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What’s New at This Week’s Excavation

Monitor View
The Control Center display shows three views of Marina Elliott and Becca Peixotto at work removing fossils from the area called the Puzzle Box. (Photo by Lee Berger)

By Becca Peixotto

At the beginning of the week, Marina Elliott, Lee Berger, Peter Schmidt, and I sat in Lee’s office at Wits University studying photos from last November of the area of high density of fossils we call the “Puzzle Box.”

We set priorities for this week’s renewed excavation, imagined contingencies, reviewed equipment, and, always important for archaeologists, discussed methodology and procedures.

With any find, but particularly with one of this significance, we don’t just grab what we see willy-nilly. There is a body of theory and practice behind what we do.

Just like last November, we will still 3D scan and photograph every step of the way to ensure thorough documentation, use toothpicks and bamboo tools to limit the damage to the fossils, and bag and bring to the surface all the sediment so it can be searched in the lab for the tiniest fossil fragment and other clues about the site. However, with the benefit of hindsight and Ashley Kruger’s countless hours rendering the 3D scans, we have modified some of the procedures to make digital recreation of the excavation easier and faster. That will aid the analysis and interpretation of both individual bones and the site as a whole.

We didn’t descend into the cave until the next day, but that meeting and our afternoon visit to Rising Star left Marina and I even more excited to get back to work.

Slimmed Down, But Still Strong
John Hawks mentioned in his post earlier this week that this is a slimmed down version of the original Rising Star Expedition. We are only about ten on site at any given time: two caver/scientists, three cavers providing safety and support, one logistics guru, and two to three senior scientists and technology specialists at a mini-command center just inside the entrance to the cave.

Instead of living in a small tent city on-site, we’re commuting to the cave each day, leaving Johannesburg before daybreak (to beat the traffic), and bringing fossils back (usually through heavy traffic) to Peter in the Wits lab every afternoon.

The expedition may be smaller and more muted this time but our collective enthusiasm for the cave, for science, and for the process of discovery is as lively as it was last November: each new fossil generates oohs and aahs, cheers, and giggles of excitement.

Changes Underground
It’s not only the structure of the expedition that’s different this time around. The cave itself has changed too.

Caves like Rising Star are living, breathing geological formations and are affected by natural and human-caused changes both within the cave and above ground.

The late summer in the Cradle of Humankind this year was remarkably rainy. In karst regions like this, rainwater does not stay long on the surface in creeks or rivers. Instead it quickly seeps through cracks in the dolomite.

The potential for water to seep into the caverns through the porous rock overhead is great, and could affect the fossils below. (Photo courtesy Becca Peixotto)
The potential for water to seep into the caverns through the porous rock overhead is great, and could affect the fossils below. (Photo courtesy Becca Peixotto)

The water sometimes pools in the caves, like the chilly puddle at the narrowest squeeze in the Postbox belly-crawl. No staying dry in that one! The water may hang in the air like it does in the final chamber where there is no standing water but where the humidity registers on our air monitors at 99.9%, or the rainwater may become part of an existing drip, dissolving the dolomite and slowly depositing calcium carbonate as a stalactite or other speleothem.

It is amazing to think the constant drip-drip-drip is creating one of these beautiful features at least for this season faster than normal (it will take many, many years to notice the growth of the formations). Still, it comes as a bit of shock when a cold drip unexpectedly lands on the back of your neck while you’re busy delicately moving sediment away from a fossil.

As the water percolates through the rock, it dissolves minerals and then carries them along as it drips into open areas. The accumulating minerals form stalactites where they hang, and stalagmites where they drip to the floor. (Photo courtesy Becca Peixotto)
As the water percolates through the rock, it dissolves minerals and then carries them along as it drips into open areas. The accumulating minerals form stalactites where they hang, and stalagmites where they drip to the floor. (Photo courtesy Becca Peixotto)

Stay tuned for more updates as work in the cave begins!

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Comments

  1. Lee McLaughlin
    Barrie, Ontario Canada
    September 30, 2015, 7:28 am

    I watched the Nova/Nat Geo presentation this week about the wonderful discoveries Lee and his team have made. I was left with the question of how and why this small brained, primitive species may have buried their dead when when prior studies have concluded that more advanced and sophisticated early peoples started this behavior. Why would you conclude that it was members of this species that went to the tremendous trouble to bury them? It has been known for some time that the tree of life is “bushy”, as was said on the program. Consider that these early people could have been kept as companions; slaves or pets by a more advanced hominid species, such as we keep animals for pets or companions, exploiting them for various kinds of labor. The discovery of the owl bones almost suggests the owl being placed with the bodies as a ward or guide or other cultural significance. Or perhaps it too was a revered or loved pet as well. Also the small brain versus intelligence has been studied in birds quite extensively and one conclusion for some birds remarkable intelligence was the brain size in proportion to the overall body mass and how the brain is wired so to speak. Perhaps this newly found species of people were intelligent enough to have the spiritual beliefs and culture required to bury their dead in this way. A can of worms has been opened for me I have to say.

  2. Elen Feuerriegel
    Australia
    March 29, 2014, 10:05 pm

    Becca, this is a wonderful post. I can imagine vividly what it’s like for you and the other cavers down there at the moment. The puddle in the Post Box sounds utterly unpleasant, though! The dirt through there was so fine, too; I’ll bet it’s making some amazingly slimy mud for you to crawl through.