Peru, continental shelf

Pontanen and Morris [8] compared the structure of humic acids from marine sediments and degraded diatoms by infrared and C13 and proton NMR spectroscopy. Samples of marine sediments taken from the Peru continental shelf were extracted with water, sodium hydroxide (0.05mol 1 J) and sodium pyrophosphate (0.05mol l-1) under an atmosphere of nitrogen and fractionated by ultrafiltration. Humic acids of molecular weight 300000 and above were examined. Diatoms were collected from... 

Repeta, D.J., and Gagosian, R.B. (1987) Carotenoid diagenesis in recent marine sediments. I. The Peru continental shelf (15°S, 75°W). Geochim. Cosmochim. Acta 51, 1001-1009. 

Phosphorites (manne apatites) are dense, hght-brown-to-black concretions, ranging in size from sands to nodules and irregular masses. Phosphorites have been found off Argentina, Chile, Japan, Mexico, Peru, South Africa, and Spain, and several islands in the Indian Ocean. Some also have been found off the west coast of North America and on the eastern North American continental shelf These deposits occur where water upwelling transports phosphorus and where the rate of sedimentation is slow. The... 

The Phosphoria Formation was originally thought to have formed as cold P-rich waters were delivered via upwelling to the continental shelf margin analogous to modern systems such as the one of the Peru-Chile coast. 

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