Linking onshore and offshore crustal features, integrating seismic and borehole data in the Gamtoos basin

The margin of the Southern Africa continent harbours the history about the fragmentation and separation of Gondwana in its basins. The integration of onshore and offshore geology is of primordial importance to understand the complete geological history and evolution of the southern African border. The study focuses on the Gamtoos Basin, where the sediment deposits on the onshore portion are generally unfossiliferous and therefore difficult to correlate with the offshore portion of the basin. In an attempt to do this, several datasets were integrated such as old 2-D seismic reflection data and borehole wells. This data, acquired by SOEKER in the 1970s was purchased from the Petroleum Agency of South Africa (PASA). Some data reprocessing involved digitization and conversion of the old seismic data from TIF format to SEG-Y format. Conventional seismic stratigraphic method (Mitchum, JR, et al., 1977) was used to identify seismic discontinuities and remarkable stratigraphic surfaces and units based on reflection configurations and facies characteristics, and ages of these surfaces were provided by well data. Seismic interpretation was first done on printed seismogram papers, and then integrated into the ‘Kingdom Suite’ software to ensure coherency at all crossing lines. Isochron and Isopach maps (using QGIS, Mirone and tools such as GMT) were created. The first results, allow us to estimate for the first time a precise age calibration of onshore deposit. Furthermore, the delimitation in 5 second-order seismic sequences along the Gamtoos Basin suggest a link between different basin filling dynamics and kinematic phases related to the opening of the Indian and Atlantic Oceans along the southern Africa margins. The study shows that the Gamtoos Basin is an essential area linking the geological histories of both East and Western parts of the Southern Africa continent

Linking onshore and offshore crustal features, integrating seismic and borehole data in the Gamtoos basin

The margin of the Southern Africa continent harbours the history about the fragmentation and separation of Gondwana in its basins. The integration of onshore and offshore geology is of primordial importance to understand the complete geological history and evolution of the southern African border. The study focuses on the Gamtoos Basin, where the sediment deposits on the onshore portion are generally unfossiliferous and therefore difficult to correlate with the offshore portion of the basin. In an attempt to do this, several datasets were integrated such as old 2-D seismic reflection data and borehole wells. This data, acquired by SOEKER in the 1970s was purchased from the Petroleum Agency of South Africa (PASA). Some data reprocessing involved digitization and conversion of the old seismic data from TIF format to SEG-Y format. Conventional seismic stratigraphic method (Mitchum, JR, et al., 1977) was used to identify seismic discontinuities and remarkable stratigraphic surfaces and units based on reflection configurations and facies characteristics, and ages of these surfaces were provided by well data. Seismic interpretation was first done on printed seismogram papers, and then integrated into the ‘Kingdom Suite’ software to ensure coherency at all crossing lines. Isochron and Isopach maps (using QGIS, Mirone and tools such as GMT) were created. The first results, allow us to estimate for the first time a precise age calibration of onshore deposit. Furthermore, the delimitation in 5 second-order seismic sequences along the Gamtoos Basin suggest a link between different basin filling dynamics and kinematic phases related to the opening of the Indian and Atlantic Oceans along the southern Africa margins. The study shows that the Gamtoos Basin is an essential area linking the geological histories of both East and Western parts of the Southern Africa continent

Earth Stewardship Science—Transdisciplinary Contributions to Quantifying Natural and Cultural Heritage of Southernmost Africa

Evaluating anthropogenic changes to natural systems demand greater quantification through innovative transdisciplinary research focused on adaptation and mitigation across a wide range of thematic sciences. Southernmost Africa is a unique field laboratory to conduct such research linked to earth stewardship, with ‘earth’ as in our Commons. One main focus of the AEON’s Earth Stewardship Science Research Institute (ESSRI) is to quantify the region’s natural and cultural heritage at various scales across land and its flanking oceans, as well as its time-scales ranging from the early Phanerozoic (some 540 million years) to the evolution of the Anthropocene (changes) following the emergence of the first human-culture on the planet some 200 thousand years ago. Here we illustrate the value of this linked research through a number of examples, including: (i) geological field mapping with the aid of drone, satellite and geophysical methods, and geochemical fingerprinting; (ii) regional ground and surface water interaction studies; (iii) monitoring soil erosion, mine tailing dam stability and farming practices linked to food security and development; (iv) ecosystem services through specific biodiversity changes based on spatial logging of marine (oysters and whales) and terrestrial (termites, frogs and monkeys) animals. We find that the history of this margin is highly episodic and complex by, for example, the successful application of ambient noise and groundwater monitoring to assess human-impacted ecosystems. This is also being explored with local Khoisan representatives and rural communities through Citizen Science. Our goal is to publicly share and disseminate the scientific and cultural data, through initiatives like the Africa Alive Corridor 10: ‘Homo Sapiens’ that embraces storytelling along the entire southern coast. It is envisioned that this approach will begin to develop the requisite integrated technological and societal practices that can contribute toward the needs of an ever-evolving and changing global ‘village’