共查询到20条相似文献，搜索用时 343 毫秒
1.
In this paper we present a review of sedimentological, geomorphological, lithological, geochronological and geophysical data from major, minor and satellite basins of the Baikal Rift Zone (BRZ) and discuss various aspects of its evolution. Previously, the most detailed sedimentological data have been obtained from the basins of the central BRZ, e.g., Baikal, Tunka and Barguzin, and have been used by many scientists worldwide. We add new information about the peripheral part and make an attempt to provide a more comprehensive view on BRZ sedimentation stages and environments and their relations to local and regional tectonic events. A huge body of sedimentological data was obtained many years ago by Soviet geologists and therefore is hardly accessible for an international reader. We pay tribute to their efforts to the extent as the format of a journal paper permits. We discuss structural and facial features of BRZ sedimentary sequences for the better understanding of their sedimentation environments. In addition, we review tectono-sedimentation stages, neotectonic features and volcanism of the region. Finally, we consider the key questions of the BRZ evolution from the sedimentological point of view, in particular, correlation of Mesozoic and Cenozoic basins, bilateral growth of the Baikal rift, Miocene sedimentation environment and events at the Miocene/Pliocene boundary, Pliocene and Pleistocene tectonic deformations and sedimentation rates. The data from deep boreholes and surface occurrences of pre-Quaternary sediments, the distribution of the Pleistocene sediments, and the data from the Baikal and Hovsgol lakes sediments showed that 1) BRZ basins do not fit the Mesozoic extensional structures and therefore hardly inherited them; 2) the Miocene stage of sedimentation was characterized by low topography and weak tectonic processes; 3) the rifting mode shifted from slow to fast at ca. 7–5 Ma; 4) the late Pleistocene high sedimentation rates reflect the fast subsidence of basin bottoms. 相似文献
2.
M. I. Kuzmin E. B. Karabanov A. A. Prokopenko V. F. Gelety V. S. Antipin D. F. Williams A. N. Gvozdkov 《International Journal of Earth Sciences》2000,89(2):183-192
With this paper we present a first attempt to combine the direct results on lithology, composition and age dating in the
boreholes BDP-93, BDP-96 and BDP-97 with geological and seismic data from the areas where those sections were drilled. The
sedimentary environments represented by the BDP boreholes are markedly different and possess characteristic lithological features.
The results of the deep drilling provide the essential means for testing numerous age models used in geological reconstructions
of the Lake Baikal rifting dynamics. Neither the basin-wide unconformity interpreted from seismic data, nor the interpreted
change from shallow-water to deep-water facies at the boundary of the seismic stratigraphic complexes were found in the BDP-96
boreholes on Academician Ridge. Also, lithology does not support the proposed reconstructions of intense lake level fluctuations
and transgressions during the Pliocene at Academician Ridge. The continuous deep-water hemipelagic sedimentation at Academician
Ridge has existed for the past 5 Ma. The beginning of an intense rifting phase of the Neobaikalian sub-stage and related drastic
changes in sedimentation processes were interpreted on seismic sections as the basin-wide unconformity B10. Different age
estimates for this boundary ranged from Late Pliocene (3.5 Ma) to Plio-Pleistocene boundary. As shown by BDP-96 borehole,
B10 is associated with a lithological change from diatomaceous ooze to dense silty clay and not with an erosional contact.
The new age for this boundary in BDP-96 is approximately 2.5 Ma. This new age constraint suggests that the upper sedimentary
strata of Northern Baikal (1.5–1.7 km thick) have formed during the past 2.5 Ma with average sedimentation rates of 60–70 cm/ka.
The BDP-93 boreholes at Buguldeika suggest that uplift in Primorsky Range took place prior to 1.07–1.31 Ma, a date which exceeds
the age of previous geological models.
Received: 12 March 1999 / Accepted: 10 February 2000 相似文献
3.
Seismic reflection profiles from the Lake Baikal Rift reveal extensive details about the sediment thickness, structural geometry
and history of extensional deformation and syn-rift sedimentation in this classic continental rift. The Selenga River is the
largest single source of terrigenous input into Lake Baikal, and its large delta sits astride the major accommodation zone
between the Central and South basins of the lake. Incorporating one of the world's largest lacustrine deltas, this depositional
system is a classic example of the influence of rift basin structural segmentation on a major continental drainage. More than
3700 km of deep basin-scale multi-channel seismic reflection (MCS) data were acquired during the 1989 Russian and the 1992
Russian–American field programs. The seismic data image most of the sedimentary section, including pre-rift basement in several
localities. The MCS data reveal that the broad bathymetric saddle between these two major half-graben basins is underlain
by a complex of severely deformed basement blocks, and is not simply a consequence of long-term deltaic deposition. Maximum
sediment thickness is estimated to be more than 9 km in some areas around the Selenga Delta. Detailed stratigraphic analyses
of the Selenga area MCS data suggest that modes of deposition have shifted markedly during the history of the delta. The present
mode of gravity- and mass-flow sedimentation that dominates the northern and southern parts of the modern delta, as well as
the pronounced bathymetric relief in the area, are relatively recent developments in the history of the Lake Baikal Rift.
Several episodes of major delta progradation, each extending far across the modern rift, can be documented in the MCS data.
The stratigraphic framework defined by these prograding deltaic sequences can be used to constrain the structural as well
as depositional evolution of this part of the Baikal Rift. An age model has been established for this stratigraphy, by tying
the delta sequences to the site of the Baikal Drilling Project 1993 Drill Hole. Although the drill hole is only 100 m deep,
and the base of the cores is only ∼670 ka in age, ages were extrapolated to deeper stratigraphic intervals using the Reflection-Seismic-Radiocarbon
method of Cohen et al. (1993). The deep prograding delta sequences now observed in the MCS data probably formed in response
to major fluctuations in sediment supply, rather than in response to shifts in lake level. This stratigraphic framework and
age model suggest that the deep delta packages developed at intervals of approximately 400 ka and may have formed as a consequence
of climate changes affiliated with the northern hemisphere glaciations. The stratigraphic analysis also suggests that the
Selenga Basin and Syncline developed as a distinct depocentre only during the past ∼2–3 Ma.
Received: 1 December 1999 / Accepted: 26 January 2000 相似文献
4.
5.
N. G. Vashchenkova M. T. Gorovaya A. V. Mozherovskii I. B. Tsoy 《Stratigraphy and Geological Correlation》2011,19(6):663-678
A complex (petrographic, micropaleontological, and X-ray diffraction) investigation of the sedimentary cover on the northwestern
slope of the Okushiri Ridge in the Sea of Japan revealed that its basal layers are of Oligocene age and composed of terrigenous
silty-clayey sediments, which were deposited in coastalmarine environments with calm hydrodynamics and low sedimentation rates.
The relative sea-level rise combined with regional tectonic processes at the early-middle Miocene transition resulted in widening
and deepening of sea basins and accumulation of a thick diatomaceous-clayey sequence of middle-upper Miocene sediments. Tectonic
activation in the Pliocene was responsible for development of the ridge and exhumation of rocks formerly occurring at depth
of 500–1000 m. 相似文献
6.
The Dead Sea depression sensu stricto, forms the deepest continental part of the Dead Sea rift, a transfer which separates the Levanthine and Arabian plates. It is occupied by three distinct sedimentary bodies, deposited in basins whose depocenters are displaced northward with time. They are: the continental red beds of the Hazeva Formation (Miocene), the Bira-Lido-Gesher marls and the exceptionally thick rocksalt of the Sedom Formation (Pliocene—Early Pleistocene), and the successive Amora, Lisan and Dead Sea evaporites and clastics (Early Pleistocene—Recent). Lengthwise and crosswise asymmetries of these sedimentary basins and their respective depocenters are due to: leftlateral shear combined with anticlockwise rotation of the Arabian (eastern) plate; steeper faulting of the crustal eastern margin than of the western sedimentary margin, and modification of depositional pattern by twice filling up of basins, by Hazeva red beds during Late Miocene pause of shear and by Sedom rocksalt during Pliocene marine ingression. 相似文献
7.
湖南第四纪地层划分及其下限 总被引：4，自引：0，他引：4
根据第四纪沉积物特征、孢粉组合、古脊椎动物、古地磁等有关资料，将湖南省区内第四系地层自老至新划分为：泪罗组、新开铺组、陈家咀组、白沙井组、马王堆组、白水江组、丁蜀组及水陆洲组等。原划为早更新世湖仙山组或伍家峪组均为上新世乃至中新世地层，并确定其第四纪下限为２５ＭａＢ．Ｐ． 相似文献
8.
The stress fields in the Tunka Rift at the southwestern flank of the Baikal Rift Zone are reconstructed and analyzed on the basis of a detailed study of fracturing. The variation of these fields is of a systematic character and is caused by a complex morphological and fault-block structure of the studied territory. The rift was formed under conditions of oblique (relative to its axis) regional NW-SE extension against the background of three ancient tectonic boundaries (Sayan, Baikal, and Tuva-Mongolian) oriented in different directions. Such a geological history resulted in the development of several en echelon arranged local basins and interbasinal uplifted blocks, the strike-slip component of faulting, and the mosaic distribution of various stress fields with variable orientation of their principal vectors. The opening of basins was promoted by stress fields of a lower hierarchical rank with a near-meridional tension axis. The stress field in the western Tunka Rift near the Mondy and Turan basins is substantially complicated because the transform movements, which are responsible for the opening of the N-S-trending rift basins in Mongolia, become important as Lake Hövsgöl is approached. It is concluded that, for the most part, the Tunka Rift has not undergone multistage variation of its stress state since the Oligocene, the exception being a compression phase in the late Miocene and early Pliocene, which could be related to continental collision of the Eurasian and Indian plates. Later on, the Tunka Rift continued its tectonic evolution in the transtensional regime. 相似文献
9.
Tectonics,stress state,and geodynamics of the Mesozoic and Cenozoic Rift basins in the Baikal region
The results of geological, structural, tectonic, and geoelectric studies of the dry basins in the Baikal Rift Zone and western
Transbaikalia, combined under the term Baikal region, are integrated. Deformations of the Cenozoic sediments related to pulsing
and creeping tectonic processes are classified. The efficiency of mapping of the fault-block structure of the territories
overlapped by loose and poorly cemented sediments is shown. The faults mapped at the ground surface within the basins are
correlated with the deep structure of the sedimentary fill and the surface of the crystalline basement, where they are expressed
in warping and zones of low electric resistance. It is established that the kinematics of the faults actively developing in
the Late Cenozoic testifies to the relatively stable regional stress field during the Late Pliocene and Quaternary over the
entire Baikal region, where the NW-SE-trending extension was predominant. At the local level, the stress field of the uppermost
Earth’s crust is mosaic and controlled by variable orientation of the principal stress axes with the prevalence of extension.
The integrated tectonophysical model of the Mesozoic and Cenozoic rift basin is primarily characterized by the occurrence
of mountain thresholds, asymmetric morphostructure, and block-fault structure of the sedimentary beds and upper part of the
crystalline basement. The geological evolution of the Baikal region from the Jurassic to Recent is determined by alternation
of long (20–115 Ma) epochs of extension and relatively short (5.3–3.0 Ma) stages of compression. The basins of the Baikal
Rift System and western Transbaikalia are derivatives of the same geodynamic processes. 相似文献
10.
A.V. Lukhnev V.A. San’kov A.I. Miroshnichenko S.V. Ashurkov L.M. Byzov A.V. San’kov Yu.B. Bashkuev M.G. Dembelov E. Calais 《Russian Geology and Geophysics》2013,54(11):1417-1426
Based on multiyear measurements of present-day motions in the central area of the Baikal rift system, new data on the kinematics of horizontal motions, relative horizontal deformation rates, and rotation velocities in the area of junction of the South Baikal, North Baikal, and Barguzin rift basins have been obtained. This area is an intricate structure with two transfer zones: Ol’khon–Svyatoi Nos and Ust’-Barguzin.It is shown that crustal blocks are moving southeastward, normally to the structures of transfer zones and at an acute angle to the Baikal Rift strike, which corresponds to the right-lateral strike-slip extensional faulting along the major structure. The average horizontal velocities increase from 3.0 mm yr–1 in the northern South Baikal basin to 6.5 mm yr–1 in the Barguzin basin. The elongation axes prevailing in the study region are mainly of NW–SE direction. The areas of intense deformations are confined to structures with high seismic activity in the South Baikal and, partly, Barguzin basins. This confirms the existence of a present-day zone of the Earth’s crust destruction in the Baikal rift system, which is the most likely source of strong earthquakes in the future. Two zones with rotations in opposite directions are recognized in the rotation velocity field. Clockwise rotation is typical of structures of N–NE strike (Maloe More basin, southern North Baikal basin, Barguzin Ridge rise). Counterclockwise rotation is determined for NE-striking structures (northern South Baikal basin, southern Barguzin basin). In general, the obtained data show an intricate pattern of present-day horizontal dislocations and deformations in the area of junction of NE- and N–NE-striking rift structures. This suggests left- and right-lateral strike-slip faults, respectively, within them. 相似文献
11.
V. Yu. Zabrodin 《Russian Journal of Pacific Geology》2017,11(3):155-162
The northeastern extremity of the East-Asian Rift Belt is designated as the Priokhotsky Rift, comprising the broadly north–south Torom (750 × 100 km) and Nizhneamursky (450 × 100 km) open faults formed by a system of northeast striking grabens associated with the closure of the Tan-Lu shear system and north–south striking grabens formed in a setting of oblique extension. Infilling of the grabens corresponding to the rift stage proper is the Eocene?Miocene coal-bearing molasse; the fields of the Miocene basalts are also related to it. The grabens of the rift belt are overlain by the Pliocene–Neopleistocene associations of rift basins in the forming plate cover of the Alpine platform. 相似文献
12.
E. P. Terekhov I. B. Tsoy A. V. Mozherovskii N. K. Vagina 《Stratigraphy and Geological Correlation》2011,19(3):337-351
Shikotan Island of the Lesser Kuril Ridge forms, together with the Vityaz Ridge, the outer arc of the Kuril island-arc system. Marine Pliocene sediments first registered on the island contain diatoms and palynomorphs, which allow their dating. The thin Pliocene semiconsolidated sediments constitute the upper part of sections in the coastal and central areas of the island. They rest with the erosional surface and stratigraphic hiatus upon the Upper Cretaceous-Lower Paleogene (Campanian-Danian) Malokuril’sk Formation. The Pliocene sediments were deposited in relatively shallow-water environments of open sea near the shore, with a forest-free landscape and freshwater basins. The occurrence of reworked marine Oligocene and Miocene diatoms in these sedimentary rocks indicates their development in the Lesser Kuril Ridge area and contribution of their eroded material to the formation of Pliocene sequences. Wide development of Pliocene Marine sediments on Shikotan Island is evidence for ascending movements in the region during the post-Pliocene period, which is also characteristic of the Greater Kuril Ridge islands. The composition and formation conditions of the Pliocene sediments in the outer arc of the Kuril island-arc system suggest that the southwestern (Lesser Kuril Ridge) and northeastern (Vityaz Ridge) segments of this single anticlinal structure evolved under different tectonic regimes through the Pliocene. 相似文献
13.
《Tectonophysics》2001,330(1-2):25-43
A detailed gravimetric study has been integrated with the most recent stratigraphic data in the area comprised between the Arno river and the foothills of the Northern Apennines, in northern Tuscany (central Italy). A Plio–Pleistocene basin lies in this area; its sedimentary succession can be subdivided from the bottom, in five allostratigraphic units: (1) Lower–Middle Pliocene shallow marine deposits; (2) Late Pliocene (?)–Early Pleistocene fluvio-lacustrine deposits; (3) late–Early Pleistocene–Middle Pleistocene alluvial to fluvial red conglomerates (Montecarlo Formation); (4) Middle Pleistocene alluvial to fluvial red conglomerates (Cerbaie and Casa Poggio ai Lecci Formations); (5) alluvial to fluvial deposits of Late Pleistocene age. The Bouguer anomaly map displays a strong minimum in the northeastern sector of the basin, and a gentle gradient from west to east. The map of the horizontal gradients permits to recognise three major fault zones, two of which along the southwestern and northeastern margins of the basin, and one along the southeastern edge of the Pisani Mountains. A 2.5D gravimetric modelling along a SW–NE section across the basin displays a thick wedge of sediments of density 2.25 g/cm3 (about 1700 m in the depocenter) overlying a layer of density 2.55 g/cm3, 1000 m thick, which rests on a basement of 2.72 g/cm3. The most of the sediment wedge is here referred to Upper Pliocene (?)–Lower Pleistocene, because borehole data show Pliocene marine deposits thinning northward close to the southern margin of the area. The layer below is referred to Ligurids and upper Tuscan Nappe units; the densest layer is interpreted as composed of Triassic evaporites, quartzites and Palaeozoic basement. According to Carmignani low-angle extensional tectonics began between Serravallian and early Messinian, thinning the Apennine nappe stack. At the end of Middle Pliocene, syn-rift deposition ceased in the Viareggio Basin (west of the investigated area) as demonstrated by Argnani and co-workers, and high-angle extensional tectonics migrated eastward up to the Monte Albano Ridge. A syn-rift continental sedimentary wedge developed in Late Pliocene–Early Pleistocene, until its hanging wall block was dismembered, during late Early Pleistocene, by NE-dipping faults, causing the uplift of its western portion (the Pisani Mountains). This breakup caused exhumation and erosion of Triassic units whose clastics where shed into the surrounding palaeo-Arno Valley in alluvial–fluvial deposits unconformably overlying the Lower Pleistocene syn-rift deposits. In the late Pleistocene SW–NE-trending fault systems created the steep southeastern edge of the Pisani Mountains and the resulting throw is recorded in Middle Pleistocene deposits across the present Arno Valley. This tectonic phase probably continues at present, offshore Livorno, as evidenced by the epicentres of earthquakes. 相似文献
14.
南海北部深水区LS33a钻井微体古生物年代地层格架 总被引：1，自引：0，他引：1
南海北部琼东南盆地深水区接收了渐新世以来数千米厚的海相沉积地层,蕴藏着丰富的微体古生物化石。对深水区LS33a钻井岩芯的取样和化石鉴定,识别出21个浮游有孔虫化石带（N22带～P19带）和12个钙质超微化石带（NN19带～NP24带）。通过与大洋钻探（ODP）在南海实施的184航次的钻探结果和“国际年代地层表（2012）”等的对比分析,探讨了化石事件的地质年代意义,构建了LS33a钻井生物年代地层格架。在此基础上,讨论了更新统与上新统、上上新统与下上新统、上新统与中新统、上中新统与中中新统、中中新统与下中新统、中新统与渐新统、上渐新统与下渐新统之间地层界线位置以及崖城组、陵水组、三亚组、梅山组、黄流组、莺歌海组和乐东组地层的时代归属,建立了适用于南海北部深水区的高分辨率综合年代地层格架。 相似文献
15.
贝加尔裂陷新构造特征 总被引：2，自引：0，他引：2
贝加尔裂谷系的断裂发育阶段和沉积作用过程基本一致,除沉积作用前的前裂谷断裂已经活化外,整个裂谷系的发育及演化过程大体可划分为两个阶段,即始新世中晚期-上新世早期(E22-3-N21)的开始阶段和上新世中晚期-第四纪(N22-3-Q)的主要阶段。前者属塑性形变,地形反差小,断裂活动弱;后者属脆性形变,地形反差大,断裂活动强。
贝加尔裂谷拗陷是贝加尔裂谷系中发育最早、规模最大的水下拗陷,新构造运动表现明显,升降幅度自西南向东北增大。区内及其四周断块山体及盆地多显示了自西向东翘起的特点。夷平面及冲、洪积扇发生大量拱曲和拗曲。各方向断裂力学属性组合特征,反映了NE-SW向的挤压构造应力场。 相似文献
贝加尔裂谷拗陷是贝加尔裂谷系中发育最早、规模最大的水下拗陷,新构造运动表现明显,升降幅度自西南向东北增大。区内及其四周断块山体及盆地多显示了自西向东翘起的特点。夷平面及冲、洪积扇发生大量拱曲和拗曲。各方向断裂力学属性组合特征,反映了NE-SW向的挤压构造应力场。 相似文献
16.
新生代龙门山前盆地和盐源盆地是青藏高原东缘龙门山－锦屏山冲断带内及前缘地区发育和保存最好的新生代沉积盆地，本次以地层不整合面和ESR测年资料为主要依据，将该区新生代构造地层序列划分为5个构造层序，即TS1（65－55Ma)、TS2(40-50Ma)、TS3（23－16Ma)、TS4(4．7-1.6Ma)和TS5（0．74－0Ma)，据此将青藏高原东缘新生代构造变形和隆升事件划分为5期，其中TS1与喜马拉雅地体和拉萨地体拼合事件相关，TS2与印亚碰撞事件相关，TS3与青藏高原第一次隆升事件相关，TS4与青藏高原第二次隆升事件相关，TS5与青藏高原第三次隆升事件相关。 相似文献
17.
在前人研究成果的基础上,划分出青藏高原及邻区上新世残留盆地共95个,探讨了青藏高原及邻区上新世构造岩相古地理演化。青藏高原上新世总体构造地貌格局主要受控于印度板块与欧亚板块沿雅鲁藏布江缝合带的碰撞及持续挤压,影响着青藏高原广大范围内的构造抬升。东北部昆仑山、祁连山地区是两大构造隆起蚀源区,两大山系夹持的柴达木盆地是高原东北部最大的陆内盆地,祁连山以北和以东地区则以盆山相间的格局接受周围山系的剥蚀物质,直到晚上新世(青藏运动"A"幕)高原东北部进一步强烈隆升,山间盆地抬升成为剥蚀区。新疆塔里木和青藏高原东部羌塘、可可西里地区主体表现为大面积的构造压陷湖盆-冲泛平原沉积区。高原东南部为一系列走滑拉分断裂运动形成的拉分盆地,上新世早期堆积洪冲积相砾岩,中期为湖泊、三角洲沉积,晚期随着山体的进一步抬升,盆地又接受冲洪积扇相砾岩堆积,并被河流侵蚀剥露。高原南部上新世多分布一些近南北向盆地,是响应高原隆升到一定程度垮塌而成的断陷盆地,同东南部拉分盆地类似,上新世沉积相也由早至晚分为3个阶段。恒河地区上新世由于喜马拉雅山的快速抬升,沉积以粗碎屑为主,形成狭长的西瓦利克群堆积。上新世青藏高原总体地势继承了中新世西高东低、南高北低的地貌特征,但地势高差明显较中新世增大。 相似文献
18.
ALLUVIAL STYLES AND ARCHITECTURE AS GUIDES TO CENOZOIC TECTONIC AND ENVIRONMENTAL EVENTS AT THE NORTHERN MARGINS OF THE QINGHAI—XIZANG PLATEAU 相似文献
19.
P. Halbach N. Blum U. Münch W. Plüger D. Garbe-Schönberg M. Zimmer 《Mineralium Deposita》1998,33(3):302-309
In December 1993, the first massive sulfides were recovered from the Indian Ocean floor, north of the Rodrigues Triple Junction.
The polymetallic deposit is situated in the fourth Central Indian Ridge segment, close to the rift axis; it is hydrothermally
no longer active. The deposit appears to be typical of mid-ocean ridge massive sulfide occurrences but is in a phase of disintegration
and about to be buried by sediment. The chimney structures were formed by multiple hydrothermal events and are now degraded
by mass wasting showing various stages of weathering. Later-stage, low-temperature hydrothermal mineralization processes led
to copper and gold enrichment. Here we report on the geological setting, mineral zonation, different sulfide types and stages
of formation of the “Sonne Sulfide Field”, which is part of a larger mineralized zone.
Received: 20 October 1997 / Accepted: 4 December 1997 相似文献
20.
Paleogeography of the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB) from Eocene to Pliocene 总被引：1，自引：1，他引：0
Jean-Pierre Berger Bettina Reichenbacher Damien Becker Matthias Grimm Kirsten Grimm Laurent Picot Andrea Storni Claudius Pirkenseer Christian Derer Andreas Schaefer 《International Journal of Earth Sciences》2005,94(4):697-710
Twenty paleogeographic maps are presented for Middle Eocene (Lutetian) to Late Pliocene times according to the stratigraphical data given in the companion paper by Berger et al. this volume. Following a first lacustrine-continental sedimentation during the Middle Eocene, two and locally three Rupelian transgressive events were identified with the first corresponding with the Early Rupelian Middle Pechelbronn beds and the second and third with the Late Rupelian Serie Grise (Fischschiefer and equivalents). During the Early Rupelian (Middle Pechelbronn beds), a connection between North Sea and URG is clearly demonstrated, but a general connection between North Sea, URG and Paratethys, via the Alpine sea, is proposed, but not proved, during the late Rupelian. Whereas in the southern URG, a major hiatus spans Early Aquitanian to Pliocene times, Early and Middle Miocene marine, brackish and freshwater facies occur in the northern URG and in the Molasse Basin (OMM, OSM); however, no marine connections between these basins could be demonstrated during this time. After the deposition of the molasse series, a very complex drainage pattern developed during the Late Miocene and Pliocene, with a clear connection to the Bresse Graben during the Piacenzian (Sundgau gravels). During the Late Miocene, Pliocene and Quaternary sedimentation persisted in the northern URG with hardly any interruptions. The present drainage pattern of the Rhine river (from Alpine area to the lower Rhine Embayment) was not established before the Early Pleistocene. 相似文献