Tuesday, December 29, 2009

Stonesfield Slate, Fossil Exhalations, and William Buckland

The quarry area in the small town of Stonesfield, Oxfordshire, England, has been called the “best Middle Jurassic terrestrial reptile site in the world.” Stonesfield is also the place of origin for what would be the first formally described dinosaur, Megalosaurus. From my perspective, the region’s other claim to fame is the Stonesfield slate, first used in Roman times when the famous builders roofed their homes with the local rock.

Welsh naturalist Edward Lhuyd was the first to describe fossils from Stonesfield. In his 1699 Lithophylacii Britannici Ichnographica, he illustrated two teeth, one of which he described as that of a fish. Lhuyd believed that fossils formed from “exhalations which are raised out of the sea” carrying fish-spawn that got caught in chinks in the ground and became fish fossils. He added that such fossils “have so much excited our admiration, and indeed baffled our reasoning.”

But the Stonesfield didn’t become truly famous until the 1800s and the discoveries and descriptions of William Buckland. One of my all-time favorite geologists, Buckland was an ordained priest in the Church of England; notorious for eating practically everything; one of earliest professional geology instructors, at Oxford University; a fellow of the Royal Society; and the first to recognize the importance of coprolites (he coined the term). His eccentricities earned him a famous description by Charles Darwin, who wrote of Buckland: “though very good-humoured and good-natured [he] seemed to me a vulgar and almost coarse man. He was incited more by a craving for notoriety, which sometimes made him act like a buffoon, than by a love of science.” Oh Charles, don’t be so stuffy.

William Buckland

We do not know exactly when Buckland obtained his famous fossils because he failed to jot down this fact. Those who have studied the issue have put the date as no later than 1818, due to an 1824 article by Georges Cuvier. No matter when he found them, Buckland made a formal description of a lower jaw, teeth, and a huge thigh bone on February 10, 1824, at a presentation to the Geological Society in London.

Buckland ascribed his fossils to a carnivorous reptile at least forty feet long and weighing as much as an elephant. In honor of its larger-than-life size, at least larger than any known land animal, he named it Megalosaurus, the Great Lizard. Twelve years later, Richard Owen would include Megalosaurus, along with Iguanodon and Hylaeosaurus, in his new order of animals, Dinosauria.

The Megalosaurus tooth and jaw of Buckland

Curiously, the so-called Stonesfield slate isn’t slate, which makes sense considering the source rock is so fossiliferous. It is, in fact, limestone, deposited in a shallow marine environment. The bones most likely washed into the water followed by rapid burial by sand transported offshore during storm events. Other fossils found in the quarries include fish, reptiles, mammals, ammonites, bivalves, gastropods, insects, and 13 species of terrestrial plants.

Stonesfield slate from www.gowildgardening.co.uk/buildings.htm

Quarrymen split the Stonesfield slate in a rather nifty manner. Instead of using hammer and chisel, the men relied on cold weather. They would pull the limestone out of the ground (20 to 70 feet deep) in a rough block called a “pendle” and let it sit in a field and absorb water. To ensure moisture retention, the quarrymen would pile dirt atop the blocks and/or douse the stone in water. Over several cold winters, water would penetrate the bedding planes and split the stone into usable pieces. In some cases the split piece would be round and be dubbed a potlid. Builders highly prized the thin slabs of Stonesfield slate, using them in colleges at Oxford.

Recently, English researchers have taken a new look at Megalosaurus and its family Megalosauridae (Palaeontology, v. 51, no. 2, 419-424). They have concluded that the family should be discontinued because of a lack of clear evidence allying the genera that have previously been listed as Megalosauridae. The only reptile that is clearly “megalosaurid” is the one found by Buckland. Perhaps Mr. Darwin should have been more generous in his observations.

Thursday, December 17, 2009

Texas Marble...From Maryland

Someone stole my story. Well, not really. It’s mostly a wee fit of jealously at Brian Fisher Johnson, who has a first rate article on building stone in the January issue of Earth magazine. Stretching from Ballykilchine, Ireland, to the Washington Monument, the story tells of the marble quarries and quarrymen in Texas, Maryland, and their contribution to leaving “a very material impression on the face of America.”

Brian’s story focuses on an archaeological dig run by Stephen Brighton of the University of Maryland, College Park. Brighton has been studying the Irish immigrants who left Ballykilchine and traveled to a small settlement a bit north of Baltimore. By around 1860, Texas—so named for a volunteer regiment, the Texas Greens, established for the Mexican-American War—had 600 people. Brighton says that the Irish came for the calcite, in the form of marble for quarrying and limestone for burning.

Little remains from the heyday of the Irish in Texas. Little is also available in the history books, which is what led Brighton to investigate. “It’s a huge gap…in understanding the Irish diaspora,” he says. What he has been able to piece together is unusual. The Irish stayed in Texas for generations, in contrast to the more typical dispersal out from the original center.

Brighton and his students began their dig in July 2009. Their major find was a outhouse, as well as coins, a lice comb, and numerous pieces of glass. He and his students will continue to study their artifacts in order to better understand this unusual group of immigrants.

Brian reports that the value of Texas stone was reported as early as 1811. Quarrying began in 1834 with 13 quarries opened up by 1847. Geologists call the stone the “Cockeysville Marble,” for a nearby town. First deposited 500 million years ago as limestone, the white stone turned to marble around 240 million years ago during the assembly of Pangaea.

Library of Congress description “Washington Monument as it stood for 25 year,” photographed by Mathew Brady circa 1860

The color and location of the marble led it to be the first building stone of any large amount sent by rail to Washington D.C. In 1845, builders began to use the marble from Texas in the Washington Monument. They had put up 152 feet by 1854, when money ran out. Work began again in 1879, with marble from Lee, Massachusetts, but it was too costly, so the rest of the monument was finished with marble from Cockeysville, which accounts for the color change in the big edifice.

Texas marble also went into the “porticoes of the House and Senate wings of the U.S. Capitol building and the towers of St. Patrick’s Cathedral in New York City,” writes Brian. He has written a nifty story about stone once again revealing the connection between people, geology, and history.

Sunday, December 13, 2009

Quincy - The Granite City in the Globe

The Boston Globe ran two stories today about the town of Quincy (pronounced Quin-zee) and its granite-influenced past. For nearly two centuries, Quincy supplied granite to great and small buildings of Boston and beyond. These include the dry docks in Charlestown, Massachusetts, customhouses in New Orleans, Boston, and Mobile, Alabama, and the Bunker Hill Monument, a use which led to the first commercial railroad in the United States.

One story focuses on the efforts of locals to draw more attention to the importance of granite to a town once known as The Granite City. They hope to build a Quincy Quarry and Granite Workers Museum but despite a nearly two-decade old agreement to build it, they have had no luck. The story quotes Vic Campbell who said “It seems that when it comes to the Adamses, nothing that anyone can think of is too much. When it comes to the quarries, nothing is too neglectful.’’ As someone who has written about the beautiful and historical Quincy stone and its human and geologic history, I am sad to see that so many seem to not care about their past.

The second story, Of Granite, Plugs, and Feathers, tells the history of the quarries, tracing its earliest use to around 1754 and the King's Chapel, still standing in Boston. Stone was quarried not from the solid walls of rock but from boulders, which masons split by heating with fire and cracking with heavy iron balls. Not until around 1803 did a truly effective manner of quarrying come along. The plug and feather technique originated with a man known as Mr. Tarbox, who introduced the method of drilling holes in the rock and then putting a metal wedge, or plug, surrounded by two L-shaped shims, the feathers, into the hole. Hammering a row of plugs and feathers forced the stone to split apart. Tarbox's method dropped the price of split stone by 40 percent and helped launch Quincy's long history as a granite supplier.

Let's hope that these stories can help with the development of the Quincy museum. Perhaps it will also help with my push for a Slow Stone, my movement to encourage the use of locally quarried stone.

Thursday, December 10, 2009

Duke City Stone – Part 2

After visiting some of the Duke City’s less inspired buildings I want to explore a couple of structures that caught my interest not just for their stone. My favorite building is the Cathedral of St. John. I am a sucker for sandstone, especially when completed in an historical style. Austin describes the cathedral as Brick Gothic with a dash of typical Anglican. No matter what one calls it, the church is modest, simple, and grounded. I also like the cathedral because the stone is structural and not a skin or curtain, hung merely for adornment.

Built in 1884, it has a 1930 addition, as well as a renovation from 1951. The all southwestern stone is mixed throughout to give a bit of a look of tartan. Austin suspects that the darkest sandstone comes from quarries near Las Vegas, New Mexico, not Nevada, and dates back to the late Pennsylvanian-early Permian. Much younger and much lighter is the late Cretaceous Mesaverde Formation. It is also much weaker and spalls abundantly along the base of the cathedral. Back at the entrance to the Cathedral House, you can find a third stone, the Coconino Sandstone, one of the legendary layers within the Grand Canyon. It is 275 million years and formed in a vast dune field.

Moving a bit away from my goal of looking beyond the stone, I want to point out the nifty butterfly or bookmatched pattern of an easily overlooked box around the block from the Cathedral. Austin doesn’t note the origin of the stone but does stop to point it out, I think mostly because it is a way to use geology that should be noticed more often.

Finally a quick turn to what started life as the First National Bank building. Built in 1922, it is the Duke City’s first skyscraper and first building with a steel infrastructure. Austin called it the First Security Bank, and now it is designated the Sunrise Bank building (one wonders how soon till another bank nabs the building). It looks like hundreds of buildings with lower floors set off from the upper levels by a color or material change. There is little stone used. A whitish granite from the Raymond quarries in the Sierra Nevada is the most noticeable.

Thus ends my short tour of Albuquerque and its building stone. I highly recommend that if you do go there to try and pick up a copy of George Austin’s guide. It is one of the best and most thorough written not only about specific building stone but also about the industry, quarrying, and fabrication.

Monday, December 7, 2009

South to Albuquerque for stone

Continuing my exploration of building stone in New Mexico, I traveled down to Albuquerque, aka Duke City. (One quick side note, I took the new commuter train between Santa Fe and Albuquerque. The Rail Runner Express runs regularly between the two cities and is a fun way to travel.) But back to the rock in the Duke City, where I benefited from George Austin’s excellent guide book: Albuquerque downtown from a geologic point of view—A walking tour of the city center. It is published by the New Mexico Bureau of Mines and Mineral Resources in their series Scenic Trips to the Geologic Past.

I have written about Austin’s book before but this was the first time I had a chance to use it. Today I will focus on how Albuquerque architecture illustrates one of my favorite maxims about building stone geology: Even if the architecture is boring, the stone makes the building worth seeing.

For example, the AT&T building exemplifies banal architecture but the designers clad the bottom in a quite handsome pink granite from Texas. Known in the trade as the Town Mountain Granite, and informally as Fred Red (from the quarrying site, Fredricksburg), the stone is part of the extensive Llano Uplift, a 9,000 sq. km exposed section of Laurentian rocks in central Texas. Fred Red is a little over a billion years in age. On the AT&T building the slabs have both a polished and flamed finish. A flamed finish is produced by passing the stone under a plasma torch, which explodes the surface minerals to produced a textured surface.

Fred Red and AT&T. Note how the two surface treatments creates an illusion of using two different stones.

(The Fred Red and other granitic cohorts from the Llano will be addresses in the January/February 2010 GSA Bulletin. A new analysis shows that they are not A-type granites as previous workers described. Instead they formed from a continental collision between North America and “an unknown continent that left the scene before it could be identified,” according to the press release. I suspect that any information about the unknown assailant would be appreciated!

City Hall also highlights my maxim. This time the stone is a local rock, Apache Golden Vein, quarried near Belen, New Mexico. Geologists know it is as the 340-320mya Madera Formation. Fossil rich, including crinoid stems, clams, and bryozoans, the Apache also has mustard-colored styolites, which Austin notes are “post-depositional, pre-quarrying” and produced from oxydized, porous clay. Once quarried, the panels fade from weathering.

City Hall above and the nifty panels of Apache Golden Vein below.

And finally, at least on my tour de ugly, is the Bernallilo County Courthouse. Again you can find Apache Golden Vein panels, but the more numerous panels are a concrete mixed with chunks of obsidian. Austin reports that they are not local. I note them because it is so unusual to see obsidian as building stone. In fact, I don’t know of any other buildings built with obsidian. Does anyone?

Obsidian chunks in a concrete matrix.

Later this week I will describe some of the buildings I liked not just because of their stone.

Tuesday, November 24, 2009

Santa Fe Stone, Part 3: The Tetragrammaton

Before leaving Santa Fe to address some cool stone I found in Albuquerque, I want to focus on an odd aspect of Santa Fe’s Cathedral. Carved into a triangle in the keystone of the entrance arch is a Tetragrammaton, or the Hebrew word for God. No one knows exactly why or who carved the four letters (Yod, He, Waw and He, or YHWH, pronounced Yahweh), which may be why so many stories have arisen around the inscription.

(The best single source is Floyd S. Fierman’s article The Triangle and the Tetragrammaton, which appeared in several forms. The one I consulted was from the New Mexico Historical Quarterly, v. 37, n.4, pg. 310-323, 1962.)

Many of the stories revolve around Bishop Lamy’s relationship with the Jewish community in Santa Fe, in particular with Abraham Staab. Born in Germany in 1839, Staab had emigrated in 1854, eventually arriving in Santa Fe around 1857, where he established a trading and merchandising operation throughout the southwest. By the 1870s he was a prominent businessman and in the position to lend Lamy money for the Cathedral.

Fierman wrote that the most detailed account of Staab's connection to the symbol is from William Keleher’s The Fabulous Frontier. Keleher described how Staab had lent Lamy money for the Cathedral construction and how Staab said he would absolve all debts if he could chisel one word into the building’s entrance. Of course that word was Yahweh.

Keleher wrote that the source for his version was Staab’s son-in-law, who claimed that Staab had told this story on many occasions. In contrast, Fierman notes that Staab’s son Edward “avers under no circumstances” was there a trade of money for said carving. His father did destroy the notes, however, but “he did not bargain with the highest religious officer of the diocese.”

Continuing to seek out a reason for the symbol, Fierman wrote to Fray Angelico Chavez of the Cathedral, who had done extensive research into the history of the building. Chavez responded that the placement of the Tetragrammaton in a triangle was a common Christian symbol in Europe. It represented the holy trinity and was most likely something Lamy had seen in his youth in France. Chavez concluded “It also could be, once the emblem was carved, that these Jewish friends, totally ignorant of the triangle’s meaning, were actually pleased and did consider it a friendly gesture by Lamy! Which is all to good in this world of strife and misunderstanding among peoples.”

Friday, November 20, 2009

Santa Fe Stone, Part 2: The Cathedral

Santa Fe’s wonderful Cathedral Basilica of St. Francis of Assisi is far better known than the Courthouse. Work on it began in 1869, under direction of Bishop Jean Baptiste Lamy, made famous by Willa Cather in Death Comes for the Archbishop. Lamy laid the cornerstone on Sunday, October 10, 1869 but the following week some “heathen with infamous hands” stole it, along with its contents, including gold, silver, and copper coins and a list of donors. Perhaps the theft was a sign because problems plagued the Cathedral throughout its construction.

A French architect and stone cutter, Antoine Mouly, prepared the original drawings for the church from plans made by Lamy and an assistant. The building would be Romanesque in style, 200 feet long by 115 feet wide, with an 85-foot-high dome, and two towers, soaring a hundred feet tall. And it was to be built around an adobe church. Work proceeded slowly, depending on money, a problem that also led to a gradual reduction of Lamy’s grandiose plans. Mouly supervised construction until he returned to France in 1874, because of fading eyesight. He left his son, Projectus (what a great name) in charge, but little work took place for several years and he quit in 1878.

Another French architect, Francois Mallet, came over to aid the project. He made new plans, which would involve 75-foot spires topping the two towers, but apparently did not devote all his energy to design work. Instead, Mallet was putting the moves on the wife of Bishop Lamy’s nephew. The younger Lamy shot and killed Mallet on September 1, 1879. A judge found him not guilty for reasons of insanity.

Lamy also hired French and Italian stone masons to work on his Cathedral. By 1880, the new walls had risen high enough to hide the old adobe church. Late the next year, the workers installed the beautiful circular window, cut by Vicente Digneo, Cajetano Palladino, and Michael Machebeuf (Again, I had to list there names because they are so splendid.). Money issues still delayed construction. Lamy died in 1888, seven years before the official Cathedral dedication. Mallet’s spires have never been built.

But back to geology. I have been surprised by how hard it has been to track down information on the stone. Most sources report that some material came from property owned by Bishop Lamy about 17 miles south of Santa Fe (the area is now called Lamy). Said sources disagree as to whether said stone is limestone, sandstone, or granite. The New Mexico Bureau of Geology and Mineral Resources geology map of the Galisteo quadrangle, however, indicates a sandstone quarry on Cerro Colorado, a hill rising above Lamy, in a unit known as the Diamond Trail Formation. It has been dated as early Tertiary.

Most writers agree that a “red volcanic lava, exceedingly light” was quarried from a small mound 12 miles west of Santa Fe, known as Cerro Mogino (of which I could find no information). (One modern writer, however, referred to the stone as “volcanic tuft,” which sounds a bit like a hoodoo.) Rock, said to be an “ochreous limestone for the exterior” also came from within Santa Fe, in the Arroyo Sais.

Willa Cather also wrote about the stone. In her colorful prose, Lamy in the guise of Bishop Latour, said “It is the stone I have always wanted, and I found it quite by chance…This hill is only about fifteen miles from Santa Fe; there is an upgrade, but it is gradual. Hauling stone will be easier than I could have hoped for.” She further described the stone as “a strong golden ochre, very much like the gold of the sunlight” and “melted gold—a color that throbbed in the last rays of the sun.”

In a concluding section Cather has Bishop Latour say “Yes…that rock will do very well…Every time I come here, I like this stone better…I would rather have found that hill of yellow than have come into a fortune to spend in charity. The Cathedral is very near my heart, for many reasons.” Perhaps not the most benevolent words a bishop could utter but as many of us know stone can lead to a religious experience.

Wednesday, November 18, 2009

Stone in Santa Fe: Part 1

Although Santa Fe is known for its signature stucco architecture, the diligent stone seeker can find rock-clad buildings. Two buildings stand out: the Santiago E. Campos United States Courthouse and the Cathedral Basilica of St. Francis of Assisi. Both use local stone and both are quite handsome structures. I will focus on the Courthouse today and follow up later this week on the Cathedral, which will require two reports.

Construction on the Courthouse began in 1853 and on what was intended to become the territorial capitol. Initial plans called for “lime stone” though a letter written in 1853 by the Commissioners of Public Lands, noted “No building of like description or of like materials has ever been attempted here…[Yet] in May last when the Commissioners desired to commence the Masonry of the building not a single Stone Mason could be found in the Territory.” This dearth of qualified local masons led to the contractor “borrowing” soldiers from the US military, who did have experience with stone.

Like many other public structures around the United States in middle 1800s, the Courthouse is classic Greek Revival style. The rough cut limestone was quarried in the Sangre de Cristos mountains, about eight miles from Santa Fe, in what is now Hyde Memorial State Park. Quoins and lintels came from Cerrillos, about 20 miles southwest of Santa Fe. Wagons and pack animals provided the only means of transporting the stone. A lack of money and masons, as well as the advent of the Civil War, eventually conspired to halt construction.

Santa Fe’s Tertio-Millennial Celebration in 1883, which commemorated the city’s founding 333 years earlier, did lead to a temporary roof but further construction did not begin in earnest again until 1888. By this time competent masons had moved to Santa Fe and they finished the courthouse the following year. The building, however, never served its original purpose as a state house.

To reach the Courthouse, head north out of the Plaza on Lincoln Ave, which dead ends at the building. You can also see an addition, tacked on in 1929-1930. More information can be found in the following paper, which provided many of the details I used.

Thursday, November 5, 2009

Two Fine Books of Science

As we enter the critical book buying season (hint-hint), I would like to recommend two recent books. Both focus on science and even better perfectly complement each other. They would make a nice pair of presents for anyone interested in understanding science and the passions that drive scientists. The books are Darwin’s Armada: Four Voyages and the Battle for the Theory of Evolution by Iain McCalman and The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science by Richard Holmes. Holmes’ book came out in 2008 and McCalman’s in 2009.

Dense, yet readable, Age of Wonder focuses on what Holmes calls the second scientific revolution, inspired by novel developments in astronomy and chemistry. (The first revolution centered around Newton.) Holmes book ends his period around two legendary voyages: James Cooks’ round-the-world expedition started in 1768 and Charles Darwin’s voyage in the HMS Beagle, which ended in 1836. It was a period of brilliant insights, dangerous experimentation with electricity and nasty chemicals, and lone scientists devoted to pushing the frontiers of their subjects.

Holmes does an excellent job of detailing the lives of his vast cast of characters, which ranges from chemist Humphry Davy to astronomer William Herschel to novelist Mary Shelley to explorer Mungo Park (what a cool name to have!). In presenting Herschel and his work, Holmes clearly shows how Herschel, the man who found Uranus (the first planet discovered in more than 1,000 years), couldn’t have succeeded without his equally talented sister Caroline. Davy also stands out for his work with laughing gas, development of a safe, underground mining lamp, and popular lectures on science, which drew hundreds. In addition, Holmes interfingers the science with poetry through the work of Samuel Coleridge and William Wordsworth.

Coincidentally, Darwin’s Armada picks up exactly where Age of Wonder stops. McCalman details the formative voyages and expeditions of Darwin, botanist Joseph Hooker, Thomas Huxley, and Alfred Russell Wallace. Less dense and a bit lighter in tone, Armada shows how their work in the southern hemisphere shaped each man’s understanding of science and the natural world and in turn led them down the paths to insights into evolution. And once on those paths, these four men were the prime movers in discussing, debating, and fleshing out natural selection. McCalman also shows how the four became deep friends who helped each other through scientific, family, and financial challenges.

In reading each of these books, I was constantly amazed to see the excitement of new discoveries but also the dangers of working with new materials and visiting wild places. It is a wonder at times that any of the great scientists discussed here didn’t die young. We are fortunate they didn’t and fortunate that they come to life in the pages of these two fine books.

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?

Wednesday, September 30, 2009

StoneFest: Making Mortar

Several times during the research for my book on building stone, I came across references to making or using mortar. In particular, in my chapter on coquina, I described how the Spanish burned oyster shells to make lime for mortar. I sort of understood the basic process, but again, not until StoneFest, did I get the process of what the Spanish did. One of the first projects at StoneFest this year was to make lime for mortar.

Irish stonemason Patrick McAfee was our teacher. Patrick is the author of two excellent books on masonry, Irish Stone Walls and Stone Building, with over 40 years experience. He lives and works in Ireland, an ideal place to practice his stone masonry. As he said “The land was so poor all you could grow was stone.” And they ended up in the 4,000 castles, 25,000 bridges, and 250,000 miles of stone walls found on the Emerald Isle.

As with letter carving and making windows, the process of making lime was easy in the hands of a master. We began by building the kiln, basically a tower of stacked cement blocks. We enhanced it by cutting holes in the corners, to allow air in, laying a metal screen on the first row of blocks, and by holding it together with steel beams and tape. The gang took about 40 minutes to build the kiln.

Building the kiln.
Raw Texas limestone before being put in the kiln.

We put coal and limestone on the screen and continued to add these two ingredients in about equal parts as the kiln grew. And this was all we needed to make lime. We could also have used wood or peat for fuel and shells or marble for our lime source. Our limestone came from Texas but historically builders would have used the local materials, as the Spanish did when they burned shells collected from middens made by people who had lived in the area more than 5,000 years ago.

Raw coal before putting it in the kiln.
Feeding the kiln with wood. Note the holes in the corners for air intake.

When we opened the kiln the next day, the limestone had been converted to quicklime, white lumps of CaO. The heat had driven off the CO2, changing the calcite (CaCO3) to quicklime, a highly reactive material when mixed with water, a process known as slaking. The reaction produces lime putty, calcium hydroxide (Ca(OH)2). Lime putty can be used by itself or mixed with an aggregate to make mortar. Patrick told us that lime putty gets better with age, as not all of the quick lime hydrates. The Romans waited at least three years to use theirs and Patrick knew of Polish lime putty aged for more than 100 years.

A bucket of quick lime: these pieces resulted from driving the carbon dioxide off of the calcite.
Our final product: slaked lime or lime putty.

In a little over 24 hours we had made one of the key ingredients of construction used for more than two thousand years. Yes, we had cheated a bit some using modern items but this was because we were in a class with a goal of learning how to make the lime. But basically we had performed a task that would not have looked too strange to Roman builders. Patrick said “We are in a parallel universe for the next four days.” He was right. Our universe was one that relied on simple tools, basic, but highly honed skills, local materials, and practical know how to generate beautiful and lasting products. I hope I get to return to StoneFest next year to continue my stone education in this parallel universe.