An astronomical time scale of early Pliocene from the Mediterranean Sea, Egypt

Farouk, Sherif; Ren, Chuanzhen; Salama, A. A.; Abdeldaim, Ahmad; Wu, Huaichun

doi:10.1016/j.gloplacha.2022.103869

Cited by 9 publications

(5 citation statements)

References 28 publications

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“…Elevated readings in uranium (U) and total gamma-ray (GR) measurements serve as indicators of maximum flooding surfaces, signifying phases of transgression and increased accommodation space. This phenomenon has been noted in various studies (Davies et al, 1996;Ehrenberg and Svana, 2001;Halgedahl et al, 2009;Farouk et al, 2022;Farouk et al, 2023). The presence of enriched U and total gamma-ray values is linked to the deposition of organic-rich marine sediments in deep-water environments.…”

Section: Uranium and Gamma-ray In Sequence Stratigraphysupporting

confidence: 62%

“…In the grain-dominated Lower Mahil Formation, the relationship between gamma-activity and grain size is not evident. Previous studies have shown that low gamma-readings are typical of coarse-grained sediments, while high gammaactivity characterizes finer-grained sediments (Berstad and Dypvik, 1981;Dypvik and Eriksen, 1983;Tavakoli, 2017;Farouk et al, 2022;Farouk et al, 2023). However, this pattern is not observed in this formation.…”

Section: Uranium (U) and Gamma-ray Log Response To Lithofaciesmentioning

confidence: 97%

“…Conversely, during regression within carbonate systems, carbonate production slows down, leading to an increased proportion of coarser materials. This shift results in negative decreasing deviations in uranium and total gamma-ray logs (Halgedahl et al, 2009;Kalvoda et al, 2011;Tavakoli, 2017;Farouk et al, 2022;Farouk et al, 2023). Consequently, uranium values in the Saiq Plateau section tend to be slightly lower than those in the Wadi Sahtan section.…”

Section: Uranium and Gamma-ray In Sequence Stratigraphymentioning

confidence: 99%

“…Brecciated floatstone microfacies within thick mud-supported beds with various fossils show some elevated U and total GR readings. This could be attributed to readings from the mudmatrix, unseen fractures filled with "uranium-rich" matter, minor siliciclastic inputs, presence of stylolite, fossils, and the duration of subaerial exposure, which affects U and total GR readings (Luczaj, 1998;Ehrenberg and Svana, 2001;Halgedahl et al, 2009;Tavakoli, 2017;Farouk et al, 2022;Farouk et al, 2023).…”

Section: Uranium (U) and Gamma-ray Log Response To Lithofaciesmentioning

confidence: 99%

“…δ 18 O variations provide valuable information on climate changes and diagenetic fluids (Sharifi-Yazdi et al, 2019;McConnaughey, 1989;deMenocal et al, 1990;Moustafa et al, 2016). Spectral gamma-ray logs offer valuable insights into stratigraphy, formation composition, and lithology (Fertl and Rieke, 1980;Davies et al, 1996;Hampson et al, 2005;Tavakoli, 2017;Khalifa and Mills, 2020;Farouk et al, 2022;Farouk et al, 2023). These logs measure natural radioactivity resulting from unstable isotopes in rocks (Buccianti et al, 2009;Klaja and Dudek, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Gamma-ray, stable carbon and oxygen isotope chemostratigraphy and sequence stratigraphy of the Lower Mahil Formation (KS-1 Khuff-Equivalent), Northern Oman

Moustafa,

Al Raqaishi,

El-Ghali

et al. 2023

Front. Earth Sci.

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This research presents findings from a study focused on the Lower Triassic (Induan) Lower Mahil KS-1 Formation, situated on a homoclinal carbonate platform in Northern Oman. The sequence stratigraphy of this formation is characterized by a considerable thickness variation, slumps, and breccia deposits related to active normal faults coupled with intra-basin growth faults. The main objective was to establish a reliable stratigraphic framework for the Lower Mahil KS-1 Formation by integrating high-resolution carbon isotope data along with high-resolution spectral and total gamma-ray data. To achieve this, whole-rock samples were analyzed for δ13C and δ18O isotopes. Spectral and total gamma-ray records were obtained for the formation. Isotope sampling is conducted every 0.5 m in the Saiq Plateau and Wadi Sahtan sections. Furthermore, spectral gamma-ray measurements were taken at intervals of 10 cm from the logged sections. Within the third-order sequence, the spectral gamma-ray data revealed a distinct sea-level trend, leading to the division of KS1 into two different parts. Five fourth-order depositional sequences were identified by analyzing stable carbon isotopes, uranium, and total gamma-ray profiles. Four of these sequences displayed complete patterns, reflecting transgression and regression phases, while the fifth sequence was incomplete and solely comprised a transgressive phase. An essential outcome of the study is the correlation of the δ13C curve of the Lower Mahil KS-1 Formation with other similar formations around the Tethys region. This correlation indicates that the Lower Mahil KS-1 Formation captures the near-primary signal of carbon isotope variations in coeval seawater. As a result, it holds promise as a reference section for future investigations and studies in this field. Compared to the prior investigation, this study utilizes data with higher precision, capturing spectral gamma-ray measurements at 10 cm intervals and isotope measurements at 50 cm intervals. Furthermore, the study’s focus is confined explicitly to KS1.

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Section: Uranium and Gamma-ray In Sequence Stratigraphysupporting

confidence: 62%

Section: Uranium (U) and Gamma-ray Log Response To Lithofaciesmentioning

confidence: 97%