Origin and Evolution of the Late Cretaceous Reworked Phosphorite in the Sirhan-Turayf Basin, Northern Saudi Arabia

Yunlong Zhang,Ziying Li,Abdullah M Shammari,Longsheng Yi,Guochen Li,Saleh M Dini,Zhixing Li,Ahmed S Banakhar,Mingkuan Qin,Abdullah M Memesh

doi:10.3390/min11040350

Yunlong Zhang, Ziying Li + Show 8 more

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https://doi.org/10.3390/min11040350

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Abstract

The redeposition of pristine phosphorite plays an important role in phosphorus accumulation, which created reworked phosphorite extensively on the continental shelf. This paper, using geochemical analysis combined with data from petrology and diagenesis, focuses on the reconstruction of the formation processes of the Late Cretaceous Thaniyat phosphorite deposition in northwestern Saudi Arabia, which is a part of the famous large Neo-Tethys Ocean’s phosphorite deposit. The results of our study illustrate that the phosphorites represent the reworked products from the north, close to the edge of the Neo-Tethys Ocean’s shelf, where upwelling had accreted the pristine phosphorite. The reworked phosphatic grains were redeposited near the shore in sandstone, forming sandy phosphorite and on a carbonate platform and creating calcareous phosphorite. The microscale sedimentological and geochemical information hosted in the eroded phosphorite grains indicates that the source sediment, pristine phosphorite, occurred under a fluctuating geophysical condition and in a relatively limited geochemical environment. They were physically crushed and transported landward and deposited under oxic conditions, forming the Thaniyat phosphorites. Early diagenesis in the Thaniyat phosphorite was evidenced by recrystallization of the phosphate minerals, geochemical depletion, and C and O isotope excursion.

Highlights

As one of the three major macronutrients, phosphorus is a crucial element for the growth of organisms [1,2] and plays an important role in the origin of life, e.g., [3]
The Middle East hosts the majority of the global phosphorite reserves; exhaustive mining of phosphate has appeared in the northern part of Jordan, etc.; China, which has less than 5% of the global phosphorite reserves, dominates the global phosphate products [9,10,11]
Thediameter compacted grains are varies crushed and0.1 partially cemented by cal(Figure of phosphate the phosphate grain from to 1.0 mm

Summary

Introduction

As one of the three major macronutrients, phosphorus is a crucial element for the growth of organisms [1,2] and plays an important role in the origin of life, e.g., [3]. As the majority of the phosphorite, reworked phosphorite commonly occurred in offshore environments near the west coast of the ocean, such as Namibia and Peru in the west of the Atlantic and Pacific Ocean [12,13]. These reworked phosphorites were related to upwelling, which brought in an abundance of nutrients and accumulated phosphorus via blooming and burial of plankton [12,14,15,16]. Hydrolysis and microbial catalysis of the buried phosphorus-rich organic matter form the precursor of the pristine phosphorite [17,18] and the fluctuation of the sea-level are possible causes of erosion and physical transportation of the pristine phosphorite landward, forming reworked phosphorite [19]

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