Sand and Sandstone

Closure of the Proto-Tethys Ocean and Early Paleozoic amalgamation of microcontinental blocks in East Asia

https://cyberleninka.org/article/n/651108.pdf

Application of organic petrography in North American shale petroleum systems: A review

Cambrian to Devonian evolution of alluvial systems: The sedimentological impact of the earliest land plants

From static to dynamic provenance analysis—Sedimentary petrology upgraded

http://meetingorganizer.copernicus.org/EGU2013/EGU2013-1285.pdf

Provenance and recycling of Arabian desert sand

This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U–Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris–Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U–Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U–Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al-Batin fossil alluvial fan or even from Mesozoic sandstones of the Arabian margin accreted to the Cenozoic Zagros orogen. Due to extensive recycling and the fact that zircon is so resistant to weathering and erosion, the U–Pb age signatures are much less powerful a tracer of sedimentary provenance than framework petrography and heavy minerals. Actualistic provenance studies of dune fields at subcontinental scale shed light on the generation and homogenization of aeolian sand, and allow us to trace complex pathways of multistep sediment transport, thus providing crucial independent information for accurate palaeogeographic and palaeoclimatic reconstructions.

/pdf/the-euphrates-tigris-karun-river-system-provenance-recycling-4j6atx8chl.pdf

The Euphrates-Tigris-Karun river system: Provenance, recycling and dispersal of quartz-poor foreland-basin sediments in arid climate

Petrology and depositional evolution of the Paleozoic rocks of Iraq

\n The Middle Miocene Fatha Formation (previously Lower Fars Formation) in northern Iraq was deposited in a broad and shallow foreland basin adjacent to the Zagros and Taurus Mountains. It forms a transgressive-regressive sequence comprising numerous shallowing-upward cycles of alternating mudrocks, limestones, gypsum and/or anhydrite and halite. These cycles reflect rapid changes in accommodation space in settings that ranged from open and restricted hypersaline marine to continental (sabkha and fluvio-deltaic). In the marginal parts of the basin, continental siliciclastics (red and variegated marls, silts and fine sandstones) represent either aeolian deposition or a combined lagoonal- and/or fluvial-dominated delta system. Eustasy, rather than tectonics, caused the high-frequency cyclicity seen in the Fatha Formation. We present twelve sections dominated by evaporites from the Sinjar and Fatha sub-basins to represent the main lithologic constituents of the formation. Our detailed analysis of the sedimentary succession focuses on the three main lithofacies (siliciclastics, carbonates and evaporites). Petrographic, geochemical and scanning electron microscope analysis of these units are presented. We identified a range of carbonate lithotypes: marly, arenaceous (detrital), organic-rich (fossiliferous), dolomitic limestone and dolomite. Dolomitic limestones occur mostly in the lower part of the lower member of the formation, which was deposited in a barred lagoonal environment with high salinity. The presence of peloidal lime-wackestone with bioclasts, particularly in the upper part of the lower member of the formation, may reflect quiet, shallow-water marine conditions with moderate depths and low energy. The bioclastic-peloidal grainstone-packstone microfacies, with a common and diverse fossil assemblage, may reflect high to moderate energy, shallow-water environments. Evaporites comprise the main sediments of the Fatha Formation. Nodular gypsum is the dominant gypsum type, although laminated, thick-bedded, and secondary gypsum (selenite and satin spar) also occur. In the subsurface, anhydrite and halite are the principal minerals.

/pdf/the-middle-miocene-fatha-lower-fars-formation-iraq-2145wg4q59.pdf

Ali I. Al-Juboury

Papers

Provenance and recycling of Arabian desert sand

Provenance and recycling of Arabian desert sand

The Euphrates-Tigris-Karun river system: Provenance, recycling and dispersal of quartz-poor foreland-basin sediments in arid climate

Petrology and depositional evolution of the Paleozoic rocks of Iraq

The Middle Miocene Fatha (Lower Fars) Formation, Iraq