It’s been two years since we moved from California to Virginia, time flies! We really love where we live now, but there are times where I do miss California. I especially miss exploring the outcrops along the coast. Many of these wave-washed bluffs have gorgeous exposures of bed-scale sedimentary geology, a real delight for those who like sedimentary structures.
The above photo shows some Paleocene turbidites along beach cliffs in the town of Gualala, a few hours north of the Bay Area.
This photo is from the past field season in Patagonia. We wanted to get to these rocks on the other side of the river. My student eventually got there … by going ~30 km downstream to where there was a proper bridge and then driving on some gnarly roads for a couple hours. If only we had jet packs. Drones are all the rage these days … drones shmones, I want jet packs!
Summer is in full swing and this summer is all about lab work. An undergraduate researcher and I are in the midst of extracting the terrigenous (land-derived) sediment from marine sediment. We are interested in the grain-size and compositional characteristics of the terrigenous component to better understand the history of a long-lived oceanic current that transported the sediment. Isolating the terrigenous material means we have to get rid of the other components, namely the biogenic (marine microfossils made of carbonate and opal) and authigenic (metalliferous oxyhydroxides that formed in place) material. We are using this method with some tweaks from a helpful collaborator.
I have >1,000 samples from IODP Expedition 342 (see this post for more about that expedition) that will eventually be processed in this way. But, because we have not done this before and are still getting the lab fully equipped, we are currently using ‘practice’ sediment (a chunk from one of the core catchers) to fine-tune the methodology. That is, when we make a mistake — which is inevitable when learning something new — we won’t be sacrificing a ‘real’ sample. This training will pay off in a couple weeks as we ramp up and start processing samples in batches.
While we work on that two of my graduate students are busy crushing, grinding, sawing, drilling, etc. rock samples for their respective Ph.D. projects. We’ve got mineral separation underway for bedrock thermochronology, sample preparation for stable isotope measurement of carbonate rocks, and thin sections being made.
Here’s a shot of the sand dunes not far from Stovepipe Wells in Death Valley National Park from this past March. Check out this Flickr set for a whole bunch more. Happy Friday!
This week’s photo is from the deck of the JOIDES Resolution drill ship last summer. Before IODP Expedition 342 I had spent only a few days at sea, and even then it wasn’t more than ~20-30 km from land. Being out in the open ocean — several hundred km from land — was an experience I didn’t think about or appreciate before I did it.
I never grew tired of watching the sea during that two months. The interaction of swells of different sizes and forms moving in different directions resulted in unique displays of nature. And it’s quite different than watching the sea near the coast. Watching the water pile up into ‘mountains’ and ‘ridges’, creating a constantly changing topography, was actually quite therapeutic during an incredibly busy expedition.
See this photo and many more from IODP Expedition 342 on my Flickr page.
I just had to share this image that Commander Chris Hadfield, an astronaut currently on the International Space Station, posted yesterday. I really like this perspective of the Mississippi River delta. It’s nice to get a view that isn’t a standard map (north to the top and looking straight down). This slightly oblique view emphasizes how ‘delicate’ the bird’s foot part of the delta is, that the boundary between what is land and what is not is a bit blurred.
I’ll also use this post as a plug for Commander Hadfield’s Twitter feed. It’s really quite simple — he takes photos of the Earth out the window of the space station and shares them. There isn’t a link to some busy web page or other social media noise, just a beautiful photo of our planet. And he does several each day. Simple and awesome.
This week’s photo is from Panamint Valley in southeastern California (the valley to the west of Death Valley). This example of a stretched-pebble conglomerate is actually a boulder in a wash and not in place. Therefore, I’m not exactly sure of it’s age, but it’s likely from the Proterzoic Kingston Peak Formation, which crops out in the Panamint range. It’s pretty awesome to think about pebbles in a conglomerate getting deformed and stretched like this.