Sequence stratigraphy of the lacustrine rift basin in the Paleogene system of the Bohai Sea area: Architecture mode, deposition filling pattern, and response to tectonic rifting processes

2020 ◽  
Vol 8 (2) ◽  
pp. SF57-SF79
Author(s):  
Changgui Xu ◽  
Lu Huan ◽  
Song Zhangqiang ◽  
Jia Donghui

The Bohai Sea area is a complex lacustrine rift basin characterized by multistage rifts, polycycle superimpositions, and multiple genetic mechanisms. We recognized three types of sequence boundaries from the Paleogene strata of offshore Bohai, including 2 first-, 3 second-, and 10 third-order sequence boundaries. The third-order wedges, composed of the low-stand system tract (LST), lake expansion system tract (EST), and high-stand system tract (HST), are significant for hydrocarbon exploration. The sequence stratigraphic patterns vary in different periods. We discovered that the LST and EST are mainly developed in the rifting stage, whereas the HST is developed in the subsidence stage. Sequences developed in different depressions present significant variations, but the migration of the depocenter from the margin to the center during basin evolution can still be clearly recognized. Vertically, episodic tectonism plays an important role in controlling the formation of sequence boundaries, sequence structural features, and sequence architectural patterns. However, various rift basin marginal tectonics control the lateral sequence architectures. Because each structure belt is characterized by a unique sequence framework due to the strong influence of basin rifting processes, we establish a corresponding sequence stratigraphic model for the specific tectonic environment using process-based sequence stratigraphic methods.

GeoArabia ◽  
2005 ◽  
Vol 10 (2) ◽  
pp. 189-192 ◽  
Author(s):  
Moujahed Al-Husseini ◽  
Robley K. Matthews

The recent publication of GTS 2004 (Gradstein et al., 2004) provides an opportunity to recalibrate in time the late Carboniferous, Permian and Early Traissic Arabian Stratigraphy (GeoArabia Special Publication 3, Edited by Al-Husseini, 2004) as represented by the rock units in subsurface Interior Oman (Osterloff et al., 2004a, b) and the Haushi-Huqf Uplift region (Angiolini et al., 2004) (Figure). Additionally, sequence stratigraphic models of orbital forcing (Matthews and Frohlich, 2002; Immenhauser and Matthews, 2004) provide new insights in regards to the time calibration of depositional sequences: the “Rosetta Stone” approach. The Rosetta Stone approach predicts that the period of a third-order depositional sequence is 2.430 ± 0.405 my (denoted DS3 and here adjusted to increase the fourth-order ‘geological tuning fork’ from 0.404 to 0.405 my based on Laskar et al., 2004). The present calibration is also tied to the orbital-forcing model developed by R.K. Matthews (in Al-Husseini and Matthews, 2005; this issue of GeoArabia) that predicts that a second-order depositional sequence (denoted DS2) consists of six DS3s that were deposited in a period of about 14.58 my (6 x 2.430 my); the DS2 being bounded by two regional second-order sequence boundaries (SB2) corresponding to sea-level maximum regression surfaces.


2019 ◽  
Vol 23 (10) ◽  
pp. 1855-1860
Author(s):  
F.O. Amiewalan ◽  
E.O. Bamigboye

: Biostratigraphic study of Well DX has yielded Cretaceous miospores and dinoflagellates cysts which heightened the recognition of sequence boundaries (SB), Maximum Flooding Surfaces (MFS) and associated Systems Tracts. Five maximum flooding surfaces between 95.6 Ma and 89.0 Ma, four sequence boundaries between 96.4 Ma and 93.0 Ma and threedepositional sequences were identified with varying average thicknesses of sediments interpreted from the gamma ray log and biostratigraphic data. The threedepositional sequences interpreted are -depositional sequence I (96.4 Ma - 95.4 Ma) (8240 ft. - 8120 ft.), depositional sequence II (95.4 Ma - 94.0 Ma) (8120 ft. - 7850 ft.) and depositionalsequence III (94.0 Ma - 93.0 Ma) (7850 ft. - 7550 ft.). All the depositional sequences fall within the third order cycle. The age of the well was attempted based on the presence of some selected marker fossils - Ephedripites spp., Classopollis spp., Spiniferites spp., Cyclonephelium distinctum, Cyclonephelium vannophorum, Subtilisphaera spp., Eucomiidites spp., Triorites africaensis, Odontochitina costata and Droseridites senonicus recovered from the studied intervals and was dated Albian - Santonian. The Sequence stratigraphic interpretations are useful in further deepening the knowledge of thesubsurface geology of the studiedwell in Gongola Sub Basin, Upper Benue Trough of Nigeria.Keywords: Sequence Boundary, Maximum Flooding Surface, System tracts, Depositional sequence


2013 ◽  
Vol 734-737 ◽  
pp. 111-116
Author(s):  
Lei Zhang ◽  
Lun Wei Zhu ◽  
Xue Juan Zhang

According to the fundamental principles of high resolution sequence stratigraphy, this paper focused on the application of high resolution sequence stratigraphy to Silurian strata in Tazhong area. Based on the comprehensive study of logging, drilling and seismic information, the high resolution sequence boundaries of Silurian strata and two scales of datum level cycles (long-term and intermediate-term) can be recognized in Tazhong area. Seven chronstratigraphic boundaries can be recognized in Silurian strata, including four sequence boundaries, which were the transformation from datum level falling to datum level rising, and three flooding surfaces, which the transformation from datum level rising to datum level falling. The Silurian strata in Tazhong area can be divided into three third-order sequences which correspond to three long-term datum level cycles, and 11 fourth-order sequences (parasequence sets) relating to 11 intermediate-term datum level cycles. The classification aforementioned can much better solved the corresponding problem between the six lithological sections of Silurian strata and sequence formations, finally establishes the high resolution sequence stratigraphic framework of Silurian strata in Tazhong area.


2016 ◽  
Vol 53 (8) ◽  
pp. 763-773 ◽  
Author(s):  
Christopher D. Aucoin ◽  
Carlton E. Brett ◽  
Benjamin F. Dattilo ◽  
James R. Thomka

The “butter shale” Lagerstätten of the Cincinnati Arch have produced an abundance of articulated trilobites, along with assorted bivalves and cephalopods. These bluish gray shales are rich in clay, poorly calcified, and show vague internal bedding in outcrop. Butter shales form a repetitive motif with similar lithological and paleontological characteristics, suggesting conditions existed that can be explained by the interference between different orders of sequence stratigraphic cyclicity. The characteristics that define butter shales include rarity of coarser interbeds, homogenous, fine grain size, and abundance of burial horizons. The overriding control is siliciclastic sediment supply. During third-order transgressions, sediment supply to the basin is too low to produce thick shale-prone intervals. Conversely, during third-order falling stages, sediment supply is generally too high to favor butter shale deposition. Butter shales formed preferentially during a third-order highstand systems tract, and two subtly different variants resulted from the superimposed effects of higher order cycles. Highstands moderated by small-scale transgressions are characterized by lower background sedimentation and fewer, thinner mud deposition events. Superposition of small-scale sea-level fall on highstands produced increased background sedimentation, higher silt, and patchy fossil occurrences. Juxtaposition of various scaled highstand systems tracts provided the optimal butter shale conditions, characterized by elevated mud influx and frequent episodic burial events, leading to abundant, articulated trilobites and associated fauna. In these scenarios, episodic events provide sufficient mud to smother local faunas and create a soft, fine-grained substrate that prohibited recolonization by taxa adapted to firm substrates. Each scenario differs from the others with respect to sedimentology and faunal composition.


GeoArabia ◽  
2012 ◽  
Vol 17 (3) ◽  
pp. 85-128 ◽  
Author(s):  
Michael Obermaier ◽  
Thomas Aigner ◽  
Holger C. Forke

ABSTRACT The investigated Middle to Upper Triassic Upper Mahil Member, representing a Jilh outcrop equivalent in the Northern Oman Mountains, illustrates the proximal portion of a flat epeiric carbonate ramp. A sedimentological study of well-exposed outcrops in Wadi Sahtan may serve as a reference section for a sequence-stratigraphic framework and detailed facies description of the Upper Mahil Member. It also provides an insight into the seal and reservoir potential of carbonates in a low-accommodation inner ramp setting. Outcrop observations and thin section analyses yielded 14 different lithofacies types ranging from a supratidal marsh to high-energy subtidal shoal environment. Vertical facies stacking patterns show three basic small-scale cycle motifs (fifth-order). While mud-rich backshoal cycles with claystone intercalations and rooted/bioturbated mud-/wackestones illustrate potential baffles and seal units around the center of the Upper Mahil, potential reservoir units occur stratigraphically in the upper part of the formation. There, a few meter-thick trough cross-bedded oolitic-/peloidal-rich grainstone depicts maximum accommodation within backshoal to shoal cycle types below the erosional base-Jurassic unconformity. The investigated outcrop section in Wadi Sahtan was subdivided into nine almost complete third-order sequences. Two to four of these sequences are further stacked into three second-order super-sequences which are well reflected in the gamma-ray pattern. The highest reservoir potential occurs around second-order maximum floodings. Internal seals can be observed at third-order sequence boundaries where shales and muddy carbonates are up to 20 m thick. A regional correlation with subsurface data from Yibal and Lekhwair in Oman shows that the apparent thickness changes in the Upper Mahil (Jilh) are mainly determined by the Late Triassic/Early Jurassic erosional truncation. The occurrence of thick anhydrite units in the subsurface indicates a more proximal setting towards the southwest.


2011 ◽  
Vol 10 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Peiyan Sun ◽  
Zhenhui Gao ◽  
Lixin Cao ◽  
Xinping Wang ◽  
Qing Zhou ◽  
...  

2019 ◽  
Vol 59 (2) ◽  
pp. 863
Author(s):  
Claudio L. de Andrade Vieira Filho ◽  
Mark Reilly ◽  
Suzanne Hurter ◽  
Zsolt Hamerli

A new sequence stratigraphic framework (SSF) for the Early–Late Jurassic Surat Basin, eastern Australia, is evolving. A second and third order framework based upon an integrated methodology of well-to-well correlations supported by well tied seismic data is being developed. The integration of an additional dataset (palynology) to test for regionally consistent sequence stratigraphic well correlations offers an improvement in defining sequence boundaries related to the geological timescale. The palynological data from 33 wells covering the north-east Surat Basin were extracted from the Queensland Digital Exploration (QDEX) open-file reports, some of which date back to the 1960s. These data were correlated and superposed on the SSF for age comparison. The dataset used in this study represents only a subset of all existing palynology information, as not all data are captured in QDEX. However, the palynology data in this exploratory study generally fits and supports the new SSF with only one exception, the reason for which is not understood at this stage. We recommend expanding this study to include more data because palynology can support stratigraphic interpretation, especially in wells that do not intercept, or have log data across, regional datums.


2017 ◽  
Vol 5 (4) ◽  
pp. ST35-ST51 ◽  
Author(s):  
Changgui Xu ◽  
Xiaofeng Du ◽  
Hongtao Zhu ◽  
Donghui Jia ◽  
Wei Xu ◽  
...  

The “source-to-sink” concept originated in the study of global change and atmospheric pollution. In recent years, the concept of a source-to-sink system has been widely applied in continental margin sedimentary analysis. In our research, the idea of source-to-sink is applied to the continental rift basin sedimentary system in the Bohai Sea area. The idea emphasizes that the sedimentation dynamics, including erosion, transportation, and accumulation, are considered as a complete source-to-sink system. The sand-rich region often corresponds to a source-to-sink coupling system in a complex continental rift basin, which includes the effective provenance, high-efficiency routing system, and base-level transition. In addition, (1) the effective provenance can be subdivided into explicit and implicit provenance systems in which the implicit provenance system has been shown to be a significant advancement in reservoir prediction for the Bohai Sea area, (2) the sediment-transport pathways and slope-break zone constitute the routing systems, and (3) the base-level transition is one of the allogenic factors that controls the position of the sandstone distribution in a sequence. Based on a large number of previous studies and different characteristics of sequence-stratigraphic models in the Bohai Sea area, we have evaluated three types of source-to-sink systems, including the fault-steep slope, strike-slip fault slope, and gentle slope pattern. In addition, the fault-steep-slope source-to-sink coupling system can be further subdivided into four types, namely, the corner, relay ramps, fault-throw diminishment-type, and valley-type source-to-sink systems. The source-to-sink system of the gentle slope pattern includes the uplift axis valley-type source-to-sink system and the slope-valley-type source-to-sink system. A small-scale, thick layer of fan delta is formed in the fault-steep-slope zone. A continuous braided river delta is formed in the strike-slip fault slope zone. A large-scale, thin layer of braided river delta is formed in the gentle slope zone. The characteristics of source-to-sink systems in continental rift basins are established for the exploration or prediction of favorable zones in the study area, as well as in similar basins.


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