Sunday, November 24, 2019

Hunting the history of the Channel Islands mammoths

My visit to Santa Rosa Island back in June was just part of a larger project on Channel Islands National Park, for which I've been gathering information, researching, and writing for a number of months. Part of that work is summarizing the history of paleontological investigations, which go back well into the 19th century, and one of the most important parts of that is the history of mammoth finds on the islands. As often happens the story turned out to involve many more parts than I thought.

Sunday, November 17, 2019

Your Friends The Titanosaurs, part 18: Mendozasaurus, Microcoelus, and Mnyamawamtuka

The three guests for this entry are Mendozasaurus neguyelap from Argentina, Microcoelus patagonicus also from Argentina, and Mnyamawamtuka moyowamkia from Tanzania. Mn. moyowamkia is one of the most recent additions to Titanosauria, Me. neguyelap is a reliable sort that doesn't get a lot of publicity outside of the technical literature, and Mi. patagonicus is more or less a historical afterthought.

Sunday, November 10, 2019

Ferrisaurus sustutensis

You may have come across a reference to the Sustut dinosaur over the years. It's now been formally described as a new genus and species of leptoceratopsid dinosaur: Ferrisaurus sustutensis. Victoria Arbour, as lead author and someone who has dealt with this specimen for nigh-on fifteen years, has a personal take over at Pseudoplocephalus. For those of you playing along at home, Ferrisaurus is the first named nonavian dinosaur from British Columbia.

Sunday, November 3, 2019

At the Grand Canyon

When I left off back in October, we'd just left Flagstaff for Grand Canyon National Park. The object of my visit was to support a paleontology project at Grand Canyon National Park, including our big National Fossil Day event.

The event is over now, but you can still see things like this display put together by GIPs Diana and Klara with park staff. As usual, I was too caught up in working the event to take a lot of pictures.

Of course, people who are interested in geology hardly need to be told to go to the Grand Canyon.

Pictured: geology, as far as the eye can see.

With billions of years of geological history on display, showing evidence of everything from high-grade metamorphism, to volcanic eruptions, to sea level changes, to eolian processes, to cave formation, there's something there for just about every area of geological study. Granted, a lot of things aren't immediately accessible due to the whole "enormous canyon" factor, but even if you've only got a few hours you can visit the historic Yavapai Geology Museum and take a quick tour of the park's geological formations on the Trail of Time.

Left: entering the trail. Right: a time marker, from near the "present" end of the trail, where time is less compressed.

The Trail of Time uses a series of time markers spaced evenly along the trail, with a couple of shifts in the order of magnitude. For example, starting from the Yavapai Geology Museum, the first markers are yearly. Pretty soon, though, the markers are for every million years. As you go along, stones from the various formations are placed according to their ages.

A couple of examples. Left: a close view of the stromatolitic rock chosen to represent the Awatubi Member of the Kwagunt Formation. Right: the Sixtymile Formation is one of the most obscure units of the Grand Canyon, and actually has had its age revised significantly since the Trail opened in 2010; it's now known to be early Cambrian in age (Karlstrom et al. 2018). This particular sample bears a striking resemblance to a Nut Goodie bar.

Once you get used to the rocks, you'll become able to pick out the different formations at long distances.

As the display shows, the top four formations of the Canyon can be readily picked out. Below the Hermit Formation is the Supai Group, which is responsible for giving the underlying steep cliffs of the Redwall Limestone its red walls (it's naturally gray).

There are also many trails which offer glorious views and the opportunity to commune closely with the rocks. (Don't plan on hiking to the bottom and back up in one day, though!) I went down part of the Grandview Trail as part of a day survey.

And it certainly lives up to its name! Try identifying the upper formations using the previous image.

There's also some human geological history of the Canyon at the Grand Canyon Pioneer Cemetery, where several notable geologists and paleontologists have been laid to rest. Edwin "Eddie" McKee is the person most indelibly associated with the Canyon, having quite literally written the book on most of the sedimentary formations of the park, but there are also: Bill Breed of the Museum of Northern Arizona; John Maxson of the California Institute of Technology; Glen Sturdevant, the park's first naturalist; and David White, who described the park's plant fossils in the 1920s. Some of the species described by White are depicted on his monument.

It's a little difficult to make out the plants, but they are present in three of the four corners of White's plaque.

Just keep an eye open for wildlife...

Foggy mornings are a lot less frequent than elk.

Aphonopelma marxi (a.k.a. A. behlei) enjoying a walk on the Trail of Time.


Karlstrom, K., J. Hagadorn, G. Gehrels, W. Matthews, M. Schmitz, L. Madronich, J. Mulder, M. Pecha, D. Giesler, and L. Crossey. 2018. Cambrian Sauk transgression in the Grand Canyon region redefined by detrital zircons. Nature Geoscience 11:438–443. doi:10.1038/s41561-018-0131-7.