My Marriage’s Rocky Start

Amy and I met over 11 years ago while we both worked for a tourism group in New London, Connecticut. The company we worked for had a trolley that provided tours around the city of New London. It was fun while it lasted. For me, I used my knowledge as a local historian to keep the tourists interested and amused. It was a lot of fun. For Amy’s part, she had to drive and navigated the replication trolley through the route of narrow and congested New London streets. Not an easy job, at all. After some time had passed, Amy began sharing her knowledge of the local geology, and furthermore, the industries that sprung from the local “ground.” She’s was an historian, after all. To this day she can look at the lay of the land, its various geological formations and components and spin a wonderful story of how it all came about. It’s like being in front-row seats seeing (with some imagination) how it all came together. It’s absolutely stimulating and sensational.

What I’ve learned from Amy over the years is that there is an incredible story to the formation of the terrain we live and work around. For the most part, we take it for granted. Around here, in Connecticut, it’s a geological showcase that includes volcanoes, terminal moraines, fault lines, shifting tectonic plates, sedimentary formations, aquifers, kettles, glacial rebounds, and on-and-on it goes. We are blessed to be around such a vast witness to the earth’s marvels and it’s ever-revealing history.

This morning I opened today’s New London Day (The Day) to see another wonderful and arousing revelation of our area’s geological record. Here’s the story for your review and comment:

Scientists Get A ‘Gander’ At State’s Geological Past By Judy Benson

Add one more layer to the already complicated geological story of this small state.Some 400 million years ago, when the masses of rock we call continents were shifting and moving, and the map of the world looked a lot different from today, a small continent called Gander found its way across the primeval ocean and sidled up against what was then North America. Parts of it were welded onto Atlantic Canada, Maine and New Hampshire. That much of the story has been accepted by geologists for years, since Gander was named after the town in Newfoundland where it was first identified.

Now, it seems, there’s also a bit of Gander in Connecticut – southeastern Connecticut, to be precise. A couple of small pieces of Gander make up the Fenwick section of Old Saybrook, and areas around Clinton and Branford, but the main one is a bulbous area known to geologists as the Lyme Dome. The dome has long been thought to be part of Avalonia, a different one of the six land masses that aligned to form Connecticut millions of years ago. Five of these became part of the state with the various continential movements, and the sixth is a rift basin that opened up in the middle when the land masses were separated and stretched when the continents pulled back apart.

”The western edge (of Gander) goes through Uncas Pond in the Nehantic State Forest (in Lyme),” said Prof. Robert Wintsch of Indiana University, who reached his conclusions with two colleagues from the U.S. Geological Survey and published the findings in the American Journal of Science, out of Yale University, a year ago.

”Nickerson Hill in the Nehantic forest is part of Avalonia,” Wintsch said. “The core of Gander is centered in the village of Old Lyme, the mantle is under the town of East Lyme, and there’s a bit in Waterford, near where I-395 leaves 95.”

Avalonia, an inverted L-shaped band that cuts across southeastern Connecticut and north to Putnam, wedged itself into Gander when it joined Connecticut. Gander plunged beneath Avalonia, revealed at the Lyme Dome only due to erosion, Wintsch said. Like Gander, Avalonia was a “ribbon continent” – picture Baja California for a modern equivalent – that started around the equator near present-day Africa, and jammed into North America to make up not only southeastern Connecticut, but also Rhode Island and coastal Maine and Massachusetts.

”Gander was there, and along comes Avalonia crashing in,” said Wintsch, who’s been studying Connecticut geology for 30 years, traveling to the state nearly every summer for field work.

No one knows the size of the original Gander, but geologists do know it extended from Newfoundland to New England, and perhaps beyond.

After Avalonia glommed itself onto Connecticut, all the major land masses began converging into one supercontinent, Pangea, squashing Avalonia and Gander, and forming the Appalachian mountains in the process.

But oneness was not to be. The continents started drifting apart again, and in the process, Avalonia and Gander were both severed, with parts of each drifting eastward with the European and African continents, and the other staying with North America. The Atlantic Ocean filled in the middle, and to this day is still widening gradually.

Today, rocks identical to those in southeastern Connecticut that are part of Avalonia and Gander can be found in Morocco and other parts of Africa, as well as Scotland, said Wintsch. Gander rock is distinguished by analysis that dates when it moved to its current locations and when it underwent intense heating with various geologic events.

Ralph Lewis of Lyme was the state geologist until his retirement in 2003. The new description of the Lyme Dome as Gander is well accepted, he said, and well supported by the research done by Wintsch and his USGS colleagues, Gregory Walsh and John Aleinikoff.

To most people, the addition of Gander to the state’s geological map may seem like little more than an esoteric exercise, but for geologists and others who want to understand the landscape, it’s an important development.

”It’s a big deal for Connecticut,” said Lewis. “It helps to solve some of the conundrums people have had.”

It answers what had been lingering questions about the dome. It never quite fit that the dome was just part of Avalonia, Lewis said, because a ring of ocean bottom rock surrounds the Lyme Dome, and that typically occurs where two land masses once separated by an ocean converge.

An emerging story

Wintsch and his colleagues used sophisticated chemical analysis to compare rocks in the Lyme Dome with those in Avalonia.

”We looked at their isotopic structures, what constitutes a rock’s DNA,” said Wintsch.

Differences in the rocks from the two areas are invisible to the naked eye, he said, in part because the rocks have been heated, cooled, melted together and metamorphosed by cataclysmic forces over the millennia.

Connecticut’s geological story just became known in the last 20 to 25 years, said Lewis, who teaches at the University of Connecticut’s Avery Point campus and works with the Long Island Sound Resource Center. It was then that geologists started to understand the role of plate tectonics in shaping the oceans and the continents, and advances in the ability of computers to analyze rock in different ways enabled experts to unravel the events of millions of years ago as never before.

So it’s not surprising, he said, that Connecticut’s particular story is still being revised.

Related Material:

Connecticut Geology – Wesleyan University

Geology of Connecticut – Yale-New Haven Teachers Institute

Geology of Connecticut – Wikipedia

An Eye for Rich Geology – New York Times (Featuring our friend Stan Gaby)

The Importance of Field Geology – University of Pittsburgh

Connecticut’s Stone Quarries

The Portland Brownstone Quarry

Click on map to enlarge image

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