posted on 2020-04-21, 10:51authored byJulian S Marsh, Peter R Hooper, Jakub Rehacek, Robert A. Duncan, Alasdair R. Duncan
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: Springbok
Flats
Location of Borehole RL1 (SF
samples) – S24.9367 deg; E 28.3750 deg
Location of Borehole RTL1 – S
24.4400 deg; E 29.1767 deg
Location of Borehole WD4 – S
24.6483 deg; E 28.7450 deg
Location of Borehole LB1 – S
24.8817 deg; E 28.5833 deg
Borehole TF2 – base of volcanic
sequence – 768m
Borehole TF1 – base of volcanic
sequence – 357m
All Sr-, Nd- and Pb-isotope
values are MEASURED values.