Friday fold: the Grand Canyon
Deep in the Grand Canyon of Arizona, Steve Mirsky found a Friday fold to share with you.
Gabion
Do you remember the blog post four years ago about documenting the doomed outcrops at Scientists’ Cliffs, Maryland? It was the site of gorgeous Miocene fossil exposures in the Calvert Formation. Here’s what the site looks like now: Photo by Peter Vogt That ugly thing at the base of the cliff is a gabion, … Read more
Parasite Rex, by Carl Zimmer
I’ve always been fascinated by parasitism. Parasites are organisms that live on or in another organism (or organisms) in a way that detracts from the vitality of the host. Nothing in nature is redder in tooth and claw than the parasite. They represent a stark repudiation of the naive way many people think of evolution, … Read more
Basaltic strata, faulting, and glaciation in western Iceland
Today, let’s journey to Iceland, to a bit northwest of Reykjavík. This is a view from the top of the Grábrók cinder cone, across the valley to the east. With very few exceptions, Iceland is a big pile of basalt, and that shows through in the walls of this valley, which display a stack of … Read more
Q&A, episode 1
A new series takes science and nature questions and answers them. Read the answers to the first two questions and submit your own!
Friday fold: Squaw Creek Schist, Idaho
The edge of ancestral North America can be found in the canyon of the Salmon River in western Idaho. Folds exposed the Squaw Creek Schist near Riggins record the stresses of adding terranes on during North America’s westward movement since the breakup of Pangaea. The Friday fold crinkled up during the accretion of a terrane to the growing North American continent.
Banded iron formation in Barberton Mountain Land
Banded iron formation is an “extinct rock” that can be found in ancient marine strata such as those found in the Barberton Greenstone Belt. Visit an outcrop on the Barberton GeoTrail and contemplate the bizarre anoxic world that Earth used to be.
An oddball at Eshaness
In eastern Shetland, the sea chews away at the innards of a Devonian stratovolcano. But there’s an odd visitor there too – and we’re not talking about the blogger.
Bucking the trend
It has been a stressful few days for the United States of America. Our President enacted a ban on people entering the country from several Muslim-majority countries, and it triggered confusion and protests at several international airports. A federal judge imposed a stay on the order, and yet Customs and Border Protection agents at Dulles … Read more
Three kids’ books
Cosmology, evolution, and ethics for the four-year old set? It can be done! Join Callan for a brief review of three excellent books for children.
Friday fold: the Bradshaw Layered Amphibolite
The Friday fold can be found along the Fall Zone, where crystalline metaigneous rocks of the Piedmont meet the gently sloping strata of the Atlantic Coastal Plain. Contemplate their high metamorphic grade and their tight folding, and imagine the mighty mountains that once rose on this spot.
Dore Holm
The scenic arch of Dore Holm (“Door Island”) in Shetland shows off the most efficient way of breaking a slab of rock. The island’s shape is a reflection of the parsimonious nature of natural deformation.
Y-shaped joints on a basalt flow, Lake Mývatn, Iceland
A basalt flow in Iceland shows both enticing pahoehoe and fractures with a Y-shaped intersection pattern. Comparisons to bread loaves and east Africa suggest a reason why.
Science policy in the Trumpocene
It looks like the Trump Administration is going to be tough on science. We all suspected that, but since Friday’s inauguration (now proclaimed by the new president as a “Day of Patriotic Devotion,” seriously taking a page from North Korea), there have been several incidents that raise serious, serious concerns. I’ve not been shy about … Read more
Friday fooled
It’s Friday, time for a … discussion of the role of misinformation in the modern media landscape and civil society? Yep, no fold this week, folks.
In honor of the Inauguration, it’s our first ever Friday Fooled.
Shear zones in Scottish gabbros
A quest to visit the “first shear zones” described in the scientific literature leads to an alternate location, and some GIGAmacro images of samples from the real, original spot.
Friday fold: Smaull Graywacke at Saligo Bay, Islay
On the western coast of Islay, Saligo Bay showcases turbidites of the Neoproterozoic Colonsay Group. The Smaull Graywacke shows Caledonian (late Ordovician) folding and cleavage superimposed on world-class graded bedding. There’s also a nice dolerite dike to examine.
More Messengers from the Mantle
Since I showed off the 3D kimberlite intrusion breccias yesterday, I feel as if I owe you some other photos from that lovely exhibit at the IGC. I apologize for the poor quality of these photos – the gorgeous samples were behind glass and brightly lit, which made photography difficult. But the rocks are sooooooooo … Read more
Two kimberlite intrusion samples presented in 3D model format
While in Cape Town for the 35th meeting of the International Geological Congress in August/September, I was delighted at the “Messengers from the Mantle: Craton Roots and Diamonds” exhibit on kimberlites. It was a world-class collection of excellent specimens that traveled to the Congress from across the city at the University of Cape Town. I … Read more
Friday fold: helicopter and anticline in the Yukon
The Friday fold is airborne over the Yukon Territory’s border with the Northwest Territories, high up in Canada’s Mackenzie Mountains. Helicopter for scale.