Biostratigraphy and Systematic Palaeontology of Late Cretaceous Heterohelicidae Foraminifera from Kurdistan Region North-eastern Iraq

Abstract

The biostratigraphical importance and systematic palaeontology of Early Turonian to Early Maastrichtian Heterohelicidae Planktic foraminifera from Kurdistan region, NE Iraq are described. Some 24 species from 11 genera are recorded. Species abundance and diversity increase from the Early Turonian to Early Maastrichtian, perhaps signifying cooler sea temperatures in the Arabian sector of the Tethys Ocean during the Early Maastrichtian. Despite the long biostratigraphical ranges of some species, the importance of the biserial and multiserial Planktic foraminifers in Late Cretaceous biostratigraphy is emphasized. From a biostratigraphic perspective, heterohelicids are important for the definition of the Campanian-Maastrichtian boundary in Kurdistan region, with Planoglobulina species being especially important in this respect, as they are in Iran, Turkey and North Africa.

Facies Analysis, Diagenetic Features and Depositional Environment of the Kometan Formation from Northeastern Iraq

“…In the current study, this environment was identified according to the presence of planktonic foraminifera, particularly the keeled type, and the mud-supported groundmass. A microscopic study shows that most of the Kometan microfacies were deposited in deep basinal environmental zones that are characterized by their fine micritic texture and high content of planktonic foraminifera (Figures 8,11,and 13). The upper bathyal microfacies are represented by (W1, W2, W3, P2, and P3) are distributed throughout the formation in both the studied sections (Figure 13), whereas, the middle bathyal are represented by P1 microfacies that exist in the middle part of the formation.…”

“…Due to its economic importance and wide distribution, the formation has been described in a variety of academic publications ([e.g. [7][8][9][10][11][12][13][14]. Most of them were focused on bio-and lithostratigraphy, the origin of stylolite and chert nodules, sequence stratigraphy, and paleoenvironmental proxies of the Kometan Formation in Iraq.…”

Identificación de cortes en sección delgada de las especies Clavihedbergella simplex y Clavihedbergella moremani presentes en rocas cretácicas provenientes de la parte central del Valle Medio del Magdalena, Colombia

“…El uso de secciones delgadas para la clasificación de foraminíferos planctónicos es un método poco implementado en estudios bioestratigráficos hechos en Colombia y su uso frecuente es relativamente reciente fuera del país (Renz, 1936;Bolli, 1945;Robaszynski et al, 1984;Sýkora et al, 1997;Jaff, 2021;Kalanat et al, 2021;Khan et al, 2021) en comparación con el método tradicional de extracción. El uso de secciones delgadas ha demostrado ser particularmente útil en ofrecer una vista de la muestra en condiciones de depósito con una abundancia y diversidad fósil representativa de la roca original.…”

Calcareous Nannofossils from the Shiranish Formation at Bekhaer anticline, Dhouk area, Northern Iraq

“…This formation has been studied by many researchers with different specializations, where [4,5] studied it with other formations based on fossils of Ostracoda, foraminifera, and some other groups. The formation was studied by relying on foraminifera fossils, such as [6,7,8,9,10,11,12,13,14,15,16,17,18,19]. The formation based on calcareous nannofossils has also been studied by [20,21,22].…”