Summary:
The phosphate formations in the Upper Cretaceous and Eocene levels cover about 60% of the total area of Jordan. The phosphate formations of the Upper Cretaceous lie near the surface in the central part of the country, covering a wide belt. The Al-Hassa phosphate deposit is found in two horizons, deposit has a lenticular.
The phosphorites of Jordan are present within Al-Hisa Phosphorite Formation (AHP). In general, the AHP consists of phosphorites, bedded chert, limestones, oyster buildups, organic-rich marl (oil shale) and other rock types.
The AHP consists of three formal members, from older to younger Sulatani, Bahiyya and Qatrana. In central Jordan, the Sultani Member consists of alternating limestones, bedded chert and minor phosphorites. The Bahiyya Member consists of oyster banks or buildups up 30 m in thickness that are made of oyster fragment in clinoforms dipping general to the SE (Abed and Sadaqah, 1998). The Qatrana Member is the host of the high grade phosphorites. The grade phosphorites are friable with little calcareous cement. They are present as lenses (small basins) with a diameter ranging up to few kilometers and a thickness up 13 m.
In Eshidiyya Basin, the three formal members are present only in the northern parts of the basin. The Bahiyya coquina thins gradually towards the SE until it disappears completely. The Sultani Member or the lower member is hosting the main (high) grade phosphorite deposits. It is divided by the miners into three producing phosphate horizons from top to bottom; A1, A2 and A3, separated by non phosphorite strata like; chert, porcelanite, and minor beds of marl, limestone and dolomite. (Sofremines, 1987; Abed et al., 2007). The A3, at the base, is rich in quartz sand, while A2 is a friable, high grade phosphorite. The A1 is a low grade indurated by calcite cement. The Qatrana Member or the upper member is designated A0 and consists of up to 3 m of friable high grade phosphorite in the north thinning to the SE to few centimeters only.
In sedimentary deposits such as those found in Jordan, the ore generally consists of phosphate particles ranging from 20 mm to 50 microns in size, sand and clay ranging from one mm to less than two microns. Clay can be present in large lumps, but scrubbing and wetting with water will generally reduce it to its natural grain size of less than two microns. The ore beds generally rest on hard limestone and are overlain by overburden sand.