The forces that are created are enormous and no rock type can resist these forces. The dark minerals are usually dominated by pyroxene, often with olivine. Lead sulphide, PbS, with a metallic grey-blue colour. Usually occurs as cubic crystals. Dark minerals are usually biotite and amphibole.
Dark minerals are usually biotite and amphibole.
A term used to refer to rock fragments between 2 and 64 mm in diameter. Water which fills pores and fractures in superficial deposits and bedrock. Groundwater makes up the underground part of the water cycle. A valley where the valley floor lies at a significantly higher level than the valley it joins. Ice ages last approximately 100,000 years.