Archive for January, 2012

Wooster’s Most Beautiful Building Stones

January 31st, 2012

Wooster, OH – Volcanoclast is hosting the latest Accretionary Wedge, and since I have exactly 2 hours left until the end of January, I thought I’d post a last-minute entry. The theme is countertop geology, or more broadly, stones that are “decorative and completely detached from their origin.” My contribution is inspired by my weekly “Research Friday” routine.

Perhaps the most crucial countertop in my life is the one at the Old Main Cafe, where my Research Friday mornings begin. Photo courtesy of Matthew Gardzina.

 

While waiting on my caffeinated beverage, I admire their choice of countertop: a perthitic, alkali-feldspar-rich "red" granite.

 

Leaving Old Main, I pass the Kauke Arch (shown here packed with snow) and the Old Main patio (on the garden level below the arch), which are paved with anorthosite tiles. Photo courtesy of Matthew Gardzina.

If you look closely, you can see the striations and play of colors in the plagioclase crystals.

With my latte in hand, I make my way to the Timken Science Library.

Not only do I get to see this gorgeous granite at the Timken check-out desk, but also on the entrance floors and caps of the entryway walls.

I wonder…would my Research Friday routine be different if I weren’t an igneous petrologist?

Wooster’s Fossils of the Week: Bivalve escape trace fossils (Devonian and Cretaceous)

January 29th, 2012

It is time again to dip into the wonderful world of trace fossils. These are tracks, trails, burrows and other evidence of organism behavior. The specimen above is an example. It is Lockeia James, 1879, from the Dakota Formation (Upper Cretaceous). These are traces attributed to infaunal (living within the sediment) bivalves trying to escape deeper burial by storm-deposited sediment. If you look closely, you can see thin horizontal lines made by the clams as they pushed upwards. These structures belong to a behavioral category called Fugichnia (from the Latin fug for “flee”). They are excellent evidence for … you guessed it … ancient storms.
The specimens above are also Lockeia, but from much older rocks (the Chagrin Shale, Upper Devonian of northeastern Ohio). Both slabs show the fossil traces preserved in reverse as sediment that filled the holes rather than the holes themselves. These are the bottoms of the sedimentary beds. We call this preservation, in our most excellent paleontological terminology, convex hyporelief. (Convex for sticking out; hyporelief for being on the underside of the bed.)

The traces we know as Lockeia are sometimes incorrectly referred to as Pelecypodichnus, but Lockeia has ichnotaxonomic priority (it was the earliest name). Maples and West (1989) sort that out for us.
Uriah Pierson James (1811-1889) named Lockeia. He was one of the great amateur Cincinnatian fossil collectors and chroniclers. In 1845, he guided the premier geologist of the time, Charles Lyell, through the Cincinnati hills examining the spectacular Ordovician fossils there. He was the father of Joseph Francis James (1857-1897), one of the early systematic ichnologists.

References:

James, U.P. 1879. The Paleontologist, No. 3. Privately published, Cincinnati, Ohio. p. 17-24.

Maples, C.G. and Ronald R. West, R.R. 1989. Lockeia, not Pelecypodichnus. Journal of Paleontology 63: 694-696.

Radley, J.D., Barker, M.J. and Munt, M.C. 1998. Bivalve trace fossils (Lockeia) from the Barnes High Sandstone (Wealden Group, Lower Cretaceous) of the Wessex Sub-basin, southern England. Cretaceous Research 19: 505-509.

Wooster’s Fossil of the Week: A syringoporid coral (Lower Carboniferous of Arkansas)

January 22nd, 2012

This specimen was collected from the Boone Limestone (Lower Carboniferous) near Hiwasse, Arkansas. It is a species of Syringopora Goldfuss 1826, sometimes known as the organ-pipe coral (but not the real organ pipe coral!).

Syringoporids are tabulate corals, a group that is always colonial. The corallites (tubes that contained the individual polyps) are vertical and were connected by small horizontal tubes, through which they shared common tissue. Some colonies had hundreds of corallites and built mounds up to a meter in diameter. Syringopora is the longest-ranging genus in the family, having started in the Ordovician Period and going extinct in the Permian.

Syringopora was first described by Georg August Goldfuss (1782-1848), a German paleontologist and zoologist. (Goldfuß is the proper spelling, if I can use that fancy Germanic letter.) He earned a PhD from Erlangen in 1804 and later in 1818 assumed a position teaching zoology at the University of Bonn. With Count Georg zu Münster, he wrote Petrefacta Germaniae, an ambitious attempt to catalog all the invertebrate fossils of Germany (but only got through some of the mollusks).
Georg August Goldfuß portrait by von Adolf Hohneck (1812-1879), 1841.

References:

Girty, G.H. 1915. Faunas of the Boone Limestone at St. Joe, Arkansas. U.S. Geological Survey Bulletin 598.

Goldfuß, G.A. 1826-1844. Petrefacta Germaniae. Tam ea, quae in museo universitatis Regia Borussicae Fridericiae Wilhelmiae Rhenanae servantur, quam alia quaecunque in museis Hoeninghusiano Muensteriano aliisque extant, iconibus et descriptionibus illustrata = Abbildungen und Beschreibungen der Petrefacten Deutschlands und der angränzenden Länder, unter Mitwirkung von Georg Graf zu Münster, Düsseldorf.

Nelson, S.J. 1977. Mississippian syringoporid corals, southern Canadian Rocky Mountains. Bulletin of Canadian Petroleum Geology 25: 518-581.

Wooster’s Fossil of the Week: Marrella splendens (Burgess Shale, Middle Cambrian, British Columbia)

January 15th, 2012

The first story about this iconic fossil is the trouble I went through to get the photograph above. Our specimen of Marrella splendens is preserved in the common Burgess Shale fashion as a thin dark film on a black piece of shale. A normal photograph would show just a black rock with a grayish smudge. To increase the contrast, I coated the fossil with mineral oil and used very bright lights to capture the image. I then tweaked the contrast further with Photoshop. Curiously, a black envelope appeared around the specimen that resembles the famous dark stain found with some Burgess Shale fossils. It may be remnants of body fluids.

Before I go further, I must clarify the origins of this fossil from the Burgess Shale (Middle Cambrian) near Burgess Pass, British Columbia, Canada. I did NOT collect it. The Burgess Shale is a UNESCO World Heritage Site, so collecting there is restricted to a very small group of paleontologists who have gone through probably the most strict permitting system anywhere. I had a wonderful visit to the Burgess Shale with my friend Matthew James in 2009, and we followed all the rules. (The above is a photo of the Burgess Shale outcrop and its extraordinary setting.) Our Wooster specimen was in our teaching collection when I arrived. I suspect it was collected in the 1920s or 1930s. Marrella splendens is one of the most common Burgess Shale fossils, so no doubt there are many out there in older collections.

(Reconstruction from Stephen Jay Gould's famous Burgess Shale book titled "Wonderful Life".)

Marrella splendens is supposedly the first fossil Charles Doolittle Walcott discovered in the Burgess Shale in 1909. He called it a “lace crab”, and then later as a strange trilobite. Later work by Harry Whittington demonstrated that it was neither a crab nor a trilobite. It is likely a stem-group arthropod (near the base of arthropod phylogeny).

Marrella splendens was probably a bottom-dwelling deposit-feeder living on organic material in the seafloor sediment. There are thousands and thousands of specimens known in the Burgess Shale. They are preserved in many different angles, providing the first evidence that some sort of sedimentary mass movement was involved in the formation of this famous unit.

Walcott invented the name Marrella in honor of John Edward Marr (1857-1933). Marr was a paleontologist at Cambridge University in England. By the end of his career he was a Fellow of the Geological Society and the Royal Society, hence FGS and FRS follow his name.

Reference:

García-Bellido, D.C. and Collins, D.H. 2006. A new study of Marrella splendens (Arthropoda, Marrellomorpha) from the Middle Cambrian Burgess Shale, British Columbia, Canada. Canadian Journal of Earth Sciences 43: 721-742.

Wooster’s Fossil of the Week: A scale tree (Late Carboniferous of Ohio)

January 8th, 2012

We haven’t had a plant fossil in this blog for awhile. Lepidodendron Sternberg 1820, pictured above, is one of the most common fossils brought to me in Wooster by amateur collectors. It is abundant in the Upper Carboniferous (Pennsylvanian) sandstones, shales and coals in this area. People sometimes call them “fossil snakes” because they are cylindrical and appear to have scales. Appropriately, the extinct plants they represent are called “scale trees” (the literal meaning of the genus name). The fossil above is an external mold of the trunk of this tree-like organism.
A plant as large and complex as Lepidodendron has many distinctive components that are often found separate from each other in the fossil record. These parts were given their own scientific names and only relatively recently were reunited into the genus Lepidodendron. The specimen above, for example, is traditionally known as Stigmaria and represents the roots of Lepidodendron.

From Book 15 of the 4th edition of Meyers Konversationslexikon (1885-90; figure 10). Lepidodendron is the tall tree on the left.

Diagrams of the trunk leaf scars (from Lesquereux, 1879).

Lepidodendron was up to 30 meters high in Carboniferous forests. It was tree-like, branching at the top and with a trunk covered with leaf scars. They are often called “club mosses” but are really related to modern quillworts (Isoëtes). They reproduced by spores, probably only once before death.
Lepidodendron was named and described by Kaspar Maria von Sternberg (1761-1838), a Czech naturalist who virtually founded the field of paleobotany. He was a philosophy student at the University of Prague when he began to collect fossils, minerals and plants, most of which eventually formed the nucleus of the National Museum in Prague. Oddly enough, he was also a theologian and received ordination in the Catholic church. He gave up his churchly duties early, though, and worked as a full-time scientist at various institutions in Central Europe. His description of Lepidodendron came from his deep studies of the fossils associated with coal mines in Bohemia.

References:

Lesquereux, L. 1879. Atlas to the coal flora of Pennsylvania and of the Carboniferous Formation throughout the United States. Second Geological Survey of Pennsylvania, Report of Progress.

Sternberg, K.M., von. 1820-1838. Versuch einer geognostisch-botanischen Darstellung der Flora der Vorwelt.

Wooster’s Fossil of the Week: A Tully Monster! (Late Carboniferous of Illinois)

January 1st, 2012

We have several examples of one of the strangest fossils known: Tullimonstrum gregarium Richardson 1966 — otherwise affectionately known as the Tully Monster. The above specimen is from the Francis Creek Shale Member (Carbondale Formation) at Mazon Creek near Chicago, Illinois. Even if it wasn’t labeled this is an easy call: all Tully Monsters are from the same place!

The above diagram is from Johnson and Richardson (1969, Fig. 63). It shows just about all we know about the morphology of Tullimonstrum gregarium. It was a soft-bodied animal preserved as an outline in ironstone concretions split in half, so we usually get this long view. They have three body regions: head, trunk and tail. The head has a stalk-like proboscis with a sharp-toothed claw on the end. The anterior of the trunk has two bar organs of unknown function (you can just barely see them on our specimen). The tail has two fins.

Above is another of our Tullimonstrum specimens, this one folded inside its concretion. The transverse bar and one of the bar organs is visible.

Tullimonstrum cannot be placed in any known phylum. It may be some kind of worm (that’s always easy to say!), a mollusk, or somehow related to the arthropods, but it has no features sufficient to classify it. It looks a bit like Opabinia, a strange beast from the Cambrian with a similar clawed proboscis. We can at least say both were swimming carnivores!

The first specimen of what would become Tullimonstrum gregarium was found by an amateur collector, Francis Tully (pictured above courtesy the Field Museum). He was collecting in waste piles from strip mines near Chicago, splitting open ironstone concretions. The concretions formed around dead and decaying organisms in a shallow embayment during the Late Carboniferous. They preserved impressions and outlines of soft tissues, making the Mazon Creek Fauna a famous lagerstätte.

A charismatic fossil like the Tully Monster gets plenty of attention. One of the best visual reconstructions is on the sides of U-Haul trucks! It is also the state fossil of Illinois.

This entry is posted, by the way, on the one-year anniversary of Wooster’s Fossil of the Week. It is the 53rd in the series. Here is the very first post, which was on a gorgeous little Devonian auloporid.

References:

Johnson, R.G. and Richardson, E.S. 1969. Pennsylvanian invertebrates of the Mazon Creek Area, Illinois: the morphology and affinities of Tullimonstrum. Fieldiana: Geology 12: 119-149.

Richardson, E.S., Jr. 1966. Wormlike fossil from the Pennsylvanian of Illinois. Science 151 (3706): 75–76.