Other magma was injected under pressure between horizontal sedimentary strata and cooled to form extensive horizontal sills of dolerite. Dolerite, being an intrusive igneous rock, contains no …

As volcanic activity subsided, the remaining magma cooled in the cracks as circular bands (dykes) of volcanic rock (mainly syenites and foyaites). The rate of cooling and the composition of the …

roup. During the Jurassic, the volcanic Drakensberg were formed and cracks in the earth’s crust were filled with molten lava that cooled to form dolerite dykes. Magma injected horizontally …

Other magma was injected under pressure between horizontal sedimentary strata and cooled to form extensive horizontal sills of dolerite. Dolerite, being an intrusive igneous rock, contains no …

The layered rocks of the Bushveld Complex are generally believed to be the result of crystals settling out of magma during slow cooling. The magmatic events petrogenetically related to …

Geology and Soils The area is largely dominated by the dolerite dykes and sills that formed as the result of magma intruding through sedimentary rocks of the Beaufort group of the Karoo …

The age of these rocks is around 2200 million years old and they are from primary magma, and not sedimentary. Based on the age the rocks do not contain fossils and have not incorporated …

oled to form dolerite dykes. Other magma was injected under pressure between horizontal sedimentary strata and cooled to form extensive horizontal sills of dolerite. This dolerite forms …

The underlying rocks are part of the western limb of the Rustenburg Layered Suite which comprises a complete differentiation sequence for a basic magma. These intrusive rocks have …

Dolerite (Jdo) sic aged dolerite represents the intrusion of magma into the volcanic Lebombo Group of rocks in the st