Constraints on the diagenesis, stratigraphy and internal dynamics of the surface-piercing salt domes in the Ghaba Salt Basin (Oman): A comparison to the Ara Group in the South Oman Salt Basin

Abstract

In the South Oman Salt Basin (SOSB), the Ara carbonates form an extensively cored, deeply buried intra-salt hydrocarbon play. Six surface-piercing salt domes in the Ghaba Salt Basin (northern Oman) provide the only outcrop equivalents for carbonates and evaporites of the Ediacaran – Early Cambrian Ara Group (upper Huqf Supergroup). Based on fieldwork, satellite images and isotope analysis it is concluded that most of the carbonate bodies (so-called stringers) in the Ghaba salt domes are time-equivalent to the stratigraphically uppermost stringer intervals in the SOSB (A5–A6). Maturity analyses demonstrate that the carbonate stringers in the salt domes were transported with the rising Ara Salt from burial depths of c. 6 to 10 km to the surface. Petrographic and stable-isotope data show that their diagenetic evolution during shallow and deep burial was very similar to the Ara carbonate stringer play in the SOSB. However, during the retrograde pathway of salt diapir evolution, the carbonate stringers were exposed to strong deformation in the diapir stem and diagenetic alterations related to dedolomitisation. As the salt domes contain facies that are in all aspects identical to the deeply buried Ara play in the SOSB, this study provides substantial additional information for hydrocarbon exploration in southern Oman. Moreover, our work has implications for the hydrocarbon prospectivity of the Ghaba Salt Basin and possibly of other Ediacaran – Lower Cambrian evaporite basins in the Middle East, such as for the time-equivalent Hormuz salt basins.

The Mahout Structure in the Central Desert of Oman: A Possible Simple Impact Crater

“…The salt domes of Oman belong to the Ara Formation (Lower Cambrian). There is no evidence of salt domes cutting through Proterozoic strata in the Mahout crater area [32,33]. Furthermore, salt domes lack the lithic and polymict breccia, crater rim, and ejecta observed at the Mahout crater.…”

“…The Mahout structure is one of the structures speculated by local geologists to be related to deep-seated faults and salt domes e.g., [32,33]. However, no previous studies have been conducted or have reported on this structure to confirm its origin.…”

Structural diagenesis and dolomitization of Cenozoic post-rift carbonates in the Red Sea rift basin: A multiproxy approach

“…Carbonate precipitated in veins and fractures can be used as an archive for the oxygen isotopic composition of the diagenetic fluid and the temperature of precipitation of the mineral (Moore and Wade, 2013). Previous integrated studies combining paleo-thermometry analysis, such as stable isotope and fluid inclusion analysis (e.g., Kenis et al, 2000;Immenhauser et al, 2007;Reuning et al, 2009;Vandeginste and John, 2012;Vandeginste et al, 2017;Koeshidayatullah et al, 2020), have been conducted to reconstruct fluid origin and temperature from fracture-related samples. The δ 18 O values of calcite decrease with increasing temperature (Moore and Wade, 2013;Hoefs, 2019).…”

A two‐stage, fault‐controlled paleofluid system at the southern termination of the Gypsum Valley salt wall, Paradox Basin, Colorado, USA

“…Although a number of field‐based studies have examined issues related to salt‐sediment interaction, near‐salt deformation, and the geometry and evolution of a variety of salt structural styles (e.g., Alsop et al, 2016; Giles & Lawton, 2002; Hearon et al, 2015; Ringenbach et al, 2013; Rowan et al, 2003) the majority of work on salt‐related fluid systems is derived from numerical modelling, seismic data, well logs, and fluid pressure and chemistry data (e.g., Canova et al, 2018; Esch & Hanor, 1995; Nikolinakou et al, 2018; Steen et al, 2011; Zechner et al, 2019). Field and laboratory studies of salt‐related fluid systems are less common and have typically focused on diagenesis and economic mineralization in the vicinity of classic, pillar‐shaped salt stocks (e.g., Enos & Kyle, 2002; Ghazban & Al‐Asam, 2010; Reuning et al, 2009; Rouvier et al, 1985; Vandeginste et al, 2017). Many of these studies have implicated faults and diapir margins as conduits for fluid migration, but most did not specifically investigate fault zone structure, permeability, or mineralization.…”