Track Lighting: Dinosaur "Dance Floor" in Bolivia -- Over 5,500 Footprints

       These late Cretaceous dinosaur footprint fossils on a near-vertical outcrop in Bolivia represent at least 294 different dinosaurs (and, at least 8 species) with over 5,500 footprints.

       The paleontological site, known as Cal Orck'o, is located a few kilometers south of Bolivia's Sucre city center.

       Although, I imagine there was more chasing than dancing on this "Dinosaur Dance Floor," it is an exquisite find, uncovered in 1994, in a cement quarry. Both carnivores and herbivores are represented. This longest set of tracks is over 350 footprints! Parco Cretacio is now open to the public; 68 million years in the making!

     The tracks were likely created by a juvenile Tyrannosaurus rex, nicknamed Johnny Walker ;-).

     And these footprints were likely made by an Iguanodon.

      

      The extent of dinosaur footprints on over 25,000 square meters is being studied by Christian Myer and Martin Lockley (of Colorado Morrison Dinosaur Ridge footprint fame). The largest prints are 3 feet long.

     Tectonic uplift moved these fossil footprints to a 70 degree plus angle. Pretty wild dance party ;-).

Have you been to see the Bolivian dinosaur footprints? Have you seen dino tracks in the Connecticut River Valley or elsewhere?

Steph


{The Colorado Dinosaur Ridge footprints are quite spectacular, but are not nearly as extensive as the Bolivian tracks.}

Cryptobiotic Soil Crusts: Take Nothing but Photos and Don't Leave Any Footprints!

     The cryptobiotic soil crusts of Arches National Park, Utah, are the inspiration for this week's post. 

    Cryptobiotic soil crusts are communities of living organisms on the soil surface in arid and semi-arid ecosystems. They are found worldwide.

        Cryptobiotic soil crusts perform important ecological roles including carbon fixation, nitrogen fixation, soil stabilization, altering soil albedo and affecting germination and nutrient levels in vascular plants. 

        The "crypto" part of the name refers to the hidden nature of the crusts. The crusts form very slowly and can look like surrounding soil in the first few decades. A footprint on these soils can cause damage that may take 250 years to recover in low rainfall areas like Arches' Fiery Furnace.

     A Scanning Electron Microscope (SEM) image of this crust reveals a complex array of cyanobacteria (the bacteria formerly known as blue-green algae), lichen (see our 100th post on litmus and lichen), and mosses.

     This one-minute video shows the effect water has on part of the mosses in the cryptobiotic soil crust.

     Yes, a very delicate organism surrounds much of Delicate Arch in Arches N.P. and all over Utah. Treading lightly on marked trails will preserve these important, complex cryptobiotic soil crusts.

      Have you encountered cryptobiotic soil crust at Arches or elsewhere? May you have photos but no footprints to share. . .

      I am also curious about whether reddish-orange landscapes are more appealing to each of you than the green and blue ones. I grew up in the greener landscapes of New England (NE!) but I have learned to love the red-oranges after living in the west for more than half my life. The blue-greens are beautiful, too, of course.

Crustily and cryptically,
Steph

Arches: Delicate Arch and La Sal Mountains

Bryce: Peakaboo Trail

Zion: Near Angel's Landing Trail