9 August 2012

Orange oncolites from Consolation Lakes

Posted by Callan Bentley

My Canadian Rockies class and I hiked into the Consolation Lakes area from Moraine Lake, a spot in Banff National Park near Lake Louise.

At Consolation Lakes, we were greeted by glacial spalling in the distance (a boom and then the roar of ice chunks cascading down the cliffs) and a lack of grizzly bears. We had lunch, and then explored the talus. I found something odd there…

So far, they appear to be oolitic (or pisolitic / oncolitic, based on their 2 to 3 cm diameters). But there were other structures in the same rock that had an internal structure that appeared to be radially layered with texture, a sort of “thrombolitic” (branching, clotted) texture. My brain’s pattern-recognition center thought that they resembled sections through a coelomate animal:

Weird, right? Here are two more:

In this last one, note the “oncolites” looking like gobstoppers in a row (lower right) next to this monster spongey thing with the radiating branching tubules and the dark central “heart”…

Does anyone have any idea what these things are?

Are they different expressions of the same basic phenomenon? Are we looking at mega-ooids plus something else? (…and if so, what?)

My undying gratitude in exchange for a coherent and satisfying answer…