/epidote
ratios. The distribution of the mineral ratio is consistent with stratigraphic division in heavy mineral data using correspondence
analysis and fuzzy C-means clustering. Variations in heavy mineral association and mineral ratio in core Q43 revealed changes
in provenance and depositional environment of the southern outer shelf of the East China Sea since the late Pleistocene, well
corresponding to interglacial and glacial cycles. 相似文献