USC Dana and David Dornsife College of Letters, Arts & Sciences > Blog

July 30, 2014

Moving forward by retreating

Filed under: Life in Lima,Preparing for the expedition — Kathleen Ritterbush @ 11:10 pm

Hola folks at home,

It’s been a packed couple of days in Lima.

Lima is amazingly similar to Los Angeles. Outside, too many cars on too few streets. Inside, great food and great people. It’s the winter here, so mid to low 60s, also just like Los Angeles.


We each have different ambitions and hopes for the field work. We need to balance these ambitions and decide a specific set of goals for the field work. Some of us are new at this kind of collaboration and new to the language, habits, and motivations of other kinds of scientists.

It takes years to know the rocks properly. I came in 2012 wondering if there were any sponge fossils. I returned to LA with dubious results from the field, unsure of what I’d seen. In the microscope that year I slowly learned, YES! there were sponges. So I came back in 2013 to determine when the sponges arose in time, how widespread they were, and how specifically they impacted the surrounding environment.


Yesterday geochemist Josh asked me, “Here on the schematic you indicate there are 60 m of mudrocks that are useful for geochemical analyses. Why did you only sample them every 10 meters?” The answer was that I had no idea they would be any good for geochemical analyses last year, or even certainty that they were mud rocks. Now that we know that, we can sample again.

It’s surprisingly valuable to be in Lima because we are all separated from our usual distractions. We spend the entire day talking about science. Some of these are conversations we’ve been musing over all year, but haven’t had time, focus, or clarity to resolve. The result is sort of spectacular to watch, as we are all very gradually adjusting our expectations and ambitions, and getting to know each other a little better. We’re here for logistics an preparations for the field, but it’s also becoming a “retreat” for the research group to regain our focus and ambition.

We’re assertive about our expectations and requirements for the work, about our desires to see more rocks that fit each of our needs. But we know we need a synthesis, and I’ve been so pleased that everyone has been patient and thoughtful as hours of discussions turn into days. Juxtaposing our different foci gets goofy. At a restaurant tonight after Frank’s talk:

Paleontologist Kathleen: Dave, do you want some of this squid?

Paleontologist Dave: Mmmmm, cephalopods! Kathleen is our enthusiast for ammonites.

Geochemist Josh: Wait, are cephalopods mollusks!?

Paleontologist Joyce: [long incredulous stare]

Geochemist Josh: What’s the molecular weight of Tungsten!??

Running with such a diverse crowd means we can’t declare things to be “obvious.” It’s fun to be reminded of this and to remember to keep a broad perspective. The paleontologists expect everyone to understand references to the taxonomy of long-dead critters, and the geochemist points out that this is like expecting us to have currently memorized the periodic table.

Today Silvia took us to lunch at an archeology museum near the college where a few of us paid to see the exhibits of pre-Inca pottery and metal work. It was spectacular. I took a few photos for my dad, who’s a pre-Columbian art enthusiast. And it was his birthday today! After 45 minutes we needed to head to Frank’s lecture for the Peruvian Geological Society.


It was fascinating for me to watch Frank’s talk. Two years ago I gave a talk to the same society, the day after my field work. I hardly scraped together photos of my immediate field results, and I was still in the dark about the microscopic sponge evidence. I didn’t present a strong discussion to make sense of why I was here. Tonight Frank gave a thorough and compelling overview of the mass extinction, climate and chemical environmental change, and the significance of the siliceous sponge expansion. The talk had many overlapping parts with faculty audition job talks I’ve delivered lately, as Frank helps critique my presentations and he was presenting results from my last two years of work, in the context of our overall project. Over the years my relationship to the rocks, to the science, and to the intellectual camaraderie evolves, and that is a wonderful process.

A fun day, but now we’ve got another big day tomorrow. Negotiations, contemplation. We’ll go to a local ruin, I think of a pre-Incan coastal society. It’s so interesting to get a chance while we’re here and debating our science, to see these ancient structures and stretch a different part of our intellect. We have days-long conversations broken up by stretches of looking at the wonder and mystery of a far more human past.

Sleep now, more meetings and adventures and negotiations tomorrow. Adios Los Angeles, Thousand Oaks, Fairbanks, and Chicago!

Preparing the Expedition: Chicago to Lima

Filed under: Getting to Peru,Preparing for the expedition — Kathleen Ritterbush @ 3:44 pm

O’hare Airport, Chicago Illinois, 7:05 am

“…Stormy, husky, brawling,

City of the Big Sholders…”



"Cloud Gate" aka "the bean" in Chicago's Milenium Park

“Cloud Gate” aka “the bean” in Chicago’s Milenium Park

I spent the last few days hustling around Hyde Park and downtown Chicago getting ready for Peru. The last six month’s I’ve lived here as a postdoctoral researcher at the University of Chicago. I experienced my first winter, first fireflies, and at Friday’s geology department softball game against the chemists, my first mulberries!


On this expedition I’m planning to show off the work I’ve done the last few years to a gaggle of ambitious professors and collaborators bent on new research directions. As a paleontologist I look for signs of animal life, and indications of how those animals interacted with each other and with their ocean home. Two of our collaborators are chemists who study how erosion on land feeds crucial minerals to the seas, and how this changes the ocean through time.  We’re interested in how Pangea volcanically splitting apart influenced ocean chemistry, how the chemistry influenced the animals, and how the animals influenced their coastline homes.


Two hundred million years ago Pangea was splitting and an astronomical number of animals went extinct on land and in the oceans. Afterwards, dinosaurs got a good boost on land by expanding into new ecological opportunities. I spent the last few years looking at what happened in the oceans, and in addition to the usual new clams and new snails, there was a radical reorganization of which animals ruled the roost on the coasts.


Sea sponges spread out over vast areas previously occupied molluscs and crinoids, turning something that might have looked like the Florida coast into something more like the sponge meadows of the Antarctic shelf. I spent the last three years searching for their fossilized parts in the American west and Peru. When I found their tiny needles in microscope slides of rocks, I knew they were close. When I found their bodies preserved as three-dimensional blobs and sacks and vases strewn over fossilized seafloor rock layers, I couldn’t even believe my eyes. With a lot of help from professors and other grad students, I spent a few years analyzing the fossils in the lab and under the microscope, and returning to the field to look for more.


That search led to Peru, and to a remarkable professor who did her dissertation on a pack of rocks that happen to contain one of the best marine records of the Triassic/Jurassic history ever found. Several professors at University of Southern California decided to push for more funding, and now we’re on our way. It’s my job to show the chemists the rocks with the sponge fossils. It’s our job together to decide how to get more out of these rocks, how to take samples that might, after careful work in the lab, reveal what happened in the ocean 200,000,000 years ago.
In some ways I’ve been preparing for this trip since last May, when we learned our grant proposal was funded. I transformed a solo month of Peruvian field work into a scramble for materials the chemists could try out in the lab. A series of taste tests, if you will.  Now we go back together, armed with preliminary results.


We’re going to present our research at an international symposium in Lima, then head to the high Andes for two weeks. I prepared field guides for the crew, and I’m still preparing more detailed field notes for myself. Over the past year I’ve been scrutinizing almost 200 microscope slides I had made from the Peruvian samples from six different Andean mines and mountainsides. I’ve drafted schematics to represent the rocks, the fossils, and the microscopic contents. Together we’ve submitted two academic articles on the results, and I used these figures to prepare field guides for the crew.


There’s never enough time. I always want one more hour on the microscope, one more hour with my computer drafting station, one more hour to read over accounts of previous expeditions from the 1980s and 1990s. Then I export myself into the field and have only what’s in my head. This year I’m making a technological leap and using an iPad mini – my first tablet – to keep the photographs and microscope results and chemical test results at my fingertips in the field. I’m hoping the new graduate student on our team – Joyce Yeager – can show me some clever ways to use it.


I didn’t brush up on my Spanish enough, and what’s more I’ll be surrounded by the team members speaking English, which challenges my emersion. I didn’t write blog posts over the past month like I planned, and I still need to submit my research symposium abstracts for the big international meeting in October. I figure I have time for that in Houston before our Lima flight.


One last minute priority that paid off was getting physically and mentally into better shape. The cruel “polar vortex” winter, a cross country move, and time away from rocks took a toll on my motivation. After long consideration I took the plunge and joined a Dutch style Muay Thai kickboxing club. Learning to casually kick an opponent in the thigh is actually a combination of about eight sophisticated tricks of balance and rotation. Turns out it’s physically impossible to fret about job applications or impending research deadlines when someone’s about to punch me in the face. Three weeks later I’m feeling more human, and hoping my lungs do a bit better in the Andes. Academia can bring subtle isolation and stress that we each need to navigate cleverly to survive. I’ve been sparing and boxing; I’ve been getting my own big Chicago shoulders.


Cycling around Chicago's brief wonderful summer, at Buckingham Fountain

Cycling around Chicago’s brief wonderful summer, at Buckingham Fountain

I’ve been worried about the upcoming trip, and discouraged, and unsure how it will go. I know it’s going to be cold, I know I’m going to wish I’d looked at my slides differently, and I know I’m going to wish I had another week on the rocks. Every time I revisit a field site I see it with new eyes, and bringing a pack of wily senior scientists along is sure to revolutionize my perspective. I find field work so captivating because it is completely transformative. Sure I like the llamas and the food and the people and the travels, but the way a week’s passing brings a whole new outlook on science and deep time is just unbeatable. I don’t know what I’ll find, but I’m expecting the good kind of trouble.


We’re keeping a team blog too:

August 4, 2012

Craft Time! Traveling Jake Staff

Filed under: Preparing for the expedition — admin @ 1:10 am

Build your own jake staff!

A Jacob’s staff is a meter stick used for field surveying.  They vary in size and shape.  Formal ones are often a meter and a half and accomodate a compass mounted on top.  I prefer an informal jake staff design.  I like mine to be about a meter and round, with jaunty red stripes.  This size is excellent for pretending to be leading a parade or marching band or circus while trudging through the field with a pack on and one field assistant with, hopefully, a good sense of humor.

This is my first international expedition, and the first time I’m flying to my field site.  My office mate Lydia made an amazing travel jake staff that screws together like a pool cue.  It’s the envy of the paleolab and she lent it to Liz, who’s off adventuring, before I could ask.  Drat!  So I had to make my own simple last minute version.

A jake staff is especially handy for “measuring a section”.  We approach a pile of rocks as a series of layers laid down through time.  To get an idea of how much time, and in what conditions the material accumulated, the first step is just to measure and descibe the rocks themselves.  Then we look closer and closer – until we’re looking through a microscope – at clues in the rock.  So a handy jake staff is marked off in 10 centimeter stripes.

I got some 3/4 pvc and a male/female screw end adaptors.  The clerk at Home Depot was kind enough to cut it for me.  Next, a t-square to mark off the intervals, some red electrical tape, and little rubber nubs for the ends.  My labmate Scott sold me on the rubber nubs – it’s fun to toss the stick and watch it bounce away from you when you’re frustrated.  Plus the rubber nubs are easy to replace and prevent wear on the staff itself.  The finished staff, with my dog Giligan for scale:

And of course it comes apart, so it can slide into my carry on luggage:

Well that’s it for the night.  More work tomorrow!  Microscope time in the morning!  I’m guessing I’ll dream about field work tonight.

Just keep swimming…

Filed under: Preparing for the expedition — admin @ 12:57 am

Little details.  Today is full of them.  I’m under the impression that I’ll do better at altitude if I boost my cardiovascular health.  Usually I spend much of May and June in the desert collecting fossils and hiking between canyon outcrops.  Whoops.  This year I stayed home to work on a quantitative project, so I’ve been indoors and sitting in front of a computer for months!  With two weeks til the trip, I decided to get in shape the fast and “fun” way: scaling the Baldwin Hills Scenic Overlook staircase three or four times a week.

It’s a surprisingly happening spot here in south central los Angeles.  From the top of a 340 foot staircase, you get a nice view from downtown to the beach, with USC and my neighborhood as a bonus.  Weekend days, weekday mornings and evenings, the stairs are packed with people of all shapes and sizes; it’s nice to see angelenos getting some exercise.  Plus, it’s pretty humbling to be catching my breath and slowly plodding when a four year old suddenly jets past me.  After two weeks of this and some yoga, I’m feeling a little more human.  Not that I’ll be racing around in the Andes, but I should at least be able to keep upright.

We often joke that it’s easy to hike if we have rocks in front of us.  It’s so true!  If I need to climb up a mountain, or a canyon, or a hill, I might look at the top and trudge along.  If I have some rocks in front of me?  If those rocks might contain the fossils I’m looking for?  If those rocks there – just another ten feet – just five more feet – just! I get going pretty quick.  So here I’ve been, in Los Angeles, and the faster I climb the harder my brain is trying to interpret the “rocks” on these darned stairs.  Layers of concrete, layers of gravel… It will feel amazing to have actual 200 million year old rocks under my feet – and in front of my face – once again.

In the past when Dave and I have met to discuss my research, I’ve often been overwhelmed by the immensity of the tasks ahead.  To many canyons, too complex of mountain fault systems between them, two many fossils, too many questions.  Dave would lean back in his chair and say, “Remember last month when we were at Eagle Mountain, how far we got from the suburbans once Frank said which fossil to search for?  This project is just like that.  I’ve had students who look at the top of the mountain and they never can start. They just stand there saying, ‘You want me to go up there!?’  But if you just take it one step at a time…” And he’d convince me to write a proposal, or an abstract, or a paper.

Now here I am.  Last year of grad school. Near the top of the dissertation mountain.  It feels pretty good.

Talk is cheap, though.  Ask me how I feel about this next week, when the mountain is real, and it’s in the Andes.


August 2, 2012

The rocks are only going to tell you what the rocks are going to tell you.

Filed under: Preparing for the expedition — admin @ 2:25 pm

I’m going to Peru to see if its fossils are similar to the ones I’ve found in Nevada. I may as well tell you a bit about how we work, and what I found in Nevada.  Plus, it’s nice to think about Nevada fossil hunting while I’m stuck in this sweltering Los Angeles laundry mat this morning.

The rocks are only going to tell you what the rocks are going to tell you.

This simple fact of paleontological field work best characterizes our challenge in science.  It would be easy to say, “I’m going to determine what happened to bottom-dwelling marine animals after the mass extinction by studying Early Jurassic fossil crabs.”  Answering this question with fossil crabs would be difficult, however.  Crunchy though they are, crabs’ delicate exoskeletons often get smashed as layers of seafloor muck transform into sedimentary rocks over tens, thousands, millions of years. Consequently nice fossil crabs are rare, and if they occur sporadically in great numbers, one needs to wonder what particular conditions set that pile of crabs apart from others.

The rocks are only going to tell you what the rocks are going to tell you.  So, in lieu of fossil crabs, one could look for fossilized burrows made by crabs, shrimps, and similar animals.  Fossil burrows can be preserved in rocks surprisingly well.  From them we can ask general questions.  How did the size and abundance of burrow-makers change during a certain part of earth history?  Did the diversity of types and shapes of burrows change?

My advisor Dave Bottjer is well known internationally for his extensive work on fossil burrows, “trace fossils”, and what they tell us about both specific environments and grand transitions in global biology.  Here he is on a beach in San Diego, showing our paleo class some gorgeous burrows – small disturbances in the otherwise nicely layered yellow sediments.


I hit a wall early in grad school. A very large wall.  Here’s a picture of me standing on it.

This cliff is made of millions of years – about two million years – of rock formed from compressed seafloor muck.  I went to this particular cliff to study bottom dwelling shelly fossils.  “I see some pretty large snails right after the mass extinction, which is surprising.  What happened to the mollusks? How did size change in snails in the aftermath from the mass extinction?  Was it gradual or sudden?”  I spent some time in the field asking this question.  I examined the layers of rocks, made microscope slides of them, and hunted for fossils.  Sure enough I found plenty of snails – and scallops and corals and clams – but not until about 2 million years after the mass extinction. What about earlier in the Jurassic?  Where the heck were all the snails?


Apparently these rocks were not going to tell me much about snails.  I did find burrows though!  Yes, plenty of burrows.  The kind made by small shrimps that build big dividing chambered tubes deep in the muck, burrows named, “Thalassinoides”.  We name the burrow because we’re rarely sure exactly who made it, but different distinctive burrow characteristics can still be tracked.

During my first years in grad school I learned how to ask the rocks different questions.  For example, when burrows stand open, they can become filled with sand and bits and pieces of other fossils that sweep across the sea floor. The shrimp-like burrows I found in Nevada had a distinctive black, glassy color. Chert.  That’s a rock made with tons of silica – basically it’s rock made of glass or infused with bits of silica and oxygen – the parts that make up glass and the mineral quartz.  When I looked at microscope slides made from cross sections through the shrimp-like burrows, I found tons of tiny fossils!  They look like little donuts and tubes.

Sponges are filled with tiny glass needles – silica again – which usually fall apart and toss around in the sediments after the sponges die.  My shrimp-like burrows were filled with microscopic sponge bits!  So that meant there were a ton of sponges around at the time – enough sponges that their microscopic bits filled burrows covering the seafloor for over a kilometer.  Those layers of burrows became handy – I followed them in different canyons, different cliff faces, and used them to tell me I was in the right place.

It wasn’t until my third field season that I got a big break.  My friend Yadi and I were following layers of storm-smashed snail shells, trying to determine which way the current was heading.  When ancient storms kick up shells on the seafloor, they spread them across the deep, making a nice marker of an instant in geologic time. We kept finding odd mushroom and blob shaped cherty knobs interrupting the storm deposits.  It finally dawned on me, what if there were some sponges standing on the seafloor that didn’t get smashed?  What if they didn’t all get obliterated by storms and time?

The next day Yadi found them.  Sponges.  Beds of the seafloor life frozen in time, showing clusters and bunches of small sponges nestled together with a few scallops.  We couldn’t believe our luck.  Sponges rarely preserve such nice fossils – and to see the actual seafloor snapshots!

But we’re cynics, Yadi and I.  We couldn’t quite believe our eyes.  What if it was just an illusion? That day we decided to cut the trip short.  We packed up our best samples of potential sponges, drove back to California, and started analyzing them that night in the lab. Over the next two days we poured acid on them, made microscope slides, and looked at pieces of sponge under the Scanning Electron Microscope. There was no question.  These were fossil sponges.  A week later I was back in Nevada with my sidekick Amir, and we found their friends – the whole damned mountain is made of sponges!

The rocks are only going to tell you what the rocks are going to tell you.  Sometimes I go out to find snails, and I find sponges instead!  This sponge story goes deeper – and it goes around the world.  But this is enough for one blog post and my laundry’s almost dry.  Next time I’ll tell you why we’re going to Peru and what we might find.  But I’ve got to remember, even the rocks in Peru are only going to tell me certain things, and I don’t know until I go look.

Four more days

Filed under: Preparing for the expedition — admin @ 7:56 am

“Oh, shoot, is it after midnight?” I blink at my computer.  I check the calendar.  ”Oh.  Shoot.  Is today the SECOND?  of AUGUST?”

Yeah. It’s after midnight. Should I correct my abstracts and send them to my co-authors, or should I start that new blog?


Life as a grad student.  My mother tells me I’m in training to be an absent minded professor.  It’s not that I’m absent minded, exactly… it’s just that I rarely know what day it is.  I should explain.

I’m going to Peru on Monday.  Monday.  Today is… Thursday.  That leaves very few days to, say, regain conversational spanish.  I also need to do laundry, wash the dog, and order some cool bugs stuck in amber for the undergraduates to look at. When I get back from Peru, school starts.

The most outrageously valuable commodity to a grad student in my position is uninterrupted time to think.  And BOY have I been thinking.  I actually woke up this morning convinced that the statistical results I’d dreamed about were publishable because dreams are random and therefore unbiased.  I read textbooks over breakfast; I draw diagrams on the train platform; I write code in my head while I walk the dog.


Two hundred million years ago the super continent Pangea split apart in a fiery mess of volcanoes.  Resultant climate and chemical changes were bad news for any marine animals who wanted to keep the shells on their backs.  In the sea, the global mass extinction event was even worse than the more famous time all those dinosaurs died.

I want to know what happened afterwards.  If I were a snail, or a sponge, or a crab, living on the seafloor in the earliest Jurassic period, what was the ecological scene?  Did life bounce back?  Were ecosystems dominated by one particular group?   What if I were  an ammonoid, a shelled squid?  Would there be other swimmers in the water?  Drifters? Who were the winners and losers as life rebuilt?

As a PhD student at the University of Southern California I get to tackle these questions the fun way.  I go to the desert where rocks record layers of marine muck laid down in the Jurassic seas, and I look for fossils to answer these ecological questions.  People always ask me, “Do you go on digs?”   Mostly, I hit rocks with a hammer.  I carry a little whisk broom and brush things off.  My favorite places have few animals and fewer plants, so the rocks are exposed under a clear sky, ready to share their secret history.

At work in the desert.



But, as my advisor Dave always likes to say, “The rocks are only going to tell you what the rocks are going to tell you.”

That is hands-down the most crucial instruction of my grad school career.  The only hard part about what we do is deciding what rocks, and how to ask.  The rest is high adventure and midnight oil.