Development of a palaeovalley complex on a Late Ordovician glaciated margin in NW Saudi Arabia

S. Tofaif; D. P. Le Heron; J. Melvin

doi:10.1144/sp475.8

Late Ordovician scolecodonts from the Qusaiba-1 core hole, central Saudi Arabia, and their paleogeographical affinities

Review of Palaeobotany and Palynology ◽

10.1016/j.revpalbo.2014.08.013 ◽

2015 ◽

Vol 212 ◽

pp. 85-96 ◽

Cited By ~ 12

Author(s):

Olle Hints ◽

Florentin Paris ◽

Sa'id Al-Hajri

Keyword(s):

Saudi Arabia ◽

Late Ordovician ◽

Core Hole

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Late Ordovician agglutinated foraminifera from the Ra'an Shale Member, Qasim Formation of Saudi Arabia as indicators of the O40 Maximum Flooding Surface

Stratigraphy ◽

10.29041/strat.16.1.27-39 ◽

2019 ◽

Vol 16 (1) ◽

pp. 27-39

Author(s):

Michael A. Kaminski ◽

Pramudya Perdana ◽

Mohamed O. Abouelresh ◽

Lamidi Babalola

Keyword(s):

Saudi Arabia ◽

Late Ordovician ◽

Maximum Flooding Surface ◽

Agglutinated Foraminifera

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Late Ordovician–earliest Silurian chitinozoans from the Qusaiba-1 core hole (North Central Saudi Arabia) and their relation to the Hirnantian glaciation

Review of Palaeobotany and Palynology ◽

10.1016/j.revpalbo.2014.10.005 ◽

2015 ◽

Vol 212 ◽

pp. 60-84 ◽

Cited By ~ 17

Author(s):

Florentin Paris ◽

Jacques Verniers ◽

Merrell A. Miller ◽

Sa'id Al-Hajri ◽

John Melvin ◽

...

Keyword(s):

Saudi Arabia ◽

Late Ordovician ◽

Core Hole ◽

North Central

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Lithofacies, depositional environments and stratigraphic architecture of the Wajid Group outcrops in southern Saudi Arabia

GeoArabia ◽

10.2113/geoarabia200149 ◽

2015 ◽

Vol 20 (1) ◽

pp. 49-94

Author(s):

Hussain Fahad Al-Ajmi ◽

Martin Keller ◽

Matthias Hinderer ◽

Claudio Miro Filomena

Keyword(s):

Saudi Arabia ◽

Depositional Environment ◽

Wide Spectrum ◽

River System ◽

Late Ordovician ◽

Depositional Environments ◽

Geological Time ◽

Geological Time Scale ◽

Shallow Marine ◽

Sand Sheet

ABSTRACT The Wajid Group is a Palaeozoic siliciclastic succession of southern Saudi Arabia. In the outcrop belt it is ca. 500 m thick, whereas in the subsurface, the thickness increases to more than 4,500 m. The siliciclastic sediments have great reservoir potential for hydrocarbons and for groundwater. Although they represent one of the most important aquifers of the Arabian Peninsula, neither their sedimentologic, lithostratigraphic, nor their reservoir characteristics are satisfactorily known. In this study, a detailed description of lithology and sedimentology is given and the Wajid Group sediments are interpreted in terms of depositional environment and facies architecture. Thirteen lithofacies (LF 1 to LF 13) have been recognised, most of them composed of different subfacies. These lithofacies are grouped into 9 lithofacies associations (LF-A1 through LF-A9). LF-A1 through LF-A3 and LF-A7 represent shallow-marine siliciclastic environments. The remaining lithofacies associations describe periglacial environments of the Hirnantian (Late Ordovician) and Permian Gondwana glaciations. Except for a few pro-glacial fluvial deposits, fluvial successions and aeolian sediments are absent in the outcrops of the Wajid Sandstone. Five formations are recognised in the Wajid Group: the Dibsiyah, Sanamah, Qalibah, Khusayyayn, and Juwayl formations. They are all separated by major unconformities. The Dibsiyah Formation represents a vast sand-sheet complex with core and margin facies formed under shallow-marine conditions. These marine conditions enabled an abundant fauna to proliferate and leave its traces in the form of Skolithos piperock and Cruziana sp. A late Cambrian to Early Ordovician age is inferred for these deposits from regional considerations. The Sanamah Formation records the Late Ordovician Hirnantian glaciation with coarse sandstones and conglomerates. A variety of glacier-induced sedimentary structures are present. The internal succession is composed of three major sediment packages reflecting three ice advance-retreat cycles. The latest of these cycles is overlain by a few metres of marginal-marine sediments of the Qalibah Formation. The Khusayyayn Formation was deposited probably during Early Devonian times. It also represents a sand-sheet environment characterised by the dominance of mega-scale and giant cross beds and bed sets. A marine depositional environment is assumed from scarce Skolithos sp., and because nearly all indicators of a braided river system are absent. The Juwayl Formation of Permian age was deposited at the interface of the Late Palaeozoic Gondwana ice shield with a large lake that may have covered most of southern Arabia and adjacent areas. Proglacial sandstones and conglomerates were deposited close to the glaciers, whereas fine-grained sediment with dropstones, boulder pavements and a wide spectrum of soft-sediment deformation are characteristic of the lake environment. While the two glacial successions and the Khusayyayn Formation can rather confidently be attributed to the geological time scale, either through seismic correlation or biostratigraphically, the Dibsiyah Formation has not yet been biostratigraphically well dated.

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