The Ebe-Khaya dike belt 400 km long has been found in the north of the
Siberian Platform. Within this belt, two types of magma - tholeiite-b
asalt and alkaline olivine-basalt - are associated in space and follow
each other in time. The tholeiite magma produced Lower Triassic doler
ite sills and dikes. They were involved in the development of trap syn
eclises and are typically platform formations. Subsequent development
of the Yenisei-Khatanga and Lena-Anabar troughs caused melting at grea
ter depths to form an alkaline olivine-basalt melt which produced firs
t dikes of trachydolerite porphyrites as well as dikes and stock-like
bodies of monzonite-porphyries. It is believed that magmatic activity
ceased in the Lower Jurassic.