Key elements to clarify the 110 million year hiatus in the Mesozoic of eastern Syria

Abstract

Log correlations, biostratigraphical results and seismic data were combined to show that from Late Triassic Norian to Early Cretaceous Aptian times, the Euphrates area (Eastern Syria) was part of a huge saddle-like northeast-trending ridge (the Hamad Uplift) characterized by a prolonged stratigraphic hiatus. This uplift, developed in the Late Triassic, was multiply reactivated during the Mesozoic, particularly in the Early Cretaceous Aptian-Albian times, during a major reorganization phase of the Neo-Tethyan rift system. This uplift marked the separation between two regions with distinctive tectono-sedimentary evolutions: an eastern isolated and starved region (Euphrates Graben) and a western region that was mainly influenced by the sedimentary dynamics of the westerly Bishri Trough, linked to the Palmyrides Basin. The Hamad Uplift broke-up into a N140°E-oriented graben system in late Albian times. This early NE-trending extensional stage was accompanied by volcanic activity and introduced the main phase of horst-and-graben development within the Euphrates Graben in the Late Cretaceous Senonian times.

Overview of the Triassic System in Syria: Lithostratigraphic and biostratigraphic correlations with neighboring areas

“…In most wells within Syria, this formation is generally composed of black, pyrite-bearing silty shale with fine grey calcareous intercalations. The formation reaches its maximum thickness in the Palmyride (138 m) and in the Levantine basins (168 m), while it is missed in Aleppo Plateau and along the northern edge of the northern Arabian Platform (Kammar, 1994), in Hamad area (Caron et al, 2007;Caron et al, 2000;Brew et al, 2001;Al Bassam et al, 1983;Best et al, 1993), in the Euphrates Graben (Jamal et al, 2000) and in the Rutbah area (southwest of Iraq) (Buday, 1980) (Figure 10). This implies that the Triassic sea invasion was restricted to the Levantine zone and the Palmyride Basin along a NE-elongated bay (Figure 11).…”

“…During the Triassic, the Abu Fayad Formation's sediments covered the Syrian platform, except the major part of Hamad area (Tanf and Swab wells), where Permian quartzite is overlain by Cretaceous sandstones (Best et al, 1993). Accordingly, the Hamad area was emergent at that time (Hamad Uplift, Caron and Mouty, 2007), surrounded by the Triassic sea, which deepened northwest (Palmyride Basin) and southeastwards (Rutbah Basin) (Figures 10 and 11).…”