The Duomo and the Dinosaur: Not?

Finally we have a nice uniting of science and religion and boy has it titillated the Internet. Apparently for the past 350 years or so the fine parishioners of the Cathedral of St. Ambrose (aka Sant’Ambrogio) in Vigevano, Italy, have been praying and genuflecting with a dinosaur fossil in their midst, or so says paleontologist Andrea Tintori. The fossil has been right in their sight, in fact just to the left of the center of their altar, though there are a few skeptics who doubt Tintori’s observations. (read further)

Photo from Discovery News, courtesy of Andrea Tintori

University of Milan paleontologist Tintori has determined that the early Jurassic age (~190mya)-stone slab contains the cross section of a dinosaur skull with visible nasal cavities and numerous teeth. Total length is about 12 inches. Tintori also found a second part of the skull in another slab. He hopes to get the first slab removed to do additional work.

Photo from Discovery News, courtesy of Andrea Tintori

Built between about 1532 and 1660, the cathedral, or duomo in Italian, contains a wide array of stone. The fossil-rich slab comes from quarries in Arzo, Switzerland, about 40 miles due north of Vigevano. They were first opened in the thirteenth century but didn’t become widely used till the seventeenth and eighteenth centuries, when the stone was used primarily for altars. It is a purple-red, grey-veined limestone with skeletal grains of crinoids and goes by various names but broccatello (brocaded) is the most common. (I wonder why builders wanted this stone for altars. Is there something about its color and pattern that conveys a message suitable to getting closer to God?)

The broccatello became popular as a replacement for the legendary Portasanta stone of Rome, the rock used for the Holy Door (Porta santa) of St. Peter’s Basilica in Rome. Builders often combined the Arzo stone with red and grey limestone from Bergamo, black limestone from Lake Como, and white marble from the Apuan Alps. You can see the broccatello throughout Italy and Switzerland. No other dinosaur fossils have been reported.

In regard to Tintori’s dinosaur, one person I corresponded with wrote back. “ALERT: this seems to be a cross-section of an ammonite!”

After my initial posting, I received one more note about the fossil.Ammonites are well known from the Broccatello Formation, which is entirely marine and devoid of terrigenous sediment derived from the continent. The Broccatello preserves a rich fauna of marine fossils, sponges, sea lilies, brachiopods, bryozoans, solitary corals and the like and has been deposited in waters near the base of the photic zone [down to 600 feet]. The preservation looks also typical for an ammonite. The test [or shell], originally composed of the mineral aragonite, an unstable form of calcium carbonate would have been dissolved and the void filled by calcite, the stable mineral form of calcium carbonate. The photograph is not good enough to see the crystal fabric of the calcite, but I have no doubt about my diagnosis. If this is the head of a dinosaur, I’ll give up geology and eat my rock hammer.” Perhaps the sexiness of finding a dinosaur in a church made Tintori see more than meets the eye.

If you read the comments on various sites reporting this story, you will see that many note the irony of a catholic church having a fossil in it. Hundreds of church buildings are fossil rich so this isn’t really a new irony to report in regard to religion and evolution. I can only hope though it will get more people to take notice of the stone in their religious institutions, which seems to me to be one of the best reasons I can think of for visiting a church, synagogue, or mosque.

Tucson Gem/Mineral: Acres of Ammonites

Judging from the fossils that I have seen at the Tucson Gem and Mineral show, ammonites once ruled the world. I have only seen one small section of the displays but ammonites are by far the most abundant group of fossils, numbering in the thousands. You can buy them individually, by the bag, and by the the pound. They range in size from less than an inch to four feet in diameter.

A gaggle of ammonites

They come from places as diverse as Morocco, Russia, Columbia, and Madagascar. Most are whole. Some are split in two, revealing mineralized chambers. Many have been polished. Others are pyritzed. At one display, in a hotel room, the ammonites have been mounted elaborately with wee ones glued to bigger ones and split with whole. I also saw one massive ammonite-choked chunk of rock from Morocco that had been drilled out to create a wine rack.

A rafter nifty specimen from Canada

I was lucky to see the massive four foot diameter specimens. They had sold to an undisclosed buyer from Austin, Texas. He had paid $9,000 in cash for two of the giants, both of which had been cut in half. According to the guys getting ready to box and ship the ammonites, one was going to the buyer’s home and one to a museum.

A boy and a very, very big ammonite

My only disappointment was in how little information was listed with the fossils. A handful had the scientific name, age, and locality, but most had nothing but price. Still the show of ammonites is impressive.

A table of ammonites from Madagascar