Thursday, August 9, 2012

Stromatolites then ... wildflowers now

Even though my blog is called In the Company of Plants and Rocks, I managed to get away with having no rocks whatsoever in the header photo for almost a year.  The problem has been fixed.  The new header features alpine wildflowers growing on two-billion-year-old metadolomite in the Snowy Range of southeast Wyoming.
Varileaf cinquefoil (yellow; Potentilla diversifolia) and alpine clover (white/pink; Trifolium dasyphyllum) in a planter of ancient metadolomite.
Fossil stromatolite and alpine clover.
The metadolomite of the Nash Fork Formation contains abundant fossil stromatolites, among the oldest records of life on earth.  Two billion years ago, these were domes and reefs made of marine algal mats and trapped sediment.  In spite of continental collision and several mountain-building episodes, the rocks have undergone only low-grade metamorphism and stromatolite structures are easy to discern.
Sparky found quite a nice fossilized stromatolite.
From Knight, S.H.  1968.  Precambrian stromatolites, bioherms and reefs in the lower half of the Nash [Fork] Formation, Medicine Bow Mountains.  Rocky Mountain Geology 7:73-116.
Several stromatolitic “reefs” of the Nash Fork Formation are well-exposed in the Snowy Range (Medicine Bow Mountains) a short distance north of US Highway 130 and east of Libby Lake.  When we were there in mid-July, the old marine reefs were brightly decorated with wildflowers.
Yellow flowers of common stonecrop (Sedum lanceolatum).
A mass of alpine phlox flowers (Phlox pulvinata).
Colorado columbine (Aquilegia coerulea) and greenleaf bluebells (Mertensia viridis; on left, click to view).
Alpine clover sprawls over remains of ancient algal mats.
Rock art of the Nash Fork Formation.
In the company of plants and rocks.  Photo by Jim LoCascio.

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7 comments:

  1. Suvrat KherAugust 9, 2012 at 11:14 AM

    very nice photos of stromatolites and wildflowers..

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    1. HollisAugust 9, 2012 at 11:34 AM

      Thanks! and later today, I'll see if I can get that paper ...

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  2. Lucy Corrander Now in Halifax!August 10, 2012 at 5:48 AM

    The geology is generally beyond me - but you give me a sense of something that is almost beyond comprehension - and of beauty. The era I live on here is mostly Jurassic. Very different atmosphere.

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    1. HollisAugust 10, 2012 at 8:30 AM

      Thanks, Lucy, for your kind comments. "almost beyond comprehension" is the perfect way to put it -- really old geology is something I can just barely put my mind around, leaving lots of room for awe and wonder.

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  3. HollisOctober 18, 2012 at 12:55 PM

    Thanks for reading ... and have a wonderful hike!

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  4. UnknownJuly 31, 2018 at 7:48 AM

    What a wonderful account of early life Hollis, before animals, before terrestrial plant life, before the oxygen was made by such algal forms and the the air and land life became liveable, protected from worst UV rays by the newly form ozone layer. I have a slice of stomatolite from Wesetern Australia, showing greenish grey algal colonies in oval like segments. Also my partner and I have recently returned from the dry Flinders Ranges. We were fortunate ti be among the first small group to enjoy a guided visit to the Ediacarian fossil site in central South Australia where new discoveries of earliest animal life almost 550-600M years old have been found and new discoveries will soon be published. (The Prof leading the paleo team of students mostly was from Univ of Calif.) Some animal impressions in the sandstone looked more like marine plants!

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    1. HollisAugust 6, 2018 at 6:51 PM

      Thanks, Eugene, for the kind Comment. We are very proud of our stromatolites. They are in such a beautiful area, the Snowy Range, and easily accessible. Wow! ... that's super exciting to go to an Ediacarian site!!

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