what is dolorite?
A dolerite is the medium-grained equivalent of a basalt-a basic rock dominated by plagioclase and pyroxene. Dolerite can contain clinopyroxene and/or orthopyroxene and plagioclase is more calcic than andesine (50% anorthite). Dolerites also often include olivine or quartz and can be alkali basalts, olivine tholeiites or quartz tholeiites. They can contain a wide range of accessory minerals including hornblende and biotite.