Saturday, 29 August 2015

Chris Hartnady and Rowena Hay - Umvoto

Dr Chris Hartnady has achieved international renown in geotectonics and geodynamics, making fundamental contributions to the computer-based modelling of past and ongoing motions of the African plates, and discovering a major new plate (‘Lwandle’) in the global tectonic system. His work in the areas of integrated water resource development, monitoring and management, in addition to hydro- and geo-hazard analysis, geo-risk assessment and mitigation is widely acknowledged. He is currently Research and Technical Director at Umvoto. He and Umvoto Managing Director, Rowena Hay, generously volunteered their time and expertise on the Snake Eagle Thinking Path project. Chris tells us how they became involved.

“On 21st May 2012 I received from Anni Snyman what she described as an ‘unsolicited mail’ (we were introduced some time earlier by Eugenie Grobler), asking me for ‘…  advice on an artwork that I am planning to do in the Karoo to protect some part of it against the fracking, and also to provide a symbolic focus for the people that want to protect her from such destruction’. Thus began an email conversation that started with the Karoo Siren, fracture patterns in rocks, dolerite dykes in the Karoo, some lessons on hydrogeological terminology, and led –after a few days – to the subject of the ‘euxinic Whitehill shale’, that is to say, the black, carbonaceous shales that are the main target for shale-gas exploration in the Karoo.  I had observed, you see, that Anni’s Karoo Siren was located quite close to surface exposures of the Whitehill Formation in the Tanqua Karoo.

“We discussed the reason for its name (it contains a lot of pyrite or iron sulphide, which - when it weathers and oxidizes - gives rise to surface crusts of calcium sulphate or gypsum) and I told her that the ‘stratotype’ locality of the formation is Whitehill railway siding near Matjiesfontein. So on 25th May 2012 I sent her a Google Earth image, showing ‘ … where the N1 crosses the Whitehill outcrops around the hinge zone of the Laingsburg syncline’. And I asked ‘ … Is there also a land art opportunity here?’

“On 8th August 2014, Anni Snyman sent me a Google Earth JPEG image on which the Snake Eagle had been sketched. A few days later a Google Earth KMZ file arrived with the first layout of the geoglyph. Rowena Hay and I arrived in Matjiesfontein on 30 August, in advance of the main geoglyph party, equipped with hand-held Global Positioning System (GPS) devices, the KMZ sketch and a basic geoglyph grid plan that I had laid out. In the course of that first week’s work (31 August-5 September), we very soon discovered that locating and orienting the grid was not that easy, but in the learning process, the eastern wing of the Snake Eagle appeared on the ground, with just a few (easily remedied) glitches.

 Rowena Hay and Chris Hartnady hard at work on the Snake Eagle Thinking Path site.

 "For the next work session (2-7 November 2014), we roped in our Umvoto colleague Richard Wonnacott, trained in land surveying and one of the country’s most experienced geodesists, brought precision-geodetic GPS instruments, a theodolite and long surveyor’s tape, and laid out the framework for the body and western wing of the Snake Eagle, with the complete grid-plan then in place for the path ‘sweeping’ to begin.”

“And here we are today at the Snake Eagle Thinking Path…”

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