Coarse-Grained Facies in Intracontinental Rift Basins: Relations to Base Level, Depositional Systems and System Tracts: ABSTRACT

AAPG Bulletin ◽  
1995 ◽  
Vol 79 ◽  
Author(s):  
Hercules T. F. Da Silva, L. P. Magn
2018 ◽  
Vol 10 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Rui Yuan ◽  
Rui Zhu ◽  
Jianhua Qu ◽  
Jun Wu ◽  
Xincai You ◽  
...  

Abstract The Mahu Depression is an important hydrocarbon-bearing foreland sag located at the northwestern margin of the Junggar Basin, China. On the northern slope of the depression, large coarse-grained proximal fan-delta depositional systems developed in the Lower Triassic Baikouquan Formation (T1b). Some lithologic hydrocarbon reservoirs have been found in the conglomerates of the formation since recent years. However, the rapid vertical and horizontal lithology variations make it is difficult to divide the base-level cycle of the formation using the conventional methods. Spectral analysis technologies, such as Integrated Prediction Error Filter Analysis (INPEFA), provide another effective way to overcome this difficultly. In this paper, processed by INPEFA, conventional resistivity logs are utilized to study the base-level cycle of the fan-delta depositional systems. The negative trend of the INPEFA curve indicates the base-level fall semi-cycles, adversely, positive trend suggests the rise semi-cycles. Base-level cycles of Baikouquan Formation are divided in single and correlation wells. One long-term base-level rise semi-cycle, including three medium-term base-level cycles, is identified overall the Baikouquan Formation. The medium-term base-level cycles are characterized as rise semi-cycles mainly in the fan-delta plain, symmetric cycles in the fan-delta front and fall semi-cycles mainly in the pro-fan-delta. The short-term base-level rise semi-cycles most developed in the braided channels, sub-aqueous distributary channels and sheet sands. While, the interdistributary bays and pro-fan-delta mud indicate short-term base-level fall semi-cycles. Finally, based on the method of INPEFA, sequence filling model of Baikouquan formation is established.


Author(s):  
Ivan Martini ◽  
Elisa Ambrosetti ◽  
Andrea Brogi ◽  
Mauro Aldinucci ◽  
Frank Zwaan ◽  
...  

AbstractRift-basins are the shallow effects of lithosphere-scale extensional processes often producing polyphase faulting. Their sedimentary evolution depends on the mutual interplay between tectonics, climate, and eustasy. Estimating the role of each factor is generally a challenging issue. This paper is focused on the tectono-sedimentary evolution of the Neogene Siena-Radicofani Basin, a polyphase structural depression located in the inner Northern Apennines. Since Miocene, this basin developed after prolonged extensional tectonics, first as a bowl-shaped structural depression, later reorganized into a half-graben structure due to the activation of high-angle normal faults in the Zanclean. At that time the basin contained coeval continental and marine settings controlled by the normal faulting that caused the development of local coarse-grained depositional systems. These were investigated to: (i) discriminate between the influences of tectonics and climate on sedimentation patterns, and (ii) provide detailed time constraints on fault activity. The analysed successions were deposited in an interval between 5.08 and 4.52 Ma, when a climate-induced highstand phase occurred throughout the Mediterranean. However, evidence of local relative sea-level drops is registered in the sedimentary record, often associated with increased accommodation space and sediment supply. Such base-level fluctuations are not connected to climate changes, suggesting that the faults generally control sedimentation along the basin margins.


2018 ◽  
Vol 6 (2) ◽  
pp. SD13-SD27 ◽  
Author(s):  
Xiaomin Zhu ◽  
Rong Pan ◽  
Shunli Li ◽  
Hongbao Wang ◽  
Xin Zhang ◽  
...  

A variety of genetic types of reservoirs with good hydrocarbon accumulation conditions have been developed in petroliferous rift basins. The near-provenance, coarse-grained depositional system on the steep slopes of rift basins has become an important oil and gas exploration area. However, due to the large changes in lithologies and difficulties in its identification and characterization, the challenges in oil/gas exploration are significant. Seismic sedimentology, in this case, provides an effective means of identifying and characterizing the complex, coarse-grained sediments. We use a large number of cores, logs, and seismic data and establish the third- and fourth-order sequence frameworks in the Shahejie Formation on the steep slope of the northern Dongying Sag in eastern China. Three types of lithofacies, including conglomerates, sandstones, and mudstones with 12 subspecies facies types have been identified and the relationship between different lithofacies types and depositional systems is determined. The relative changes of the lake level control the distribution of depositional systems in a sequence framework. Lowstand system tracts of SQ3 and SQ4 in the Shahejie Formation mainly developed near-shore subaqueous fans and a small number of slump turbidite fans. Small-scale offshore fans mainly develop in lacustrine transgressive systems tracts, and fan deltas, flood-type sublake fans, slump turbidite fans, and near-shore subaqueous fans mainly developed in highstand systems tracts. The study of seismic sedimentology, based on the theory of seismic lithology and seismic geomorphology, have been carried out. Stratal slices are used to identify and characterize the morphology and temporal-spatial distributions of various types of sand-gravel bodies on the steep slopes of the Dongying Sag based on core calibration and establish the model of seismic sedimentology for various types of sand-gravel bodies in different systems tracts.


2009 ◽  
Vol 60 (5) ◽  
pp. 397-417 ◽  
Author(s):  
Crina Miclăuş ◽  
Francesco Loiacono ◽  
Diego Puglisi ◽  
Dorin Baciu

Eocene-Oligocene sedimentation in the external areas of the Moldavide Basin (Marginal Folds Nappe, Eastern Carpathians, Romania): sedimentological, paleontological and petrographic approachesThe Marginal Folds Nappe is one of the most external tectonic units of the Moldavide Nappe System (Eastern Carpathians), formed by Cretaceous to Tertiary flysch and molasse deposits, piled up during the Miocene closure of the East Carpathian Flysch basin, cropping out in several tectonic half-windows, the Bistriţa half-window being one of them. The deposits of this tectonic unit were accumulated in anoxic-oxic-anoxic conditions, in a forebulge depozone (sensuDeCelles & Giles 1996), and consist of a pelitic background sporadically interrupted by coarse-grained events. During the Late Eocene the sedimentation registered a transition from calcareous (Doamna Limestones) to pelitic (Bisericani Beds) grading to Globigerina Marls at the Eocene-Oligocene boundary, and upward during the Oligocene in deposits rich in organic matter (Lower Menilites, Bituminous Marls, Lower and Upper Dysodilic Shales) with coarsegrained interlayers. Seven facies associations were recognized, and interpreted as depositional systems of shallow to deeper water on a ramp-type margin. Two mixed depositional systems of turbidite-like facies association separated by a thick pelitic interval (Bituminous Marls) have been recognized. They were supplied by a "green schists" source area of Central Dobrogea type. The petrography of the sandstone beds shows an excellent compositional uniformity (quartzarenite-like rocks), probably representing a first cycle detritus derived from low rank metamorphic sources, connected with the forebulge relief developed on such a basement. The sedimentation was controlled mainly by different subsidence of blocks created by extensional tectonic affecting the ramp-type margin of the forebulge depozone.


2018 ◽  
Vol 55 (7) ◽  
pp. 677-708 ◽  
Author(s):  
David R. Sharpe ◽  
André J.-M. Pugin ◽  
Hazen A.J. Russell

The Laurentian trough (LT), a depression >100 km long, >3000 km2 in area, and 100 m deep at the base of the Niagara Escarpment, extends from within Georgian Bay to Lake Ontario. It has a complex erosional history and is filled and buried by up to 200 m of interglacial and glacial sediment. The primary depression fronts a cuesta landscape and is attributed to differential erosion by fluvial, glacial, and glaciofluvial processes, exposing Ordovician rocks along the Canadian Shield margin. The fill succession includes sediments from the last two glacial periods (Illinoian, Wisconsinan) and the intervening interglacial time (Sangamonian), a poorly dated succession with at least three regional unconformities. A subaerial (interglacial, Don Formation) unconformity relates to low base level mainly preserved in lows of the LT, succeeded by a long period of rising water levels and glaciolacustrine conditions as ice advanced into the Lake Ontario basin. A second unconformity, within the Thorncliffe Formation, is the result of rapid channel erosion to bedrock, forming an ∼north–south network filled with coarse-grained glaciofluvial, transitional to fine-grained glaciolacustrine subaqueous fan sediment. The overlying drumlinized Newmarket Till, up to 50 m thick, is a distinct regional unit with a planar to undulating base. A third unconformity event eroded Newmarket Till, locally truncating it and underlying sediment to bedrock. Three younger sediment packages, Oak Ridges Moraine (channel and ridge sediment), Halton, and glaciolacustrine overlie this erosion surface. Significant regional aquifers are hosted within the LT. Upper Thorncliffe Formation sediments, north–south glaciofluvial channel–fan aquifers, are protected by overlying mud and Newmarket Till aquitards. Similarly, Oak Ridges Moraine sediments comprise a north–south array of glaciofluvial channel–fans and east–west fan aquifers, locally covered by silt–clay rhythmite and till aquitards.


2009 ◽  
Vol 72 (3) ◽  
pp. 431-442 ◽  
Author(s):  
Irene Zembo ◽  
Laura Panzeri ◽  
Anna Galli ◽  
Riccardo Bersezio ◽  
Marco Martini ◽  
...  

AbstractOptically Stimulated Luminescence (OSL) enables the chronology of the late Pleistocene evolution for the Val d'Agri intermontane basin of Southern Apennines to be defined in the frame of Mediterranean geodynamic and climate changes. Quartz sand from braided floodplain and alluvial fan depositional systems was analyzed using the coarse-grained, single-aliquot regenerative-dose (SAR) technique. The obtained optical ages are mostly consistent with other assessments (radiocarbon, tephrochronology) and stratigraphic constraints. OSL allows for the dating to 56–43 ka of an asymmetric subsidence stage that forced alluvial fan progradation, filling of a former lacustrine area, and development of an axial alluvial plain. A short period of Mediterranean-type pedogenesis, recorded at the top of the prograding-aggrading fans (OSL age bracket 43–32 ka), corresponds with MIS 3. During the subsequent stage of decline of vegetation cover, possibly corresponding to MIS 2, the latest progradation of alluvial fans occurred. The subsequent uplift and breakthrough of the basin threshold during the latest Pleistocene and Holocene induced entrenchment of the drainage network. The results presented here provide an example of the usefulness of OSL dating in intermontane continental settings where other geochronological constraints are scarce.


Geologos ◽  
2012 ◽  
Vol 18 (3) ◽  
pp. 135-161 ◽  
Author(s):  
Maria I. Waksmundzka

Abstract Fining-upwards cyclothems found in five boreholes in the Carboniferous (Lower Bashkirian) of the Lublin Basin were analysed sedimentologically. It was established that the cyclothems represent fluvial deposits, and the lithofacies were grouped into lithofacies associations. Most lithofacies associations represent three types of sand-bed braided rivers: (1) high-energy, (2) deep and (3) distal sheetflood-affected. Other associations represent hyperconcentrated flows. Both coarse-grained (type I) and fine-grained (types IIa and IIb) occur among the fining-upward cyclothems. The formation of most thick cyclothems was related mainly to allocyclic factors, i.e. a decrease in the river’s gradient. The thickest fining-upward cyclothems are characteristic of hyperconcentrated flows and braided-river channels. The aggradation ratios were commonly high. During the early Namurian C and early Westphalian A (Early Bashkirian), the eastern part of the Lublin Basin was located close to the source area. The sedimentary succession developed due to a transition from high-energy braidedrivers and hyperconcentrated flows to lower-energy braided rivers, controlled by a rise of the regional base level.


Geologos ◽  
2013 ◽  
Vol 19 (4) ◽  
pp. 257-272 ◽  
Author(s):  
Aleksandra Vierek

Abstract Late Devonian coarse-grained carbonate deposits in the Holy Cross Mountains were studied for possible storm depositional systems and catastrophic tsunami events, as it must be assumed that the investigated area was strongly affected by tropical hurricanes generated in the open ocean North of Gondwana. This assumption appears consistent with diagnostic features of carbonate tempestites at several places in the Holy Cross Mountains. Sedimentary structures and textures that indicate so are, among other evidence, erosional bases with sole marks, graded units, intra- and bioclasts, different laminations and burrowing at the tops of tempestite layers. It has been suggested before that a tsunami occurred during the Late Devonian, but the Laurussian shelf had an extensional regime at the time, which excludes intensive seismic activity. The shelf environment also excluded the generation of tsunami waves because the depth was too shallow. Additionally, the Holy Cross Mountains region was surrounded in the Devonian by shallow-marine and stable elevated areas: the Nida Platform, the Opatkowice Platform and the Cracow Platform to the South, and the elevated Lublin-Lviv area to the NE. Thus, tsunami energy should have been absorbed by these regions if tsunamites would have occurred.


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