scholarly journals Sedimentological study of the Lower-Middle Miocene Sequences at Selected Wells in Jambur and Khabaz oilfields, NE Iraq

2019 ◽  
Vol 23 (10) ◽  
pp. 51
Author(s):  
Ruia Yilmaz Ahmad1 ◽  
Lifta Selman Kadhim1 ◽  
Mohammed Ahmed Mohammed Al-haj2
Keyword(s):  
Thin Section ◽  
Marine Environment ◽  
Middle Miocene ◽  
Planktonic Foraminifera ◽  
Tropical Environment ◽  
Microfacies Analysis ◽  
Reef Environment ◽  
Lagoon Environment ◽  
Petrographic Study

The study includes petrographic and stratigraphical chraractrstic of the lower-middle Miocene sequence at selected wells from Jambur and Khabaz oilfields. Four hundred and sixty thin section from Jeribe, Serikagni, Euphrates, Dhiban, Anah and Azkand formations in four wells from Jambur and Khabaz oilfields are studied. The stratigraphic study indicates that contact between Jeribe and Faꞌtha formations, Jeribe and Dhiban formations are unconformable in all wells under study, while the contact between Jeribe and Anah, Anah and Azkand, Euphrates and Serikagni formations are conformable. The petrographic study reveals that most of the studied formations are limestone rich in benthonic foraminifera especially in Jeribe and Anah formations, with low percentage of planktonic foraminifera such as Globigerina species in Serikagni and Azkand formations. Additionally, echinoids, coral algae, ostracoda and intraclast remains are present. Non-skeletal component such as, pellets and ooids are rare in Euphrates Formation. Microfacies analysis shows the presence of several microfacies distributed in the studied formations. The environments of lower-Middle Miocene formations have been concluded from petrography and microfacies studies. Jeribe Formation was deposited in lagoonal or semi lagoonal environment, while Serikagni and Euphrates formations were deposited in deep marine environment and shallow open lagoon environment respectively. Closed lagoonal environment is assigned for deposition of Dhiban Formation, while slope and reef environment is recognized for the Azkand Formation and tidal and supratidal with reef marine tropical environment for the Anah Formation.   http://dx.doi.org/10.25130/tjps.23.2018.169 

scholarly journals Lithostratigraphy and microfacies analysis of Avanah Formation (Middle Eocene) in Gomaspan section northeast Erbil City, Kurdistan region, Iraq

2021 ◽  
Author(s):  
Irfan Sh. Asaad ◽  
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
Petrographic Analysis ◽  
Microfacies Analysis ◽  
Dolomitic Limestone ◽  
Kurdistan Region ◽  
Thin Sections ◽  
Lithostratigraphic Units ◽  
Lagoon Environment

Lithostratigraphy and microfacies analysis of the Avanah Formation (Middle Eocene) were studied in the Gomaspan section in the Bina Bawi anticline, northeast of Erbil city, Kurdistan Region, Iraq. The field observations refer that the formation attains 56 m of medium to thick bedded yellow limestone, grey dolomitic limestone and blue marly dolomitic limestone interbedded with thin beds of blue marl and dark grey shale with an interval of sandy limestone in the middle part and thin to medium bedded limestone interbedded with red mudstone. The petrographic study of 29 thin sections of Avanah carbonates revealed that the majority of the matrix is carbonate mud (micrite) with few microspar. The skeletal grains include benthic foraminifera, dasycladacean green algae, ostracods, calcispheres, pelecypods, rare planktonic foraminifera and bryozoa in addition to bioclasts. Non-skeletal grains encompass peloids, oncoids, intraclasts and extraclasts with common monocrystalline quartz. Based on the field observation and petrographic analysis, three different lithostratigraphic units were identified. They are in ascending order: A-Thick bedded dolomitic marly limestone interbedded with shale. B- Bedded dolomitic limestone interbedded with shale and marl. C- Thin to medium bedded limestone interbedded with red mudstone. Depending on detailed microfacies analysis of carbonate rocks, three main microfacies and 12 submicrofacies are recognized. From the sum of all petrographic, facies, textural analyses, it is concluded that Avanah Formation in Gomaspan section, was deposited in shallow marine environment, semi restricted lagoon, in lower and upper parts and open lagoon environment in the middle part interval.

scholarly journals Lithostratigraphy and microfacies analysis of Avanah Formation (Middle Eocene) in Gomaspan section northeast Erbil City, Kurdistan region, Iraq

2021 ◽  
Author(s):  
Irfan Sh. Asaad ◽  
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
Petrographic Analysis ◽  
Microfacies Analysis ◽  
Dolomitic Limestone ◽  
Kurdistan Region ◽  
Thin Sections ◽  
Lithostratigraphic Units ◽  
Lagoon Environment

Lithostratigraphy and microfacies analysis of the Avanah Formation (Middle Eocene) were studied in the Gomaspan section in the Bina Bawi anticline, northeast of Erbil city, Kurdistan Region, Iraq. The field observations refer that the formation attains 56 m of medium to thick bedded yellow limestone, grey dolomitic limestone and blue marly dolomitic limestone interbedded with thin beds of blue marl and dark grey shale with an interval of sandy limestone in the middle part and thin to medium bedded limestone interbedded with red mudstone. The petrographic study of 29 thin sections of Avanah carbonates revealed that the majority of the matrix is carbonate mud (micrite) with few microspar. The skeletal grains include benthic foraminifera, dasycladacean green algae, ostracods, calcispheres, pelecypods, rare planktonic foraminifera and bryozoa in addition to bioclasts. Non-skeletal grains encompass peloids, oncoids, intraclasts and extraclasts with common monocrystalline quartz. Based on the field observation and petrographic analysis, three different lithostratigraphic units were identified. They are in ascending order: A-Thick bedded dolomitic marly limestone interbedded with shale. B- Bedded interbedded with red mudstone. Depending on detailed microfacies analysis of carbonate rocks, three main microfacies and 12 submicrofacies are recognized. From the sum of all petrographic, facies, textural analyses, it is concluded that Avanah Formation in Gomaspan section, was deposited in shallow marine environment, semi restricted lagoon, in lower and upper parts and open lagoon environment in the middle part interval.

scholarly journals Age determinations of Neogene sediments from the English Channel and Western Approaches

1986 ◽  
Vol 5 (1) ◽  
pp. 5-6
Author(s):  
D. Graham Jenkins ◽  
Erlend Martini
Keyword(s):  
Middle Miocene ◽  
Planktonic Foraminifera ◽  
English Channel ◽  
Calcareous Nannoplankton ◽  
Lower Miocene ◽  
Published Evidence ◽  
Neogene Sediments ◽  
Age Range ◽  
Age Determinations

Abstract. Original published evidence indicated an age range of early Lower Miocene to early Middle Miocene for Globigerina silt samples from the English Channel and the Western Approaches. Suggested younger ages for these samples are refuted on the basis of planktonic foraminifera and calcareous nannoplankton.

scholarly journals Petrology and genesis of the Bhainskati iron ore deposit of Palpa District, western Nepal

2013 ◽  
Vol 15 ◽  
pp. 63-68
Author(s):  
Sujan Devkota ◽  
Lalu Prasad Paudel
Keyword(s):  
Marine Environment ◽  
Mineral Assemblage ◽  
Iron Ore ◽  
Ore Deposit ◽  
Shallow Marine ◽  
Shallow Marine Environment ◽  
Long Time ◽  
Iron Ore Deposit ◽  
Petrographic Study ◽  
Oolitic Ironstone

The Bhainskati Formation of the Tansen Group in the Palpa area is known for hematite iron ore deposit for long time. A prominent band of hematite of about 1-2 m thickness and extending >5 km was identified in the upper part of the Bhainskati Formation in the present study. The band is repeated three times in the area by folding and faulting. Petrographic study shows that it is oolitic ironstone of sedimentary origin. Main minerals in the band are hematite, goethite, quartz, calcite, siderite and albite. Hematite content varies considerably among samples and occurs mainly as oolite and cement. The Bhainskati ironstone with its ferrous mineral assemblage and well-rounded texture of the ooids suggests shallow marine environment (prodeltaic to estuarine) with reduced clastic input. DOI: http://dx.doi.org/10.3126/bdg.v15i0.7418 Bulletin of the Department of Geology, Vol. 15, 2012, pp. 63-68

scholarly journals Petrology and Genesis of the Bhainskati Iron Ore Deposit of Palpa District, Western Nepal

2013 ◽  
Vol 28 (1-2) ◽  
pp. 153-160
Author(s):  
Lalu Poudel ◽  
Sujan Devkota
Keyword(s):  
Marine Environment ◽  
Mineral Assemblage ◽  
Iron Ore ◽  
Ore Deposit ◽  
Marine Origin ◽  
Shallow Marine ◽  
Long Time ◽  
Iron Ore Deposit ◽  
Petrographic Study ◽  
Oolitic Ironstone

The Bhainskati Formation of the Tansen Group in Palpa area is known for hematite iron ore deposit for long time. A prominent band of hematite of about 1-2 km thickness extending >5 km was identified in the upper part of the Bhainskati Formation in the present study and the band is repeated three times in the area by folding and faulting. Petrographic study shows that it is oolitic ironstone of sedimentary shallow marine origin. Main minerals in the band are hematite, goethite, quartz, calcite, siderite and albite. Hematite content varies considerably among samples and occurs mainly as oolite and cement. The Bhainskati ironstone with its ferrous mineral assemblage and well-rounded texture of the ooids suggests prodeltaicto estuarine with shallow marine environment reduced clastic input.

scholarly journals Sedimentary geology and biostratigraphy of the Mianwali Formation, Kala Chitta Range, Northern Pakistan

1999 ◽  
Vol 19 ◽  
Author(s):  
Kaleem Akhtar Qureshi ◽  
Ali Nasir Fatmi ◽  
Riaz Ahmed Sheikh ◽  
Aftab Ahmad Butt
Keyword(s):  
Marine Environment ◽  
Normal Wave ◽  
Microfacies Analysis ◽  
Northern Pakistan ◽  
The Third ◽  
Shelf Margin ◽  
Normal Salinity

Microfacies analysis and ammonite biostratigraphy of the Mianwali Formation of the Kala China Range were worked out on the basis of stratigraphic sections from Chak Jabbi and Bagh. Four microfacies were identified from the Chak Jabbi section while amrnonite biostratigraphy was studied from both the sections. Filamentous bivalves in micrite deposited along a shelf margin below normal wave base represent the first microfacies. The second microfacies contains bioclastic wackestone deposited in an open marine environment of normal salinity. The third microfacies consists of lime mudstone formed in a stressed environment of lagoonal conditions, whereas the fourth microfacies of dolomitised carbonate mudstone was formed by the diagenetic dolomitisation of the third microfacies. The new collection of ammonites includes Arctoceras tuberculatum, Anakashmirites aff. evolutus, Meekoceras gracilitatis, Stephanites sp., Pseudoceltites sp., Subvishnuites aff. welteri, Arnautoceltites sp., Owemtes sp. indet, Subvishnuites aff. enveris, Pseudosageceras sp. indet, Paranannites sp., Subcolumbites sp., Anasibrites sp., and Pseudaspidites sp, confirming the already known Sctythian age of the Mianwali Formation.

scholarly journals Timing of the Middle Miocene Badenian Stage of the Central Paratethys

2014 ◽  
Vol 65 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Johann Hohenegger ◽  
Stjepan Ćorić ◽  
Michael Wagreich
Keyword(s):  
Sea Level ◽  
Middle Miocene ◽  
Planktonic Foraminifera ◽  
Sea Level Changes ◽  
Vienna Basin ◽  
Central Paratethys ◽  
Polarity Reversals ◽  
Global Events ◽  
Geomagnetic Polarity ◽  
Climate Transition

Abstract A new and precisely defined chronometric subdivision of the Badenian (Middle Miocene, regional stage of Central Paratethys) is proposed. This uses global events, mainly geomagnetic polarity reversals as correlated chronometric boundaries, supported by climatic and sea-level changes in addition to isotope events and biostratigraphic data. The Karpatian/ Badenian boundary lies at 16.303 Ma, at the top of Chron C5Cn.2n, which is near the base of the Praeorbulina sicana Lowest-occurrence Zone (LOZ). The Badenian/Sarmatian boundary is placed at the top of polarity Chron C5Ar.2n, thus at 12.829 Ma. In relation to three sea level cycles TB 2.3, TB 2.4 and TB 2.5 and astronomically confirmed data, the Badenian can be divided into three parts of nearly equivalent duration. The Early Badenian as newly defined here ranges from 16.303 to 15.032 Ma (top of polarity Chron C5Bn.2n). The younger boundary correlates roughly to the base of the planktonic foraminifera Orbulina suturalis LOZ at 15.10 Ma, the HO (Highest Occurrence) of the nannofossil Helicosphaera ampliaperta at 14.91 Ma (NN4/NN5 boundary) and the Lan2/Ser1 sequence boundary at 14.80 Ma. The subsequent Mid Badenian ranges from 15.032 Ma to 13.82 Ma; the latter datum correlates with the base of the Serravallian, characterized by a strong global cooling event reflected in the oxygen isotope event Mi3b. The main part of cycle TB 2.4 falls into the Mid Badenian, which can be subdivided by a short cooling event at 14.24 Ma during the Middle Miocene Climate Transition (14.70 to 13.82 Ma). The HCO (Highest common occurrence) of the nannofossil Helicosphaera waltrans at 14.357 Ma supports this division, also seen in the tropical plankton Zones M6 Orbulina suturalis LOZ and M7 Fohsella peripheroacuta LOZ that correspond roughly to the lower and upper Lagenidae zones in the Vienna Basin, respectively. The Late Badenian is delimited in time at the base to 13.82 Ma by the Langhian/Serravallian boundary and at the top by the top of polarity Chron C5Ar.2n at 12.829 Ma. The Mediterranean Langhian/Serravallian boundary can be equated with the Mid/Late Badenian boundary at 13.82 Ma. However, the Karpatian/Badenian boundary at 16.303 Ma, a significant event easily recognizable in biostratigraphy, paleoclimate evolution and sequence stratigraphy, cannot be equated with the proposed global Burdigalian/Langhian, and thus Early/Middle Miocene boundary, at 15.974 Ma

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