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Home / Journals / General Science / New Horizons Journal of Basic and Applied Sciences
Research Article
Received: Mar. 22, 2025; Accepted: Apr. 08, 2025;
Published Online Jun. 01, 2025
Abdel Galil A. Hewaidy1, Alaa Mostafa2, Kamel H. Mahfouz2,* and Islam El-Sheikh2
1 Geology Department, Faculty of Science, Al-Azhar University, Cairo, Egypt
2 Geology Department, Faculty of Science, Al-Azhar University, Assiut, Egypt
https://doi.org/10.62184/nhjbas.jnh10020251
Hewaidy, A. G. A., Mostafa, A., Mahfouz, K. H., & El-Sheikh, I. (2025). Biostratigraphy and sequence stratigraphy of the Upper Cenomanian-Turonian successions at Southern Galala Plateau, North Eastern Desert, Egypt. New Horizons Journal of Basic and Applied Sciences, 1–14. https://doi.org/10.62184/nhjbas.jnh10020251
Upper Cenomanian; Turonian; Ammonites biostratigraphy; Sequence stratigraphy; Eastern Desert, Egypt.
The Upper Cenomanian-Turonian strata are well studied at two sections; the first is Wadi (W.) El Dakhl section towards the north and the second is W. Um-Artah section towards the south, which is introduced for the first time in the manuscript. This study aims to provide stratigraphic, biostratigraphic, and sequence stratigraphic data, and correlate its depositional sequence with local and international ones. The studied successions represent the initial major sea level transgression, mainly consisting of siliciclastic/carbonate facies rich in macrofaunal contents. Five ammonite zones covering the Late Cenomanian-Turonian interval are identified. The integrated field, lithologic, and biostratigraphic criteria led to define four 3rd depositional sequences (DS1-DS4) during this interval. These depositional sequences are bounded by five sedimentary unconformity surfaces (Ce4, Ce5, Tu1, Tu2, and Tu3 sequence boundaries), which correlate with others in Tethyan regions. This correlation indicates that the sequence boundaries of the latest Cenomanian-Turonian (Ce5, Tu1, Tu2, and Tu3) match with those of the Middle East, North Africa, and Europe regions. While the early-Late Cenomanian sequence boundary (SB Ce4) mismatch at the same regions.
1. Introduction
The Upper Cenomanian-Turonian successions covered large provinces in north Egypt. These successions are represented by siliciclastic and carbonate marine facies which rich with diverse macrofaunal assemblages. Several biostratigraphic and palaeoecological studies have been carried out on these faunal assemblages [1-11]. However, some localities in the North Eastern Desert are still uninvestigated until now; one of these localities is the Um-Artah area (Figure 1). So, the most important goal of the present study is to fill the gap in information on the Um-Artah section, whereas there is no information about this area. Therefore, this study firstly introduced details stratigraphic studies about the Upper Cenomanian-Turonian transition at the Um-Artah area. At the same time, it aims to establish a detailed biostratigraphic and sequence stratigraphic framework for the Upper Cenomanian-Turonian successions of the Southern Galala Plateau, and hence, correlated its depositional sequence with local and international ones.
Figure 1. (A) Location map shows the studied area (B) Geological map shows the distribution of the rock units at the studied area and the location of the study sections (modified after [12]).
2. Materials and methods
Two stratigraphic sections were described, measured in detail in the Upper Cenomanian-Turonian strata at the Southern Galala area (Figure 2) with a focus on their macrofossil content (especially ammonites). The first outcrop is located in the southern part of W. El Dakhl section (at latitude 28° 39' 48" N and longitude 32° 24' 58" E) and the second section is at W. Um-Artah section (at latitude 28° 34' 58" N and longitude 32° 23' 01" E). These sections were described in detail. The stratigraphic ranges of the macrofossil content were identified and traced, and therefore, biostratigraphy records were established. These macrofossils were photographed. The integrated stratigraphic data were interpreted in the sequence stratigraphic framework.
Figure 2. Field photographs showing: A. Malha/Galala formational boundary (SB Ce 4), W. Um-Artah section. B. Oysrer bank in Galala Formation, W. Um-Artah section. C. Vascoceras cauvini horizon within the uppermost part of Galala Formation, W. Um-Artah section. D. Pteroceras incerta (D’orbigny) within Galala Formation, Um-Artah section. E. Thalassinoides within Galala Formation, El Dakhl section. F. Galala/Maghra El-Hadida formational boundary, El Dakhl section. G. Maghra El-Hadida/Matulla formational boundary, Um-Artah section. H. Maghra El-Hadida/Matulla formational boundary, El Dakhl section.
3. Lithostratigraphy
Two rock units are analyzed: Galala (at the base) and Maghra El-Hadida (at the top) formations. These two formations represent the Upper Cenomanian-Lower Turonian transition. They are unconformably underlain by the Malha formation and overlain by Matulla formation. Due to the vertical lithologic variations between Malha/Galala and Maghra El-Hadida/Matulla formational boundaries, these formational contacts are easily detected in the field. The unfossiliferous cross-bedded sandstones of the Malha formation vertically change to fossiliferous shale of the Galala Formation (Figures 2-4). At the same time, there is a vertical facies change between the uppermost part of Maghra El-Hadida formation (carbonate facies) and the Matulla formation (clastic facies). These formational contacts are characterized by unconformity surfaces (Figures 2-4).
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