Calcareous Nannofossils Biostratigraphy of Late Cretaceous–Paleocene Successions from Northern Jordan and Their Implications for Basin Analysis

Abstract

Local geological and tectonic processes have been pivotal in shaping the diverse sedimentation patterns observed in Jordan, forming sub-basins characterized by elevated organic matter content (TOC). This study aims to characterize the Maastrichtian basin, focusing on sedimentation rates using calcareous nannofossils and understanding paleoecological and paleo-oceanic conditions. It offers insights into the paleoenvironmental factors impacting oil shale deposition in the late Maastrichtian–Paleocene period. It employs classical biostratigraphical, semi-quantitative, and statistical methodologies to achieve its objectives of age determination and paleoecological insights. A total of 116 smear slides from two sites were obtained: the first, consisting of WA-1 (23 samples), WA-2 (18 samples), and WA-3 (11 samples), and the second, with 60 samples. Notably, the sites exhibit varying topography. WA-1 and WA-2, situated at lower elevations, have the highest Total Organic Carbon (TOC) levels, while areas with higher elevations in section four are visually identified by a light color. The study revealed varying patterns of calcareous nannofossil richness in the two investigated sites. These patterns were instrumental in defining biozones, with the utilization of marker species such as Lithraphidites quadratus, Micula murus, Micula prinsii, and Cruciplacolithus tenuis. Chronologically, these sections were classified as Maastrichtian–Paleogene, encompassing the following biozones in sequential order: UC-20a, UC-20b, UC-20c, UC-20d, and NP-2. Furthermore, the study identified two hiatus intervals, observed in sections WA-1 and KAS-1. The absence of certain biozones in the analyzed sections suggests that these sections correspond to distinct geological blocks within the basin, underscoring the role of tectonic forces during the deposition period. The sedimentation rate initially commenced at low levels but gradually increased due to topographic alterations. Notably, the biozone UC-20c demonstrated a clear trend toward warming and enhanced nutrient availability. In this context, the abundance and diversity of species were associated with increased continental influx into the sub-basin, resulting in rising nutrient levels and the number of calcareous nannofossils. This study enhances the understanding of the local and global effects such as tectonic and climates of the continuity of basins by deciphering calcareous nannofossil patterns and their correlation with sedimentation factors.

Characteristics of Cenomanian–Turonian Oceanic Anoxic Event 2 and its Impact on Organic Carbon Accumulation in the Abu Roash (F) Organic-Rich Carbonate Rocks in the Abu Gharadig Field, Egypt

“…The deposition of organic-rich sediments within shallow basins during the Upper Cretaceous was affected by the basin architecture …”

“…The deposition of organic-rich sediments within shallow basins during the Upper Cretaceous was affected by the basin architecture. 96 In the current study, the knowledge of OAE2 and its sedimentary depositional characteristics, including paleosalinity, paleoredox, and paleoclimatic conditions were studied. Organic carbon deposition is restricted by different paleoenvironmental settings and ecological processes during deposition, as shown in Figure 21.…”

Geochemical and Organic Petrological Characteristics of the Bituminous Carbonate Succession (Upper Cretaceous Shu’ayb Formation) in Northern Jordan: Implications for Organic Matter Input and Paleosalinity, Paleoredox, and Paleoclimatic Conditions

“…Accumulation of organic-rich sediment within shallow basins during late Cretaceous is affected by the complex topographic relief of the basins. , In this context, the organic carbon accumulation in the studied bituminous carbonate succession of the Upper Cretaceous Shu’ayb Formation is controlled by different paleoenvironmental conditions and ecologic processes during deposition, as shown in Figure . This depositional model is characterized by low terrigenous input in a shallow-to-deep open marine environment (Figure ).…”

Calcareous nannofossils biostratigraphy of well Uche 1, Offshore Lagos, Eastern Dahomey Basin, South Western Nigeria

“…The studied interval is not older than 20.94Ma MFS within the NN2 zone. However, in relation to past works such as that of [22], [24] where he considered the age of the Oshosun Formation to be Early to Middle Eocene on the basis of foraminifera and ostracods. A more recent work [23] suggested the age of the exposed section of the Oshosun Formation in the Shagamu quarry to be of Late Paleocene to Early Eocene due to the occurrence of diagnostic cysts.…”