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.
This is my first time attending an EGU (European Geosciences Union) meeting and it’s been great. It’s a rather short trip for the distance traveled — just three nights here in Vienna, Austria — but it has been worth it. The meeting reminds me of the annual AGU meeting held every December in San Francisco, although a bit smaller.
My main motivation for traveling all this way was to give an invited talk in a session convened by Alex Whittaker, Sebastien Castelltort, and Philip Allen called Tectonics, Sedimentation, and Surface Processes yesterday morning. Jon Tennant (@protohedgehog) of the EGU blog Green Tea and Velociraptors took this photo of me (above) beginning my talk.
This talk discussed some new research a close collaborator and good friend of mine is doing comparing crystallization age (U-Pb) and cooling age ([U-Th]/He) of detrital zircons from Magallanes foreland basin (southern Chile/Argentina) sedimentary rocks. Constraining the crystallization age and cooling age of a single zircon grain provides valuable information about the sediment source area, timing of exhumation (when that mineral grain became a sedimentary particle, roughly), and whether or not the grain experienced additional heating through burial.
For this session we used these new data to highlight the recycling of sediments over ~50 million years of fold-thrust belt and foreland basin evolution. The occurrence of recycling of material in such systems has been known for decades, but these newer geo-/thermochronologic techniques can be used to determine the timing/duration of these processes more accurately. For this talk, I discussed these new data within the context of reconstructing ancient sediment-routing (or, source-to-sink) systems. For example, how might recycling of older foreland basin deposits influence our ability to use general grain-size trends to better understand system morphology (e.g., Whittaker et al., 2011)? In the spirit of sharing new ideas and preliminary results I posed more questions than answers in the talk — with the hopes of initiating discussion. I got some great feedback from people throughout the day and ended up having numerous conversations with others doing similar work. This is the whole point of conferences and makes the trip worth it.
My other motivation for attending EGU was to interact with researchers whose work I’ve been following but had not actually met in person yet. It’s great to put faces to names and to get to know people beyond their published papers.
Last month I traveled to Bremen, Germany along with the rest of the IODP Expedition 342 scientists to help sample the sediment cores we acquired from the bottom of the North Atlantic Ocean last summer. As I mentioned in a post a few weeks ago, the sampling of these archives is a key step for the expedition goals.
The video above (~8 minutes long) does a great job explaining this stage of the science. If the embedded video is not showing up go to this page: http://www.youtube.com/watch?v=J0r2u5xdS7E&feature=youtu.be
This week’s photo features a rather famous alluvial fan, the Badwater Fan just south of the tourist stop in the lowest spot in the continental United States (at -282 ft) in Death Valley National Park. The east side of Death Valley has numerous small and steep (for depositional systems) alluvial fans. These piles of sediment are aggrading as fast as they can to keep up with the basin dropping out from under them. Further evidence of the movement along the boundary fault (between the uplifting range and the downdropping basin) are the fault scarps in the photo above. Good stuff.
Here are a couple GoogleEarth snapshots of this fan.
More photos from a trip to Death and Panamint Valleys here.
I’m not sure why this event is called a sampling ‘party’, unless you considering extracting various-sized bits of mud from core several hours of day for a week to be a party. More like a sampling binge. That doesn’t mean it wasn’t a great experience, it definitely was. It was fantastic to reconnect with all the great colleagues and friends I made after two months on the JOIDES Resolution last summer. And, of course, a team of >30 scientists working in two shifts at 5-7 stations can get a lot of work done.
The sampling party is a critical component of any Integrated Ocean Drilling Project (IODP) expedition. After all, the whole point of an expedition is to acquire samples of material (sediment and/or rock) from the ocean floor and below. Although a tremendous amount of work is done on the ship as the cores are collected (see the expedition preliminary report here) the expedition itself is really just the beginning.
The overarching goal of Expedition 342 is to examine several of Earth’s climate events/transitions from the Paleogene period (~65 to 23 million years ago) at high resolution. That is, we already know quite a bit about events like the Paleocene-Eocene Thermal Maximum (PETM) and the Eocene-Oligocene transition; however, most records are at temporal resolutions that make it challenging to understand dynamics and effects at shorter timescales. These past events are like ‘experiments’ that the Earth conducted and we need to use them to better understand current, and possibly future, global change. Paleoclimatologists have been able to obtain higher resolution (thousands to tens of thousands of years) with archives from the past two million years (the Quaternary), so another way to put this is: we want to do Quaternary-style paleoclimate analysis on much older records. To make a long story short — this goal requires A LOT of samples. I’m not sure what the latest number is, but it’s something on the order of 50,000 total samples.
Although their is an overarching goal, each scientist has a specific request in terms of what time interval, and what resolution, and how much material they need. As a result, the sampling plan is highly coordinated and the cores are brought out in a systematic fashion to ensure samples are taken as efficiently as possible. (IODP staff are quite good at this.) What’s really great about the sampling party is that the entire science party pitches in. You don’t show up to get just your own samples and then take off. For example, several people on the other shift or working at another station would be taking my samples and I would be taking theirs. And the discussions during sampling were great — a mix of serious science with lots of joking around, which helped maintain some sanity while doing very repetitive tasks.
What’s next? Well, once we all get our samples into our respective labs the analysis will commence. The majority of these samples will be used to generate various isotope data that are useful as climate proxies. Others will be examining the paleobiology/paleoecology of the different types of microfossils and others still will examine ocean chemistry preserved in the sediment. I will be measuring grain size of the terrigenous (land-derived) fraction to better understand the history of the long-lived current that brought sediment to the site. I still have much work to do to get my lab fully operational and the methods perfected, but progress is being made.
Photos: Upper left — stacks of core in the refrigerator; Upper right — in the process of taking 30 cubic centimeter samples; Lower left — lobby of Bremen Core Repository; Lower right — what’s left of one of the cores after sampling. All photos taken by me with my iPhone.