Stratigraphy and age of Karoo basalts of Lesotho and implications for correlations within the Karoo igneous province. Semongkong Section.xls

The Lesotho remnant contains the type succession for Karoo low-Ti basalts of central southern Africa. The 40Ar/39Ar dating indicates that the sequence was emplaced within a very short period at about 180 Ma and consists of a monotonous pile of compound basalt lava flows which lacks significant palaeosols and persistent sedimentary intercalations. We have used geochemistry to establish a stratigraphic subdivision of the lava pile. Thin units of basalt flows, the Moshesh's Ford, Golden Gate, Sani, Roma, Letele, and Wonderkop units, with diverse geochemical character and restricted geographical distribution, are present at the base of the succession. These are overlain by extensive units of compositionally more uniform basalt, the Mafika Lisiu, Maloti, Senqu and Mothae units, which build the bulk of the sequence.

Location of this section is described in Marsh et al. (1997) AGU Geophysical Monograph, 100, 247-272.

Title of data set: Semongkong Section

This section is entirely located in the Lesotho Formation and does not go down to the Clarens Formation contact with the base of the volcanic sequence.