Phosphates are sedimentary rocks, formed from the remains of long-dead organisms. Around 60 to 70 million years ago the Mediterranean and its margins marked the site of a large sea that separated Europe and Asia from Africa. This sea, known as the Tethys, extended across the Middle East and North Africa and was marked by a strong westerly current that flowed across an area that begins in north-west Saudi Arabia and continues through Jordan, Egypt, Tunisia, Algeria and Morocco. Together they represent the worldâ€™s largest phosphate province, for this current deposited decaying organic remains of plants and animals (mainly plankton) into a sedimentary series containing shales, dolomites, and limestones. Upon diagenesis this ocean organic ooze became phosphorus deposits.