Laminated structure in rocks formed as a result of deformation. 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.