Honours Field School

The Honours Field School is an important part in the training of 4^th year geology students at Rhodes University. It is run in April/May as a 6 weeks module including preparation time, a two weeks field course in the Western and Northern Cape Provinces, and time set aside for subsequent thin section petrography and report writing.

A significant part of the Field School costs are covered by a generous donation from Remote Exploration Services. Without these funds we would not be able to run the field school in its current form and the Department of Geology is very grateful for this support.

The focus of Honours Field School is the development of field skills with emphasis on lithological and structural mapping at 2-5 km² scale. Although lithological and structural maps are part of the final product the field school aims to develop essentially to develop descriptive and analytical skills at exposure scale including the classification and interpretation of rocks and structures in terms of the geological environment in which they have formed. In addition, grid mapping and stream sediment sampling is part of the course. More details about the course content and course assessment can be found in the Honours Field School Guide‌.

Exercises include the collection of meaningful structural data using the geological compass, documentation of data and observations in annotated 3D sketches, stereonets, maps and cross sections, and their further assessment in written form. The kinematic analysis and interpretation of shear structures from the brittle field to granulite facies ductile shearing is an important component of the course.

Anticline in the Bokkeveld Group near Meiringspoort	View to the west from Gamsberg (Aggeneys)	Swartoup Hills mapping area

Field work is carried out in three different geological environments:

1. The Cape Fold Belt, where slates, siltstones and quartzites of the Cape Supergroup underwent folding and thrusting under greenschist facies conditions.
2. The lithologically variable amphibolite facies rocks of Bushmanland Group at Aggeneys, which experienced polyphase contractional deformation during the Namaqua Orogeny between ~1250 and 1000 Ma.
3. Metabasites, diatexites, marbles, calc-silicate rocks and granites and magmatic breccias of the Arribees Group in the Swartoup Hills (central Namaqua Belt). The region shows granulite facies metamorphism and deformation at peak and retrograde conditions including high-temperature mylonites and deformation in presence of melt.

In addition we will undertake a grid mapping exercise and collect stream sediment samples for later chemical analysis and evaluation. The aim of these exercises is the training of field work routines and descriptive and analytical skills that are needed for successful mineral exploration in a variety of crustal settings.

In addition to the mapping exercises the Field School visits a number of geologically important sites in the Namaqua belt such as:

• “Steep structures” associated with mafic and ultramafic mineralised dykes in the O’okiep copper district
• Historic copper mines at Concordia
• Gossans associated with the Gamsberg zinc deposit
• Late- to post-Namaquan pegmatites near Kakamas.

Student performance is assessed via practical test assignments in the field and by a short report that is produced after the return to Grahamstown. The report is submitted in the format of a professional research paper. Students are encouraged to follow recommendations made in the Report Guide‌ which may help to improve the report quality.