Sedimentary system and coal seam distribution in the coal-bearing sequence stratigraphic framework in the Paleogene Meihe Formation (Meihe Basin, NE China)

Abstract The Meihe Basin is one of the important Paleogene coal-bearing fault basins of northeastern China in the Dunhua-Mishan Fault Zone. The Lower Coal-bearing Member and the Upper Coal-bearing Member are the primary layers studied. Through field observation, core description and observation under microscope, fan delta facies and lake facies are observed as the main sedimentary facies of the coal-bearing layers, and subfacies of fan delta plain, fan delta front, shallow lake and swamp have also been recognized. Coal seams primarily accumulated in the subfacies of swamp and fan delta plain. The study on sequence stratigraphy is based on outcrop section, well-log analysis, core observation and geochemical analysis. From the Lower Coal-bearing Member to the Upper Coal-bearing Member, three third-order sequences have been recognized; the Lower Coal-bearing Member developed in Sequence I and the Upper Coal-bearing Member developed in Sequence III, both sequences have developed the lowstand systems tract (LST), the transgressive systems tract (TST) and the highstand systems tract (HST). Single-factor analysis and the multifactor comprehensive mapping method have been used to rebuild the lithofacies palaeogeography of each system tract in Sequence I and Sequence III. Through analysis of contour maps of total stratum thickness, sandstone thickness and sand content, as well as contour maps of thicknesses and numbers of layers of coal seams, the results indicate that the sedimentary environments and coal seam distributions are variable in different system tracts. Coal types accumulating in the swamp facies are primarily developed in the transgressive systems tract (TST) and the highstand systems tract (HST) of Sequence I with a wide range of continuous and large thicknesses and may be mined commercially. Both the balanced accommodation growth rate with peat accumulation rate and little or no influence from sediment supply and channel migration promote to form the stable coal accumulating environments.

Download Full-text

Outcrop analysis and facies model of an Upper Permian tidally influenced fluvio-deltaic system: Northern Sydney Basin, SE Australia

Geological Magazine ◽

10.1017/s0016756818000973 ◽

2019 ◽

Vol 156 (10) ◽

pp. 1715-1741 ◽

Cited By ~ 2

Author(s):

Jake Breckenridge ◽

Angelos G. Maravelis ◽

Octavian Catuneanu ◽

Kevin Ruming ◽

Erin Holmes ◽

...

Keyword(s):

Source Region ◽

Depositional Environments ◽

Sediment Supply ◽

Upper Permian ◽

Delta Front ◽

Sediment Grain Size ◽

Sequence Stratigraphic ◽

Delta Plain ◽

Facies Associations ◽

The Impact

AbstractAn integrated study of sedimentological, sequence-stratigraphic and palaeodispersal analysis was applied to the Upper-Permian clastic sedimentary succession in the Northern Sydney Basin, Australia. The succession is subdivided into fifteen facies and three facies associations. The facies associations are further subdivided into eight sub-facies associations. The sedimentary evolution involves progradation from delta-front to delta-plain to fluvial depositional environments, with a significant increase in sediment grain size across the unconformable contact that separates the deltaic from the overlying fluvial system. In contrast to the delta front that is wave/storm- and/or river-influenced, the delta plain is significantly affected by tides, with the impact of tidal currents decreasing up-sequence in the delta plain. The general lack of wave-influenced sedimentary structures suggests low wave energy in the delta plain. The abrupt termination of the tidal impact in the fluvial realm relates to the steep topographic gradients and high sediment supply, which accompanied the uplift of the New England Orogen. The sequence-stratigraphic framework includes highstand (deltaic forest and topset) and lowstand (fluvial topset) systems tracts, separated by a subaerial unconformity. In contrast to most of the mud-rich modern counterparts, this is an example of a sand-rich tidally influenced deltaic system, developed adjacent to the source region. This investigation presents a depositional model for tidal successions in regions of tectonic uplift and confinement.

Download Full-text

Controls of Short-Term Base-Level Cycle on Macroscopic Heterogeneity of Reservoir: a Case Study of the Major Oil Layer of Liuzan Oilfield in Nanpu Sag

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.347-353.56 ◽

2011 ◽

Vol 347-353 ◽

pp. 56-59

Author(s):

Rui Zhang ◽

You Liang Ji

Keyword(s):

Short Term ◽

Delta Front ◽

River Sand ◽

Significant Control ◽

Plain Area ◽

Delta Plain ◽

The Third ◽

Base Level ◽

Fan Delta ◽

Nanpu Sag

Based on the depositional model and characteristics of fan delta, the short-term base-level cycle of the third submember of the third member of Shahejie Formation （Es33）in North region major oil layer of Liuzan Oilfield of Nanpu Sag is divided into three basic categories applying high-resolution sequence stratigraphy with the reference to core and logging data, namely, deepening-upward asymmetrical type, shallowing-upward asymmetrical type and symmetrical type. Different variation models for macroscopic heterogeneity of reservoir belonging to different categories of short-term base-level cycle were established in this paper; it was further pointed out that the changes of base-level and the ancient landform were major factors controlling the characteristic discrepancy of macroscopic heterogeneity of reservoir. In fan delta plain area, the ancient landform is smooth. Deepening-upward asymmetrical cycle is mainly composed of braided river sand body, and the changes of base-level exert little control on porosity with significant control on permeability. At the delta front slope, the landform becomes steep. Deepening-upward asymmetrical cycle is mainly composed of underwater distributary channel with genetic mechanism of gravity flow. The vertical variations of porosity and permeability inside the cycle are rather complicated. Since the physical properties are mainly manifested as the control on autogenic cycle, they do not directly influence the changes of base level.

Download Full-text

Deltaic sedimentation in an unstable tectonic environment – the Lower Limestone Group (Lower Carboniferous) of East Fife, Scotland

Geological Magazine ◽

10.1017/s0016756800010189 ◽

1988 ◽

Vol 125 (3) ◽

pp. 241-255 ◽

Cited By ~ 16

Author(s):

C. R. Fielding ◽

M. Al-Rubaii ◽

E. K. Walton

Keyword(s):

Shallow Water ◽

Organic Soils ◽

Coal Seams ◽

Delta Front ◽

Delta Plain ◽

Tectonic Environment ◽

Facies Associations ◽

Free Drainage ◽

Deltaic Sedimentation ◽

Clastic Sedimentary

AbstractThe Lower Limestone Group, which outcrops extensively on the east coast of Fife, southeast Scotland, consists of interbedded sandstones, siltstones and claystones with occasional coal seams, and limestone beds. Several of the coals have been mined economically in the past.The sequence was deposited in a shallow-water, deltaic setting. Three facies associations have been distinguished; (1) laminated claystones, and marine bioclastic limestones, which were deposited in prodelta and marine shelf environments, (2) crudely coarsening-upward sandstone units, interpreted as delta front deposits of fluvially-dominated though wave-influenced, shallow-water deltas, and (3) interbedded clastic sedimentary rocks and coals, deposited in delta plain environments. The sequence as a whole accumulated by repeated progradation and abandonment of deltaic complexes.Palaeosol profiles of four types are superbly preserved within the delta plain facies association. These are (1) organic soils (peats), now coal seams, (2) gley palaeosols, which formed in persistently waterlogged conditions, (3) freely drained soils which formed on a quartz sand-rich substrate, and (4) similar profiles formed by free drainage through variable substrates and involving B horizon accumulation of concretionary iron oxides. Compound palaeosols are common.Deposition of the Lower Limestone Group was influenced by the tectonic and volcanic instability of the Fife area during Visean times. Frequent seismic events centred on active fault lines caused local uplift of parts of the normally waterlogged delta plain environment, allowing the formation of well-drained soils. Peats (coals) were best developed and least affected by oxidation in an elongate, fault bounded zone of enhanced subsidence.

Download Full-text

Small-amplitude lake-level fluctuations recorded in aggrading deltaic deposits of the Upper Pleistocene Thimi and Gokarna formations, Kathmandu Valley, Nepal

Journal of Nepal Geological Society ◽

10.3126/jngs.v25i0.32049 ◽

2001 ◽

Vol 25 ◽

Author(s):

Tetsuya Sakai ◽

Ananta Prasad Gajurel ◽

Hideo Tabata ◽

Bishal Nath Upreti

Keyword(s):

Small Amplitude ◽

Lake Level ◽

Fine Sediment ◽

Sediment Supply ◽

Kathmandu Valley ◽

Delta Front ◽

Lake Level Fluctuations ◽

Delta Plain ◽

Wet And Dry Cycles ◽

Sand Beds

Small-amplitude lake-level fluctuations have been recognized from the aggrading delta-plain deposits in the lower parts of the Thimi and Gokarna formations, Kathmandu Valley, Nepal. The delta-plain deposits consist or gravelly sand beds of fluvial channel origin (coarse-sediment interval) and alternation of' fine to very line sand and sandy silt beds (line-sediment interval). Wave generated structures occur in the sand beds or the fine sediment intervals. The vertical and lateral facies changes suggest that the deposition or a set of coarse- and fine-sediment intervals associated with prograding delta front deposits was controlled by a lake-level rise and fall sequence superimposed on a long-term lake level rise trend. The aggradation of fluvial sediments occurred during a lake-level rise period with sufficient sediment supply to fill a newly created accommodation space on the delta plain. The observation or wave-generated structures in an overlying fine-sediment interval suggests that the delta plain was subsequently inundated due to further lake-level rise, exceeding the sedimentation rate. Subsequent delta progradation occurred during a lake-level stabilized phase after a lake level fall. The small-amplitude lake-level changes are thought to be attribute able to seasonal wet and dry cycles, as inferred based on the presence of peculiar aggrading delta successions, implying that lake-level fluctuations may have occurred over short time scales, and on the results of a previous palaeopalynological study in which a moist palacoclimate was inferred in the lower part of the Gokarna Formation in particular.

Download Full-text

Applicability of the authigenic 10 Be/ 9 Be dating to deltaic deposits: Preliminary results from the Slanicul de Buzau section, Pliocene, Romania.

10.5194/egusphere-egu21-13808 ◽

2021 ◽

Author(s):

Kishan Aherwar ◽

Michal Šujan ◽

Katarína Šarinová ◽

Régis Braucher ◽

Arjan de Leeuw ◽

...

Keyword(s):

Isotopic Ratio ◽

Accumulation Rate ◽

Radioactive Decay ◽

Relative Content ◽

Carbonate Content ◽

Delta Front ◽

Continuous Growth ◽

Delta Plain ◽

Dating Method ◽

Good Proxy

Abstract The authigenic 10Be/9Be dating method utilizes the ratio of cosmogenic radionuclide 10Be produced in the atmosphere and of stable 9Be derived from chemical erosion of rock massifs.Different origin of both nuclides points to difficulty in determination of the initial isotopic ratio, which radioactive decay is the base of age calculation using the equation N1=Noe-&#955;t. The initial ratio could be affected by several factors and might change through time. Mixing of riverine and basinal (lacustrine or marine) waters appear to be one of the significant effects, since surficial streams are the major source of the dissolved 9Be and its relative content is expected to decrease towards the open basinal environment due to the continuous growth of authigenic rims around particles (Wittmann et al., 2017: Geophys. Res. Lett.). This effect should be traceable when analyzing different facies from open shelf through prodelta and delta front up to the delta plain environments, however, a study focusing on the mentioned issue is missing.This study aims to examine, how change in sediment source proximity across a deltaic parasequence affects the applicability of the authigenic 10Be/9Be dating method. Two early Pliocene deltaic parasequences D and E were selected for this purpose from the Slanicul de Buzau section in the Dacian Basin (Romania), with an established robust geochronological model based on magnetostratigraphy (Jorissen et al., 2018: Sed. Geol.). Hence, the parasequences are of known age of 4.46&#8211;4.44 Ma (D) and 4.39&#8211;4.36 Ma (E). The authigenic 10Be/ 9Be ratio of 19 samples was compared to granulometric and geochemical analyzes in order to trace and interpret the variability of the data.In our study it was found that 10Be/ 9Be ratios are relatively stable for both parasequences without significant different trend from distal to proximal facies. Grain size of all samples are generally comparable, indicating silt (71.45&#8211;82.64 vol. %) with content of clay (8.09&#8211;23.78 vol. %) and low content of sand (1.5&#8211;13.32 vol. %). There are three significant outliers regarding 10Be/ 9Be ratio. One sample in the parasequence D exhibit increase of 10Be correlating with high carbonate wt. % and an increase of CIA index. The carbonate content appears to be a good proxy for a decrease in riverine sediment input and lower accumulation rate, which favors higher relative content of 10Be. Both parasequences exhibit almost identical weighted mean authigenic 10Be/ 9Be ratio after excluding the outliers, what is an expected result considering analytical uncertainty of the method in ca 4.5 Ma old sediments. The low variability of 10Be/ 9Be ratios within parasequences and in their comparison is encouraging for the method applicability.This research was financially supported by the Slovak Research and Development Agency under contract No. APVV-16-0121.

Download Full-text

Sedimentary Characteristics Analysis and Sedimentary Facies Prediction of Jurassic Strata in the Northwest Margin of Junggar Basin—Covering the W105 Well Region in the Wuerhe Area

Minerals ◽

10.3390/min12010068 ◽

2022 ◽

Vol 12 (1) ◽

pp. 68

Author(s):

Shiqi Liu ◽

Yuyang Liu

Keyword(s):

Cross Sections ◽

Oil And Gas ◽

Junggar Basin ◽

Sedimentary Facies ◽

Delta Front ◽

Delta Plain ◽

Fan Delta ◽

Single Well ◽

Northwest Region ◽

Sand Bodies

As the northwestern area of the Junggar Basin is a key area for oil and gas exploration, the sedimentary facies of the Jurassic formations in the Wuerhe area has long been a focus of research. The target strata are Jurassic strata, including five formations: the Lower Jurassic Badaowan and Sangonghe, the Middle Jurassic Xishanyao and Toutunhe and the Upper Jurassic Qigu. Disputes over the are sedimentary facies division exist in this area. Considering the W105 well region in this area as an example, the overall sedimentary facies of single-well logging facies is analyzed and then expanded to two cross-sections and characterized. Based on previous studies, a detailed overview of the regional stratigraphy is obtained by well logs and other data. Then, two cross-sections are selected and analyzed. The single-well and continuous-well facies of 10 wells in the sections are analyzed to grasp the sand bodies’ spatial distribution. Finally, a planar contour map of the net to gross ratio is mapped to analyze the sources and the distribution of the sand bodies in each period. The sedimentary facies map is also mapped to predict the sedimentary evolution. The results show that the sedimentary facies of the Badaowan Formation in the study area was an underwater distributary channel of the fan-delta front, and the sand body spread continuously from northwest to southeast. The Sangonghe Formation entered a lake transgression period with a rising water level, at which time shore–shallow lacustrine deposits were widespread throughout the region. The period of the Xishanyao Formation entered a regression period, the northwest region was tectonically uplifted, and the central and southeastern regions facies were dominated by the fan-delta front and shallow lacustrine. During the Toutunhe Formation period, the northwest region continued to uplift and was dominated by delta plain facies. During the period of the Qigu Formation, the thickness of stratigraphic erosion reached its maximum, and the non-erosion area of the study area was mainly deposited by the fan-delta plain. Overall, the Jurassic system in the W105 well area is a fan delta–lacustrine–fan delta sedimentary system.

Download Full-text

Sequence Stratigraphy and Depositional Environment of the Zubair Formation in Rumaila Oilfields, Southern Iraq: Microfacies and Geochemistry

Iraqi Geological Journal ◽

10.46717/igj.54.2b.3ms-2021-08-23 ◽

2021 ◽

Vol 54 (2B) ◽

pp. 28-41

Author(s):

Hamid A. A. Alsultan

Keyword(s):

Sea Level ◽

Sequence Stratigraphy ◽

Gamma Ray ◽

Sediment Supply ◽

Delta Front ◽

Delta Plain ◽

Quartz Arenite ◽

Sandy Shale ◽

Sonic Logs ◽

Southern Iraq

In the Rumaila oilfields in southern Iraq, the Zubair Formation was deposited in a shallow environment as three main facies, delta plain, backshore, and delta front depositional conditions indicating a transition from delta front and delta plain to a highstand level due to the finning upward mode. The facies of the Zubair clasts show well-sorted quartz arenite sandstone, poorly sorted quartz arenite sandstone, clayey sandstone that has not been properly sorted, sandy shale, and shale lithofacies. The minor lithofacies were identified using well-logging methods (gamma ray, spontaneous potential and sonic logs) and petrography. The Zubair clasts are of transition environment that appears to be transported from freshwater and deposited in a marine environment forming many fourth-order cycles reflect sea level rise fluctuations and still-stand under tectonics developed the sequence stratigraphy. A misalignment between relative sea-level and sediment supply caused asymmetry sedimentary cycles. A shallower environment of shale-dominated rocks rich in organic matter and pyrite were exposed. The basinal shale of Ratawi at the Zubair bottom and the shallow carbonate of Shuaiba emplace on the Zubair represent the beginning of the delta build up (delta front and delta plain) to a highstand stage.

Download Full-text

GEOLOGICAL CONTROLS ON EXPLOITABLE COAL SEAM GAS DISTRIBUTION IN QUEENSLAND

The APPEA Journal ◽

10.1071/aj05019 ◽

2006 ◽

Vol 46 (1) ◽

pp. 343 ◽

Cited By ~ 44

Author(s):

J. J. Draper ◽

C.J. Boreham

Keyword(s):

Coal Seam ◽

Vitrinite Reflectance ◽

Gas Production ◽

Gas Content ◽

Burial History ◽

Coal Seam Gas ◽

Gas Generation ◽

Delta Plain ◽

Wide Range ◽

Gas Fields

Methane is present in all coals, but a number of geological factors influence the potential economic concentration of gas. The key factors are (1) depositional environment, (2) tectonic and structural setting, (3) rank and gas generation, (4) gas content, (5) permeability, and (6) hydrogeology. Commercial coal seam gas production in Queensland has been entirely from the Permian coals of the Bowen Basin, but the Jurassic coals of the Surat and Clarence-Moreton basins are poised to deliver commercial gas volumes.Depositional environments range from fluvial to delta plain to paralic and marginal marine—coals in the Bowen Basin are laterally more continuous than those in the Surat and Clarence-Moreton basins. The tectonic and structural settings are important as they control the coal characteristics both in terms of deposition and burial history. The important coal seam gas seams were deposited in a foreland setting in the Bowen Basin and an intracratonic setting in the Surat and Clarence-Moreton basins. Both of these settings resulted in widespread coal deposition. The complex burial history of the Bowen Basin has resulted in a wide range of coal ranks and properties. Rank in the Bowen Basin coal seam gas fields varies from vitrinite reflectance of 0.55% to >1.1% Rv and from Rv 0.35-0.6% in the Surat and Clarence-Moreton basins in Queensland. High vitrinite coals provide optimal gas generation and cleat formation. The commercial gas fields and the prospective ones contain coals with >60% vitrinite.Gas generation in the Queensland basins is complex with isotopic studies indicating that biogenic gas, thermogenic gas and mixed gases are present. Biogenic processes occur at depths of up to a kilometre. Gas content is important, but lower gas contents can be economic if deliverability is good. Free gas is also present. Drilling and production techniques play an important role in making lower gas content coals viable. Since the Bowen and Surat basins are in a compressive regime, permeability becomes a defining parameter. Areas where the compression is offset by tensional forces provide the best chances for commercial coal seam gas production. Tensional setting such as anticline or structural hinges are important plays. Hydrodynamics control the production rate though water quality varies between the fields.

Download Full-text

The Type and Characteristics of the First Member of Nantun Formation’s Sedimentary Facies in Wunan Sub Depression

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.733.88 ◽

2015 ◽

Vol 733 ◽

pp. 88-91

Author(s):

Ming Xue Zhang ◽

Bai Ze Kai ◽

Lei Zhou

Keyword(s):

Tectonic Evolution ◽

Sedimentary Facies ◽

Sediment Supply ◽

Deep Lake ◽

Delta Plain ◽

Fan Delta ◽

Core Logging

Through the study of a large number of core, logging, and logging data, on the basis of previous research (Nantun Formation is divided into two period which are the first member of Nantun Formation and the second member of Nantun Formation), combined with the characteristics of the seismic, the sedimentary facies of Wunan sub depression is researched. The sedimentary facies characteristics in different periods are mainly controlled by tectonic evolution and sediment supply. The first member of Nantun formation mainly develops two kinds of sedimentary facies which are fan-delta facies and lake facies, and four subfacies which are fan-delta plain, frontal fan-delta, shore-shallow, deep lake and semi-deep lake.

Download Full-text

Macerals Analysis Seam M2 Muaraenim Formation, : Implication Toward Coal Facies and Coal Rank in Kendi Hill, South Sumatra

Journal of Geoscience Engineering Environment and Technology ◽

10.24273/jgeet.2018.3.2.670 ◽

2018 ◽

Vol 3 (2) ◽

pp. 94 ◽

Cited By ~ 1

Author(s):

Yonathan Mangatur Rajagukguk ◽

Stevanus Nalendra Jati

Keyword(s):

Coal Seam ◽

Selection Process ◽

Vitrinite Reflectance ◽

Research Area ◽

Mineral Matter ◽

Coal Seams ◽

Delta Plain ◽

Southern Central ◽

Coal Facies ◽

Index Value

The Muaraenim Formation is a coal bearing formation in South Sumatra Basin of the Late Miocene – Pliocene. Shell (1978) divides this formation based on coal seam content are: M1, M2, M3, and M4. Coal seam in this area include in seam M2 member, with the general characteristics of the presence of silicified coal on the roof and floor of coal seams as a marker. The administration of the research area is located in east Kendi Hill, South Sumatra. The Kendi Hill is composed of adesite igneous rocks that intruded Muaraenim Formation in unconformity at the time of Pleistocene. This study aims to determine the environment of coal depositional based on maceral analysis and determine the factors influence the physical characteristics of coal seams in Kendi Hill. Data that has been obtained from the field, then conducted a selection process. The number of samples analyzed were nine sample based on near and far to the Kendi Hill spread from the southern, central, and northern of the location. The result of the analysis will display the maceral diagram. Megascopically, coal seam in the Kendi Hill are black, dull with bright, uneven – subchoncoidal, blackish brown in streak, have a pyrite and resin. The thickness of the coal seams ranges from 0,45 to 14 meters. Based on the maceral analysis, the coal seam in the Muaraenim Formation is composed dominated by vitrinite, then liptinite, inertinite and mineral matter pyrite (1,6-6,6%). Vitrinite reflectance of coal in the research area ranges from (0,37-0,48%) that included to the Sub bituminous – High Volatile Bituminous C. From the results of Tissue Preservation Index and Gelification Index value indicated that the environment of coal depositional in the research area was a limnic to wet forest swamp. Whereas the deposition of the Muaraenim Formation in deltaic environment (Transitional lower delta plain).

Download Full-text