Today some our team members reached new heights, literally. Here
we follow Ngqondi, Haajiera and Ndidi as they summit some of the higher peaks
within the Richtersveld, all in the name of geology. The day started relatively
simple with a short section into what’s fast becoming quite the controversy,
namely the difference between a sheared tillite, or sheared diamictite. Tillite
being a diamictite (conglomeratic rock with at least bimodal clast type)
deposited by a glacier, and a dimictite deposited by any other means. A short
section to the west of the main gravel road outside the National Park gates
would show a simple stratigaphic change from diamicite/tillite to carbonaceous shales
and dolomite, likely being part of the upper Hilda Subgroup (Wallekraal into
Dabie River formations).
Some ptygmatic folding within the Phyllite units, and the team doesn't look to phased by the altitude
Later in the day, this team then began a section through,
what they would later discover, a tectonic melange. This section involved
climbing some 500 m through a thrust stacked sequence of phyllite, dolomite and
siliclastic sediments. Several sequences were found to be repeated due to
repetitive thrusting. These thrusts were clearly marked with the presence of
thick brecciated vein quartz and an increase in the foliation. The dramatic
topography was also discovered to be as consequence to the immense thrusting in
this region with the upper peaks thrust-bounded with breccia. Lower diamicitite
and phyllite had undergone ductile shearing and developed clear shear sense
indicators. These all illustrated a top-to-the-west sense of shear, maintaining
consistency with the regional shearing direction. This was a structure-heavy
section and will really test the team’s abilities of interpreting the field
relations and illustrating it on their geological maps.
High, but Haajiera getting even higher!
After the hike the team felt good. Ndidi was asked about her
experience and said: “Haai, no this was too much…”. Rest will be well deserved
this evening, and they’ll need it before tomorrow!
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