共查询到20条相似文献，搜索用时 31 毫秒
1.
Sedimentary facies, depositional environments and palaeogeographic evolution of the Neogene Denizli Basin, SW Anatolia, Turkey 总被引：2，自引：0，他引：2
The Denizli Basin (southwestern Anatolia, Turkey) contains a record of environmental changes dating since the Early Miocene. Detailed facies analysis of the Neogene formations in this half-graben enables us to document successive depositional regimes and palaeogeographic settings. Sedimentation commenced in the Early Miocene with the deposition of alluvial-fan and fluvial facies (K?z?lburun Formation). At this stage, alluvial fans sourced from elevated areas to the south prograded towards the basin centre. The Middle Miocene time saw the establishment of marginal lacustrine and wetland environments followed by the development of a shallow lake (Sazak Formation). The uppermost part of this unit consists of evaporitic saline lake and saline mudflat facies that grade upward into brackish lacustrine deposits of Late Miocene-Pliocene age (Kolankaya Formation). The lake became shallower at the end of the Pliocene time, as is indicated by expansion shoreface/foreshore facies. In the Early Quaternary, the Denizli Basin was transformed into a graben by the activation of ESE-trending normal faults. Alluvial fans were active at the basin margins, whereas a meandering river system occupied the basin central part.Oxygen isotope data from carbonates in the successive formations show an alternation of wetter climatic periods, when fresh water settings predominated, and very arid periods, when the basin hosted brackish to hypersaline lakes. The Neogene sedimentation was controlled by an active, ESE-trending major normal fault along the basin's southern margin and by climatically induced lake-level changes. The deposition was more or less continuous from the Early Miocene to Late Pliocene time, with local unconformities developed only in the uppermost part of the basin-fill succession. The unconformable base of the overlying Quaternary deposits reflects the basin's transformation from a half-graben into a graben system. 相似文献
2.
S. V. Popov M. P. Antipov A. S. Zastrozhnov E. E. Kurina T. N. Pinchuk 《Stratigraphy and Geological Correlation》2010,18(2):200-224
Sea-level fluctuations in the terminal Eocene, Oligocene, and Neogene of the Eastern Paratethys are quantitatively assessed
on the basis of facies and old coastlines traced on the northern platform shelf, levels of river valley incisions, and the
study of seismic profiles. The first data massif allows the characterization and correlation of transgression stages in the
history of the Eastern Paratethys. The greatest transgressions fall within the first half of the Late Eocene, mid-Early Oligocene,
initial Late Oligocene, initial Early Miocene, the initial Tchokrakian, Karaganian and Sarmatian in the Middle Miocene, the
middle and late Sarmatian and early Pontian in the Late Miocene, and the Akchagylian in the Caspian basin of the Pliocene.
In contrast, the greatest incisions of northern rivers running from the platform allow us to establish the time and extent
of the main declines in the base levels of the erosion. Maximal incisions date back to the terminal Eocene-initial Oligocene,
terminal Solenovian time in the terminal Rupelian, the terminal Maikop in the Early Miocene, the terminal Sarmatian and middle
Pontian in the Late Miocene, and the Early Pliocene in the Caspian basin. Large regressions also formed unconformity surfaces,
traced on seismic profiles as erosion boundaries of several orders. The surfaces are confined to the Eocene/Oligocene boundary,
middle and late Maikop, Sarmatian/Meotian boundary, middle Pontian, and terminal Miocene-initial Pliocene, as well as being
traced even in the most deep-water basins. The synthesis of these data suggests a preliminary version for the curve of transgression-regression
cyclicity. Its correlation with the eustatic curve shows their similarity only in the lower part-prior to the initial Middle
Miocene, when Paratethys became a semi-closed basin. 相似文献
3.
大洋钻探工程” 1 2 5航次的 782 A钻孔位于西太平洋菲律宾海东北部 ,井深 4 76.8m。基底为安山岩 ,上覆盖层为中始新统—更新统的沉积层 ,其中保存有低丰度的有孔虫。自下而上可划分出 8个浮游有孔虫带。由于出现 Catapsydrax dissimilis,C.stainforthi为 N5 、N6 带的带化石 ,表明本钻孔存在早中新世的地层。同时由于缺失浮游有孔虫带 P1 5 — P1 6 下部 ,N3上部—N4,N7—N1 1 带的带化石 ,说明在中始新世与晚始新世之间、晚渐新世与早中新世之间、早中新世与中中新世之间存在 3个沉积间断。钻孔中的有孔虫标志本区当时处于温暖亚热带环境。根据不同时期温度的变化 ,可划分出 5个阶段 ,包括 3个偏暖时期和 2个温凉时期。 相似文献
4.
研究了菲律宾海盆东北部“大洋钻探工程”１２５航次７８２Ａ孔晚始新世以来的放射虫化石。根据Ｓａｎｆｉｌｉｐｐｏ等１９８５年的分带,将研究区自下而上划分为１０个带。讨论了始新世与渐新世、渐新世与中新世、中中新世与晚中新世、中新世与上新世以及上新世与第四纪的界线。研究区存在两个沉积间断,分别位于晚渐新世与早中新世晚期之间和中中新世与晚中新世之间。研究区第四纪放射虫化石仍以暖水分子为主,冷水分子分布较浅。依据放射虫化石分异度曲线得出,晚第三纪以来本区存在５个相对暖水期和５个相对较凉期,渐新世时处于冷水期,这与钙质超微化石复合分异度和碳酸钙含量曲线的变化是一致的。晚渐新世与早中新世晚期之间的沉积间断是由于中新世南极冰盖扩展造成大洋底层洋流活动加剧而形成的。 相似文献
5.
《Geodinamica Acta》2001,14(1-3):45-55
Field studies on the Neogene successions in south of İzmir reveal that subsequent Neogene continental basins were developed in the region. Initially a vast lake basin was formed during the Early–Middle Miocene period. The lacustrine sediments underwent an approximately N–S shortening deformation to the end of Middle Miocene. A small portion of the basin fill was later trapped within the N–S-trending, fault-bounded graben basin, the Çubukludağ graben, opened during the Late Miocene. Oblique-slip normal faults with minor sinistral displacement are formed possibly under N–S extensional regime, and controlled the sediment deposition. Following this the region suffered a phase of denudation which produced a regionwide erosional surface suggesting that the extension interrupted to the end of Late Miocene–Early Pliocene period. After this event the E–W-trending major grabens and horsts of western Anatolia began to form. The graben bounding faults cut across the Upper Miocene–Pliocene lacustrine sediments and fragmented the erosional surface. The Çubukludağ graben began to work as a cross graben between the E–W grabens, since that period. 相似文献
6.
新疆叶城晚新生代山前盆地演化与青藏高原北缘的隆升--Ⅱ沉积相与沉积盆地演化 总被引：15，自引：0，他引：15
叶城盆地属于塔里木盆地的西南坳陷 ,在晚新生代沉积了巨厚的磨拉石建造。盆地的演化具有阶段性 ,反映了西昆仑山不断的隆升。中新世 ,盆地的沉积环境为曲流河和辨状河等河湖相环境 ,到上新世早期变为冲积扇的远端。晚上新世 (～ 3.6 Ma)开始 ,盆地的沉积环境发生了质的变化 ,沉积物以粗颗粒砾岩为主 ,沉积环境为干旱气候条件下的冲 -洪积扇近端。沉积相的变化 ,反映了昆仑山在晚上新世有强烈的隆升。 相似文献
7.
《Earth》2008,86(3-4):161-186
Pollen records from fluvial deposits in The Netherlands have traditionally been used to establish continental stages for the Neogene in NW Europe. These stages are still widely used across Europe for stratigraphic correlations and palaeoclimatic studies. Despite their extensive use, the validity of this continental correlation scheme for the Plio- and Pleistocene has never been tested in the area where they were originally proposed: the Roer Valley Graben (RVG). The fluvial and deltaic depositional setting in this area is controlled by a complex pattern of tectonic and climatic processes, which strongly complicates the definition of stages and sub-stages of regional or supra-regional significance.Here, the original palynological data used to define the Praetiglian, Reuverian, Brunssumian, Susterian, and ‘Linne’ (sub-)stages are assessed and compared to new borehole data. With a multivariate (Correspondence Analysis) approach we show that most of these stages cannot be distinguished by numerical analysis of the pollen assemblages. A tripartition of pollen assemblages is possible, which results in a cooler Pleistocene cluster, warm-temperate to sub-tropical Pliocene cluster, and a warm and relatively dry Late Miocene to Early Pliocene cluster. However, no further stages, sub-stages or clear climatic phases can be consistently recognized in these data.A detailed lithostratigraphic framework of the study area allows a correlation of the sections independent of the pollen data. Results confirm the numerical analyses and furthermore point to a strong lithological (depositional) bias on the pollen assemblages. Variations in the abundance of Sequoia and Taxodium, originally used to define the Brunssumian/Reuverian transition and Brunssumian A–C sub-stages, are shown to represent mostly local changes. The number and absolute percentage of the fluctuations in Sequoia and Taxodium abundances depend largely on the sample resolution and the site location within the RVG.Our data assessment indicates that long-distance chronostratigraphic correlations based on the original continental Neogene stages likely are invalid. Furthermore, the palaeoclimatic reconstructions that have been based on the RVG successions are largely over-interpreted. The present palaeoclimate reconstructions from the RVG reflect variations in the highly-dynamic fluvial depositional setting, taphonomic effects and environmental conditions, including climate. A sequence-stratigraphic approach combined with the analysis of interfingering marine sediments is potentially better suited to establish absolute ages and associated climatic conditions of the Neogene deposits within the RVG. 相似文献
8.
对南京—仪征地区新近纪砂砾层层序、时代进行了讨论。该地区新近纪砂砾层地层层序为中新世中期的洞玄观组(Nld)、中新世晚期的六合组(N1l)、黄岗组(N1h)及上新世的雨花台组(N2y)，认为雨花台组沉积是位于六合组之上的另一套砂砾层，其沉积时代为上新世晚期。还分析了新近纪砂砾层在中新世中期、中新世晚期、上新世的沉积环境，探讨了区内古长江的形成与演化，认为古长江是在古近纪断陷盆地的基础上，经历了中新世多个汇水盆地的发育阶段至上新世形成古长江雏形，并于更新世早期基本定型，其形成及演化过程均与新构造活动息息相关。 相似文献
9.
Fetheddine Melki Taher Zouaghi Mohamed Ben Chelbi Mourad Bédir Fouad Zargouni 《Comptes Rendus Geoscience》2010,342(9):741-753
The structural pattern, tectono-sedimentary framework and geodynamic evolution for Mesozoic and Cenozoic deep structures of the Gulf of Tunis (north-eastern Tunisia) are proposed using petroleum well data and a 2-D seismic interpretation. The structural system of the study area is marked by two sets of faults that control the Mesozoic subsidence and inversions during the Paleogene and Neogene times: (i) a NE-SW striking set associated with folds and faults, which have a reverse component; and (ii) a NW–SE striking set active during the Tertiary extension episodes and delineating grabens and subsiding synclines. In order to better characterize the tectono-sedimentary evolution of the Gulf of Tunis structures, seismic data interpretations are compared to stratigraphic and structural data from wells and neighbouring outcrops. The Atlas and external Tell belonged to the southernmost Tethyan margin record a geodynamic evolution including: (i) rifting periods of subsidence and Tethyan oceanic accretions from Triassic until Early Cretaceous: we recognized high subsiding zones (Raja and Carthage domains), less subsiding zones (Gamart domain) and a completely emerged area (Raouad domain); (ii) compressive events during the Cenozoic with relaxation periods of the Oligocene-Aquitanian and Messinian-Early Pliocene. The NW–SE Late Eocene and Tortonian compressive events caused local inversions with sealed and eroded folded structures. During Middle to Late Miocene and Early Pliocene, we have identified depocentre structures corresponding to half-grabens and synclines in the Carthage and Karkouane domains. The north–south contractional events at the end of Early Pliocene and Late Pliocene periods are associated with significant inversion of subsidence and synsedimentary folded structures. Structuring and major tectonic events, recognized in the Gulf of Tunis, are linked to the common geodynamic evolution of the north African and western Mediterranean basins. 相似文献
10.
临夏盆地的晚新生代沉积中富含哺乳动物化石,以晚渐新世巨犀动物群、中中新世铲齿象动物群、晚中新世三趾马动物群和早更新世真马动物群的化石最为丰富。晚新生代是青藏高原快速隆升的时期,临夏盆地的4个主要哺乳动物群在构造剧烈变化的背景下发生了显著的更替。通过对不同动物群所代表的生态特征的分析,恢复了临夏盆地晚新生代以来的气候环境演变过程:晚渐新世以温暖湿润的森林环境为主,间杂有一些开阔地带;中中新世的森林更加茂密,水体更加丰富;晚中新世演变为炎热半干旱的稀树草原环境,季节性变化加强;早更新世气候寒冷而干燥,并伴有显著的海拔升高。青藏高原在晚渐新世的隆升幅度还不足以阻挡大型哺乳动物在高原南北的交流,但到中中新世已成为明显的障碍,至晚中新世对动物迁徙的阻碍作用更加突出,而临夏盆地在早更新世已经达到相当大的高度,产生了一个高原或高山的动物群 相似文献
11.
A palynological analysis of the Late Miocene and Early Pliocene successions of the Cappadocian Volcanic Province (Central Anatolia, Turkey) has been carried out with the aim of reconstructing the palaeovegetation and palaeoclimatic conditions. The samples are collected from outcrop sections from three different localities (A: Akda?, B: Bayramhac?l? and G: Güzelöz). The pollen spectra reveals the existence of a steppe vegetation dominated by Amaranthaceae–Chenopodiaceae and Artemisia, typical of present day arid and semi-arid continental areas (i.e. Middle East), and Asteraceae Asteroideae in the A section (Late Miocene) developed in arid climatic conditions. The flora of the G (Early Pliocene) and lower part of the B (Late Miocene) sections reflects steppes on which Asteraceae Asteroideae was dominant. This flora also indicates arid conditions. The development of trees in the upper part of the B section was possibly related to local paleoenvironmental conditions rather than a climatic change. This study provides the first palynological data to reveal the presence of an Amaranthaceae–Chenopodiaceae and Artemisia steppe already during the Late Miocene in Turkey. 相似文献
12.
Can Ş. Genç Şafak Altunkaynak Zekiye Karacık Metin Yazman Yücel Yılmaz 《Geodinamica Acta》2013,26(1-3):45-55
AbstractField studies on the Neogene successions in south of ?zmir reveal that subsequent Neogene continental basins were developed in the region. Initially a vast lake basin was formed during the early-Middle Miocene period. The lacustrine sediments underwent an approximately N-S shortening deformation to the end of Middle Miocene. A small portion of the basin fill was later trapped within the N-S-trending, fault-bounded graben basin, the Çubukluda? graben, opened during the Late Miocene. Oblique-slip normal faults with minor sinistral displacement are formed possibly under N–S extensional regime, and controlled the sediment deposition. Following this the region suffered a phase of denudation which produced a regionwide erosional surface suggesting that the extension interrupted to the end of Late Miocene–Early Pliocene period. After this event the E–W-trending major grabens and horsts of western Anatolia began to form. The graben bounding faults cut across the Upper Miocene–Pliocene lacustrine sediments and fragmented the erosional surface. The Çubukluda? graben began to work as a cross garden between the E–W grabens, since that period. © 2001 Éditions scientifiques et médicales Elsevier SAS 相似文献
13.
Mongi Chikhaoui 《Comptes Rendus Geoscience》2004,336(12):1131-1136
During the Neogene, the sedimentary succession changed from marine shallow water formations during the Early and Middle Miocene to lagoonal and continental formations during the Late Miocene and the Pliocene. This succession is subdivided into three sedimentary major cycles that are mainly due to compressional tectonic events. Propagating folds above a detachment within the evaporitic Triassic strata caused the formation of the tectonics. To cite this article: M. Chikhaoui, C. R. Geoscience 336 (2004). 相似文献
14.
对取自沱沱河盆地、通天河盆地、那曲盆地、东温泉盆地、乌郁盆地的新近纪湖相沉积与取自巴斯错、错鄂、纳木错的晚第四纪湖相沉积,进行孢粉分析;结合西宁—民和盆地、伦坡拉盆地、南木林盆地、渭河盆地的孢粉资料,分析青藏及邻区新生代晚期古植被和古环境的演化过程。发现渐新世晚期—中新世早期青藏与周边邻区的古环境发生了显著分异,导致青藏地区热带亚热带植物濒临消亡,与全球温暖气候条件和青藏地区古纬度环境不符,是青藏高原隆升的重要标志。中新世早期—第四纪晚期,青藏高原落叶阔叶林和针叶林呈现总体减少趋势和准周期性波动,与全球气候变化呈良好对应关系。第四纪晚期草本植物含量逐步增高,出现蒿—松—桦为主,针叶林、落叶阔叶林、灌木、草本植物混生的植被景观。 相似文献
15.
Evaporitic‐lagoonal marl and dolomite laminar fill sediments are preserved in relict dry caves of the Dead Sea Fault Escarpment (Israel) which has been tectonically active since the Late Neogene. The hosting caves are located within Turonian massive carbonate bedrock and at higher altitudes than previously documented fill sediments of the Dead Sea depression. Based on the relative altitudes of the cave sediments, the ‘reversed stratigraphy’ of the Dead Sea depression fill sediments, possible partial correlation of the cave sediments with other fill sedimentary units of the depression, and sedimentary, geochemical and mineralogical characteristics, it is concluded that: (i) the cave sediments are among the oldest of the depression fill; and (ii) the deposition of the cave sediments took place in hypersaline dolomite‐precipitating water bodies of Late Neogene age, during the initial morphotectonic stages of the depression formation. Variable and relatively low Sr/Ca and δ34S ratios of the cave sediments (assuming precipitation from sea water) suggest variable fresh water input into the depositional brine. The present altitudes of the cave sediments reflect Late Neogene levels of water bodies in the depression, modified by vertical post‐Late Neogene tectonic movements within the still active fault escarpment. According to these altitudes, a 50 to 250 m uplift of the western margins of the depression since the Late Miocene to Early Pliocene is inferred. 相似文献
16.
Regional provenance from southwestern Colombia fore‐arc and intra‐arc basins: implications for Middle to Late Miocene orogeny in the Northern Andes 
下载免费PDF全文
下载免费PDF全文 Sebastián Echeverri Agustín Cardona Andrés Pardo Gaspar Monsalve Victor A. Valencia Carlos Borrero Sebastián Rosero Sergio López 《地学学报》2015,27(5):356-363
Andean orogenic processes controlled the spatial and temporal distribution of the magmatic and sedimentary record. This contribution integrates new U/Pb zircon ages, heavy mineral analyses and biostratigraphic constraints from the Neogene sedimentary record of the fore‐arc and intra‐arc basins and volcano‐plutonic rocks of southwestern Colombia, to reconstruct these orogenic processes. The results reveal continuous arc magmatism since the Late Oligocene, with a major post‐Middle Miocene magmatic peak and exhumation. When integrated with other geological constraints, the tectonic evolution of the margin includes Eocene‐Oligocene oblique convergence with limited magmatic activity, followed by the initiation of a Late Oligocene‐Early Miocene arc that migrated to the east in the Middle Miocene, when it experienced a major increase in magmatic activity, crustal deformation, exhumation and thickening. This orogenic evolution is related to the shallowing of the slab dip due to the subduction of the Neogene Nazca Plate. 相似文献
17.
Late Neogene tectonics in northwestern Victoria: Evidence from the Late Miocene–Pliocene Loxton Sand
The Late Miocene–Pliocene Loxton Sand strandplain extends across the western part of the Murray Basin in southeastern Australia. Gamma logging on groundwater bores surrounding Lake Tutchewop, which lies close to the eastern limit of this strandplain, showed that a heavy mineral layer within the Loxton Sand is displaced across the northern extension of the Leaghur Fault. A crevasse splay sand within the overlying Pliocene Shepparton Formation is also displaced, indicating that tectonic activity along the Leaghur Fault occurred in the Early Pliocene. This coincides with the Kosciusko Uplift, a major phase of Neogene tectonism across southeastern Australia, which also resulted in movement along the Danyo, Hindmarsh, Tyrell and Avoca Faults in northwestern Victoria. 相似文献
18.
Neogene deep sea benthic foraminiferal diversity in the Indian Ocean: Paleoceanographic implications
The species diversity indices, as defined by the number of species,S; Shannon-Wiener index,H(S) and Buzas-Gibson index,É, of DSDP sites 219, 220, 237 and 238 were measured to determine the benthic foraminiferal diversity patterns in the Indian Ocean deep sea sequences during the Neogene. The Time-Stability hypothesis could satisfactorily explain the observed diversity patterns. The general patterns of diversity suggest environmental stability during the Neogene. However, few small fluctuations in diversity during the Middle Miocene (c.14·8 Ma), Late Miocene (c.6·0 Ma) and Late Pliocene (c.2·0 Ma) may possibly be the effects of Antarctic Bottom Water (AABW) activity in this region. The benthic foraminiferal diversity in the tropical Indian Ocean is more than the high latitudinal areas with comparable depths. 相似文献
19.
《Russian Geology and Geophysics》2007,48(4):337-348
On the basis of combined (paleomagnetic, lithological, and paleontological) data, a scale of Neogene geomagnetic polarity is proposed for the West Siberian Plate (WSP). It comprises 17 large orthozones of normal and reversed polarity. The scale was compiled by comparing and correlating the Neogene key sections of the Kulunda and Baraba plains, Irtysh regions between Omsk and Pavlodar and near Tara, and Ob’ region near Tomsk. The reliability of paleomagnetic data is confirmed by component analysis of natural remanent magnetization and by a possibility of determining its primary component. In the studied Neogene rocks this is a high-temperature component related to magnetite, hematite, and maghemite, which decays at 420–675 °C. In the period from Early Miocene to Late Pliocene, the Late Cenozoic geomagnetic field reconstructed from NRM vectors for WSP rocks of Neogene age experienced 17 reversals (at the level of orthozone boundaries), with eight regimes of normal polarity and nine regimes of reversed polarity. Comparison of the WSP Neogene scale with Berggren’s scale provided absolute age boundaries of the Late Cenozoic series on the WSP regional stratigraphic scale. The 23.8 Ma boundary between the Oligocene and Miocene is recorded in the regional scale at the sole of the Lyamin beds of the Abrosimovka Formation, at the bottom of Orthochron R1N1aq, and the Miocene-Pliocene 5.2 Ma boundary (Chron C3r), in the Novaya Stanitsa Formation (top of the Cherlak beds). 相似文献
20.
DENG Tao Institute of Vertebrate Paleontology Paleoanthropology Chinese Academy of Sciences Beijing 《《地质学报》英文版》2005,79(6):739-750
1 Introduction In recent years, field works in the Hezheng area resulted in an explosive growth of new knowledge of Chinese mammalian faunas of the Late Cenozoic. A continuous sedimentary sequence from the Oligocene to the Pleistocene is developed and exposed in the Linxia Basin, Gansu Province, which contains a large number of mammal fossils. The Hezheng area comprises almost the whole Hezheng County, the western half of Guanghe County, the southern half of Dongxiang County, Linxia C… 相似文献