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

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

<p><strong>Abstract</strong></p><p><br>The authigenic <sup>10</sup>Be/<sup>9</sup>Be dating method utilizes the ratio of cosmogenic radionuclide <sup>10</sup>Be produced in the atmosphere and of stable <sup>9</sup>Be 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 N<sub>1</sub>=N<sub>o</sub>e<sup>-λt</sup>. 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 <sup>9</sup>Be 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.</p><p>This study aims to examine, how change in sediment source proximity across a deltaic parasequence affects the applicability of the authigenic <sup>10</sup>Be/<sup>9</sup>Be 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 4.46–4.44 Ma (D) and 4.39–4.36 Ma (E). The authigenic <sup>10</sup>Be/ <sup>9</sup>Be ratio of 19 samples was compared to granulometric and geochemical analyzes in order to trace and interpret the variability of the data.</p><p>In our study it was found that <sup>10</sup>Be/ <sup>9</sup>Be 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 (71.45–82.64 vol. %) with content of clay (8.09–23.78 vol. %) and low content of sand (1.5–13.32 vol. %). There are three significant outliers regarding <sup>10</sup>Be/ <sup>9</sup>Be ratio. One sample in the parasequence D exhibit increase of <sup>10</sup>Be 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 <sup>10</sup>Be. Both parasequences exhibit almost identical weighted mean authigenic <sup>10</sup>Be/ <sup>9</sup>Be 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 <sup>10</sup>Be/ <sup>9</sup>Be ratios within parasequences and in their comparison is encouraging for the method applicability.</p><p>This research was financially supported by the Slovak Research and Development Agency under contract No. APVV-16-0121.</p>

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

2020 ◽  
Author(s):  
Yueyue Bai ◽  
Qingtian Lv ◽  
Zhaojun Liu ◽  
Pingchang Sun ◽  
Rong Liu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Accumulation Rate ◽  
Mapping Method ◽  
Sediment Supply ◽  
Coal Seams ◽  
Delta Front ◽  
Contour Maps ◽  
Delta Plain ◽  
Fan Delta ◽  
Wide Range

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.

scholarly journals Facies analysis of Sunakothi Formation, Kathmandu basin, Nepal and its significance

2014 ◽  
Vol 47 (1) ◽  
pp. 57-64
Author(s):  
Mukunda Raj Paudel
Keyword(s):  
Lake Level ◽  
Facies Analysis ◽  
Flood Plain ◽  
Delta Front ◽  
Gravel Beds ◽  
Delta Plain ◽  
Facies Associations ◽  
Ripple Sand ◽  
Lacustrine Delta ◽  
Lacustrine Facies

This study decipher facies characteristic of Sunakothi Formation at southern part of Kathmandu Basin. Thick sandy and muddy sequence is found on an open lacustrine facies of the Kalimati Formation. Five facies associations have been recognized within the sandy and muddy facies. These are: (a) muddy rhythmites and silt and laminated to ripple sand bed of the prodeltaic origin (pd), (b) association of cross-stratification, rippledrift and parallel lamination in the lacustrine delta front origin (df), (c) muddy flood-plain and alteration of the fine and coarse sediments of delta-plain origin (dp), (d) sandy to silty rhythmites of the marginal shallow lacustrine origin above the delta-plain (ml), and (e) association of fluvial origin (fl ). Former three associations are interbeded by the thick gravel deposits, which is gravelly braided river origin. Transition from lacustrine to alluvial system is characterized by fluvial and deltaic system in the south. Sedimentology of the Sunakothi Formation indicates deposition during rapid lake level rise and also the thick channelized fluvial gravel beds within the sandy and muddy sequence indicate lake level fall. The cause could be climatic as well as activity of the basin margin tectonics. Sunakothi Formation is the southern counterpart of the Thimi-Gokarna Formations distributed in the northern part of the basin.

Lithofacies and fluvial–lacustrine environments of the Palaeogene Sevkhuul and Ergil members (Ergiliin Zoo Formation, South Gobi, Mongolia)

2006 ◽  
Vol 143 (2) ◽  
pp. 165-179 ◽  
Author(s):  
H. G. DILL ◽  
S. KHISHIGSUREN ◽  
J. BULGAMAA ◽  
KH. BOLORMA ◽  
F. MELCHER
Keyword(s):  
Source Area ◽  
Field Work ◽  
Late Eocene ◽  
Climatic Conditions ◽  
Heavy Minerals ◽  
Gobi Desert ◽  
Carbonate Minerals ◽  
Delta Front ◽  
Delta Plain ◽  
Sheet Silicates

The clastic sequence of the Ergiliin Zoo Formation stretches along the Mongolian–Chinese border in the southern Gobi Desert, Mongolia. Its members (Sevkhuul, Ergil) exposed in the Erdene Sum region are well known for their vertebrate remains of Late Eocene and Oligocene age. Based upon field work, the continental red beds were subdivided into four units described as (I) prodelta/mud-sand flat, (II) delta front, (III) delta plain and (IV) calcretes. All sub-environments are in a fluvial–lacustrine setting. Electronmicroprobe analysis, in addition to conventional thin-section examination, was applied to shed some light on the complex mineral association made up of light minerals (quartz, plagioclase, ternary feldspar, orthoclase, smectite, illite, rare palygorskite), heavy minerals (almandine–pyrope solid solution series, zoisite–epidote s.s.s.) and abundant goethite and carbonate minerals (calcite, dolomite). Igneous rocks being exposed in the source area have contributed to the formation of carbonate minerals and Mg-bearing sheet silicates during diagenesis. Higher up on the delta plain transitional between distal alluvial and deltaic deposits, fluids emerged from the distal alluvial–fluvial deposits and formed calcareous duricrusts. Drawing conclusions from the rock colour, the mineral assemblage and the palaeoecological data, the climatic conditions may be described as alternating wet and dry seasons, closely resembling those conditions of a modern savannah.

scholarly journals The occurrence of marine fossils in the Upper Cretaceous deltaic sediments at Pautut, central West Greenland

1991 ◽  
Vol 39 ◽  
pp. 111-122
Author(s):  
Torben Olsen ◽  
Gunver Krarup Pedersen
Keyword(s):  
Depositional Environment ◽  
Upper Cretaceous ◽  
Sediment Accumulation ◽  
Accumulation Rates ◽  
Delta Front ◽  
Delta Plain ◽  
Facies Associations ◽  
Marine Fossils ◽  
Stratigraphic Position ◽  
Marine Influence

Finds of Upper Cretaceous marine macrofossils from Pautut have been reported since 1874. Subsequent investigations have led to contrasting views concerning the stratigraphic position of the fossils, the general depositional environment, and the amount of marine influence. During a brief visit to Pautut in the summer of 1989, a section of the exposed sediments was described. The sediments can be divided into 4 facies associations reflecting deposition on a prograding delta front, in distributary channels, on a subaerial to limnic delta plain and on an abandoned delta lobe during a marine transgression. The sedimentological model predicts that marine fossils, if present, should occur in the delta front association. The sediments were thoroughly searched for marine macrofossils, which were found in the lower part of the prominent coarsening-upward delta front sequences. The number of fossils is generally low. Bivalves and echinoids constitute the dominant groups of fossils and seem to have been well adapted to a life in muddy marine bays, subject to fluctuations in salinity and rate of deposition and with much suspended sediment. The fossils indicate that the beds at Pautut were deposited during latest Santonian to earliest Campa­nian times. Sediment accumulation rates were high. The stratigraphy within the Pautfit area is discussed and all the Cretaceous sediments are referred to the Atane Formation.

scholarly journals Linking the Variation of Sediment Accumulation Rate to Short Term Sea-Level Change Using Cyclostratigraphy: Case Study of the Lower Berriasian Hemipelagic Sediments in Central Tunisia (Southern Tethys)

2021 ◽  
Vol 9 ◽  
Author(s):  
Hamdi Omar ◽  
Anne-Christine Da Silva ◽  
Chokri Yaich
Keyword(s):  
Magnetic Susceptibility ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Sediment Accumulation Rate ◽  
Carbonate Content ◽  
Milankovitch Cycles ◽  
Central Tunisia ◽  
Level Change ◽  
Two Samples ◽  
Lower Berriasian

High-resolution magnetic susceptibility and % CaCO3 records (5 to 10 cm sampling interval) are used to track astronomical cycles from a Lower Berriasian record from central Tunisia. Six hundred and twenty two samples were measured for magnetic susceptibility and carbonate content as paleoclimate proxies for the detection of potential Milankovitch cycles. Elemental data using X-Ray fluorescence analyses was acquired from 19 samples to prove the reliability of the MS signal on recording the past paleoclimatic changes. We performed multiple spectral analyses and statistical techniques on the magnetic susceptibility signal, such as Multi-taper Method, Evolutive Harmonic Analysis, Correlation Coefficient, Time-optimization, and Average Spectral Misfit to obtain an optimal astronomical model. The application of these spectral analysis techniques revealed a pervasive dominance of E405-kyr and e100-kyr cycles showing that the climate turnover across the early Berriasian—middle Berriasian seems to had been governed by the long and short orbital eccentricity cycles. The identification of Milankovitch cycles in the record also allowed to propose a floating astronomical timescale of the studied section, with ~4 long eccentricity cycles (E405) extracted, which points to a duration estimate of ~1.6 Myr with an average sediment accumulation rate (SAR, after compaction) of 2.77 cm/kyr. The inferred floating ATS was tuned to the La2004 astronomical solution. In addition, we applied the DYNOT and ρ1 methods for seal-level change modeling to reconstruct a local eustatic profile which matches the previously published local and global eustatic charts.

scholarly journals The Serbian Lake Pannon formations - their significance and interregional correlation

2021 ◽  
pp. 7-7
Author(s):  
Filip Andjelkovic ◽  
Dejan Radivojevic
Keyword(s):  
Geothermal Energy ◽  
Pannonian Basin ◽  
Construction Materials ◽  
Seismic Survey ◽  
Petroleum Geology ◽  
Delta Front ◽  
Lake Pannon ◽  
Delta Plain ◽  
Lithostratigraphic Correlation ◽  
Basin System

The problem of correlating Lake Pannon sediments across its basin has been the occupation of many geologists. At first, it was hampered by the prevalence of biostratigraphic, rather than lithostratigraphic correlation. The task became accomplishable when, thanks to seismic survey data, the strongly progradational character of Lake Pannon sedimentation had been understood. Thus, this paper aims to describe the formations from all parts of Lake Pannon and compare them to the ones described in Serbia. Material used includes published and unpublished data from all countries w ith Pannonian Basin System upper Miocene and lower Pliocene deposits, in the form of seismic, borehole and outcrop data. Even though the system is strongly asymmetric, both spatially and temporally, the formation synthesis framework should help better understanding among geologists operating w ithin the basin. For the first t ime the informal formations are proposed for all Lake Pannon sediments in Serbia. The formations are linked to a progradational deltaic system w ithin the following succession: basinal plain-turbidite-slope-delta front-delta plain-lacustrine and alluvial environments. The lithostratigraphic correlation has a huge potential in the context of industry. The main potential surely lies in petroleum geology, but it could be also very useful for exploration of geothermal energy, hydrogeology and construction materials.

A Research for Division and Correlation of Fuyu Oil Layer in Northern Honggang Area

2014 ◽  
Vol 962-965 ◽  
pp. 622-625
Author(s):  
Xi Cheng Cao ◽  
Ming Ming Tang
Keyword(s):  
Songliao Basin ◽  
Western Slope ◽  
Delta Front ◽  
The West ◽  
Delta Plain ◽  
The North ◽  
Facies Types

Northern Honggang Area is situated in the north of Daan-Honggang terraces, southern Songliao Basin, bounded on the west of the western slope, on the northeast by Cologne sag, and on the southeast by Changling sag. The facies types of Northern Honggang District are mainly delta. The upper part of Fuyu oil layer is dominated by delta-front facies, the lower part is dominated by delta-plain facies.

scholarly journals Reflection of Scandinavian Ice Sheet Fluctuations in Norwegian Sea Sediments during the Past 150,000 Years

1995 ◽  
Vol 43 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Karl-Heinz Baumann ◽  
Klas S. Lackschewitz ◽  
Jan Mangerud ◽  
Robert F. Spielhagen ◽  
Thomas C.W. Wolf-welling ◽  
...  
Keyword(s):  
Early Stage ◽  
Accumulation Rate ◽  
Ice Sheet ◽  
Carbonate Content ◽  
Calcareous Nannofossils ◽  
Norwegian Sea ◽  
The Past ◽  
Glacier Fluctuations ◽  
Late Weichselian ◽  
Glacial Oscillations

AbstractThe record of glacier fluctuations in western Scandinavia, as reconstructed from continental data, has been correlated with records of ice-rafted detritus (IRD) from well-dated sediment cores from the Norwegian Sea covering the past 150,000 yr B.P. The input of IRD into the ocean is used as a proxy for ice sheet advances onto the shelf and, thus, for the calibration of a glaciation curve. The marine results generally support land-based reconstructions of glacier fluctuations and improve the time-control on glacial advances. The Saalian ice sheet decayed very rapidly approximately 125,000 yr B.P. In the Early Weichselian, a minor but significant IRD maximum indicates the presence of icebergs in isotope substage 5b (especially between 95,000 and 83,000 yr B.P.). Reduced amounts of calcareous nannofossils indicate that surface waters were influenced by meltwater discharges during isotope substages 5d and 5b. An extensive build-up of inland ice began again during isotope stage 4, but maximum glaciation was reached only in early stage 3 (58,000-53,000 yr B.P.). Marine sediments have minimum carbonate content, indicating strong dilution by lithogenic ice-rafted material. Generally, the IRD accumulation rate was considerably higher in stages 4-2 than in stage 5. A marked peak in IRD accumulation rates from 47,000 to 43,000 yr B.P. correlates well with a second Middle Weichselian ice sheet advance dated by the Laschamp/Olby paleomagnetic event. Minimum ice extent during the Ålesund interstade (38,500-32,500 yr B.P.) and several glacial oscillations during the Late Weichselian are also seen in the IRD record. Of several late Weichselian glacial oscillations on the shelf, at least four correspond to the North Atlantic Heinrich events. Ice sheet behavior was either coupled or linked by external forcing during these events, whereas internal ice sheet mechanisms may account for the noncoherent fluctuations.

Late Pleistocene sedimentary history of multiple glacially dammed lake episodes along the Yarlung-Tsangpo river, southeast Tibet

2014 ◽  
Vol 82 (2) ◽  
pp. 430-440 ◽  
Author(s):  
Shao-Yi Huang ◽  
Yue-Gau Chen ◽  
George S. Burr ◽  
Manoj K. Jaiswal ◽  
Yunung Nina Lin ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Depositional Environments ◽  
Optically Stimulated Luminescence ◽  
Delta Front ◽  
Delta Plain ◽  
History Of ◽  
Southeast Tibet ◽  
Yarlung Tsangpo ◽  
Dammed Lake ◽  
Yarlung Tsangpo River

AbstractWe present a reconstructed lithologic column compiled from a series of lacustrine outcrops along a tributary of the Nyang River, a major tributary of the Yarlung-Tsangpo in southeast Tibet. The deposits were preserved between terraces at altitudes of 2950–3100 m asl. The stratigraphic record features at least two sets of coarsening-upward sequences depicting episodic aggradation and progradation of a glacially dammed lake related delta. Recognized facies changes illustrate the evolution cycles of depositional environments from pro-delta, delta front, to delta plain. Radiocarbon and optically stimulated luminescence dates reveal an aging-downward trend in stratigraphic order and provide an approximate timeline for the formation of glacially dammed lakes in late Pleistocene. This result reflects that the Zelunglung Glacier had progressively advanced to block the Yarlung-Tsangpo river and the dam materials had stepwise stacked up to an altitude of 3095 m asl during Marine Oxygen Isotope Stages 4 to 2.

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

2019 ◽  
Vol 156 (10) ◽  
pp. 1715-1741 ◽  
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.

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