Palaeoenvironment, sequence stratigraphy and palaeogeography of the Lower Cretaceous deposits of Mehdi Abad, Yazd Block, Central Iran

2020 ◽  
Vol 295 (1) ◽  
pp. 61-89
Author(s):  
Mohammad Safaei ◽  
Asadollah Mahboubi ◽  
Soroush Modabberi ◽  
Reza Moussavi-Harami
Keyword(s):  
Sequence Stratigraphy ◽  
Coastal Plain ◽  
Tidal Flat ◽  
Lower Cretaceous ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Deep Basin

Four Lower Cretaceous sections in the southern Yazd Block were measured and studied to interpret the palaeoenvironments, synsedimentary tectonics, and sequence stratigraphy. The Early Cretaceous sedimentary record of this block, consisting of the Sangestan, Taft, Abkuh, and Darreh Zanjir formations, was mainly influenced by synsedimentary tectonic activities in a tectonically unstable basin. Field observations and laboratory studies were used to identify lithofacies and microfacies, based on which six depositional environments were identified: upper coastal plain (alluvial fans), shore, tidal flat, lagoon, shoal, and open marine. A carbonate-siliciclastic shallow platform including an alluvial-coastal plain and an inner platform is suggested for the depositional environment of the Sangestan Formation. The depth of the overall shallow sedimentary basin of Sangestan Formation increases from west to east and deposition was controlled by long- term sea-level changes. A carbonate platform consisting of inner and outer parts, including tidal flat, lagoon, open marine belts, is suggested for the depositional environment of the Taft and Abkuh formations, while the Darreh Zanjir Formation accumulated in a deep basin. The predominant facies demonstrate an overall transgression-regression cycle (the 2rd order cycle) during the depositional time of these formations in the southern Yazd Block.

scholarly journals Stratigraphy and Depositional Environment of Mauddud Formation in Ratawi Oil wells of Southern Iraq

2021 ◽  
Vol 877 (1) ◽  
pp. 012030
Author(s):  
Maha Razaq Manhi ◽  
Hamid Ali Ahmed Alsultani
Keyword(s):  
Deep Sea ◽  
Lower Cretaceous ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Oil Wells ◽  
Oil Field ◽  
Microfacies Analysis ◽  
Thin Sections ◽  
Southern Iraq

Abstract The Mauddud Formation is Iraq’s most significant and widely distributed Lower Cretaceous formation. This Formation has been investigated at a well-23 and a well-6 within Ratawi oil field southern Iraq. In this work, 75 thin sections were produced and examined. The Mauddud Formation was deposited in a variety of environments within the carbonate platform. According to microfacies analysis studying of the Mauddud Formation contains of twelve microfacies, this microfacies Mudstone to wackestone microfacies, bioclastic mudstone to wackestone microfacies, Miliolids wackestone microfacies,Orbitolina wackestone microfacies, Bioclastic wackestone microfacies, Orbitolina packstone microfacies, Peloidal packstone microfacies, Bioclastic packstone microfacies, Peloidal to Bioclastic packstone microfacies, Bioclastic grainstone microfacies, Peloidal grainstone microfacies, Rudstone microfacies. Deep sea, Shallow open marine, Restricted, Rudist Biostrome, Mid – Ramp, and Shoals are the six depositional environments in the Mauddud Formation based on these microfacies.

scholarly journals Lithostratigraphy and sedimentary evolution of the Triassic, Jurassic and Lower Cretaceous of Bornholm, Denmark

1982 ◽  
Vol 7 ◽  
pp. 1-51
Author(s):  
Peter Gravesen ◽  
Flemming Rolle ◽  
Finn Surlyk
Keyword(s):  
Tidal Flat ◽  
Lower Cretaceous ◽  
Flood Plain ◽  
Depositional Environments ◽  
Coarse Grained ◽  
Sea Level Changes ◽  
New Members ◽  
Barrier Beach ◽  
Sedimentary Evolution ◽  
Lower Berriasian

A new lithostratigraphic subdivision of the Triassic to Lower Cretaceous sequence of Bornholm is presented including 2 new groups, 3 new formations and 10 new members. The Late Ladinian-Carnian variegated clay, sand and conglomerates of arid flood-plain origin with thin marine intercalations are tentatively referred to the Kagerod Formation. The Jurassic sediments are placed in the Bornholm Group (new) comprising a lower Hettangian-Sinemurian Rønne Formation (new) which contains a succession of lacustrine clay, fluviatile sand and coal, and tidal flat and marsh heteroliths and sand. The overlying Lower Pliensbachian Hasle Formation (new) includes shallow marine fossiliferous sandstone, while the Bajocian-Bathonian Baga Formation (new) is characterized by fluviatile fining-upwards sand-clay-coal sequences and resedimented conglomerates. This is followed by the Lower Cretaceous Nyker Group (new), comprising a basal Rabekke Formation (Lower Berriasian, possibly extending down into the Tithonian and up into the Upper Berriasian) which contains fluviatile coarse, sometimes ferruginous sand and sandy clay, and swamp and lagoonal dark grey clay. This is overlain by the Robbedale Formation (Upper? Berriasian) which comprises tidal flat, beach and lagoonal fine-grained sand and clay and rather coarse-grained barrier beach and shelf sand. Then follows the Jydegard Formation (uppermost Berriasian - Valanginian) comprising back-barrier and washover fan sand, and lagoonal clay, clay-ironstone and silt with thin sands. The Triassic-Lower Cretaceous sequence thus reflects deposition in a variety of coastal environments, and while eustatic sea-level changes seem to have controlled the main facies evolution, the local depositional environments and breaks in sedimentation seem to reflect the interplay between eustacy and synsedimentary tectonic phases.

Paleoenvironmental Evolution of the Coastal Plain of Marathon, Greece, during the Late Holocene: Depositional Environment, Climate, and Sea Level Changes

2006 ◽  
Vol 222 ◽  
pp. 424-438 ◽  
Author(s):  
Kosmas Pavlopoulos ◽  
Panagiotis Karkanas ◽  
Maria Triantaphyllou ◽  
Efthimios Karymbalis ◽  
Theodora Tsourou ◽  
...  
Keyword(s):  
Sea Level ◽  
Coastal Plain ◽  
Late Holocene ◽  
Depositional Environment ◽  
Sea Level Changes ◽  
Paleoenvironmental Evolution ◽  
And Sea Level

scholarly journals Large-scale vertical movements in Cenomanian to Santonian carbonate platform in Iberia: Indicators of a Coniacian pre-orogenic compressive stress

2021 ◽  
Author(s):  
Simon Andrieu ◽  
Nicolas Saspiturry ◽  
Marine Lartigau ◽  
Benoit Issautier ◽  
Paul Angrand ◽  
...  
Keyword(s):  
Large Scale ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Deep Basin ◽  
Vertical Movements ◽  
Flexural Response ◽  
Kinematic Models ◽  
Far Field Stress ◽  
Iberian Margin

The Cenomanian to early Santonian interval is usually considered a time of postrifting tectonic quiescence around the northern margins of Iberia that preceded the onset of the Pyrenean convergence by crustal thrusting in the latest Santonian. However, plate kinematic models of the Mesozoic evolution of Iberia poorly constrain the Turonian-Santonian position of Iberia relative to Eurasia. This study reconstructs changes in the sedimentary facies and architecture of the Iberian carbonate platform throughout the Late Cretaceous and sheds new light on the geodynamic evolution of the Iberia-Eurasia relationship at that time. Sixteen outcrop sections were described and 24 sedimentary facies identified that define 5 depositional environments ranging from the basin to the continental setting. From these and previously published field data we reconstruct the evolution of the Pyrenean carbonate platform, on an east-west transect nearly 400 km long, on the basis of 11 short-term depositional sequences and 5 long-term systems tracts. In our interpretation, the Cenomanian and Turonian correspond to a postrift stage during which the European and Iberian margins, together with the deep basin between them, subside gently, as shown by accommodation rates varying from ~15 to 30 m/My in the margins and ~100 to 150 m/My in the basin. The Coniacian and early Santonian are characterized by a large-scale flexural response consisting of (1) uplift of the southern Iberian margin, with negative accommodation rates, karstified surfaces and paleosols, and (2) increasing subsidence rates in the basin and its edges (the northern Iberian margin and eastern Aquitaine platform), with accommodation rates several times greater than during the Turonian. We propose that far-field stress associated with slight northward motion of the Iberia plate led to the incipient large-scale flexural deformation in the Pyrenean domain. The late Santonian and Campanian are an early orogenic stage marked by rapid subsidence throughout the Pyrenean domain, except at its western end. We argue that the initiation of the Pyrenean convergence, usually considered to occur during the latest Santonian, occurred in the Coniacian.

scholarly journals Bioecostratigraphy of the Shu’aiba Formation, Shaybah field, Saudi Arabia

GeoArabia ◽  
2000 ◽  
Vol 5 (4) ◽  
pp. 545-578 ◽  
Author(s):  
Geraint Wyn Hughes
Keyword(s):  
Saudi Arabia ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Carbonate Reservoir ◽  
Reservoir Rocks ◽  
Paleoenvironmental Interpretation ◽  
Sequence Boundaries ◽  
Shallow Carbonate Platform ◽  
Reservoir Facies

ABSTRACT The Aptian Shu’aiba Formation forms a major carbonate reservoir in the Shaybah field of eastern Saudi Arabia. Lack of exposures and poor seismic data have forced the cored intervals to be fully exploited to provide evidence of the depositional environment and layering of the reservoir rocks and associated lithofacies. Rudist, foraminiferal and coccolith evidence indicates an Aptian age for the entire Formation, most of it being early Aptian. A major unconformity at the top of the Shu’aiba separates it from the overlying Nahr Umr Formation. Rapid biofacies variations suggest possible sequence boundaries within the Shu’aiba Formation. Semi-quantitative macropaleontological and micropaleontological analyses indicate significant paleoenvironmentally influenced lateral and vertical bioassemblage variations. Lagoon, rudist-associated back-bank, bank-crest and fore-bank, and upper-ramp depositional environments have been interpreted, of which the bank represents the gradual amalgamation of earlier isolated rudist shoals. Integrating the micropaleontological analyses with rudist assemblages has facilitated the prediction of rudist-associated reservoir facies. Variations in the micro- and macrofacies permit the Formation to be divided into three layers. (1) The “lower Shu’aiba” (without rudists) is dominated by a regionally extensive, moderately deep marine planktonic foraminiferal/algal association of Palorbitolina lenticularis-Hedbergella delrioensis-Lithocodium aggregatum and the benthonic foraminifera Debarina hahounerensis, Praechrysalidina infracretacea, Vercorsella arenata and rotalids. (2) The “middle Shu’aiba” shows the significant lateral and vertical differentiation of a rudist-rimmed shallow carbonate platform typically associated with a marine highstand. A predominance of rudist species Glossomyophorus costatus and Offneria murgensis occurs together with Lithocodium aggregatum, Palorbitolina lenticularis, Trocholina spp. and miliolid foraminifera. (3) The “upper Shu’aiba” represents an expansion of the lagoon (associated with a marine transgression), and a predominance of Agriopleura cf. blumenbachi and A. cf. marticensis rudists, together with Debarina hahounerensis, Praechrysalidina infracretacea and Vercorsella arenata. The localized distribution of the rudist Horiopleura cf. distefanoi in association with corals, is a feature of the eastern flank of the field. A coarse assemblage-based biozonation for the Shu’aiba has been proposed, but a detailed scheme is precluded by rapid diachronous biofacies variations across the Shaybah field. In addition to the major biocomponent assemblages, minor variations reveal high-frequency depositional cycles that may assist in the interpretation of the distribution and correlation of reservoir facies. The identification of bioassemblages, and the paleoenvironmental interpretation of formation micro-imager logs from vertical cores in exploration wells, has assisted the calibration of images from uncored horizontal development wells.

scholarly journals SEDIMENTOLOGI DAN STRATIGRAFI HOLOSEN DATARAN PANTAI MEDAN - BELAWAN SEKITARNYA, SUMATERA UTARA

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Herman Moechtar ◽  
Herman Mulyana ◽  
Indyo Pratomo
Keyword(s):  
Sea Level ◽  
Coastal Plain ◽  
Depositional Environment ◽  
Depositional Environments ◽  
Quaternary Sediments ◽  
Quaternary Deposits ◽  
Vertical Variation ◽  
The North ◽  
Global Events ◽  
Channel Deposit

Studi sedimentologi dan stratigrafi endapan Kuarter di dataran pantai Medan – Belawan dibedakan menjadi enam lingkungan pengendapan. Yaitu endapan-endapan rawa, laut, pantai, rawa bakau, dataran banjir, dan alur sungai. Berdasarkan korelasi perubahan lingkungan pengendapan secara lateral dan vertikal, rangkaian sedimen Kuarter tersebut dapat dibedakan menjadi empat Interval Pengendapan (I – IV). Setiap interval dicirikan oleh berubahnya lingkungan yang dikontrol oleh perubahan iklim dan muka laut Holosenl. Perkembangan dari endapan Kuarter dan pengisisan cekungan cekungan di daerah dataran pantai Medan – Belawan dipengaruhi oleh peristiwa global. Perubahan dari sirkulasi iklim dan turun naiknya muka laut selama proses pengendapan berlangsung adalah berkaitan dengan perisitiwa global tanpa dipengaruhi oleh efek tektonik. Studi yang dilakukan mencakup analisis sedimentologi dan stratigrafi terhadap empat belas pemboran yang dilakukan di sepanjang lintasan yang berarah utara – selatan dari Medan hingga Belawan. Kedalaman pemboran berkisar antara 5,0 hingga 15,0 m.Kata Kunci: Sedimentologi dan stratigrafi, Holosen, dataran pantai Studies of sedimentology and Stratigrafi on Quaternary deposits in the coastal plain of Medan– Belawan surroundings, North Sumatera revealed six depositional environments. These are swamp, marine, beach, marsh, floodplain, and channel deposit environments. Based on the correlation of the lateral and vertical variation of the depositional environment, whereas the successsion of the Quaternary sediments can be divided into four sedimentary intervals (I – IV). Each interval is typically for environment changes which is controlled by sea level and climatic especially during Holosen. The development of the Quaternary sediments and basin fill in the coastal plain of Medan to Belawan area was influenced by global events. Changes in climatological and relative sea level during during depostional processes were included clobal changes without influenced by tectonic. The study was based on analyses of sedimentology and stratigraphy of fourteen borehole information obtained along the North to South traverse from Medan to Belawan. The penentration of the bore head varied from 5.0 to 15.0 m. Keywords: Sedimentology and stratigraphy, Holosen, coastal plain

New insights into the depositional environment and stratigraphic position of the Gugu Breccia (Pădurea Craiului Mountains, Romania)

2021 ◽  
Vol 21 (11) ◽  
pp. 215-233
Author(s):  
Traian Suciu ◽  
George Pleş ◽  
Tudor Tămaş ◽  
Ioan I. Bucur ◽  
Emanoil Săsăran ◽  
...  
Keyword(s):  
Lower Cretaceous ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Type Locality ◽  
Carbonate Platforms ◽  
Terrigenous Input ◽  
New Information ◽  
The Matrix ◽  
Stratigraphic Position ◽  
Sedimentary Formation

The study of the carbonate clasts and matrix of a problematic sedimentary formation (the Gugu Breccia) from the Pădurea Craiului Mountains reveals new information concerning its depositional environment and stratigraphic position. The identified microfacies and micropaleontological assemblages demonstrate that all the sampled limestone clasts from the Gugu Breccia represent remnants of a fragmented Urgonian-type carbonate platform. The Barremian age of the clasts suggests that the stratigraphic position of the Gugu Breccia at its type locality could be uppermost Barremian-lowermost Aptian, a fact demonstrated also by the absence of elements from Lower Cretaceous carbonate platforms higher in the stratigraphic column (e.g., Aptian or Albian) of the Bihor Unit. The sedimentological observations together with the matrix mineralogy bring new arguments for the recognition of terrigenous input during the formation of the Gugu Breccia.

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