The Lesotho remnant contains the type succession for Karoo low-Ti
basalts of central southern Africa. The 40
Ar 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
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.