Tuesday, August 7, 2012

A Brief Look

Kyle Leaf

SP crater is a cinder cone volcano that exists to challenge climbers.
Getting to the top is a truly difficult task, but from the top the
lava flow is beautifully defined, and very easy to identify. Climbing
is 2 steps up, one step sliding down, but going down is like a
downhill roller-blade trip. The view from the top was amazing, making
SP crater a distinct highlight of the trip.

The Grand Canyon is big. Really, really big. I was expecting a sheer
cliff that one could look down and see a river at the bottom, with the
other side at most a few hundred yards away. But no, its bigger.
Hiking 3 miles down (and back up) the Bright Angel Trail (2,044 feet/
623 meter elevation change) was a very rewarding few hours.

I would like to thank Dr. Rice, Dr. Burkhart, and Dr. Shultz for making the experience amazing. Thanks again to Cynthia for putting the entire LPSA program together. And thanks to Aaron and Nicole for being such great staff assistants all summer. If anyone reading this has never had a NASA internship, apply now! The experience is awesome, I hope to have another like it next summer, and you should too!

Adventure through the Millennia

Tanner Hamann

For something so massive it can be seen from space, the Grand Canyon has a way of sneaking up on you. My first sight was hazy blue visible through a gap in the bushes, which took a moment for me to recognize as rocks. We kept walking and almost in a flash, the Canyon was laid out before us. Looking at all the rocks and cliffs distorted by shear distance, I had trouble believing what I was seeing. It seemed unreal, impossible that I was looking across a gulf miles wide. The blazing sun lit the canyon walls, making it even harder to distinguish the intricacies of the terrain. What I did believe was just as suddenly as the Canyon appeared, the ground ahead of us abruptly ended in a near vertical cliff. To put it mildly, heights are not my thing. My uncertainty was replaced by awe as our guides started rattling off facts about the Canyon and then delved into a lecture on the various layers forming the Canyon walls. So much history encapsulated in layers upon layer of sediment. I never could have appreciated the age and change represented by this place had there not been someone how understood this science, who spoke the language of chemistry and rock.

The Grand Canyon was definitely the largest natural formation we saw and explored, but it was only one place. As part of observing Earth analogues to Martian features, we went to multiple craters and many other sites of geological interest. I especially liked the trek to Colton Crater, since it was the first cinder volcano that I climbed to the top. An ancient explosion made that easier by pretty much reducing the steep north face to a moderate hill. It also blew away the top of the volcano, so there was an impressive crater left behind. The crater was so deep that the few people who ventured to the bottom looked barely larger than specks. Standing at the rim, I did not expect the gusts of wind that rolled over the crater’s edge. One of them actually sent me scrambling after Cynthia’s and my hats, desperately trying to grab them before they could fly away. I was not caught unawares a second time, so my focus fell more on the terrain, the striations in the crater walls, and the remnants of a miniature cinder volcano at the crater floor. Fascinating is too mild a word for this place.

I came to Arizona not sure what to expect besides sun, hours of field work, and this “dry heat” everyone keep touting as a good thing. I found all those things, but I also found an adventure that took me though millennia of history and across a variety of landscapes. I learned a lot, walked a lot, and got a glimpse into perspective of geologists, a.k.a. rock people. I doubt I will get as excited about basalt and limestone as they did, but I can appreciate the intricate story such things contain and the art of reading that story. The trip is an experience I will always remember, one of many since the summer began, and I thank Cynthia Cheung and the Lunar and Planetary Science Academy for making it all possible.

The Geologic Record

Jordan Hildebrandt

Interestingly, the Grand Canyon, for all its press, is not terrifically useful for determining specifics about a particular section in time.  The Redwall Limestone, from the Mississippian period, is about 250 meters of rock representing around 60 million years, or about 4mm of rock record for every 1,000 years.  That's not much to go on, at all.  Now, geologists can still obtain a great deal of information from these short-spanning outcrops, but it's not very good resolution.  There are sections elsewhere in the world that record much more information per unit time - a random strat column from Pakistan reveals a section with a rate of 1m per 1,000 years - 2 orders of magnitude more information about.  It's neat that the canyon samples such a large time frame - spanning billions of years, but that only means that there are heaps upon heaps of data gaps.
Gaps in the geological record are caused by periods of either loss of material or non-deposition - grains are being removed as or more quickly as they are being deposited.  Such holes in the record are known as "unconformities," in that one layer does not conform properly with the adjacent layer - there's not a fluid recording of the flow of time.
To end on a less lighthearted note, here is a joke I made up on one of the car rides:
What do you call a volcano in the Vatican?

A cardinal cinder.

Thursday, August 2, 2012

Megascopic Processes and Lessons of Continuity

Jillian E. Votava

DAY ONE: Drive from Phoenix to Flagstaff
First impression of AZ: It’s deathly hot and dry. As we drive out of the airport and head north along the highway though, we see a pleasant sight: Carnegiea gigantean>> Saguaro cacti, the giant trademarks of the desert. The drive from 1,200 ft asl to 6,900 ft asl is most noticeable through air temperature. 110°F turns steadily into 79°F as we gain 6,000+ feet in elevation. Along the highway, a remarkable shift occurs: one moment you are passing an endless sea of Saguaro, then tufts of yucca amid prickly-pear, followed by shrubs and small trees. The final leg of the drive from Sedona to Flagstaff holds the largest surprise: Pinus ponderosa>> massive pine trees dominate and tower over the road. We’ve just driven over a text-book example of a basin-and-range region that has the added “spice” of regional uplift (known as the Colorado Plateau). Ending the day with a sunset dinner at Humphrey’s Peak included the additional surprise of Aspen and Pine tree-climbing.
Sound of the day: wind through the tree leaves.

DAY TWO: Volcanic Craters
First impression of SP Crater: simple cones, “fluffy” lava flows. Classic cone-shaped volcanic hills dot the flat landscape northeast of Flagstaff and the large lava flow snakes for four miles north of this steep, rocky hill.
Sound of the day: wind across bare rocks, “clink-clink” footsteps across the 70,000 year-old basalts.
 First impression of Colton crater: rounded and eroded. Colton is a large cinder-cone volcano that was explosive and fast-lived. It is known as a hydro-volcanic crater: a rising body of magma met ground water, creating an extremely volatile mix. The “cone” part of the volcano is gone, it blew off! 500 feet deep and one mile in circumference is a large volume of solid rock to expel and one can only image what such an event would have looked like.
Fun word of the day: Palagonitic Tuff (pah-lag-on-it-ik).

DAY THREE: Crater comparisons and petrified trees
First impression of Meteor crater: “striking”, pun only slightly intended. You look across this flat landscape east of Flagstaff, seeing only a couple mesas on the horizon, and then WHAM, huge hole in the ground. Thinking about a meteor the size of a 50m by 50m building makes you panic slightly, feel small and vulnerable. This feature is a tangible analog to our rocky neighbors in the sky. Both Mars and (more so) the Moon are covered with impact craters. The “clinkery” rocks of yesterday’s crater cones are gone. Here the rims are made of loosely consolidated fragments of the strata seen in beautiful profile that make up the crater walls. All three rock formations are of sedimentary-type; they formed from consolidation of pre-existing materials and/or by precipitation in an aqueous environment.
The main point: Meteor(ites) can strike ANYWHERE; volcanic-, sedimentary-, or loose- rocks in a pile, even in the ocean! Volcanic craters occur in volcanoes, the rim is made of volcanic rocks.
Day 3 ended with a visit to a landscape known as “bad-lands”. This is when fluvial processes create a deeply incised and heavily sculpted landscape of loosely-lithified sediments within an arid environment. The water is long gone but the gullies and channels are preserved in place. The colorful pink, orange, and purple layers as well as the mud-cracked appearance of the ground tell you the area is full of clay. “Clay” is a broad category of many minerals but all have variable amounts of water (H+ and OH-) in their mineral structure. This is the Painted Desert, located within the Petrified Forest National Park. Here, large, Cretaceous tree-logs have avoided the usual route of decay and re-cycle by a sudden burial that removed them from oxygen and thus allowed their overall structure to remain intact. At some point, silica-rich waters entered the system and replaced all the carbon with an amorphous form of quartz. The original cellulose framework remained however, and today these logs have made their way back to the surface in an impressive documentation of past life. Seeing these ancient tree remains is quite an experience. A unique set of conditions tens of millions of years ago had to be met in order for us tourists to see them now. 

DAY FOUR: A natural wonder of the world
First impression: Brain-freeze…immensity, incomprehensible dimensions… You ask, “Is that real?”  Your brain does not believe your eyes, “How CAN it be that big?”15 miles across and one mile deep… “How did it form?” There is a river over there, partially hidden from view, although it’s hard to imagine the scale of time and amount of water needed to carry away such an enormous amount of material. The origin of the Grand Canyon is still debated and includes postulates of rapid uplift with fluvial incision or even the idea of a giant, catastrophic sudden release of water from an upstream ancient lake.
This calm day was spent hiking down to mile 1.5 with head up, mouth gaping, and eyes glued to the dramatic canyon walls. Below, the trail continues across a lower bench of orange strata and then dips down out of sight to the canyon floor. The most difficult part of this hike is NOT the inclined ascent but instead, not seeing around the next corner. After all, “curiosity” is what drives the field of SCIENCE.

DAY FIVE: Trip’s end at the “Day’s End”: Sunset Crater
First impression: diverse, dramatic landscape. The final trip is a pleasant visit to Sunset Crater National Monument. The short trail walks over small, pebble-sized black gravel known as “cinders”. The larger (>10cm) cinders produce a pleasing “tink” sound when stepped on. The “tinkery” noise reveals the glassy nature of these young, volcanic rocks.
Word of the day: Hornito, or spatter-cone: these are the smaller vents from which lava flowed out across the land only 900 years ago! How did the people living here feel at the time of the eruption? The creation of earth inevitably includes destruction as well. Today, life has returned in full strength to this now fertile and nutrient-rich volcanic dust. 

Final Remarks: Post-mission debrief
Geology is largely an observational science and this field excursion demanded most of these skills and all of my attention. The planetary analog focus of the trip pushed my observations to the next level: to compare and hypothesize about similar features millions of miles away on other bodies in the solar-system. I feel privileged to have participated in such an event and appreciative of all the planning that occurred to make it happen. Thanks to Dr. Cynthia Cheung, Aaron Silver, and Nicole Thom for organizing the trip. Thanks to our leaders: Dr. Patrick Burkhart, Dr. Jim Rice, Dr. Charles Shultz, Dr. Shawn Wright, and Andy Ryan.