Drilling Program

Drilling is planned at four sites at the southeast end of the Samail Ophiolite Complex, near to Muscat.

Geological map of the southwesten Samail Ophiolite showing drillsite locations.

Map data from Nicolas, Boudier & co-workers.

Wadi Dima Drill Site

Active alteration

Wadi Gideah Drill Site

Crustal transect

Wadi Gideah in the Wadi Tayin massif is the most promising site for the study of an intact crustal section. Wadi Gideah drains southward from a divide near the crust-mantle transition. Around the Wadi, the crustal section dips gently to the south, exposing deeper levels upstream, to the north, and shallower levels to the south, culminating with submarine lava flows in the “Ibra syncline”. The section is well mapped by different groups, and recently this Wadi has been extensively sampled by Oman DP PIs Koepke, T. Müller, Bähre, Garbe-Schönber, S. Müller and Ildenfonse in order to establish a reference profile through the whole Samail paleocrust, considering petrological, geochemical and structural features, providing the basic framework for the three 400 m long cores to be obtained at the three sites, GT1 (lower crust), GT2 (mid-crust) and GT3 (dike/gabbro transition).

Maqsad Diapir Drill Site

Crust-mantle transition

 

 
 

Wadi Mansah (MOD Mtn) Drill Site

Site BT1 Basal thrust between Samail mantle with listvenite bands and metamorphic sole

Site BT1 is located on the north side of the wide gravel plain of Wadi Mansah (23.366°N, 58.184°E). Geologically, the drill site is just above the basal thrust of the ophiolite, juxtaposing mantle peridotites in the hanging wall and underlying metasediments and metabasalts of the metamorphic sole and the Hawasina Group sediments. Extensive bands of listvenites (fully carbonated peridotites) occur within partially serpentinized residual mantle peridotites. A 250 m deep, fully cored borehole will be drilled in the listvenite, penetrating the underlying harzburgite, passing through a band of metabasalt with pillow structures and terminating in phyllitic metasediments of the metamorphic sole and the Hawasina Group. Objectives are to perform thorough sampling of contacts between listvenite and harzburgite, harzburgite and the metamorphic sole, and the metamorphic sole and underlying Hawasina sediments. The goal is to conduct a detailed study of mass transfer from subducting sediments into mantle peridotites.