Wednesday, October 28, 2009

The Barnacle and The Building

Phil Bock discovered a new barnacle species in an unlikely place in 2006. He wasn’t in the typical environment for barnacles, in shallow water, but on the steps of the Old Magistrates’ Court in downtown Melbourne, Australia. The building, now managed by Royal Melbourne Institute of Technology (RMIT) University, is made of Miocene age Batesford Limestone, which was deposited in a warm, subtropical sea on the shallow waters of the inner-shelf. The Batesford is highly fossiliferous with at least 12 species known from the Old Magistrates Court walls. Bock, a retired RMIT geologist, noticed the small barnacle at the base of column and then alerted John Buckeridge, a barnacle specialist at RMIT.

The Barnacle before removal (photo used courtesy of John Buckeridge)

Buckeridge recognized the specimen as a member of the genus Tetraclitella but that it was an unusual one, which prompted a formal analysis. Tetraclitid barnacles generally live in high energy environments in the Indo-Pacific region, with 10 extant species and three known only from fossils. Because of their high energy environment, they tend not to fossilize, particularly as complete specimens. Buckeridge wrote in 2008, however, that “against all odds, [this barnacle] has survived transport to deeper, quieter conditions within a submarine slurry approximately 19 million years ago.” (Integrative Zoology, vol. 3, pg. 68-74, 2008)

Where the barnacle was found (photo used courtesy of John Buckeridge)

In order to study the barnacle, Buckeridge proposed to remove it from the structure, but he faced a problem. Under the Heritage Act of 1995, established in part to protect Melbourne’s historic buildings from urban renewal, it is illegal to remove, damage, or alter protected buildings. He knew the risks weren’t large, as it would require minimal surgery to remove the barnacle, but he still applied for a permit. He further worried that if the barnacle was reported and described someone less ethical might try to remove it.

The Old Magistrates Court (photo used courtesy of John Buckeridge)

Fortunately, Buckeridge’s request passed muster and in March 2006, under the lights and cameras of television crews, he got his barnacle, though during the final stage the edge of the fossil cracked. This was fortuitous as it facilitated a more thorough study of the fossil. The surgery left a scar 78 millimeters wide and 20 millimeters deep, which will slowly weather and fade to match the rest of the building.

The post removal scar (photo used courtesy of John Buckeridge)

Two years after obtaining his new specimen, Buckeridge published a paper formally naming it. (Zootaxa 1897, 43-52, 2008) In honor of its type locality, he dubbed the barnacle Tetraclitella judiciae. It is quite a handsome little beast and shows the importance of paying attention. You never know where you’ll find an interesting story.

Monday, October 26, 2009

Burps, Coprolites, and Puckers - GSA in Review

As with other geobloggers I had a fine and chaotic time at GSA. Here are a few fun highlights of my time in Portland.

Puckers and Pull ThroughsLidya Tarhan gave an interesting talk on enigmatic, Ediacaran biogenic structures, consisting of mostly parallel lineations extending out from a flat surface. The shapes have been dubbed “mops” for their resemblance to the famed cleaning apparatus. Ranging in size from centimeters to decimeters, the mops formed when flowing water pulled on the frond-like upper part of ubiquitous Ediacaran species, Aspidella, and then uprooted the Aspidella by its holdfasts. Tarhan referred to the mops as a unique “action shot” of the Ediacaran. Who needs digital when you have stone?

Drink UpKevin Pogue’s talk asked “Can you taste basalt in wine?” Yes and no was the answer with a caution that there is a whole lot of “fluff and BS” put out by oenophilic propagandists. He found that grapes grow in basalt-derived soils from the Azores (directly in pahoehoe) to the Canary Islands (in basalt pits) to eastern Washington (in Jory soils). Basalt’s main influence seems to be through its effect on soil and air temperatures, though his most compelling observation was that the great weight of the Columbia Plateau flood basalts made viticulture possible in eastern Washington because it depressed the land surface resulting in a warmer climate. Here’s to basalt! Cheers!

Cambrian Coprolites – Being a fan of all things coprolitic, I was excited to read of the title for Whitey Hagadorn’s talk: Cambrian coprolites. Unfortunately, he offered credible evidence that much of what people have described as Cambrian poop had not “passed through the anus of an organism.” He did propose that some of the elongated masses could be coprolites but they needed further study. Sounds like a PhD dissertation to me.

Mammoth Burps – Moving from one end of the body to the other, Felisa Smith presented a fun thought experiment on whether the Pleistocene extinction of herbivorous megafauna could have altered the climate by reducing the production of methane. Yes, was her answer with many caveat emptors. She and her colleagues found that the elimination of such big burpers as mammoths, mastodons, bison, and sloths could account for a 12.5 to 100% reduction in methane, which in turn could have contributed to causing the Younger Dryas. This certainly seems as plausible an idea as the impact theory for causing the Younger Dryas. (If you missed the Wednesday morning sessions, it wasn’t pretty as speaker after speaker trashed the evidence for an impact-induced climate change 12.9 ka.)

Quotes – I like to end with a few things I heard.

In a discussion about those who don’t believe in evolution, Kevin Padian referred to the other side’s “fake, crypto-science non-sense.”

At the same session Randy Olsen said that his biggest concern in science is the “anti-science movement.”

“Comets and Clovis and Mammoths Oh My” – title of slide by Vance Holliday

“You could probably sweep the floor here and find magnetic and carbon microspherules.” Speaker at one session on the Younger Dryas impact event

“They use primitive methods.” Todd Surovell, in reference to a question about why his data was the opposite of some unnamed researchers studying the Younger Dryas

“The client refused to pay so we sued his butt.” Wayne Isphording, in reference to a group who wanted Ishording’s lab to prove that they had real Apollo 11 soil samples. The samples were fake, and if they had been real, they would have been illegal to own.

Thursday, October 22, 2009

GSA - Portland Building Stone Update

A quick follow up to my pre-GSA Portland building stone blog. Here are a few more photos of the First Congregation Church. It is a quite handsome building. I have no idea where the stone for the columns comes from but it beautifully complements the sandstone.

Unfortunately, one of the structures I mentioned in my previous post is no longer there. The Belgium basalt cobble wall is gone, replaced by an ugly cinder block wall. Apparently the wall had cracked and become “dangerous.” I won’t add to the ugliness by posting a photo.

In contrast, I did stop by the historic central library for Multnomah County (SW 10th Ave. and SW Yamhill St.) Opened in 1917, it is a brick building with highlights of Salem Limestone. It is very rich in fossils, which stand out in places where the softer, surrounding matrix has weathered and eroded more. Plus, I was quite taken with this panel of names. A rather nice cast of scientific characters.

And finally, I also found another Morton Gneiss building, on the south side of Burnside between NW 9th and NW 8th Avenue (just a block away from Powells). Again, the building is architecturally uninspired but with gorgeous stone. This time, however, the builders chose to use a white marble with black streaks instead of limestone. I suspect it is a Vermont marble. That’s all for now.

Wednesday, October 14, 2009

Portland Building Stones for GSA

With GSA just around the corner, I thought I would highlight some of the local building stones in Portland. Most of what I will be discussing is across the river, in the downtown part of the city. The area is a short walk from the convention center and perhaps might offer a welcome diversion when you get glassy eyed during a talk or two.

I will start with some of the local stones used in buildings. One of the best showcases is the First Congregation Church on the southwest corner of Madison and Park Avenue. Started in 1880 but not completed till 1895, the church formerly had three towers, but only the 185-foot-tall one remains. The base is made of black Oregon basalt, from one of the many great Columbia Plateau basalt flows. These flood basalts, which erupted primarily from 17 mya to 15 mya, are the second most voluminous on the planet. They cover much of the Columbia Plateau, and flowed down the Columbia River basin to Portland. Outcrops of the basalt occur throughout Portland.

The First Congregational Church (from Trey Rice's Flickr account)

Nestled around the basalt, and checkerboarded with it on the south wall, is the Tenino sandstone, from quarries 20 miles south of Olympia, Washington. Streams washing across a pre-Cascades landscape deposited the sands into deltas that poured into the Pacific Ocean. Fossils found in other parts of the region show that the climate was sub-tropical with abundant growth of palms. The Tenino deposits have been dated at around 50mya. Gray-greenish in color, they provide a nice contrast to the black basalt.

Curiously, basalt cobbles are also used in a rubble wall on the block surrounded by Fourth and Fifth and Market and Mill, but the stones are not from Oregon. Instead, they are Belgian basalt used as ballast in ships that offloaded cargo at the base of Clay Street. This wall originally encased a catholic church and the parishioners wheelbarrowed the stones up from the waterfront for their building project. As Ralph Mason notes in his splendid guide to Portland’s stone (Oregon Geology Vol. 47. No. 11, which provided most of the information for this article), the devout could have gotten basalt from a nearby cliff “which is several thousand miles closer and a downhill haul.” They say that suffering builds character, and churches.

I will end with a boring building architecturally but a fascinating one geologically. Two types of widely used stone clad the building that takes up the block between Jefferson and Columbia and 6th and Broadway. What makes it interesting is the great unconformity between the base and the upper floors. The 3.5 bya Morton gneiss in all its gaudy glory covers the base and atop it sits the 330 mya Salem Limestone, both stones of which I have blogged about before.

Oregonian building (from Wikipedia)
I have focused only on the older buildings in Portland. Many new structures showcase stone from around the world. As noted at the beginning, I highly recommend a tour. Mason also wrote an earlier tour of Portland buildings for The Ore Bin, volume 27, no. 4, April 1965.

Tuesday, October 6, 2009

Bluestone and "a thousan' rattlesnakes"

The most famous building stone in New York after brownstone is another sandstone known by its color: bluestone. The term generally refers to flagstones quarried in the Hudson River Valley in central and south New York, as well as in northern Pennsylvania. What made it so popular was the sandstone’s ability to be split into slabs of consistent thickness, which could then be used most famously for sidewalks.

Classic bluestone sidewalk, on a street of classic brownstones in Brooklyn

Beginning in the early-1800s, numerous bluestone quarries opened to provide stone for New York city. According to the Jan 17, 1872 New York Times, one “Uncle Steve” Griffin, a “noted character,” found one of the earlier quarries while out on a rattlesnake smoking expedition near Westbrookville. The area was noted for rattlesnake dens and a local pastime was to “kill the venomous inmates [by] prying and smoking them out of their places of resort.”

Antique bluestone paving for sale. (From Monterey Masonry in western Massachusetts)

Griffin had located a den and inserted his crowbar when he was “astonished by the splitting of a thin, smooth slab.” The Times added “[Uncle Steve] did not attach any importance to his discovery, merely remarking when he returned home that he had “killed more’n a thousan’ rattlesnakes, and had buried ‘em under a patent grave-stone he’d found there.” He subsequently exhibited his “patent grave-stone” to others, who at once pronounced it a blue-stone quarry.” The quarry, however, wasn’t developed for 35 years, when in 1865, six barge loads were shipped to market.

The bluestone flagging went into curbs, caps, sills, and steps—called “edge stuff”—as well as street pavement. Bluestones got their name from the blue color, though the sandstone ranges from gray to green to lilac. The quantity and type of iron controls the colors with chlorite imparting green and hematite bestowing lilac. An absence of hematite, along with unaltered iron minerals generates the famous blues.

Bluestone has also been used to describe bluish limestone, particularly in the Shenandoah Valley. Good examples of this stone are found on the James Madison University Campus. Archaeologists working at Stonehenge also refer to the igneous rocks there, such as diabase and rhyolite, as bluestone.

The majority of the quarries are in Devonian rocks. In New York the rock is the Upper Walton Formation of the West Falls Group and in Pennsylvania, this group is equivalent to the New Milford Formation. The sands were deposited in a classic delta complex, of shoreline and non-marine alluvial plains dotted with lagoons and tidal flats. Quartz is the dominant mineral with a quartz cement.

One of the best single sources on the history and geology of bluestone is a report by James Albanese and William Kelly. It was published for the New York State Geological Association meeting in 1991 and contains most of the pertinent details about the rock that I used. (It can be found in the NY Geo Assn Guidebook, vol. 63, pages 191-203.)

Although the hey-day of bluestone sidewalks passed long ago, many still recognize the beauty of the stone. For example, Marbletown, a community in the Hudson Valley, recently received $3 million in federal stimulus money to build a 3/4-mile bluestone sidewalk. Now, who says that the government does not spend our money wisely?