Characteristics of Subtle Fault Zone in Jinhu Sag

2014 ◽  
Vol 1010-1012 ◽  
pp. 1399-1403
Author(s):  
Wei Wei Zhou ◽  
Wei Feng Wang ◽  
Zhou Jie

Subtle fault zones are caused by the weak deformation generated in the sedimentary cover of a sag due to the influence of regional or local stress fields or basement faults. They are too subtle to be easily identified by conventional exploration methods and technologies and are thus usually ignored. Research results prove that there are two basement faults in the Jinhu sag referred to as the NE-and NW-trending basement faults. Parts of the NE-trending basement fault are intense enough to control sag formation and evolution (such as the faults in Yangcun and Shigang, etc.). However, the NW-trending and the rest of the NE-trending basement faults show weak activity and exert little influence on sedimentary cover deformation. These faults merely yield some weakly-deformed trend zones in the sedimentary cover, such as small en-echelon faults, small faults intermittently distributed along fixed directions, buried alluvial fans, zonal or stringy oil-gas traps, or linear structures (such as local folds, narrow and deep half-grabens, etc.). Apart from the two aforementioned types of subtle fault zones, intermittent and stringy NS-trending subtle fault zones are also induced by the EW-trending extrusion stress component in the sag generated by the regional dextral stress field. Keywords: Jinhu sag; basement faults; subtle fault zones; tectonic evolution; en-echelon; trap distribution

Author(s):  
В.Б. Свалова

Актуальность работы определяется важностью оценки и прогноза нефтегазового потенциала глубоких осадочных бассейнов, в частности, глубоких горизонтов структур, не всегда доступных глубокому бурению в поисковых и разведочных целях. Цель и методы исследования. Наряду с прикладными вопроса- ми целью исследования являются фундаментальные вопросы теоретической геодинамики формирования и эволюции осадочных бассейнов в связи с подъемом мантийных диапиров на основе методов механи- ко-математического моделирования. Прикаспийская впадина и восточный сегмент Кавказского региона, включая Каспийское море, могут рассматриваться как регионы окрестности восточной части Альпийского пояса, который в свою очередь является западной частью Альпийско-Гималайского пояса, простирающе- гося от западной оконечности Средиземного моря до Тихоокеанского побережья. Каспийское море пере- секает с севера на юг серию широтных структурных зон юго-восточной окраины древней докембрийской Восточно-Европейской платформы, молодой эпигерцинской Скифско-Туранской платформы и современ- ного Альпийско-Гималайского орогенного пояса. Прикаспийская и Южно-Каспийская впадины являются глубокими осадочными бассейнами с толщиной осадочного чехла более 20 км, обладающими высоким нефтегазовым потенциалом и большим народно-хозяйственным значением. Формирование и эволюция осадочного бассейна служат ключом для определения зон нефтегенерации осадочного чехла, что делает задачу изучения геодинамики осадочных бассейнов крайне важной и необходимой. Геодинамика релье- фа поверхности определяется глубинными мантийными движениями. Механико-математическая модель динамики литосферы дает возможность количественно связать параметры формирующегося осадочного бассейна с подъемом мантийного диапира. Анализ геофизических полей геологических структур позволя- ет оценить подъем астеносферы, а разработанная самосопряженная термогравиметрическая модель ли- тосферы делает эти оценки надежными и достоверными. Геодинамика и история развития геологических структур определяют магматизм, вулканизм, сейсмичность, геотермические характеристики, геотермаль- ную активность, нефтегазоносность, опасные природные процессы региона, что в свою очередь является обоснованием создания системы комплексного экологического мониторинга на фундаментальной научной базе, прогноза и предупреждения природных бедствий и катастроф, а также поиска полезных ископаемых, включая углеводороды. Результатом работы является количественная оценка подъема астеносферы под осадочным бассейном на примере Прикаспийской впадины The relevance of the work is determined by the importance of assessing and predicting the oil and gas potential of deep sedimentary basins, in particular, deep horizons of structures that are not always accessible to deep drilling for prospecting and exploration purposes. The aim and research methods. Along with applied questions, the aim of the study is the fundamental questions of the theoretical geodynamics of the formation and evolution of sedimentary basins in connection with the rise of mantle diapirs based on the methods of mechanical and mathematical modeling. Pre-Caspian Depression and eastern segment of Caucasus region, including Caspian Sea, can be considered as regions of area of eastern part of Alpine belt, which is western part of Alpine-Himalayan belt disposed from Mediterranean sea to Pacific Ocean. Caspian sea crosses from North to South the series of structural zones of East European platform, Scythian-Turan platform and Alpine-Himalayan belt. Pre-Caspian Depression and South Caspian Depression are deep sedimentary basins with thickness of sedimentary cover more than 20 km which have high oil-gas potential and big industrial importance. Formation and evolution of sedimentary basin is the clue for oil-gas generation zones of sedimentary cover, that makes the problem of sedimentary basins geodynamics of great importance one. Geodynamics of relief is defined by deep mantle movements. Mechanical-mathematical model of the lithosphere dynamics gives possibility to link the basin parameters with mantle diaper upwelling. Analysis of geophysical fields gives opportunity to evaluate the asthenosphere upwelling, and elaborated self-conjugated thermo-gravimetric model makes this evaluation reliable and trustworthy one. Geodynamics and evolution history of geological structures determine magmatism, volcanism, seismicity, geothermics, geothermal manifestations, oil-gas potential, natural hazards of region, that is basement for monitoring system creation and construction on fundamental scientific base, forecast and prognosis of natural catastrophes and oil-gas potential researches. The result of this work is a quantitative assessment of the rise of the asthenosphere under the sedimentary basin using the example of the Pre-Caspian Depression


2005 ◽  
pp. 17-20 ◽  
Author(s):  
Ivan Filipovic

This work presents new information about the interconnection between diverse geological resources and tectonic structures framing the Jadar block terrene. Deep fault zones are found to have been principal bearers of geothermal, thermo mineral and metallic ore resources. Increased bitumen and hydrocarbon concentrations in pre-Tertiary deposits, which may be potential oil/gas zones, are also associated with these areas.


Author(s):  
А.В. Водорезов ◽  
Д.Г. Зайцев ◽  
В.А. Кривцов

По результатам изучения отложений в днище и конусе выноса оврага с учетом датировок артефактов из культурных слоев установлено время заложения и основные этапы развития Спасского оврага, проникшего на городище Старая Рязань. Появление оврага вызвано устройством оборонительного вала и рва Северного городища. Эрозия днища рва и трансформация его в овраг происходила во второй половине XI века и после перерыва во второй половине XII века. Третий этап активного развития оврага и роста его вершин приходится на период между 1732 годом и второй половиной XIX века и был связан с распашкой поверхности городища. Мониторинг эрозионных и оползневых процессов на городище Старая Рязань в период с 1999 по 2019 год позволил выделить период активизации оползневых процессов в 2017–2019 годах, что связано с изменением климатических условий в регионе. The investigation of the bottom sediments and the alluvial fans of the gully and the dating of artifacts found in occupation debris enable researchers to estimate when the Spassky gully (Old Ryazan) was formed and to assess the stages of its evolution. The gully was formed in the process of building a defensive wall and a moat in the northern part of the old town. In the late 11th century and after a considerable lapse of time in the late 12th century through the process of bottom erosion, the moat gradually turned into a gully. The third stage of its evolution is the period from 1732 to the late 19th century when the land was actively ploughed. By monitoring erosion and landslide activity in Old Ryazan in 1999-2019, the researchers managed to single out a period of increased landslide activity in 2017-2019, which can be accounted for by climatic changes in the region.


2007 ◽  
Vol 40 (4) ◽  
pp. 1552
Author(s):  
A. Kontou ◽  
K. Gaki-Papanastasiou ◽  
H. Maroukian

In the present study two groups of alluvial fans from two different regions in Greece were comparetively studied, the first in the region of Sperchios river and the second in the region ofEurotas river. Distinct morphometric characteristics of the drainage basins of the tributaries Ts er lias, Xerias, Gorgopotamos, Kerasias, Retsas and Kakaris, as well as their fans were measured and compared. Furthermore ,the longitudinal stream profiles were mapped, pebble measurements were made and contour crenulations of the fans were studied. In gravelometry, it was found that the mean size M of the pebbles decreases from the apex to the apron of the fan. The crenulation analysis showed that the fans of the streams ofEurotas region have undergone greater erosion than those of Sperchios region. Remarkable differences exist between the fans of the two regions. These results lead to the conclusion that recent tectonism, the prevailing lithology and climate are responsible for the formation and evolution of the fans and also influence their shape, area and all the other morphometric characteristics


1997 ◽  
Vol 277 (1-3) ◽  
pp. 57-81 ◽  
Author(s):  
A.V. Ponomarev ◽  
A.D. Zavyalov ◽  
V.B. Smirnov ◽  
D.A. Lockner

2015 ◽  
Vol 186 (4-5) ◽  
pp. 223-241 ◽  
Author(s):  
Lucie Bestani ◽  
Nicolas Espurt ◽  
Juliette Lamarche ◽  
Marc Floquet ◽  
Jean Philip ◽  
...  

AbstractThe Pyrenean-Provence fold-thrust belt is characterized by a geological complexity arising from superimposed tectonic history and the propagation of the deformation through a heterogeneous mechanical substratum inherited from Paleozoic and Mesozoic times. The construction of a regional balanced cross section together with field data show that the thrust system of the southeastern Provence region is characterized by a mixed thick- and thin-skinned tectonic style related to the inversion of deep-seated late Paleozoic-Triassic extensional structures and the décollement of the Mesozoic-Cenozoic sedimentary cover above Triassic series. Earliest Cenomanian restoration state highlights the northward pinched-out of the Lower Cretaceous sedimentary series above the main long-wavelength Durance High uplift. Latest Santonian restoration state indicates a southward tilting of ~2° of the basin attributed to the initial growth of the Pyrenean-Provence prism controlling the external flexure of the foreland. Thrusts propagation in the northern part of the Pyrenean-Provence fold-thrust belt was recorded to be synchronous during latest Cretaceous to Eocene time and produced a ~7° southward basin tilting. This major tilting is attributed to the tectonic inversion and basement thrust stacking of the Cap Sicié-Sainte Baume units. Cross section balancing shows a total horizontal basement shortening of 40 km (~35 %) across the Pyrenean-Provence foreland. The main part of this shortening (~37 km) was accommodated by thick-skinned thrusts involving basement south of the Arc syncline. ~5 km of shortening were accommodated northward by the Arc syncline and eastern Sainte-Victoire thin-skin structures, resulting from slip transferred from the deep thick-skinned intercutaneous thrust wedge. Finally we interpret salt tectonic structures of the southeastern Provence as passive diapirism growth during Jurassic to late Cretaceous time, and then reactivated during Pyrenean-Provence compression. Late normal faulting related to hypothetical reactive diapirism during the Oligocene extension episode was predominantly localized above inherited salt structures and probably controlled by inherited basement faults.


2016 ◽  
Vol 153 (5-6) ◽  
pp. 827-844 ◽  
Author(s):  
HEMIN KOYI ◽  
FARAMARZ NILFOUROUSHAN ◽  
KHALED HESSAMI

AbstractA series of scaled analogue models are used to study (de)coupling between basement and cover deformation. Rigid basal blocks were rotated about a vertical axis in a ‘bookshelf’ fashion, which caused strike-slip faulting along the blocks and in the overlying cover units of loose sand. Three different combinations of cover–basement deformations are modelled: (i) cover shortening before basement fault movement; (ii) basement fault movement before cover shortening; and (iii) simultaneous cover shortening with basement fault movement. Results show that the effect of the basement faults depends on the timing of their reactivation. Pre- and syn-orogenic basement fault movements have a significant impact on the structural pattern of the cover units, whereas post-orogenic basement fault movement has less influence on the thickened hinterland of the overlying belt. The interaction of basement faulting and cover shortening results in the formation of rhombic structures. In models with pre- and syn-orogenic basement strike-slip faults, rhombic blocks develop as a result of shortening of the overlying cover during basement faulting. These rhombic blocks are similar in appearance to flower structures, but are different in kinematics, genesis and structural extent. We compare these model results to both the Zagros fold-and-thrust belt in southwestern Iran and the Alborz Mountains in northern Iran. Based on the model results, we conclude that the traces of basement faults in cover units rotate and migrate towards the foreland during regional shortening. As such, these traces do not necessarily indicate the actual location or orientation of the basement faults which created them.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2825
Author(s):  
Xianfeng Peng ◽  
Hucheng Deng ◽  
Jianhua He ◽  
Hongde Chen ◽  
Yeyu Zhang

The formation and evolution of (normal) fault affect the formation and preservation of some reservoirs, such as fault-block reservoirs and faulted reservoirs. Strain energy is one of the parameters describing the strength of tectonic activity. Thus, the formation and evolution of normal fault can be studied by analyzing the variation of strain energy in strata. In this work, we used physical simulation to study the formation and evolution of normal fault from a strain energy perspective. Based on the similarity principle, we designed and conducted three repeated physical simulation experiments according to the normal fault in the Yanchang Formation of Jinhe oilfield, Ordos Basin, China, and obtained dip angle, fault displacement, and strain energy via the velocity profile recorded by high-resolution Particle Image Velocimetry (PIV). As a result, the strain energy is mainly released in the normal fault line zone, and can thus serve as channels for oil/gas migration and escape routes connecting to the earth’s surface, destroying the already formed oil/gas reservoirs. One might need to avoid drilling near the fault line. Besides, a significant amount of strain energy remaining in the hanging wall is the reason why the normal fault continues to evolve after the normal fault formation until the antithetic fault forms. Our findings provide important insights into the formation and evolution of normal fault from a strain energy perspective, which plays an important role in the oil/gas exploration, prediction of the shallow-source earthquake, and post-disaster reconstruction site selection.


Sign in / Sign up

Export Citation Format

Share Document