Stratigraphy and Palaeontology
Hajar Mashayekh; Massih Afghah; Mahnaz Parvaneh- Nejad Shirazi
Abstract
In order to biostratigraphic studies of Gurpi Formation, a section was selected in the north-east of Noorabad city in Fars. Structurally, this section is located in the folded-thrust zone of Zagros and geographically in the Fars zone (coastal Fars). The Gurpi Formation is extended of 229 meters in thickness, ...
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In order to biostratigraphic studies of Gurpi Formation, a section was selected in the north-east of Noorabad city in Fars. Structurally, this section is located in the folded-thrust zone of Zagros and geographically in the Fars zone (coastal Fars). The Gurpi Formation is extended of 229 meters in thickness, contains limestone, shale, marly limestone and argillaceous limestone. Its lower boundary with Sarvak Formation and its upper contact with Pabdeh Formation are discontinuous. The study conducted on foraminiferal biostratigraphy in this section led to the identification of 20 species belonging to 7 genera of planktonic foraminifera. Based on the stratigraphic distribution of the planktonic foraminifera, five biozones are determined which correspond with global biozonation. Described biozones are comprised of: 1-Globotruncanita elevata Partial range zone; 2-Globotruncana ventricosa Interval zone; 3-Radotruncana calcarata Total range zone; 4-Gansserina gansseri Interval zone; 5-Contusotruncana contusa, Contusotruncana walfischensis, Globotruncanita conica Assemblage zone. Based on these biozones, the age of Gurpi Formation is assigned to early Campanian to late Maastrichtian. The absence of the Marginotruncana and Dicarinella asymetrica in the lower part of the Gurpi Formation indicates of the Santonian-Campanian boundary and the determination of the early Early Campanian age for the base of this Formation.
Stratigraphy and Palaeontology
S. Senemari
Abstract
Calcareous Nannofossils of the Gurpi Formation have been investigated at Kalchenar section (Northwest of Izeh). In this section, the Gurpi Formation is mainly consists of marls, shaly marls and marly limestones. For introducing index species, calcareous nannofossil assemblages and biozones, 150 slides ...
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Calcareous Nannofossils of the Gurpi Formation have been investigated at Kalchenar section (Northwest of Izeh). In this section, the Gurpi Formation is mainly consists of marls, shaly marls and marly limestones. For introducing index species, calcareous nannofossil assemblages and biozones, 150 slides have been studied which led to the recognition of twelve biozones. As a result, 61 species, 35 genera of calcareous nannofossils were detected. According to the identified biozones, the age of the Gurpi Formation is Late Campanian to Late Paleocene (Late Selandian) and K/Pg boundary is continuous at the studied interval, that is corresponding to CC21- CC26of zonation scheme of Sissingh (1977) and NP1- NP6 of zonation of Martini (1971).
N Abbassi; M Parvanehnezhad Shirazi; M.A Hosseinzadeh
Abstract
Albian–Cenomanian siliciclastic-carbonate sediments of northwest Rayen in south Kerman, southeast Iran (526 m) are classifiable to three informal units. Unit one includes conglomerates, sandstones and siltstones with limestone and marl intercalations. Unit two is composed of Orbitolina bearing ...
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Albian–Cenomanian siliciclastic-carbonate sediments of northwest Rayen in south Kerman, southeast Iran (526 m) are classifiable to three informal units. Unit one includes conglomerates, sandstones and siltstones with limestone and marl intercalations. Unit two is composed of Orbitolina bearing limestones with rudists, belemnoid and ammonite bioclasts. Alternations of pelagic limestones and sandstones formed the third unit. Assemblage of continental to marine trace fossils have been found in the first and third units of the studied section, that include Koilosoma isp., Ophiomorpha isp., Palaeophycus isp., Planolites isp., Skolithos isp., Taenidium isp., and Thalassinoides suevicus. These trace fossils belongs to Scoyenia, Skolithos and Cruziana ichnofacies. Abundant Thalassinoides-Phycodes compound trace fossil, however have been found in the third unit. Box-worked Thalassinoides burrow system ends to multi- branched Phycodes borrows. This compound trace fossil is interpreted as feeding-domicile biogenic structure, so that Thalassinoides domichnium ends to Phycodes excavated feeding burrows. Compound Thalassinoides-Phycodes trace fossil extended in the deeper parts of offshore shelf sediments in the studied section. Based on ichnological data, it seems that Albian–Cenomanian sediments of northwest Rayen deposited in a deepening upward sequence.
F. Rostami; V. Ahmadi
Abstract
In this research two stratigraphic sections of Lower Cretaceouse to Upper Jurassic sedimentary (Surmeh and Fahliyan Formation in Folded-Zagros Zone) have been selected. Based on microfacies studies (in 400 thin-sections) three species of Ichnofossils microcoprolites from Crustaceans related as the Follow: ...
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In this research two stratigraphic sections of Lower Cretaceouse to Upper Jurassic sedimentary (Surmeh and Fahliyan Formation in Folded-Zagros Zone) have been selected. Based on microfacies studies (in 400 thin-sections) three species of Ichnofossils microcoprolites from Crustaceans related as the Follow: Palaxius decaochetarius, Helicerina siciliana, Palaxius tetraochetarius, palaxius isp. In general, considering Ichnotaxons studies, two assemblage-zones were identified for microcoprolites Crustaceans. Assemblage-zone (No:1) of Tithonian to Berriasian and assemblage-zone (No:2) whichis lated of Valanginian, taxons Helicerina isp. Assemblage-zone (No:2) which is related.
Nasrollah Abbassi
Abstract
Cretaceous flysch deposits of the Abshar-e Asyab Kharabeh (30 meters) in west of Siah-rud village in the Jolfa area, NW Iran, consist of conglomerate, sandstone, siltstone and mud- or marlstone layers, which mainly belong to A, B, D and E divisions of Bouma sequence. A divers trace fossils preserved ...
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Cretaceous flysch deposits of the Abshar-e Asyab Kharabeh (30 meters) in west of Siah-rud village in the Jolfa area, NW Iran, consist of conglomerate, sandstone, siltstone and mud- or marlstone layers, which mainly belong to A, B, D and E divisions of Bouma sequence. A divers trace fossils preserved on the lower bedding planes of sandstones and siltstones as positive hyporelief, includes: Bergaueria hemispherica, Bergaueria isp., Cochlichnus isp., Granularia isp., Halopoa imbricate, Helminthoida crassa, Helminthopsis abeli, Imponoglyphus torquendus, Neonereites multiserialis, Paleodictyon latum, Paleodictyon cf. majus, Paleodictyon nodosum, Palaeophycus alternatus, Palaeophycus sulcatus, Phycodes templus, Phycodes isp., Planolites annularis, Planolites beverleyensis, Protovirgularia longespicata, Squamodictyon isp., Strobilorhaphe isp., Thalassinoides isp., Taphrhelminthopsis recta, Taphrhelminthopsis convolute, Treptichnus pollardi. These trace fossils are mainly grazing-feeding or feeding traces of Nereites Ichnofacies and classifiable in six rang/frequency, based ichno-assemblages. Obtained trace fossils were produced during post-event calm periods. So, muddy sediments deposited after turbulence currents and traces have been made on these layers, activates of trace makers were developing when accessible feeding materials or dissolved oxygen increased in environment. Base on founded Nereites trace fossils, these sediments deposited in the deep marine abyssal zone environment.
M. H. Kholghi; M. Vossoughi Abedini
Abstract
Safakhaneh batholith, situated at 47 km southwest of Shahin Dezh, northwest of Iran, is located in the central Iran structural zone intersecting the Cretaceous rocks. The absolute age of the batholith, determined for the first time by K – Ar method, has been calculated ...
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Safakhaneh batholith, situated at 47 km southwest of Shahin Dezh, northwest of Iran, is located in the central Iran structural zone intersecting the Cretaceous rocks. The absolute age of the batholith, determined for the first time by K – Ar method, has been calculated 69.535 Ma. showing upper Cretaceous – Paleocene epoch and Laramide tectonic orogeny. Geochemical investigations of the batholith show that the major part of the batholith is of mantle magma, in which magmatic changes of the crystalline differentiation and contaminations have occurred. The crystalline differentiation has caused the formation of different rock types of quartz monzonite, quartz monzodiorite, tonalite, granodiorite and monzogranite respectively. Primary magma of the rocks is of calc - alkaline and generally metaluminous. The specifications of batholith rocks can be compared with the I – Type Caledonian granites. From the tectonic point of view, the specifications of the batholith can be comparable with the volcanic arc granitoids (VAG).
