scholarly journals Controlling Factors Analyses of Sediment Dispersal From Source-to-Sink Systems of Lacustrine Rift Basin: A Case Study From Paleogene Shahejie-Dongying Formations of Nanpu Sag, Eastern China

2021 ◽  
Vol 9 ◽  
Author(s):  
Jifeng Yu ◽  
Tianjiao Liu ◽  
Haibo Jia ◽  
Zihao Jiang ◽  
Shuhao Wei ◽  
...  
Keyword(s):  
Catchment Area ◽  
Controlling Factors ◽  
Heavy Mineral ◽  
Fault System ◽  
Tectonic Activity ◽  
Rift Basin ◽  
Rift Basins ◽  
Sediment Dispersal ◽  
Nanpu Sag ◽  
Sand Bodies

Tectonic activity not only shapes the basic stratigraphic framework of rift basins, but also profoundly affects the sediment dispersal in rift basins. In this study, analyses of heavy mineral assemblages in different periods demonstrate that there are three obvious tectono-sedimentary evolutionary stages (Es3–Es2, Es1–Ed2, and Ed1, respectively) in the Paleogene provenance area of Nanpu Sag, and the volume of sand bodies increases from the bottom of the Paleogene Shahejie (Es) Formation to the top of the Dongying (Ed) Formation in Nanpu Sag. Besides, this study comprehensively utilize the analyses of seismic interpretation, palynology, heavy mineral, and borehole core samples to investigate the controlling factors of sediment dispersal in the rift basin. The assemblages of heavy minerals in different periods reflect the rock composition and catchment area of different provenance areas, and their vertical differences reflect the evolution process of the provenance area and reflect the uplift-denudation process of the provenance area. The results reveal that the synergy of the evolution of tectonic activity and the adjustment of topographical evolution are the main controlling factors of sediment dispersal in Nanpu Sag, while climate change is not the main controlling factor. We conclude that an increased sediment supply rate in the long term reflects the control of tectonic activity on basin topography, rather than climate fluctuations. The differences in morphological modification result in differential sediment dispersal, which is principally related to the differential extrusion of the fault system. The catchment area and provenance distance adjustment is evidenced by the vertical changes of heavy mineral characteristics of single-well and interaction and linkage of boundary faults, and the adjustment of topography evolution. A consideration is that the interaction and linkage of boundary faults and complex subsidence history are multi-directional, and differential evolution of provenance area is universal in lacustrine rift basins, all of this highlights the adjustment of sediment pathways generated by this characteristic of rift basins and emphasizes the importance of controlling factors analyses in understanding differential sediment dispersal that presents in the rift basins. Besides, four sets of sediment dispersal patterns were delineated based on different developmental regions in the rift basin, which are fault segmental point and multi-stage fault terrace, single-stage fault terrace and axial fault valley, axial fault terrace, and paleo-terrace and axial fault valley, respectively. This study has a certain guiding significance for the prediction of the spatial distribution of sand bodies in the rift basin and the exploration of potential oil and gas targets in the rift basin.

scholarly journals Late Quaternary tectonic activity and lake level change in the Rukwa Rift Basin

1998 ◽  
Vol 26 (3) ◽  
pp. 397-421 ◽  
Author(s):  
D. Delvaux ◽  
F. Kervyn ◽  
E. Vittori ◽  
R.S.A. Kajara ◽  
E. Kilembe
Keyword(s):  
Lake Level ◽  
Late Quaternary ◽  
Tectonic Activity ◽  
Rift Basin ◽  
Lake Level Change ◽  
Level Change

Hydrofractures and crustal-scale fluid flow

2021 ◽  
Author(s):  
Paul D. Bons ◽  
Tamara de Riese ◽  
Enrique Gomez-Rivas ◽  
Isaac Naaman ◽  
Till Sachau
Keyword(s):  
Fluid Flow ◽  
Large Scale ◽  
Low Flow ◽  
Fault System ◽  
Tectonic Activity ◽  
Field Evidence ◽  
Dehydration Reactions ◽  
Matrix Flow ◽  
Matrix Porosity ◽  
Fluid Sources

<p>Fluids can circulate in all levels of the crust, as veins, ore deposits and chemical alterations and isotopic shifts indicate. It is furthermore generally accepted that faults and fractures play a central role as preferred fluid conduits. Fluid flow is, however, not only passively reacting to the presence of faults and fractures, but actively play a role in their creation, (re-) activation and sealing by mineral precipitates. This means that the interaction between fluid flow and fracturing is a two-way process, which is further controlled by tectonic activity (stress field), fluid sources and fluxes, as well as the availability of alternative fluid conduits, such as matrix porosity. Here we explore the interaction between matrix permeability and dynamic fracturing on the spatial and temporal distribution of fluid flow for upward fluid fluxes. Envisaged fluid sources can be dehydration reactions, release of igneous fluids, or release of fluids due to decompression or heating.</p><p> </p><p>Our 2D numerical cellular automaton-type simulations span the whole range from steady matrix-flow to highly dynamical flow through hydrofractures. Hydrofractures are initiated when matrix flow is insufficient to maintain fluid pressures below the failure threshold. When required fluid fluxes are high and/or matrix porosity low, flow is dominated by hydrofractures and the system exhibits self-organised critical phenomena. The size of fractures achieves a power-law distribution, as failure events may sometimes trigger avalanche-like amalgamation of hydrofractures. By far most hydrofracture events only lead to local fluid flow pulses within the source area. Conductive fracture networks do not develop if hydrofractures seal relatively quickly, which can be expected in deeper crustal levels. Only the larger events span the whole system and actually drain fluid from the system. We present the 10 square km hydrothermal Hidden Valley Mega-Breccia on the Paralana Fault System in South Australia as a possible example of large-scale fluid expulsion events. Although field evidence suggests that the breccia formed over a period of at least 150 Myrs, actual cumulative fluid duration may rather have been in the order of days only. This example illustrates the extreme dynamics that crustal-scale fluid flow in hydrofractures can achieve.</p>

scholarly journals Experimental models of 'Basement'-controlled salients - application to the proterozoic fold-thrust belt of the quadrilátero ferrífero (Minas Gerais, Southeastern Brazil)

2003 ◽  
Vol 75 (2) ◽  
pp. 249-263 ◽  
Author(s):  
Caroline J. S. Gomes ◽  
Milton Pereira-Filho ◽  
Silvia C. M. Braga
Keyword(s):  
Minas Gerais ◽  
Experimental Models ◽  
Controlling Factors ◽  
Fault System ◽  
Southeastern Brazil ◽  
Thrust Belt ◽  
Existing Structures ◽  
Quadrilátero Ferrífero ◽  
Southeastern Margin ◽  
Archean Basement

Scaled sandbox models are used to simulate the development of ´basement´-controlled, salients. We investigate the controlling factors on the development of closed curvatures in map-view, considering constant both the sand pack thickness and the space between obstacles. These models are compared with the Fundão-Cambotas Fault System in the Proterozoic fold-thrust belt in the Quadrilátero Ferrífero region, along the southeastern margin of the São Francisco craton. In the experiments, a pronounced curvature resulted from the margin-controlled salient process in the presence (i) of a basal ductile detachment, or (ii) of pre-existing structures. The results suggest that the convex-to-the-foreland, west-vergent Fundão-Cambotas Fault System that borders the Archean basement highs and displaced older Transamazonian structures westward, is partly a consequence of interaction of propagating thrusts with obstacles in the foreland.

scholarly journals The “Passive” Margin of Eastern North America: Rifting and the Influence of Prerift Orogenic Activity on Postrift Development

Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 1-29
Author(s):  
Martha Withjack ◽  
MaryAnn Malinconico ◽  
Michael Durcanin
Keyword(s):  
Passive Margin ◽  
Rift System ◽  
Rift Basin ◽  
Rift Basins ◽  
Isostatic Rebound ◽  
Left Behind ◽  
Crustal Thinning ◽  
Hinge Zone ◽  
Uplift And Erosion ◽  
Ocean Boundary

Abstract We have analyzed and synthesized geologic and geophysical data from the onshore Newark rift basin and adjacent onshore and offshore basins to better understand the Mesozoic development of the eastern North American rift system and passive margin. Our work indicates that rifting had three phases: (1) an initial, prolonged phase of extension and subsidence; (2) a short-lived phase with higher rates of extension and subsidence, intrabasin faulting, and intense magmatism; and (3) a final phase with limited subsidence and deposition. Additionally, our work shows that anomalous uplift and erosion, associated with crustal-scale arching/warping subparallel to the prerift and syn-rift crustal fabric not the continent-ocean boundary, affected a region landward of the basement hinge zone. Uplift and erosion began during the final rifting phase and continued into early drifting with erosion locally exceeding 6 km. Subsequent subsidence was minimal. We propose that denudation unloading related to relic, prerift orogenic crustal thickness and elevated topography triggered the anomalous uplift and erosion. After the Paleozoic orogenies, postorogenic denudation unloading (cyclic erosion and isostatic rebound/uplift) significantly thinned the thickened crust and reduced topographic elevation. During rifting, extension stretched and tectonically thinned the crust, promoting widespread subsidence and deposition that dampened the postorogenic cycle of erosion and isostatic rebound/uplift. During the rift-drift transition, with extension focused near the breakup site, denudation unloading resumed landward of the basement hinge zone, producing significant erosion and uplift (related to isostatic rebound), crustal thinning, and topographic decay that left behind only eroded remnants of the once massive rift basins.

Synsedimentary collapse of portions of the lower Blomidon Formation (Late Triassic), Fundy rift basin, Nova Scotia

1995 ◽  
Vol 32 (11) ◽  
pp. 1965-1976 ◽  
Author(s):  
Rolf V. Ackermann ◽  
Roy W. Schlische ◽  
Paul E. Olsen
Keyword(s):  
Nova Scotia ◽  
Late Triassic ◽  
Normal Faults ◽  
Rift Basin ◽  
Rift Basins ◽  
Kink Bands ◽  
Deformation Features ◽  
Terrestrial Environments ◽  
Sediment Deformation ◽  
Fluvial Sandstone

A chaotic mudstone unit within the lower Blomidon Formation (Late Triassic) has been traced for 35 km in the Mesozoic Fundy rift basin of Nova Scotia. This unit is characterized by highly disrupted bedding that is commonly cut by small (<0.5 m) domino-style synsedimentary normal faults, downward movement of material, geopetal structures, variable thickness, and an irregular, partially faulted contact with the overlying unit. The chaotic unit is locally overlain by a fluvial sandstone, which is overlain conformably by mudstone. Although the thickness of the sandstone is highly variable, the overlying mudstone unit exhibits only gentle regional dip. The sandstone unit exhibits numerous soft-sediment deformation features, including dewatering structures, convoluted bedding, kink bands, and convergent fault fans. The frequency and intensity of these features increase dramatically above low points at the base of the sandstone unit. These stratigraphic relations suggest buried interstratal karst, the subsurface dissolution of evaporites bounded by insoluble sediments. We infer that the chaotic unit was formed by subsidence and collapse resulting from the dissolution of an evaporite bed or evaporite-rich unit by groundwater, producing dewatering and synsedimentary deformation structures in the overlying sandstone unit, which infilled surface depressions resulting from collapse. In coeval Moroccan rift basins, facies similar to the Blomidon Formation are associated with halite and gypsum beds. The regional extent of the chaotic unit indicates a marked period of desiccation of a playa lake of the appropriate water chemistry. The sedimentary features described here may be useful for inferring the former existence of evaporites or evaporite-rich units in predominantly clastic terrestrial environments.

Controlling factors on heavy mineral assemblages in Chinese loess and Red Clay

2013 ◽  
Vol 381-382 ◽  
pp. 110-118 ◽  
Author(s):  
Junsheng Nie ◽  
Wenbin Peng ◽  
Katharina Pfaff ◽  
Andreas Möller ◽  
Eduardo Garzanti ◽  
...  
Keyword(s):  
Controlling Factors ◽  
Heavy Mineral ◽  
Red Clay ◽  
Chinese Loess ◽  
Mineral Assemblages

Regional Seal as Key Controlled Elements of Petroleum Accumulation in the Rift Basin

2012 ◽  
Vol 524-527 ◽  
pp. 190-193
Author(s):  
Hai Yan Hu ◽  
Zhe Zhao ◽  
Song Lu ◽  
Hang Zhou Xiao
Keyword(s):  
Source Rock ◽  
Oil And Gas ◽  
Thickness Distribution ◽  
Normal Faults ◽  
Hydrocarbon Generation ◽  
Geological Condition ◽  
Rift Basin ◽  
Rift Basins ◽  
Northwest Germany ◽  
Petroleum Accumulation

Rift basin is an important petroleum basin type, in which about one third of oil and gas was discovered. To research on the main controlled elements of oil and gas accumulation, five typical rift basins in Europe are focused on the geological condition such as source rock, reservoir, seal, petroleum system, and accumulation with logging, hole, measured and analytical methods, and so on. The results showed the main regional seal controlled the petroleum distribution in the rift basin. Seals are defined by main regional seal, minor regional seas and local region according to thickness, distribution, lithostratigraphy. Viking Graben of North Sea has main regional seal about 3000m thick during late Jurassic and Cretaceous, about 81 percent of petroleum is in the Jurassic reservoir; Anglo-Dutch basin has main region thick seal during Triassic through Jurassic, and Permian reservoir accounted for 73 percent of basin reserves; Voring Basin has the main regional seal during Cretaceous through early Tertiary, the Jurassic reservoir has 85 percent of whole basin reserves; Northeast and Northwest Germany Basins have the evaporites as main regional seals during late Permian, and Permian reservoir accounted for more than 80 percent of basin reservoir, respectively. Rift Basin can develop reservoir like turbidite, source rock, seal in the basin dynamic opinion. Some main regional seals may develop overpressre because of quick subside and hydrocarbon generation at some conditions, it can strengthen seal capability. Oil and gas can migration to the main regional seal by normal faults caused by rifting, which can stop further migration so that they were accumulated under the main regional seal.

scholarly journals Features of lead-zinc mineralization in the Phia Dam - Khuoi Man region

2020 ◽  
Vol 61 (5) ◽  
pp. 120-134
Author(s):  
Phuong Nguyen ◽  
Dong Phuong Nguyen ◽  
Huong Thi Nguyen ◽  
Huong Thi Le ◽  
Dinh Van Do ◽  
...  
Keyword(s):  
Controlling Factors ◽  
Material Composition ◽  
Fault System ◽  
Research Results ◽  
Epithermal Deposits ◽  
Ore Bodies ◽  
Ore Minerals ◽  
Lead Zinc ◽  
Bedding Surface ◽  
New Research

The paper introduces a number of new research results on the characteristics of lead - zinc ores in Phia Dam - Khuoi Man areas based on the application of traditional geological methods, combining the method of researching material composition and method statistical maths. In the study area, there are two forms of ore bodies with characteristics described as below: the first form consists of ore bodies developed along the stratabound bedding surface, are mainly distributed in either anticlinal structures (i.e. Phia Dam region) or cuesta (i.e. Khuoi Man region) and the second form consists of ore bodies in lodes, filled in cracks or zones of fracture along the northwest – southeast faults. Primary ore minerals are mainly galena, sphalerite, pyrite, chalcopyrite, etc. and gangue minerals are calcite, dolomite, and quartz. Ore structures are nests, veins, disseminated veins, banded, speckled, or sometimes breccia - like ones. The relevant and controlling factors of lead-zinc mineralization in Phia Dam - Khuoi Man region are the northwest - southeast fault system and the lithostratigraphy. Ores are of either mesothermal or epithermal deposits (temperatures varies from 162 to 308 degrees Celcius), with a specific symbiotic combination of quartz - sphalerite - galena - chancopyrite.

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