Stuck in Girdwood

August 9th, 2014

DSC_0067

Kaitlin, Nick and Dr. Wiles.

GIRDWOOD, ALASKA – The College of Wooster Tree Ring team set off for Columbia Bay Glacier this past wednesday. After arriving in Anchorage with no troubles we drove down to Girdwood to hopefully catch a helicopter with a company called Alpine Air. Unfortunately for us the Alaskan weather had some other plans in mind. Due to a storm in the Prince Williams Sound area the rain and high winds made it impossible to fly to the glacier and forced us to be grounded in Girdwood. Thanks to the hospitallity of USGS glaciologist Shad O’Neel the College of Wooster Tree Ring team was able to stay in a condo owned by his family at the base of the local ski resort in town. The group is currently on standby waiting for any break in the weather to fly to Columbia Glacier.

DSC_0090

Devils Club along the trail in Girdwood.

The storm may have prevented us from traveling to Columbia via helicopter but it did not slow us down from collecting samples. Yesterday the group hiked up in the surrounding trails around Girdwood testing out our rain gear, exploring the beautiful Alaskan area and most importantly collecting some living tree ring samples. The group plans to travel to the intertidal later today to collect some samples from  the 1964 Great Alaskan Earthquake.

DSC_0064

Kaitlin extracting a core sample from a Mountain Hemlock in Girdwood.

DSC_0116

Girdwood, Alaska.

Wooster’s Fossil of the Week: An Early Cretaceous cobble-dwelling bryozoan

August 8th, 2014

Faringdon quartz 071714One of my formative experiences as a young paleontologist was working in the Faringdon Sponge Gravels (Lower Cretaceous, Upper Aptian) of south-central England while on my first research leave in 1985. (I was just a kid!) These gravels are extraordinarily fossiliferous with sponges, brachiopods, corals, vertebrate bones, and a variety of cobbles, both calcareous and siliceous. These coarse sediments were deposited in narrow channels dominated by tidal currents with significant energy reworking and sorting the fossil and rock debris. Above is a cobble of very hard vein quartz from the Sponge Gravels. On the left end you see an encrusting bryozoan with an unusual morphology.
LhwydThe fossils of the Faringdon Sponge Gravels have been studied for a very long time. The first formal notice of them is a museum catalogue compiled by Edward Lhwyd (image above) and published in 1699. Lhwyd (1660-1709) was a Welsh natural philosopher better known by his Latinized name Eduardus Luidus. He had an unfortunate childhood being the illegitimate son of what has been reported as a “dissolute and impractical” (and poor) father. Still, he was better off than most and had schooling all the way up to Oxford (but he could not afford to graduate). In 1684 he became an assistant to Robert Plot, the Keeper of the Ashmolean Museum in Oxford. He became a great scientific traveler and collector, specializing in plants and fossils and (eventually) ancient languages of Britain. In 1691 he was appointed Keeper at the Ashmolean. His book detailing fossils of Britain (Lithophylacii Britannici Ichnographia) was published with financial assistant from his good friend Isaac Newton.
Corynella in Lhwyd plate 18This is plate 18 from Lhwyd (1699). The fossil in the upper right is the sponge Corynella from the Faringdon Sponge Gravels.

Lhwyd’s views on the origin of fossils are with describing. This is a summary from Edmonds (1973, p. 307-308):

He suggested a sequence in which mists and vapours over the sea were impregnated with the ‘seed’ of marine animals. These were raised and carried for considerable distances before they descended over land in rain and fog. The ‘invisible animacula’ then penetrated deep into the earth and there germinated; and in this way complete replicas of sea organisms, or sometimes only parts of individuals, were reproduced in stone. Lhwyd also suggests that fossil plants known to him only as resembling leaves of ferns and mosses which have minute ‘seed’, were formed in the same manner. He claimed that this theory explained a number of features about fossils in a satisfactory manner: the presence in England of nautiluses and exotic shells which were no longer found in neighbouring seas; the absence of birds and viviparous animals not found by Lhwyd as fossils; the varying and often quite large size of the forms, not usual in present oceans; and the variation in preservation from perfect replica to vague representation, which was thought to represent degeneration with time.

What is most interesting about these ideas is that they have no reference to Noah’s Flood or other divine interventions.

In 1708, Lhwyd was elected a Fellow of the Royal Society in 1708. He didn’t enjoy this privilege long for he died of pleurisy the next year at age 49.
Reptoclausa hagenowi Cretaceous England 071714Now back to the bryozoan on the Faringdon cobble. It is the cyclostome Reptoclausa hagenowi (Sharpe, 1854). It has an odd form of irregularly radiating ridges of feeding zooids (autozooids) separated from each other by structural zooids (kenozooids). I like to think (although I have no evidence) that this morphology was resistant to abrasion in the rough-and-tumble life of living on a cobble in a high-energy channel. There are few other encrusters on the outer surfaces of the Faringdon cobbles.

The next two Fossils of the Week will also be from the fascinating Faringdon Sponge Gravels.

References:

Edmonds, J.M. 1973. Lhwyd, Edward, p. 307-308. In: Gillespie, C.C. (ed.). Dictionary of Scientific Biography, 8. Charles Scribner’s Sons, New York, 620 pp.

Lhwyd, E. 1699. Lithophylacii Britannici Ichnographia. London, 139 pages.

Meyer, C.J.A. 1864. I. Notes on Brachiopoda from the Pebble-bed of the Lower Greensand of Surrey; with Descriptions of the New Species, and Remarks on the Correlation of the Greensand Beds of Kent, Surrey, and Berks, and of the Farringdon Sponge-gravel and the Tourtia of Belgium. Geological Magazine 1(06): 249-257.

Pitt L.J. and Taylor P.D. 1990. Cretaceous Bryozoa from the Faringdon Sponge Gravel (Aptian) of Oxfordshire. Bulletin of the British Museum (Natural History), Geology Series, 46: 61–152.

Wells, M.R., Allison, P.A., Piggott, M.D., Hampson, G.J., Pain, C.C. and Gorman, G.J. 2010. Tidal modeling of an ancient tide-dominated seaway, part 2: the Aptian Lower Greensand Seaway of Northwest Europe. Journal of Sedimentary Research 80: 411-439.

Wilson, M.A. 1986. Coelobites and spatial refuges in a Lower Cretaceous cobble-dwelling hardground fauna. Palaeontology 29: 691-703.

Wooster’s Fossils of the Week: An Ordovician hardground with a bryozoan and borings — and an unexpected twist

August 1st, 2014

1 Hardground Bryo Large 071514aThe view above, one quite familiar to me, is of a carbonate hardground from the Upper Ordovician Grant Lake Formation exposed near Washington, Mason County, Kentucky. We are looking directly at the bedding plane of this limestone. The lumpy, spotted fossil covering about half the surface is a trepostome bryozoan. It looks like a dollop of thick pudding plopped on the rock. In the upper left are round holes that are openings of the trace fossil Trypanites, a common boring in carbonate hard substrates.
2 Closer hdgd bryo 071514bThis closer view shows the bryozoan details in the right half. You can barely pick out the tiny pin holes of the zooecia (the tubes that contained the individual zooids) and see the raised areas called maculae, which may have assisted in directing water currents for these colonial filter-feeders. Without a thin-section or peel I can’t identify the bryozoan beyond trepostome, but I suspect it is Amplexopora. The Trypanites borings in the hardground surface are also visible.
3 Hardground oblique Ordovician sm 071514cThis oblique view brings all the elements together. The bryozoan has closely encrusted the microtopography of the hardground surface. The Trypanites borings are shown cutting directly through the limestone of the hardground. Both of these observations confirm that the hardground was cemented seafloor sediment when the encrusters and borers occupied it.
4 Cross section hdgd 071514dHere is a full cross-section view showing the borings and the draping nature of the bryozoan. Now for the twist — I’m showing the specimen upside-down! It was actually found in place with the bryozoan down, not up. This is the roof of a small cave on the Ordovician seafloor. The bryozoan was hanging down from the ceiling, and the boring organisms were drilling upwards. The true orientation of this specimen is thus —
5 Cross section hdgd right side up 071514dThe cave was apparently formed after the carbonate hardground was cemented on the seafloor. Currents may have washed away unconsolidated muds underneath the hardground, forming a small cavity then occupied by the borers and the bryozoan: an ancient cave fauna. Brett & Liddell (1978) showed similar cavity encrustation in the Middle Ordovician, and I recorded a nearly identical situation in the Middle Jurassic of Utah (Wilson, 1998). Other detailed fossil marine caves are described from the Jurassic by Palmer & Fürsich (1974) and Taylor & Palmer (1994).

I should write up this Ordovician story someday!

References:

Brett, C.E. and Liddell, W.D. 1978. Preservation and paleoecology of a Middle Ordovician hardground community. Paleobiology 4: 329– 348.

Bromley, R.G. 1972. On some ichnotaxa in hard substrates, with a redefinition of Trypanites Mägdefrau. Paläontologische Zeitschrift 46: 93–98.

Palmer, T.J. 1982. Cambrian to Cretaceous changes in hardground communities. Lethaia 15: 309–323.

Palmer, T.J. and Fürsich, F.T. 1974. The ecology of a Middle Jurassic hardground and crevice fauna. Palaeontology 17: 507–524.

Taylor, P.D. and Palmer, T.J. 1994. Submarine caves in a Jurassic reef (La Rochelle, France) and the evolution of cave biotas. Naturwissenschaften 81: 357-360.

Taylor, P.D. and Wilson. M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62: 1–103.

Wilson, M.A. 1998. Succession in a Jurassic marine cavity community and the evolution of cryptic marine faunas. Geology 26: 379-381.

Wilson, M.A. and Palmer, T.J. 1992. Hardgrounds and hardground faunas. University of Wales, Aberystwyth, Institute of Earth Studies Publications 9: 1–131.

The Bear Post

July 25th, 2014

One of the wonderful benefits of working in the wilderness is the potential for interaction with wildlife. Sometimes, we’re entertained by energetic jackrabbits. Sometimes, camels eat our lunch. Always, we keep safety at the forefront.

The British Columbia team was fortunate to see majestic bald eagles, curious stone sheep, and many (many) marmots in their natural habitat. We also saw several bears.

Most of the bears that we saw were black bears eating the fresh grass alongside the road.

Most of the bears that we saw were black bears eating the fresh grass alongside the road.

However, the very first night in the field, we saw grizzlies.

The yellow arrow is pointing to a momma grizzly and her cub. Part of our group is standing on the edge of our campsite.

The yellow arrow is pointing to a momma grizzly and her cub. Our anxious group is standing on the edge of our campsite.

We were well prepared for a moment like this. Before going to the field, we had several long discussions about bear safety. We knew that the best strategy is to avoid a confrontation. At all times, each of us carried our own bear spray, a pepper spray with a strong propellant. We also had bear bangers, fire-cracker cartridges that are launched with a pen-like launcher. One of the first things we did when we arrived in the field was practice using the bear spray and bear bangers.

The bangers worked just as they were designed when we used them that first night. We spotted the momma grizzly and her cub walking across the ridge toward our camp. They didn’t change their course after the first bear banger, so we set off another. The second banger caused them to stop, and the third startled them into running in the opposite direction. Confrontation avoided!

As an added precaution, we set up a portable electric bear fence around our tents. The gentle tick of the fence was a comfort at night.

Wooster’s Fossil of the Week: A faulted oyster ball from the Middle Jurassic of Utah

July 25th, 2014

Split oyster ball 062914I’m returning this week to one of my favorite fossil types: the ostreolith, popularly known as the “oyster ball”. These were lovingly described in a previous blog entry, so please click there to see how they were formed and some additional images. They are found almost exclusively in the Carmel Formation (Middle Jurassic) of southwestern Utah.They are circumrotatory (a fancy word for “rolling around while forming”) accumulations of small cup-like oysters along with minor numbers of plicatulid bivalves, disciniscid brachiopods, cyclostome bryozoans (see Taylor & Wilson, 1999), and mytilid bivalves that drilled borings known as Gastrochaenolites. They are nice little hard-substrate communities originally nucleated on bivalve shells (Wilson et al., 1998).

oyster ball close 062914Here is a close view of the oyster valves on the outside of the ostreolith. They are attached to similar valves below them, and it is oysters all the way to the center.

What is special about our specimen here is that it managed to obtain a fault right through its center! The chances of this happening are slim, given that they are relatively rare in the rock matrix. The faulting was probably during the Miocene related to a “left-lateral transfer zone that displaces north-south–trending crustal blocks of the eastern Basin and Range Province to the west” (Petronis et al., 2014, p. 534). This is an interesting tectonic region between the Basin and Range Province and the Colorado Plateau.

Slickenfibers 062914A close view of the fault surface shows it is a striated slickenside. The striations (called slickenlines) are parallel to the direction of movement, not that we have to guess when we look at the ostreolith itself. There are also calcitic deposits here formed during faulting called slickenfibres. These elongated crystals have tiny step-like breaks in them that show the actual direction of movement.

Another nice specimen combining paleontology and structural geology.

References:

Petronis, M.S., Holm, D.K., Geissman, J.W., Hacker, D.B. and Arnold, B.J. 2014. Paleomagnetic results from the eastern Caliente-Enterprise zone, southwestern Utah: Implications for initiation of a major Miocene transfer zone. Geosphere 10: 534-563.

Taylor, P.D. and Wilson, M.A. 1999. Middle Jurassic bryozoans from the Carmel Formation of southwestern Utah. Journal of Paleontology 73: 816-830.

Wilson, M.A., Ozanne, C.R. and Palmer, T.J. 1998. Origin and paleoecology of free-rolling oyster accumulations (ostreoliths) in the Middle Jurassic of southwestern Utah, USA. Palaios 13: 70-78.

Iron Flows and Camera Blows

July 21st, 2014

Guest Bloggers:  Sarah McGrath (’17) and Chloe Wallace (’17), both members of Team Utah 2014

 

EPHRAIM, UTAH — No longer rookie bloggers Chloe and Sarah here, coming at you from the sweet comfort of our couch in Utah. Before collecting pounds of oncolites and encountering countless kill sites, we were just two inexperienced field geologists spending our long days becoming pros with the Trimble. The Trimble is a survey grade GPS unit. We used it to map the many iron concretions throughout the Six-Mile Canyon Formation. Over the course of a day and a half we were able to map over 200 points on one single rib of the outcrop.

As you will see below it takes a truly skilled and brave geologist to be worthy of the power that is the Trimble. Lesson learned: do not forget to zip the pocket that is holding your camera as you lean over a steep cliff just to collect a single data point. Thankfully, Sarah’s camera survived the fall and still works somehow. Nikons, people! Also as Sarah was retrieving her camera she came upon some lovely iron staining that otherwise would not have been discovered. There’s always an upside!

picture 6 - 585

How to Trimble 101: This isn’t your basic car GPS.

picture 7 - 585

Seconds before Sarah dropped her camera down the side of the cliff. All in the name of science!

picture 8 - 585

The iron staining Sarah came upon while retrieving her camera at the bottom of the cliff.

picture 9 - 585

We’ve gotten too used to this view. We’re going to miss Utah! Thanks for an amazing two weeks full of scalding heat, accessibility to more Peace Tea than one human should consume, and unforgettable geology.

 

 

Oncolites and Kill Sites

July 21st, 2014

Guest Bloggers:  Sarah McGrath (’17) and Chloe Wallace (’17), both members of Team Utah 2014

 

EPHRAIM, UTAH –  Rookie bloggers, Sarah and Chloe, coming at you from beautiful Ephraim, Utah! We’ll admit early on that are blogging skills are not the most proficient, but we’re giving it a shot (mostly because we are being “strongly encouraged”). We figure plenty of enticing pictures will make up for what we are lacking.

We began a new project in the field on Thursday. We gathered data and collected oncolites in the North Horn Formation. We measured over 50 oncolites within the rock face and collected about a dozen float samples. The following day we did more oncolite work, collecting at least 150 float samples, in the Flagstaff at “Snake Ridge,” which was cleverly named by Dr. Judge after countless rattlesnake sightings. Luckily for us, we have yet to see a single snake the entire trip. Knock on wood; still one day left in the field.

Although we haven’t seen any rattlesnakes, we’ve encountered enough kill sites to last us a lifetime. At our first sighting we ran away in disgust, but by our most recent kill site we were taking creative photos with them. We suspect our friend Freddy the mountain lion may be at fault.

picture 1 - 585

The view from the North Horn Formation.

picture 2 - 585

One bag out of many of the collected oncolites at the infamous “Snake Ledge.”  Note the medical tape holding one of the oncolites together!!

picture 3 - killsite

Most recent kill site shot. Maggots don’t scare us.

picture 4 - 585

More wildlife encountered in the field. This jackrabbit kept us quite entertained for at least thirty minutes.

picture 5 - 585

Possible homestead of the one and only Freddy the mountain lion.

 

 

Wooster’s Fossils of the Week: Silicified productid brachiopods from the Permian of West Texas

July 18th, 2014

Productids ventral valves 052514The three beauties above are productid brachiopods from the Road Canyon Formation (Middle Permian, Roadian, approximately 270 million years old) in the Glass Mountains of southwestern Texas. They are part of a series we’ve done on the silicified fauna of a block of limestone we dissolved in the lab many years ago. The calcitic shells have been replaced with silica during the process of fossilization, so they can be extracted from the carbonate matrix with hydrochloric acid. This is a primary way we can see delicate parts of a fossil, like the long hollow spines above. Ordinarily these would have been lost under the usual processes of taphonomy.

The specimens are highly convex ventral valves, which are characteristic of the productid brachiopods. The long hollow spines helped distribute the weight of these brachiopods on soft and unstable substrata, like a sandy or muddy sediment. This is often called “the snowshoe effect”. Below is a diagram reconstructing productid brachiopods on a sandy substrate with their spines keeping them from sinking below the sediment-water interface.

productid diagramProductid Permian Texas 585Here is a closer view of the ventral valve exterior of one of these productid brachiopods. You can see how delicate the hollow spines are.

Productid interior ventral Permian Texas 585This is the interior of the same valve. Each spine has a hole connecting it to the inside of the shell. The mantle, which secretes the shell and has other physiological functions, extended out into each spine to build its length and possibly carry some sort of sensory abilities.

I have been unable to identify these brachiopods because of the bewilderingly large number of them described by Cooper and Grant in the 1960s and 1970s. Maybe one of our readers can give it a shot!

References:

Brunton, C.H.C., Lazarev, S.S. and Grant, R.E. 1995. A review and new classification of the brachiopod order Productida. Palaeontology 38: 915-936.

Cooper, G.A., and Grant, R.E., 1964, New Permian stratigraphic units in Glass Mountains, West Texas. American Association of Petroleum Geologists Bulletin 48: 1581-1588.

Cooper, G.A., and Grant, R.E. 1966. Permian rock units in the Glass Mountains, West Texas, In: Contributions to stratigraphy, 1966: U.S. Geological Survey Bulletin 1244-E: E1-E9.

Cooper, G.A. and Grant, R.E. 1972. Permian brachiopods of West Texas, I. Smithsonian Contributions to Paleobiology 14: 1–228. [and five other volumes]

Shiino, Y. and Suzuki, Y. 2007. Articulatory and musculatory systems in a Permian concavo-convex brachiopod Waagenoconcha imperfecta Prendergast, 1935 (Productida, Brachiopoda). Paleontological research 11: 265-275.

Hot Springs and I.S. Frenzy

July 17th, 2014

Guest Blogger:  Kelli Baxstrom (’16), member of Team Utah 2014

 

EPHRAIM, UTAH –  A week into Utah, and feelings are mixed between slight hysteria for those who continue to fall off the couch in the evening due to exhaustion and an ongoing sense of awe of the beautiful world that exists outside Ohio.

Sunday was a day off for us, and so the four of us hopped in a van with some of the OSU field camp students – including recent CoW graduate Tricia Hall – and headed to some hot springs near Spanish Fork. We smelled like sulfur the rest of the day, but the waterfall and pools were worth it!

hotspring

​Wednesday was very I.S. focused for Michael and myself. For my part, I am a double major in Religious Studies as well as Geology. So in order to meld my I.S., Dr. Judge drove me to Nephi to meet the Chairwoman of the Paiute Indian Tribe of Utah. It was very enlightening to talk to a native and political spokeswoman of the tribe, and I learned so much of political, historical and socioeconomic activity of the Paiutes for the last millennia. Dr. Judge also enjoyed the meeting - possibly more than myself – in learning all the ways that the Paiutes have lived and prospered in the areas where she has worked and researched for several years.

After Dr. Judge and I got back from Nephi, Michael and I spread out on the floor with a multitude of topographic maps of Utah trying to decide what we would like to do for I.S. At the moment, that is a prospect Michael and I irrationally believe is completely​ unattainable. But Dr. Judge has faith in us.

Hey, Team British Columbia, here’s proof that there’s some real wildlife out here in Utah…

moose

Another Perspective on British Columbia

July 17th, 2014

Guest blogger: Liz Plascencia

15 days. 22 bears. 4 bald eagles. 47 rock samples.

Wow. What a trip. I, a native Los Angeles city dwelling kid, have had the utmost pleasure of accompanying such a dynamic and energetic team of geologists to Mt. Edziza. Northern British Columbia is absolutely unreal. Far from the city lights and piercing sirens, our camp was nestled between Pillow Ridge and Tsekone Ridge. We spent a solid five days in the field collecting a variety of physical samples such as pillow lava, breccia, lapilli tuff, xenoliths, etc. We also spent a great deal of time quantitatively and qualitatively describing pillow lava from the west side of Pillow Ridge with trend and plunge measurements, vesicularity estimates, phenocrysts estimates, and horizontal and vertical measurements. Within those five days we celebrated a birthday (HAPPY BIRTHDAY MEAGEN), Canada Day, The Fourth of July, and overall triumph of a great trip.

The team observing a dyke at Second Canyon, Wells Gray Provincial Park, BC.

The team observing a dyke at Second Canyon, Wells Gray Provincial Park, BC.

Eve Cone in the distance at dusk.

Eve Cone in the distance at dusk.

Quite possibly the greatest thrill of my life, so far.

Quite possibly the greatest thrill of my life, so far.

We are back in lab for these next couple of weeks processing the rock samples from the field. I am really going to miss these two goons. Mary and Julia were the most welcoming Scots. Hopefully there will be more Dickinson College and The College of Wooster collaborations in the near future.

« Prev - Next »