11th CGS Field School - Mapping the Gariep Belt

And so, finally we have completed another highly successful CGS Field School. This was arguably the most grueling and challenging field school yet. It all came to an end where our team set out to map in the Gariep fold and thrust belt. This of course represents a period spanning the existence of the Supercontinents' Rodinia and Gondwana. Read more about the Gariep Belt here.

Rocks

The team was split into three separate groups and allocated three different maps across the southern portion of the Gariep Belt. Each sheet was unique in its own right and required varying degrees of focus from the various groups. Throughout the mapping period the teams were exposed to several different rocks types characteristic of this region. Some of these include:

TL: Sheared 1,800 Ma Vioolsdrift (Richtersveld Suite) grano-diorite, note the development of spaced cleavage; TR: Magnetite-bearing quartzite of the Stinkfontein Group; ML: Kaigas diamictite with characteristic carbonate clasts; MR: Marble of the Hilda Subgroup; BL: Sheared Numees diamicitite; BR: Iron stone of the Jakkalsberg Member of the Numees.

Tectonics

For those who took the time to hike and closely examine the rocks, there was a continuous sense of dejavu. This was of course due to the continuous repetition of the Gariep sequence. This duplication allowed the team to really consider the tectonic history of this region. 

The tectonics characterises the period after Rodinia broke up, and in the process, formed the mighty Adamastor Ocean; and eventually the growth of Gondwana. This ocean could somewhat be synonymous to the present-day Atlantic, separating the Kalahari (KC) and Rio de la Plata (RC) Cratons. It was within the Adamastor Ocean where much of the Gariep rocks were deposited.

Imagination, and some walking is needed - But, after some time you may begin to exist in a strange space-time continuum bubble where you begin to visualise everything.

Tectonic inversion c. 555 Ma saw the RC and KC encroach, closing the Adamastor Ocean and eventually culminating with the RC accreting atop the KC during the formation of Gondwana. Several structural features were also seen characterising this event:

TL: Fault breccia within Numees diamictite; TR: Pseudotachylite development along the frontal thrust zone; BL: What was the Kaigas diamicitite, now highly deformed schist; BR: Mylonite developed along thrust zone.

Life

Another great thing about spending time in the Richtersveld is interacting with the local people, and clearing your troubled mind in vast and endless landscape.

Sometimes the roads are long and tough. Only for you to discover that this is only half the journey.

Sometimes you chose the easiest path home. Only to discover this means walking over isoclinally folded carbonates interlayered with thrust-bounded phyllite.

But, there's a story to be founded...

And history to be uncovered...

And, some crazy weather to Moer you

Come the third day of battle, look to the East!

And you'll find yourself sad to leave, because you've left a part of yourself behind...

11th CGS Field School Day 1

The 11th annual CGS field school kicked off this week. The participants were visibly excited and couldn't wait to get going. The day started with the group crossing the Transvaal and Karoo Supergroups and entering the Barberton Supergroup. They are currently living on the Komati River with no reception, but they are definitely loving life.

Matome, had this to say: "...field school is the most amazing thing that I've ever done in the CGS, I am learning so much about rock fabrics and mineral identification. I would recommend the field school for any young aspiring geologist..."

The group of 2016 ready to get going

11th Annual CGS Field School

Once again it's nearly that time of the year when the Council for Geoscience (CGS) hosts it's annual geological field school. This year will be the 11th installment of the CGS field school and the organising team is going all out to ensure that the 2016 participants experience the best of South African geology, while being exposed to the fundamental principles of field-based geological observations and interpretations.

Overview of the 11th CGS Field School 2016

South Africa has exceptional geological exposures that provide important evidence of the intricate workings of the early Earth, the origins of Life and of course, an extensive array of economical mineral commodities. The 2016 CGS Field School will aim to expose the participants to much of this with a trip across South Africa.

Notable geological features that will be visited include: 

The Barberton Greenstone Belt - here we will discuss the Archean Earth and how did it function, how was early continental crust created and we will look for early evidence of life. We will also have a two-day mapping exercise across a notable highly strained region and look for evidence supporting early Earth theories.

The Pongola Supergroup - one of the earliest volcano-sedimentary sequences that likely formed atop a continental platform, at a time where much of the Earth was still producing Greenstone Belts. What implications does this region have for the workings of the early Earth?

The Karoo Supergroup - this covers more than two thirds of the surface area of South Africa and hosts some of the world's largest coal reserves and potentially vast shale gas. This is also hosts a significant Permian vertebrate fossil record.

We will also have a mapping exercise of the Gariep Supergroup, in the Gariep Belt, see: Geology of the Gariep Belt and for our participants, do see: Things to Bring

This is just some of the geology we will encounter, for more of the geology we expect to cover, see: (CGS Field School 2015 Day 1&2); and (CGS Field School Day 3-5) and follow us for regular updates about the CGS Field School 2016 edition!