Middle Cambrian stromatolites high in the Canadian Rockies

FIELD, BRITISH COLUMBIA, CANADA–Our study group was fortunate to meet Whitey Hagadorn (Amherst College and Denver Museum of Natural History) and Sally Walker (University of Georgia) for a hike to an exposure of stromatolites in the Pika Formation (Middle Cambrian) near Lake Helen and Lake Katherine in Banff National Park. A stromatolite is a finely-laminated sedimentary rock produced by mats of cyanobacteria in a shallow sea collecting and trapping thin layers of sediment. They are relatively common features in Precambrian sediments (the oldest of fossils, in fact) and become significantly more rare in younger rocks (although they are still around today). These Cambrian stromatolites are interesting because of what they can tell us about Cambrian marine conditions, including tidal dynamics, bioturbation, and grazing herbivore pressures.

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Stromatolites exposed as domal structures in this eroding outcrop of the Pika Formation (Middle Cambrian) above Helen Lake in Banff National Park.

A natural cross-section of the Pika Formation stromatolites showing their laminated nature and sediment which has accumulated around their heads.

A natural cross-section of the Pika Formation stromatolites showing their laminated nature and sediment which has accumulated around their heads.

A hardground (light unit) exposed in cross-section in the sediment between stromatolite heads.  This is a layer of carbonate sediment which was cemented on the seafloor and then eroded by currents.  The dark sediment was deposited later on top of the scoured surface.  The hardground layer had been previously burrowed when still soft.

A hardground (light unit) exposed in cross-section in the sediment between stromatolite heads. This is a layer of carbonate sediment which was cemented on the seafloor and then eroded by currents. The dark sediment was deposited later on top of the scoured surface. The hardground layer had been previously burrowed when still soft.

Beautiful folds in the rocks above the Pika Formation stromatolites.  They are nearly recumbent in some parts.  I'll leave their interpretation to my structural geologist colleagues Sam Root and Shelley Judge!

Beautiful folds in the rocks above the Pika Formation stromatolites. They are nearly recumbent in some parts. I'll leave their interpretation to my structural geology colleagues Sam Root and Shelley Judge!

A marmot on the banks of Helen Lake.  Not at all camera shy, this little guy.

A marmot on the banks of Helen Lake. Not at all camera shy, this little guy.

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Mt. Stephen Trilobite Beds (Middle Cambrian)

FIELD, BRITISH COLUMBIA, CANADA–After a very steep and long climb, our little field party visited another restricted quarry of famous Middle Cambrian fossils: the Mt. Stephens Trilobite Beds. Charles Walcott also collected from this site when he was working on the Burgess Shale. The fossiliferous unit is about a million years old (more or less) than the Burgess Shale itself, and it has a rather different fauna dominated by large trilobites. One of the most exciting new ideas is that these fossils may represent an ancient cold seep community associated with methane degassing from the sediments.

Our Canadian guide (and paleontologist) Paul McNeil and our trip leader Matthew James in the Mt. Stephen Trilobite Beds Quarry.

Our Canadian guide (and paleontologist) Paul McNeil and our trip leader Matthew James in the Mt. Stephen Trilobite Beds Quarry.

A view from the Mt. Stephen Trilobite Beds down the mountain to Field and the Trans-Canada Highway. Note the steepness.  Nearly did me in!

A view from the Mt. Stephen Trilobite Beds down the mountain to Field and the Trans-Canada Highway. Note the steepness. Nearly did me in!

Trilobites in the Mt. Stephen Trilobite Beds. (I know -- I should have had a Canadian quarter for scale!)

Trilobites in the Mt. Stephen Trilobite Beds. (I know -- I should have had a Canadian quarter for scale!)

A beautiful complete trilobite. Very common here.

A beautiful complete trilobite. Very common here.

An appendage of one of the most famous Middle Cambrian fossils: Anomalocaris. The Mt. Stephen Trilobite Beds also have soft-bodied preservation.

An appendage of one of the most famous Middle Cambrian fossils: Anomalocaris. The Mt. Stephen Trilobite Beds also have soft-bodied preservation.

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The wondrous Burgess Shale

FIELD, BRITISH COLUMBIA, CANADA–I stepped on Paleontological Holy Ground when I visited the Burgess Shale earlier this week. It is often cited as the most important fossil locality ever. I felt the historical as well as the scientific vibrations in the Walcott Quarry, the site where the extraordinary Charles Walcott began his explorations of the unit in 1909.

The Walcott Quarry of the Burgess Shale.

The Walcott Quarry of the Burgess Shale.

There are numerous websites illustrating the famous Burgess Shale Fauna. I’ll just share some of the favorite fossils I found. (We could pick up and examine any fossil, but collecting, of course, is strictly forbidden.)

The humble sponge Vauxia. I like the less charismatic taxa in the Burgess Shale. The fancy arthropods get plenty of love!

The humble sponge Vauxia. I like the less charismatic taxa in the Burgess Shale. The fancy arthropods get plenty of love!

The primitive mollusc Scenella on the left and a trilobite on the right. The Burgess Shale fauna has plenty of skeletonized fauna along with the soft-bodied forms.

The primitive mollusc Scenella on the left and a trilobite on the right. The Burgess Shale fauna has plenty of skeletonized fauna along with the soft-bodied forms.

This is an odd breccia at the base of the Burgess Shale. The white parts are limestone fragments and the black is calcite. This may be an indication of carbonate hardgrounds -- features I study.

This is an odd breccia at the base of the Burgess Shale. The white parts are limestone fragments and the black is calcite. This may be an indication of carbonate hardgrounds -- features I study.

It is a tradition among paleontologists to pose with Charles Walcott at his famous quarry! I lack the knickers, though.

It is a tradition among paleontologists to formally pose with Charles Walcott at his famous quarry. I lack the knickers, though, and that certain set of jaw.

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The Walcott Quarry of the Burgess Shale on a beautiful day

FIELD, BRITISH COLUMBIA, CANADA–We have a small group of seven people for this expedition organized by Matthew James of Sonoma State University in California. Everyone is from California except me (although I was invited through my California roots). Our guide to the Walcott Quarry didn’t show up yesterday morning, so we joined a much larger group from Chevron — an interesting and productive mix of industry professionals and academics. Here is a movie of our exploration in the quarry:

Our Burgess Shale group.  Clockwise starting with the guy in the orange shirt: Matthew James, Howard Adams, Rebecca Perlroth, Mark Wilson, Bob Rubin, Bob Davies, Kurt Burmeister.

Our Burgess Shale group. Clockwise starting with the guy in the orange shirt: Matthew James, Howard Adams, Rebecca Perlroth, Mark Wilson, Bob Rubin, Bob Davies, Kurt Burmeister.

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Wooster geologist at the Burgess Shale

FIELD, BRITISH COLUMBIA, CANADA–I’ve been waiting to write those words! More later when I get better wireless access. The summary: my colleagues and I successfully made the long hike to the Walcott Quarry of the famous Middle Cambrian Burgess Shale today (5.5 hours to get there); it rained all morning, and then the sun appeared in time to dry out the outcrop before we arrived; we saw many wonderful fossils on this iconic outcrop.

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Walcott Quarry of the Burgess Shale in the lower right, with Emerald Glacier and Mount Wapta in the background. Stunning in all respects!

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Outcropedia

Check out the blogpost on Outcropedia, a digital repository for field-based online activities. What a great resource for taking virtual field trips!

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Saying Goodbye to 6 Weeks in Ephraim, Utah

Ephraim, Utah.  July 27.

Today, I’m spending most of the day packing rocks, field equipment, and personal belongings in order to get ready to fly out of Salt Lake City tomorrow. Leaving Ephriam most summers is often bittersweet. I’m excited to get back to Wooster to begin analyzing all of the data that was collected this summer. However, I am also amazed that the 6 weeks out here has come to an end so soon. Hiking all day long while mapping and collecting data for stratigraphic and structural projects is good for my soul and always works to rejuvenate me as a geologist. So, naturally, a part of me wants to remain out here and continue to explore the geology of central Utah, a region of geologic complexity and intrigue. Responsibilities in Wooster await, and I’m sure that Phil and Bill are as eager as I am to begin sifting through their Senior I.S. data. Wooster, here I come!!

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Operation Fossil Find (Top Secret and Classified)

Gunnison Plateau, Utah. July 26. Phil and Bill both left Utah a few days ago, with Phil flying to visit family in Colorado and Bill continuing his WooCorps job. So, I have a few days to myself to do some reconnaissance work for future I.S. projects for students and research projects for myself. I headed off to Rock and Dry Canyons with the OSU field camp. Although that was the area for their final mapping project, Terry Wilson (OSU’s structural geologist and field camp director) put me to work using my Brunton for the day. Both she and I had previously spent quite a bit of time measuring joints, veins, and stylolites at Rock and Dry for a structural analysis of the area, but a few days earlier, she came across some additional structural features. I spent a day out in the field measuring in order to determine if this would be a worthwhile addition to the structural research we already completed in the area.

Here is a view of the north-facing slope in Dry Canyon.  If you look closely, you can see the Flagstaff Limestone outlining the presence of a monocline in the area.

Here is a view of the north-facing slope in Dry Canyon. If you look closely, you can see the Flagstaff Limestone outlining the presence of a monocline in the area.

The above photo illustrates one of the conjugate vein sets that I spent the day measuring in the Jurassic Twist Gulch Formation. Measuring these conjugate vein sets perhaps next summer would add to our structural interpretation of the area.

While out at Rock and Dry Canyons, Terry stumbled upon a gorgeous vertebrate jaw embedded in a rather large block of the Colton Formation. So, the next day, we set out on “Operation Fossil Find”, the mission coined by one of the OSU TAs, Jason Kabbes. A group of us drove back to Rock and Dry Canyons, and the excavation began.

The photo above is the jaw that was found in the Colton Formation.  None of us out here are paleontologists, so naturally, we are still trying to identify the find.  By far, Terry's discovery is the best fossil that I've seen in the Colton Formation.

The photo above is the jaw that was found in the Colton Formation. None of us out here are paleontologists, so naturally, we are still trying to identify the find. By far, Terry's discovery is the best fossil that I've seen in the Colton Formation.

Operation Fossil Find team members are trying to strategize how best to remove the jaw and vertebrate bones.  All we had as tools were our trusty rock hammers and a 1/4" chisel.  But, the guys successfully removed the jaw from a piece of float, and it is now sitting in our Ephraim apartment, awaiting identification.

Operation Fossil Find team members are trying to strategize how best to remove the jaw and vertebrate bones. All we had as tools were our trusty rock hammers and a 1/4 inch chisel. But, the guys successfully removed the jaw from a piece of float, and it is now sitting in our Ephraim apartment, awaiting identification.

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All in a Day’s Fun: The Thistle Landslide, Alta Stock, Bingham Canyon Copper Mine, and the Wasatch Fault

Near Salt Lake City, Utah. Research Day 13 (July 22).

The Ohio State field camp was going on a day trip to see some great geology near Salt Lake City, so the Wooster gang decide to join them once again. Last field trip, we had a singular focus: to study the thrust sheets associated with the Sevier Orogeny. However, this field trip was different, because the goal was to see as much geology in the Salt Lake City region as was humanly possible in one day. And, 14 hours later, we succeeded in seeing a spectacular landslide, an impressive intrusion, one of the largest open pit mines in the world, and the famous Wasatch Fault.

View of the 1983 Thistle landslide, which has a depth of 60 m and initially blocked the canyon and associated Spanish Fork River.  The costs to "correct" damage caused by the landslide approached ~$200 million.

View of the 1983 Thistle landslide, which has a depth of 60 m and initially blocked the canyon and associated Spanish Fork River. The costs to "correct" damage caused by the landslide approached ~$200 million.

After the Thistle landslide, we headed toward Spanish Fork, Utah, where triangular facets are exposed along this segment of the Wasatch Fault at the mouth of the canyon.

After the Thistle landslide, we headed toward Spanish Fork, Utah, where triangular facets are exposed along this segment of the Wasatch Fault at the mouth of the canyon.

Phil and Bill seemed to enjoy Albion Basin, which was our next stop of the day.  Albion Basin, at the head of Little Cottonwood Canyon, is the location of exposures of the Alta stock.  The stock, a granodiorite, was intruded into sedimentary rocks in the area.  As a result, there is evidence for contact metamorphism that can be mapped from unique mineral assemblages.

Phil and Bill seemed to enjoy Albion Basin, which was our next stop of the day. Albion Basin, at the head of Little Cottonwood Canyon, is the location of exposures of the Alta stock. The stock, a granodiorite, was intruded into sedimentary rocks in the area. As a result, there is evidence for contact metamorphism that can be mapped from unique mineral assemblages.

After driving down from the Albion Basin, we stopped at the mouth of Little Cottonwood Canyon to view the glaciated U-shaped valley.

After driving down from the Albion Basin, we stopped at the mouth of Little Cottonwood Canyon to view the glaciated U-shaped valley.

Believe it or not, the view at the mouth of Little Cottonwood Canyon is accessible from a "geologic view park".  Land at the mouth of the canyon was donated, and a series of educational signposts describe the bedrock geology, regional glaciation, the Wasatch Fault, and the terraces of Lake Bonneville.  Bill and Phil are shown at the geologic view park relaxing and waiting for us to go to our next stop.

Believe it or not, the view at the mouth of Little Cottonwood Canyon is accessible from a "geologic view park". Land at the mouth of the canyon was donated, and a series of educational signposts describe the bedrock geology, regional glaciation, the Wasatch Fault, and the terraces of Lake Bonneville. Bill and Phil are shown at the geologic view park relaxing and waiting for us to go to our next stop.

Our next stop was the famous Bingham Canyon Copper Mine, where copper, molybdenum, gold, and silver (just to mention a few) are mined daily.  We were able to tour the visitor's center, watch a short video on Kennecott Copper's mining operations, and spend some time peering down into Earth's largest man-made excavation.

Our next stop was the famous Bingham Canyon Copper Mine, where copper, molybdenum, gold, and silver (just to mention a few) are mined daily. We were able to tour the visitor's center, watch a short video on Kennecott Copper's mining operations, and spend some time peering down into Earth's largest man-made excavation.

For our last stop of the day, the group invaded someone's backyard to look at one of the best exposures of the Wasatch Fault in the Provo area.  In this photo, we are all huddled at the fault surface, examining slickenlines, slickenfibers, and fault breccia.  Luckily, I was able to collect several samples to use as test specimens for this year's structure exams!

For our last stop of the day, the group invaded someone's backyard to look at one of the best exposures of the Wasatch Fault in the Provo area. In this photo, we are all huddled at the fault surface, examining slickenlines, slickenfibers, and fault breccia. Luckily, I was able to collect several samples to use as test specimens for this year's structure exams!

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A Day on Pleasant Island

Tree
The Woo crew in front of one of the larger cedars we found.

Today we took a skiff over to Pleasant Island to core some older cedars. Our guide and captain for the day was Wayne, an archeologist in the area. We found many huge and old cedar trees after a relatively easy hike to the site. Colin managed to get many cores to bolster his chronology for his IS.

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Dr. Wiles and Wayne help secure the skiff after landing on Pleasant Island.

Coring
Wayne looks on as Dr. Wiles and Kelly core a large, old and dead cedar. The cedar remain standing long after death.

Also interesting was a dendroarchaeological point of interest: we found several cedar that had their bark stripped by (we think) the Tlingit. Colin’s careful analysis will help us to know the year it was stripped for sure.

Adze
A dead yellow cedar that has had its bark stripped. Wayne thinks the markings were likely made by an adze.

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