Towers of Chalk in Kansas

  • By Ari Daniel
  • Posted 11.05.15
  • NOVA

The place we know as Kansas used to be covered by a sprawling inland sea. Millions of years ago, countless oysters lived and died there. And it was these oysters that helped shape perhaps the most dramatic feature of the Kansas landscape today.

Running Time: 01:11


Kirk Johnson: In western Kansas, a series of spectacular shapes burst up out of the plains. They’re called Monument Rocks. And the raw material for these towering structures was formed more than 80 millions of years ago by the smallest of creatures.

This place is amazing—I’ve been looking for just a few minutes, and here’s a shell. It’s an oyster shell. I’ve been finding these things all over the place. And this whole place is made out of shells. There’s really big ones, there’s small ones – even the chalk itself is made of microscopic shells.

So why are there shells here? Answer—Kansas used to be covered by a massive inland sea. Over time, the giant oysters living on the seafloor were buried by billions of tiny plankton shells as they died and fell to the bottom of the sea, layer after layer. Over millions of years, all that weight compressed them into chalk. When the sea finally drained, that chalk got left behind. Millions of years of erosion sculpted the chalk, leaving behind these curious outcrops that now surge skywards out of Kansas.



Produced by
Ari Daniel
Director of Photgraphy
Piers Leigh
Steve Roseboom
Kirk Johnson
Original Footage
© WGBH Educational Foundation 2015


Fluid Pictures


(main image: chalk towers)
© WGBH Educational Foundation 2015

Related Links