A long, hot day with Cretaceous phosphorites in the Negev

MITZPE RAMON, ISRAEL–This was one of Oscar’s big field days. He is shown above at his first exposure of the phosphatic zone of the Mishash Formation (Campanian, Upper Cretaceous) exposed at Wadi Hawarim (N 30.84423°, E 34.75742°). We see here the entire section from the top of a phosphate-cemented conglomerate to the base of the overlying Ghareb Formation (the brown marls at the top of the image). Oscar is working to understand the complicated stratigraphy and origin hypotheses for these phosphorites. You may be able to make out some of the red ribbons we placed while measuring the section.

This is another view of the Mishash phosphorites at Wadi Hawarim, with the Ghareb Formation in the upper left. We have six measured, sampled and described members in just under eight meters of section here. The phosphates are finely disseminated in some of the chalky units and bound up in a layer of nodules at the top.

A conglomerate within the phosphate zone of the Mishash has an interesting collection of clasts, including this large chunk of reptile bone, possibly from a dinosaur. (Which is what we always say about large bone bits from the Mesozoic!)

While Oscar and I worked on his measured section, Lizzie and Steph looked for shark teeth in the conglomerate unit. They did very well. Above is a sample of what they found. So Andrew Retzler — any ideas about what kind of sharks are represented by these tiny teeth? It looks like a small tooth in the lower row is Squalicorax kaupi.

Near the end of the day we went to one of the phosphate mine and enrichment plant owned and operated by Rotem Amfert Negev Ltd. This was a treat for Oscar who has strong interests in the economic geology of mining. We heard an excellent presentation by the chief geologist of the mine about the value of phosphate, the main markets for the their products, and the geological setting of these Negev phosphorites.

Afterwards we visited the active part of the mine, shown above. Since about 2005 the mine has been restoring land as fast as it mines it. On the right is the working face of the mine, the white unit on the floor has most of the phosphate in it and is being ground up by the vehicle slowing moving across it. On the far left are piles of overburden and “interburden” (unusable material between the three phosphate-rich layers) ready to fill in the pit once the phosphorite is removed. We also saw those parts of the area where the original topography and (they hope) cryptobiotic top soil has been restored.

It was a good day, though a long one. Tomorrow we will celebrate the Fourth of July with yet another Negev work day. Maybe we’ll have a special American-themed dinner afterwards.