scholarly journals Stratigraphic Lexicon: A revised guide to the Cenozoic Surface Formations of Qatar, Middle East (excluding the islands)

2021 ◽  
Vol 2 (4) ◽  
Author(s):  
Jacques LeBlanc
Keyword(s):  
Middle East ◽  
Middle Eocene ◽  
Lower Eocene ◽  
Lower Miocene ◽  
Field Works

The author learned first-hand about the surface stratigraphy and geology of Qatar by dedicating most of his weekends to conducting field works and public-guided field tours from 2007 to 2020 while employed by Qatar Petroleum. Here, he reviews and updates the surface stratigraphic knowledge of Qatar since the last lexicon was published back in 1975. The geology and macro-paleontology of the Lower Eocene Rus, Middle Eocene Dammam, Lower Miocene Dam, and Mio-Pliocene Hofuf formations are described in detail and well-illustrated.  

Tectono-sedimentary evolution of a fore-chain domain : example of the Habt and Sidi Mrayt basins, northwestern external Moroccan Rif ; stratigraphic precisions and tectonic modelling

2004 ◽  
Vol 175 (4) ◽  
pp. 383-397 ◽  
Author(s):  
Abdelali Zakir ◽  
Ahmed Chalouan ◽  
Hugues Feinberg
Keyword(s):  
Upper Cretaceous ◽  
Middle Miocene ◽  
Middle Eocene ◽  
Fault Propagation ◽  
Lower Eocene ◽  
Structural Trend ◽  
Sedimentary Evolution ◽  
Structural Relationships ◽  
Regional Tectonic ◽  
Ridge Structures

Abstract In this paper, a tecto-sedimentary evolution model of the northwestern external Rif zones (Morocco) is proposed. It is based on the study of structural relationships and the biostratigraphic and sedimentologic analysis of different Tertiary syn-tectonic units. This zone shows alternating foredeep basins and anticlinal ramps with a NNW-SSE structural trend and a vergence toward the WSW. The trend of turbiditic bodies and palaeocurrent directions (from the SSE to the NNW) are parallel to the regional tectonic strike. Sidi Mrayt and El Habt basins are filled with syn-tectonic middle Eocene to middle Miocene sediments; The Habt basin is subdivided in two sub-basins: Asilah-Larache and Rirha-Gzoula. The deposits are distributed in two separated turbiditic complex, each one including a stacking of turbiditic systems. The Rirha-Gzoula and Asilah-Larache sub-basins are located in front of two anticline ridge structures made up of Upper Cretaceous and Lower Eocene material; they are respectively Boujediane and Arbaa Ayacha anticlines. The distribution of turbiditic bodies, unconformities and structural relationships within the thrusts and folds system in the northwestern external Rif indicate the progression toward the external zones of fault-propagation folds and associated basins.

scholarly journals Geometric morphometrics of endophytic oviposition traces of Odonata (Eocene, Argentina)

2020 ◽  
Vol 7 (12) ◽  
pp. 201126
Author(s):  
Eugenia Romero-Lebrón ◽  
Raquel M. Gleiser ◽  
Julián F. Petrulevičius
Keyword(s):  
Geometric Morphometrics ◽  
Linear Models ◽  
Middle Eocene ◽  
Evolutionary Constraint ◽  
Mixed Linear Models ◽  
Lower Eocene ◽  
Rio Negro ◽  
Endophytic Oviposition ◽  
The Individual ◽  
First Time

The insertion of the Odonata ovipositor in the plant tissue generates a scar that surrounds the eggs (trace). In insects, individual egg traces are known to vary in size, but their variation in individual shape is mostly unknown. Twenty-four specimens were obtained from the Laguna del Hunco (Lower Eocene, Chubut) and Río Pichileufú (Middle Eocene, Río Negro), Argentina, which had 1346 oviposition traces (MEF Collection). For the first time, a study of the shape and size of a large number of individual Odonata endophytic egg traces was carried out using traditional (general and mixed linear models) and geometric morphometrics (Fourier elliptical series) to elucidate whether there are changes in size or shape of the individual endophytic egg traces associated with the substrate used at the time of oviposition, if the Lower Eocene traces have varied in relation to those of the Middle Eocene, and if the ichnological classification ( Paleoovoidus arcuatus , P. bifurcatus and P. rectus ) reflects such variations. We found differences in size ( p < 0.05), but not in shape, in relation to the variables studied. This could reflect that the shape of Odonata eggs (inferred from the traces), unlike their size, could have a strong evolutionary constraint already observed since the Eocene.

scholarly journals Identification of the African–European <i>Erymnochelys</i> group (Pleurodira, Podocnemididae) in the Belgian fossil record: first finding of <i>Eocenochelus eremberti</i> outside its type locality

Fossil Record ◽  
2017 ◽  
Vol 20 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Adán Pérez-García ◽  
Thierry Smith
Keyword(s):  
Fossil Record ◽  
Upper Cretaceous ◽  
Middle Eocene ◽  
Type Locality ◽  
Specific Level ◽  
Lower Eocene ◽  
Its Analysis ◽  
First Finding ◽  
French Region ◽  
Sciences Naturelles

Abstract. An almost complete plastron, as well as several peripherals and a costal plate of a turtle from the middle Eocene of Saint-Gilles, is presented here. Although this turtle specimen was donated to the Institut royal des Sciences naturelles de Belgique (Brussels, Belgium) more than a century ago, it remained undescribed. Its study allows us to recognize the second pleurodiran in the Belgian fossil record, where, until now, the Eocene Neochelys was the only one known. The Belgian material of Neochelys is known in lower Eocene (early Ypresian) levels, but the new pleurodiran specimen comes from the middle Eocene (early Lutetian). It is the first partial articulate shell of a pleurodiran turtle recognized in Belgium, and the only member of this clade recognized in this country at specific level. The new specimen is a representative of the so-called Erymnochelys group, this lineage being known in Africa from the Upper Cretaceous to the present but in Europe only during the Eocene. It represents the first specimen of Eocenochelus eremberti identified outside its type locality, the French region of Saint-Germain-en-Laye (Yvelines, Île-de-France), where only one specimen was found. The plastron of the Belgian individual corresponds to the most complete for this species. Its analysis allows us not only to broaden the range of paleobiogeographical distribution of Eocenochelus eremberti but also to improve the knowledge about the anatomy and variability of this taxon.

Influence de la tectonique du Pays de Bray sur les formations paleogenes au voisinage de sa terminaison orientale

1964 ◽  
Vol S7-VI (3) ◽  
pp. 357-367 ◽  
Author(s):  
A. Blondeau ◽  
Claude Cavelier ◽  
Charles Pomerol
Keyword(s):  
Late Cretaceous ◽  
Middle Eocene ◽  
Tectonic Activity ◽  
Paris Basin ◽  
Upper Eocene ◽  
Lower Eocene ◽  
Tectonic Movements

Abstract Major facies changes in the Paleogene formations at the southeast end of the Pays de Bray anticline of the Paris basin, in the vicinity of Beaumont-sur-Oise, date tectonic movements and periods of remission during the Paleogene. Although the anticline developed during the late Cretaceous, it seems to have had no significant effect upon sedimentation until its emergence and the concurrent establishment of continental sedimentation in the upper Thanetian (lower Eocene). Tectonic activity occurred again in the lower Sparnacian and the upper Cuisian (lower Eocene), the lower and the upper Lutetian (middle Eocene), the Ledian (lower Priabonian: upper Eocene), the Ludian (upper Priabonian: upper Eocene), and the lower Stampian (middle Oligocene).

scholarly journals REE Geochemistry of Euphrates River, Turkey

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Leyla Kalender ◽  
Gamze Aytimur
Keyword(s):  
Middle Eocene ◽  
River Sediments ◽  
Volcanic Rocks ◽  
Tectonic Zone ◽  
Magmatic Complex ◽  
River Bank ◽  
Euphrates River ◽  
Lower Eocene ◽  
Western Asia ◽  
Geochemical Studies

The study area is located on the Euphrates River at 38°41°32.48′′N–38°14′24.10′′N latitude and 39°56′4.59′′E–39°8°13.41′′E longitude. The Euphrates is the longest river in Western Asia. The lithological units observed from the bottom to the top are Permo-Triassic Keban Metamorphites, Late Cretaceous Kömürhan Ophiolites, Upper Cretaceous Elazığ Magmatic Complex, Middle Eocene Maden Complex and Kırkgeçit Formation, Upper Pliocene and Lower Eocene Seske Formation and Upper Miocene, Pliocene Karabakır and Çaybağı Formations, Palu Formation, and Holocene Euphrates River sediments. The geochemical studies show that87Sr/86Sr and143Nd/144Nd isotopic compositions in the Euphrates River bank sediments are 0.7053, 0.7048, and 0.7057 and 0.512654, 0.512836, and 0.512775, respectively. These values indicate mixing of both carbonate-rich shallow marine sediment and felsic-mafic rocks from Elazığ Magmatic Complex into the stream sediments. The positiveεNd (0)values (0.35, 3.9, and 2.7) are higher downstream in the studied sediments due to weathering of the mafic volcanic rocks. The chondrite, NAS, and UCC normalized patterns show that the REE compositions of the Euphrates River sediments are higher than chondrite composition but close to NAS and UCC. The river sediments in the tectonic zone and the weathered granodioritic rocks of the Elazığ Magmatic complex affect upstream water compositions.

scholarly journals Planktonic and benthic foraminiferal biostratigraphy of the Middle Eocene–Lower Miocene successions from the Sivas Basin (Central Anatolia, Turkey)

2016 ◽  
Vol 67 (1) ◽  
pp. 21-40 ◽  
Author(s):  
Aynur Hakyemez ◽  
Nazire Özgen-Erdem ◽  
Özgen Kangal
Keyword(s):  
Water Column ◽  
Benthic Foraminifera ◽  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Central Anatolia ◽  
Successive Interval ◽  
Lower Miocene ◽  
Sivas Basin ◽  
Algal Reef ◽  
Foraminiferal Biostratigraphy

AbstractPlanktonic and benthic foraminifera are described from the Middle Eocene-Lower Miocene successions in the Sivas Basin, Central Anatolia. An integrated foraminiferal zonation provides new age assignments in terms of a great number of taxa for the studied sections. Four biostratigraphical intervals are first recorded based on the concurrent ranges of sporadically occurring but well preserved planktonic foraminiferal assemblages. The first interval characterized by the co-occurrences ofAcarinina bullbrooki, Truncorotaloides topilensisandTurborotalia cerroazulensisis referable to the E11 Zone of late Lutetian–early Bartonian. An assemblage yieldingParagloborotalia opimaaccompanied byGlobigerinella obesaforms a basis for the late Chattian O5 Zone. The successive interval corresponds to the late Chattian O6 Zone indicated by the presence ofGlobigerina ciperoensisandGlobigerinoides primordiusalong with the absence ofParagloborotalia opima. The early Aquitanian M1 Zone can be tentatively defined based mainly on the assemblage ofGlobigerina, Globigerinella, GloboturborotalitaandTenuitella. The biostratigraphical data obtained from the benthic foraminifera assign the studied sections to the SBZ 21–22, SBZ 23 and SBZ 24 ranging in age from Rupelian to Aquitanian. The SBZ 23 and 24 are well constrained biozones by the occurrences ofMiogypsinella complanataandMiogypsina gunteri, respectively, whereas the SBZ 21–22 defined by nummulitids and lepidocylinids in the Tethyan Shallow Benthic Zonation is characterized dominantly by peneroplids, soritids and miliolids in the studied sections. Benthic foraminiferal assemblages suggest different paleoenvironments covering lagoon, algal reef and shallow open marine whereas planktonic foraminifera provides evidence for relatively deep marine settings on the basis of assemblages characterized by a mixture of small-sized simple and more complex morphogroups indicative for intermediate depths of the water column.

II.—A Contribution to the Molluscan Fauna of the Laki and Basal Khirthar Groups of the Indian Eocene

1932 ◽  
Vol 57 (1) ◽  
pp. 25-92 ◽  
Author(s):  
L. R. Cox
Keyword(s):  
Middle Eocene ◽  
Reliable Information ◽  
Western India ◽  
Lower Eocene ◽  
North West ◽  
Lower Horizon ◽  
The North ◽  
Molluscan Fauna ◽  
North Western

The Tertiary geology of north-western India is of particular interest on account of the extensive development of richly fossiliferous rocks of Lower Eocene (including Palæocene) age. The monographs by Cossmann and Pissarro (1909a, 1927) and Vredenburg (1928) have familiarised us with the well-preserved molluscan fauna of the Upper Ranikot beds (Palæocene) of Sind, while Lt.-Col. L. M. Davies' collection of mollusca from a slightly lower horizon in the Samana Range, on the North-West Frontier, has recently been described by myself (1930). With the exception, however, of one family, the Gisortiidæ, dealt with by Vredenburg (1927) and Schilder (1930), the mollusea of the overlying Laki group (Ypresian), as well as of the Khirthar group (Middle Eocene), have been neglected by modern workers. The well-known monograph by D'Archiac and Haime (1853–54), moreover, in which some Laki species are described, has always been a source of confusion owing to the fact that fossils from all horizons from the Danian to the Miocene are grouped together as “Nummulitic,” and no reliable information as to their respective horizons has been available.

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