Advertisement

You are browsing the archive for south africa Archives - Mountain Beltway.

25 May 2017

Chert-slab conglomerate from the Fig Tree Group, Barberton

Deep in the Archean, things suddenly got violent in the deep water of the Mapepe Formation’s oceanic setting. What was a quiet precipitation of chert suddenly was torn apart and tumbled downslope. Was an earthquake to blame? A bolide impact? This is the result.



Read More >>

No Comments/Trackbacks >>


1 May 2017

Accretionary lapilli from Archean volcanic eruptions

Volcanic “hailstones” called accretionary lapilli rained down on South Africa 3 billion years ago, and have survived to be seen in the present day, along the R40 road through Barberton Mountain Land, near the Bulembu border crossing into Swaziland.



Read More >>

1 Comment/Trackback >>


10 March 2017

Friday fold: Sheba Mine sample

When touring the geology of the Barberton Greenstone Belt last August, our group visited the Sheba Mine, a gold mine high in the hills. Their geologist kindly showed us around and allowed us to visit his history-laden office. I have no idea where this sample originated, but it was the only fold I saw in the place, nestled between sepia-toned photographs and old lanterns and rusty picks. I wonder what …



Read More >>

1 Comment/Trackback >>


2 February 2017

Banded iron formation in Barberton Mountain Land

Banded iron formation is an “extinct rock” that can be found in ancient marine strata such as those found in the Barberton Greenstone Belt. Visit an outcrop on the Barberton GeoTrail and contemplate the bizarre anoxic world that Earth used to be.



Read More >>

No Comments/Trackbacks >>


11 January 2017

More Messengers from the Mantle

Since I showed off the 3D kimberlite intrusion breccias yesterday, I feel as if I owe you some other photos from that lovely exhibit at the IGC. I apologize for the poor quality of these photos – the gorgeous samples were behind glass and brightly lit, which made photography difficult. But the rocks are sooooooooo pretty, I think you’ll enjoy viewing them just the same. Let’s start with a gargantuan …



Read More >>

No Comments/Trackbacks >>


10 January 2017

Two kimberlite intrusion samples presented in 3D model format

While in Cape Town for the 35th meeting of the International Geological Congress in August/September, I was delighted at the “Messengers from the Mantle: Craton Roots and Diamonds” exhibit on kimberlites. It was a world-class collection of excellent specimens that traveled to the Congress from across the city at the University of Cape Town. I took some photos of two specimens to make 3D models from, and my student Marissa …



Read More >>

No Comments/Trackbacks >>


28 October 2016

Friday fold: “the eye of Sauron” at Sibubule

Have a look at this week’s Friday fold – but be aware that it will be looking back!



Read More >>

No Comments/Trackbacks >>


26 October 2016

Archean meteorite impact evidence from the Fig Tree Group in Barite Valley, Barberton Greenstone Belt, South Africa

What does the sedimentary record of a giant meteorite impact look like? Turns out it is full of tsunami breccia, fine ash, hail-like spherules, and a barium-rich ocean’s crystal precipitates. Join us in the Barberton Greenstone Belt of South Africa to learn more.



Read More >>

No Comments/Trackbacks >>


24 October 2016

GIGAmacro views of komatiite

Erik Klemetti posted today at Eruptions about komatiite, which is apropos, considering I just finished imaging some samples of that ultramafic volcanic rock. Have a look at three samples from Barberton Greenstone Belt here, each from the 3.27 Ga Weltevreden Formation: Link GigaPan by Callan Bentley Link GigaPan by Callan Bentley Link GigaPan by Callan Bentley And, while we’re at it, here’s one from the Red Lake Greenstone Belt (~3.0 …



Read More >>

No Comments/Trackbacks >>


21 October 2016

Friday fold: a miniature ramp and flat

Sometimes you find big ideas in small places. Here, a South African chert boulder mimics in miniature fold and thrust belts the world over.



Read More >>

No Comments/Trackbacks >>