NASC 130 Essentials3_ch12

Turquoise essentials of geology 3rd edition by

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Formation Sedimentary deposits Banded iron formations (BIFs) Layered specular hematite (Fe2O3) and red chert (jasper) Found globally 2.5 to 2 Ga with O2 buildup in atmosphere Manganese (MnO2 to rich) nodules Rich in trace elements, these grow slowly on the sea floor Essentials of Geology, 3rd edition, by Stephen Marshak Chapter 12: Riches in Rock: Energy & Mineral Resources Ore Formation Residual mineral deposits Residual Form via extreme (tropical) chemical weathering Intense weathering strips almost everything out of soil Residual lateritic soil is enriched in Fe and Al oxides Residual Bauxite – primary ore of aluminum Essentials of Geology, 3rd edition, by Stephen Marshak Chapter 12: Riches in Rock: Energy & Mineral Resources Ore Formation Placer deposits – concentrated by flowing water Placer In high-velocity water… In Low-density minerals are suspended and washed away High-density grains are concentrated by settling out Important for gold, tin, and iron Best preserved in fossil Best stream sediments stream Essentials of Geology, 3rd edition, by Stephen Marshak Chapter 12: Riches in Rock: Energy & Mineral Resources Mineral Exploration Ores are located by evidence of metal enrichment Color – enrichment often discolors rock and soil Geophysical surveys – magnetism, gravity, radioactivity Geochemical surveys – ore can be found by chemical Geochemical analyses of water, stream sediment, soil, and biota analyses Essentials of Geology, 3rd edition,...
View Full Document

This document was uploaded on 11/25/2013.

Ask a homework question - tutors are online