Saturday, December 20, 2014

Say Goodbye to Graptolites...

Graptolite fossils from Presque Isle
It's hard to get sentimental about graptolites. The fossil of what's actually a colony of tiny animals looks more like a small saw blade than anything you might start a preservation campaign for.  It's probably for the better, too. A successful "Save the Graptolites" crusade would have preserved a world where reptiles and pine trees would never have thrived. In Silurian era Presque Isle, however there would have been no need to improve conditions for graptolites. They were already perfect.  

In a low outcrop not far from downtown Presque Isle, the pale rock feels gritty, but not coarse. This type of sediment is not the product of a deep ocean or a beach, but the sweet spot in between.  It's born in an area where prevailing winds could blow off the warm top layers of an ocean, and reveal the cold nutrient rich waters below.  Perhaps inconsequential to you or me, but life changing to a graptolite.

Certain shards of the rock slab host the shallow impressions of graptolite rhabdosomes, basically an apartment building for tiny animals called zooids.  In Silurian time the complexes either rooted themselves in coastal sediment or floated in masses at the surface.  The zooids may have reached out of the many holes in these colonial homes to grasp at and eat phytoplankton from the coastal waters, enriched by the upwelling of vital nutrients.  

In a time when Caribbean-like islands stood sentry on the coast of North America habitats like this would have been commonplace in Maine. But, Maine was changing. Three hundred eighty million years ago the tectonic block that serves as our current coast, Avalon, docked with Maine. The conjunction crumpled the graptolites' ocean habitat.  Driving fossil types of graptolites from fourteen  in the Silurian to one after the collision. Eighty million years later the jaws of Pangea snapped shut.  The huge landmass was inhospitable to the aquatic creature and by the time it had formed the graptolites were extinct.

The watery Silurian period was ideal for graptolites. The changing environment drove them out of Maine, and then to extinction.  A sad moment, perhaps. But, the transition to dry land had some advantages, too.  Plants left the coasts, invading Pangea, and in the process became trees. Amphibians bravely abandoned their shrinking watery habitats and evolved into reptiles. Graptolites didn't make it, but maybe that's okay. Perhaps their loss is our gain.

Dickson, Lisa, and Robert D. Tucker. Maine's Fossil Record: The Paleozoic. Augusta, ME: Maine Geological Survey, Dept. of Conservation, 2007. Print. 

Koren', T. N., and R. B. Rickards. "Extinction of the Graptolites." Geological Society, London, Special Publications (1979): 457-66.

"Graptolites." Common Fossils of Oklahoma. Sam Noble Museum. Web. 20 Dec. 2014.

Sunday, October 12, 2014

The Long View: Half a Billion Years in the County

The view from State Street in Presque Isle
This August I spent a week in mythic Aroostook County.  Throughout my week there I navigated rolling hills and potato fields, marched to the top of Quaggy Jo in Aroostook State Park and summited Haystack Mountain in Mapleton. The county is a geological wonderland, but it wasn't until I crested that hill in Presque Isle that I recognized the magic of the place.

The view of Haystack Mountain from State Street in Presque Isle
Traveling down State Street into Presque Isle, you turn a corner, the road dips downward, and you look across the county at Haystack Mountain. That rock has been on Earth for half a billion years.  Once the neck of an ancient volcanic island, the Aleutian-like island gained girth as the North American ocean bottom slid under a second ocean plate. The lightest of the melted ocean rock floated to the surface forming the steep-sided stratovolcano that would one day become the western view from Presque Isle.

The view of Quaggy Jo from State Street in Presque Isle
If you're not completely transfixed by Haystack, your eyes may wander south as you pass Presque Isle's school farm. As if the beautiful farm were not a sufficient view, this vantage provides sight of another prominence - Quaggy Jo of Aroostook State Park. Compared to Haystack, Quaggy Jo is a young'n.  Formed 410 million years ago, it holds an esteemed place in Maine geology, along with Traveller Mountain and Mount Kineo, as the volcanic remnants of Maine's most intense collision. A microcontinent we call Avalonia was nearing the coast of Maine.  Its leading edge plunged beneath the North American coast. Avalonia would become our coast and the melted ocean would rise up through the ocean to become the aforementioned volcanoes and their granitic roots - some of the largest mountains in Maine.

The collisions weren't over yet. When the last of Avalonia's fore-ocean descended, the sub-continent continued forward. The colliding land masses were too light to sink into the Earth's mantle below, so the smashing crushed everything skyward.  Formerly flat ocean bottom became wrinkled like a discarded sock. In some places in the Appalachians the squished rock climbed higher than today's Himalayas. Here in the county, hundreds of millions of years later, all that's left are the rolling hills that I drove over.

At that turn, on that road, I could see into Maine's geologic past. I saw an ancient ocean lap the shores of Haystack Island. Quaggy Jo volcano erupted right in front of me. The very hill I stood on rippled upward as Avalonia invaded our shore. The chaos of a half a billion years, wrapped into a single panorama on a peaceful hill. 

Boone, Gary, William  Forbes, and Chunzeng  Wang. "Haystack Volcanic Geology and Geologic History." Go Aroostook Outdoors. N.p., n.d. Web. 10 Oct. 2014. <>.

Caldwell, Dabney W.. Roadside geology of Maine. Missoula, Mont.: Mountain Press Pub. Co., 1998. Print.

Roy, David C.. "Geologic Map of the Caribou and Northern Presque Isle 15' Quadrangles, Maine." Maps, Publications and Online Data. Maine Geological Survey, n.d. Web. 10 Oct. 2014. <>.

Tuesday, August 19, 2014

Skipping Stones at Kettle Cove

An assortment of stones at Kettle Cove,
 including white quartz and gray phyllite 
Chasing my fifteen month old son at Kettle Cove beach means faster glances at the rocks. I absorb the scene but miss a lot of the details.  A lot of flat rocks - good for skipping.  "That's a little too deep bud, let's bring it in." Some nice round hunks of quartz. "It's okay, keep walking and you'll dry off ." More of the same; more flat, more quartz. Not a lot to see, but that says a lot.

Arms of dark rock contain the sands of Kettle Cove beach
Arms of dark rock supply the cove of Kettle Cove. The repeating foliations and large "knots" make it look almost like wood.  A fact that drives the untutored to ask whether it is petrified wood.  It is not.  The physical features have a more involved backstory.  Four hundred twenty million years ago this rock was sediment in a deep ocean.  Sand, silt and clay piled up in a space between continents: to the north what would one day become most of North America to the south Avalon, a microcontinent whose remains form the coast of Maine and parts of Rhode Island, Great Britain and Africa.  It might seem that these layers of rock would become the "tree rings", but the thin sheets would reveal themselves millions of years later.

"Petrified wood" is really ocean bottom rock
split by stretched bands of quartz 
Four hundred million years ago Avalon crept toward  the North American core.  The pressure on these layers escalated. The minerals in mud migrated and aligned themselves to sustain the stress.  The wavy foliations are the result.  The heat and pressure of impact had the added effect of heating quartz to liquid, sending it screaming through cracks and layers.  As things settled down the quartz solidified into extended blocks called dikes.

The collision with Avalon was prelude to the formation of Pangea. As this is now the coast, we know these impacts were not the end of the story. Africa bumped our coast, and then bounced back out to sea (carrying a piece of Avalon with it). Our "petrified wood" does not have stripes of quartz.  It is punctuated by "knots" of it.  As the continents split, the bands of quartz stretched. Some parts spaghettified into ribbons.  Other sections remained thick with tapered edges.  These bulbs, called boudins (French for sausage, which the strands of quartz resemble) become the "knots" in our wood grain.

Inevitably the rock of this formation, having been lain down, rearranged, injected with quartz and stretched, began to break down. Glaciers, rivers and waves have all had their shot at the rocks of the Maine coast, and the most recent of these don't carry rocks very far.  The smallest pieces may end up as mud on the ocean bottom or sand on the beach. The larger chunks stay local. The flattened layers become skipping stones. The round quartz knots roll back and forth in the surf. These remnants remain for my son and me to explore while perusing Kettle Cove.

Bentley, Callan. ""Boudinage" is my favorite geology word - Mountain Beltway - AGU Blogosphere." Mountain Beltway Site Wide Activity RSS. American Geophysical Union, 20 June 2011. Web. 19 Aug. 2014. <>. 

Berry , Henry N. , and Robert G. Marvinney. "The Geology of Two Lights State Park Cape Elizabeth, Maine." Geologic Site of the Month. Maine Geological Survey, n.d. Web. 19 Aug. 2014. <>. 

Friday, July 18, 2014

Tipping the Clown: Changing Density in the Deer Isle Granite

When I was young I had an inflatable clown with weights on the bottom, so you could administer whatever childhood battering you cared to, and the clown would bob back upright.  I recently read about a feature of the Deer Isle Granite that got me thinking about that clown.
Deer Isle Granite: Naskeag Point

The granite that underlies Deer Isle is long.  It extends from Flye Point on the Blue Hill Peninsula to the southern tip of Stonington in the south.  While the rock is all clearly Deer Isle Granite, it is not homogenous.  Going to Naskeag Point on the mainland presents a deep pink, while a visit to Stonington displays a much wanner stone.  The middle ground of Oak point shows something in between.  The source of the redness may lie in oxidized (rusty) iron that replaces aluminum ions typically present in a mineral called feldspar.

Deer Isle Granite: Oak Point
Liquid rock under the surface cools to form solid granite.  As a result of 4.6 billion years of sorting by density, most granite bodies tends to have fairly uniform consistency.  Deer Isle Granite is different.  For some reason, during its formation, two types of magma were mixed together.  Imagine a nice Italian dressing, shaken before being added to salad. The vigorous mixing swirled everything together, but before it could harden there was time to settle.  Less dense materials, high in silicon content drifted to the top, while the more dense, high aluminum content stuff sank to the bottom.  The aluminum portion took on its iron and its rusty hue.

Deer Isle Granite: Stonington
Under normal conditions the weighted bottom of the clown would remain pointed downward.  The Acadian mountain building event was not normal conditions.  A small continent, and the tectonic plate it rode upon, glided across the fluid mantle toward the prehistoric Maine coast and rammed the landmass.  The collision was not a child's smack, but a match full of heavyweight boxer's jabs.  This impact was enough to permanently tip the clown on its side, revealing the changing color.

Dietrich, Richard Vincent, and Brian J. Skinner. Rocks and Rock Minerals. New York: Wiley, 1979. Print.

Hooke, Roger Leb.. "A Geologic History of Deer Isle, Maine." College of the Atlantic, Serpentine Ecology Conference. July 2007. Web. 14 Oct. 2013. <

Sunday, May 25, 2014

Salt of the Earth: The Source of Sodium and Chlorine in Our Oceans

As an adult, I sometimes forget to ask the obvious questions.  Kids, though, they have their heads on straight.  Living near the coast, I have the opportunity to visit the ocean pretty often.  Every once in a while I brave the frigid waters, and inevitably taste the salty sea, but I never really think about where it came from.  

Recently, I chatted with a friend about her grade school classroom.  She shared some of the science questions her students had asked.  "Why is the ocean saltier than a lake, even though it's bigger?"  I gave her the spiel: lakes and rivers have salt, but water moves through most lakes (and all rivers).  Most of that water, including salts, end up in the ocean.  Water has an easy route out of the ocean: evaporation.  Salt has no such egress.  It stays put.  Just like the ocean, some lakes and seas without outflows collect large amounts of salt. Therefore, we have Salt Lake in Utah, or the Dead Sea in Europe.  I imagined the students' next question: "Where did the salt come from in the first place?", and realized I didn't have a clue.

There are clues however.   The first is the quantity of elements in the Earth's crust.  The most common elements in sea salt vary greatly in their places on the list of most common elements in Earth's crust.  Sodium weighs in at number 6, while chlorine doesn't even make the top 20.  Sodium, therefore, is in everything.  Wikipedia lists 139 minerals, that are composed in part of the element.  When granite breaks down in water, a mineral group called feldspar releases its sodium to the water, and the water doesn't let go.  This weathering of feldspar, and other sodium minerals, would have delivered plenty of sodium to the Earth's oceans very early in their history.

Being rarer in the crust, it might seem that chlorine levels wouldn't be nearly as high in the sea.  In the ocean, chlorine content surpasses sodium as dominant element.  Why the strange ratios?  As it turns out chlorine doesn't play well with others.  A chlorine ion, which is a chlorine atom that has stolen another poor atom's electron, is large, at least relative to other common elements on Earth's surface.  The patterns these smaller ions create don't leave room for the hefty chlorine.  Chlorine elopes with a free hydrogen ion, and escapes out a volcanic vent, having never formed a rock mineral.  At the surface the hydrochloric acid splits, with the hydrogen joining oxygen to make water, and the chlorine dissolved in the ocean.  As chlorine atoms throughout geologic history jostled their way to the surface through volcanoes the oceans grew saltier.

Curiosity has always driven my study of geology.  But sometimes I forget the obvious.  The next time I visit the ocean and watch the surf gather on the shore, I'll be thinking of dissolving rock, belching volcanoes and the rivers that  bring their remnant salt downstream, my borrowed childlike wonder having been appeased.

Lorence G., Collins. "Time to Accumulate Chloride Ions in the World’s Oceans." Reports of the National Center for Science Education 26.5 (2006): n. pag. California State University Northridge. Web. 22 May 2014.

"How did the salt get into the oceans at the beginning of their formation?." UCSB Science Line sqtest. University of California, Santa Barbara, n.d. Web. 22 May 2014. <>.

Sunday, May 4, 2014

Groundtruth: Finding Annual Moraines in My Backyard

An annual glacial moraine.
Twenty-one thousand years ago glaciers covered the northern part of the globe.  Their end point in New England can be seen by following the line of Long Island, New York across to Cape Cod and Nantucket.  This relatively straight line is an artifact of the melting edge of the glacier dropping rocks and sediments delivered from the northern part of the globe, year after year.  As the pile of rocks got deeper and deeper it laid the foundation for these scenic places in New England.  Over time the Earth warmed and the glacier receded back to Maine, but it wasn't consistent.  Each winter the glacier moved forward a bit, and each summer it backed off.  Yard by yard and year by year it retreated to its current (not-so) stronghold at the North Pole.

LiDAR image of annual glacial moraines in West Falmouth.The
image above represents about a third of a mile from north to south.

A month or so ago, I ran into a former student who was researching the glacial history of Maine at Bowdoin, and he introduced me to LiDAR (Light Detection And Ranging) hillshade images that are available for large portions of Maine, including my own backyard.  What he revealed was that with the current imaging technology, we could see not only the large scale features, like Cape Cod, but the yearly inchings of the glacier. Unfulfilled with the images on the screen, I went out into the woods to groundtruth the pictures I saw.  Small hills and low areas I have walked over for years without really thinking about their origin were shown to be moraines dropped each summer by the ice sheet as it receded northward.
Looking up a moraine from a lowpoint in the terrain.

Monday, April 21, 2014

Besting Goliath: The Formation of the Pawtuckaway Ring Dike

The Massabesic Gneiss looks like ice cream
swirled with fudge because of heat and
pressure from 500 million years on the surface
It's hard to dodge the mythological when you look at maps of Pawtuckaway State Park.  Some refer to it as the Dragon's Eye, and for good reason; the park features concentric rings of mountains, identifiable as the iris and cornea.  To see it might even conjure up thoughts of a volcanic Mordor, and as it turns out, 150 million years ago, you wouldn't have been all wrong.  Perhaps the best metaphor for the origin of this strange structure is not literary, but biblical.

The Massabesic Gneiss was Goliath.  Forged in the tectonic rift that cleaved coastal New England from its former mooring point in an ancient Africa, it survived a trek across a long vanished ocean and 500 million years of survival at the surface of the Earth.  Its bold endeavors are catalogued in folds left by heat and pressure along the way.
The ice on the trail is a good metaphor for the park.  As the pool
of magma melted the land below, and added weight above.the
land gave way, allowing magma to rise up through the crack.
Massabesic's David, was not a sling, but a hotspot.  A sedentary warm point deep below Earth's surface regularly created blobs of magma that rose upward.  As the continent shifted with the movement of tectonic plates, these blobs left a string of volcanic mountains including Mount Royal in Montreal and Mount Washington farther north in New Hampshire.  Piercing the Massabesic Gneiss would be different.  Per usual the blob rose toward the surface.  Instead of erupting, the magma sat near the surface, weakening the gneiss's structure from below.  A small eruption may have penetrated the enduring rock.  The added weight, like our misplaced feet, was enough to plunge the Massabesic gneiss into the magma below.  David had bested Goliath.

The gabbro that makes up Meloon Hill flowed up through the
cracks left when the roof of the magma chamber collapsed
Over ten million years, this crack in the armor became a passageway for eruptions of magma that had bided their time.  Magma would have oozed up through the cracks that separated the sunken gneiss from that which remained.  An arc of dark colored, large grained rock, called gabbro, confines the southwest part of the Dragon's Eye.  A disk of salt and peppered rock, called diorite, underlies the lowlands.  These darker rocks may have recollapsed and remelted.  This newer, purer magma would have seeped through cracks to form the whitest, hardest rocks in the park: monzonite. 

Millions of years of erosion laid waste to the softer diorite, and shaved quite a bit off of the gabbro.  The monzonite, more resilient than the rest, remained.  Its stark cliffs are now a monument to the epic battle between a seasoned champion and a literal  That is, until a new champion arises.

The view from one monzonite ridge to another.
In the middle are the diorite lowlands. 
Dorais, M. J.. "The Massabesic Gneiss Complex, New Hampshire: a study of a portion of the Avalon Terrane." American Journal of Science 301.7 (2001): 657-682. Print. 

Eby, G.N.. "Mount Pawtuckaway Ring Dike Complex." Geology of the coastal lowlands, Boston to Kennebunk, Maine. S.l.: New England Intercollegiate Geologic Conference, 1984. 240-248. Print. 

McGarry, MaryAnn. "Volcanoes in New Hampshire ." Plymouth Portfolio. Plymouth State University, 17 Nov. 2012. Web. 19 Apr. 2014. <>. 

Reidy, Daniel E.. "Jurassic Period." New Hampshire Geology Home Page. N.p., n.d. Web. 19 Apr. 2014. <>. 

Sunday, March 16, 2014

Reunion on Old Orchard Beach

I hadn't taken into account that water has a way of exploiting a weak point.  On geologic maps, a black line with arrows on one side suggests one slab of rock has slid underneath another.  I convinced my wife to drive out to the site of the fault, with the added enticement that it intersected the coast.  A trip to the beach, on a day above 40 in the winter was not to be passed up.  We pulled into Ocean Park, and while my wife fed my son, I scouted the site.  

What I hoped to see was a reunion.  Five hundred million years ago the rock to the south of Ocean Park and the rock to the north found their home on the fringe of a continent called Gondwana. The goliath Gondwana covered an area of Earth a tad bigger than modern Asia centered around the South Pole.  If Gondwana was Asia, then Biddeford and the rock to the south of Ocean Park were part of Japan; Old Orchard, and the rock to the north,the coast of China.  Four hundred ninety million years ago, plate tectonics ripped Gondwana apart.  These hunks of land set sail across the proto-Atlantic, their near hundred million year journey landing them on Maine's coast 400 million years ago.  Unfortunately, tectonics did not set them gently on the coast.  The force of the plates shoved the edge of the Biddeford land mass underneath the one that underlies Old Orchard.  In a moment I could see Gondwana reunited on Maine's shores.

As I climbed the dune to get a view of this collision, I'd already began to lose hope.  The wind blown sand pointed to the fact that no natural bedrock hindered the movement of sediment. Cresting the dune, I saw beautiful beach for miles in either direction, but no fault.  My wife enjoyed the beach, my son gleefully played in the sand and I pursued the only rock bigger than a pebble, only to be chased away by cold waves.  I looked up the beach at Prout's Neck, and down at Biddeford Pool, wistfully considering my chances of convincing my wife to add some miles to our trip.  If I could just see the rocks on either end, I might find evidence of the Gondwanan meeting point.  Why were they so far away?

A wave hit the shore and my mind traveled back that 400 million years.  That wave would have hit the junction of those collided islands.  It would have found the minute space in between that ancient Japan and that forgotten China.  As it rushed in it would have torn away the smallest piece of sediment.  As it poured out, it would have stolen another.  The space in between would have grown larger and larger. Grain by grain it would be filled in with the small fragments that were broken away.  For 400 million years, the trend would continue.  The end point of this scenario had become clear.  

As we walked back down the beach, on the way to our car, I looked at Biddeford Pool and Prout's Neck as stalwart survivors of an intense collision, then a slow bleed.  Each a reminder of a reunion too long ago to have withstood the relentless abrasion of water.

"Avalon Terrane Field Trip." MIT Geology Field Camp. MIT, n.d. Web. 16 Mar. 2014. <>.

Dorais, Michael J., Robert P. Wintsch, Wendy R. Nelson, and Michael Tubrett. "Insights Into The Acadian Orogeny, New England Appalachians: A Provenance Study Of The Carrabassett And Kittery Formations, Maine." Atlantic Geology 45.0 (2009): 50-71. Print.

"Geology of Massachusetts." Wikipedia. Wikimedia Foundation, 22 Feb. 2014. Web. 16 Mar. 2014. <>.

Nance, R. Damien. "Late Precambrian–early Paleozoic arc-platform transitions in the Avalon terrane of the Northern Appalachians; Review and implications."Geological Society of America Special Papers 245 (1990): 1-12. Print.

Osberg, Philip H., Hussey, Arthur M., II, and Boone, Gary M. (editors), 1985, Bedrock geologic map of Maine; Maine Geological Survey (Department of Conservation), scale 1:500,000  

Saturday, February 22, 2014

Maine Geology Timeline

I tend to write blog posts in the order I become interested in them.  I may include how long ago events occurred, but when you're dealing with hundreds of millions of years, things get a little abstract. Today I decided to present the information of my blog in timeline form.  Using a web tool at, I created this.  There are some limitations in the software - primarily, the timeline tool does not go back in time to millions of years ago, so I did some messing around with dates to make it work.  Try clicking the arrows on the slides or clicking around the timeline itself to navigate Maine geologic history.  Also, click the links on the slides to find more about each event and how it shows up in the Maine landscape.  Enjoy.

Wednesday, February 12, 2014

How to Make Bricks in Three Easy Steps

Last weekend my son and I foresook our weekly grocery shopping trip at the West Falmouth Hannaford.  Instead we crossed the bridge on the south end of the parking lot and ended up taking a walk on an ancient sea floor.  Don't get me wrong, this is not a magical bridge that can transport one to a fantasyland.  The bridge was built in 1859 by the railroad company to connect the Hobbs farm to the rest of society.  John Hobbs homesteaded the land in 1775, and before 1859 when the railroad isolated it and the Hobbs sold it, put it to a variety of industrious uses.  Like people of earlier times are fabled to have done, the Hobbs put every part of the land to use.  The trees became oak shingles, the soil was farmed and the clayey sediment was extracted to make bricks.  The story of these bricks extends far beyond the Hobbs enterprising spirit and thousands of years before the clay was first dug.

The story of our bricks began about 22,000 years ago when glaciers covering much of the globe decided to call it a day and begin the slow commute home from Long Island, New York (Long Island formed as the flowing ice of the glacier delivered gigantic piles of rock to its melting endpoint).  At this point, Maine and the rest of northern North America were buried in ice. Heavy, heavy ice.  The normally firm raft of rock, on which our continent sits, sank like a rowboat upon boarding.  As melting glaciers contributed to a growing ocean, this depressed plate would make way for the intrusion of a sea much larger than today's Atlantic.

The land above the sea couldn't wait to cast off its icy water.  Massive streams poured tons of melted ice into the growing sea, but the water didn't come alone. As the rivers raced to the sea their fast current picked up every stone, pebble, sand grain or mote of clay they could carry.  Massive material, like stones and pebbles may have been dropped long before reaching the sea.  When the stream met the water, it rapidly decelerated. Upon slow down, enough sand was dropped to create a river delta as deep with sand as a football field is long.  The sand from this river's mouth can still be spied along I95 between Gray and Lewiston and is currently being quarried in Gray.  But what about the bricks?

The slow moving water, at this point, would have dropped nearly everything.  Robbed of most of its energy by the trudge into the ocean, the sluggish water couldn't carry much.  Luckily, clay is small and light.  The water transported these small grains the farthest, finally dropping them at the sight of the future Hobbs' farm.  About 13,000 years ago, with the weight of ice removed, the plate rebounded, and the sea level dropped.  The acreage of the Hobbs' farm was revealed.  Soil developed.  Oaks grew.  Eventually, the Hobbs would dig up their bricks and my son's and my weight would leave footprints in the ancient seabed.  

McCully, Betsy. "Ice Age." New York Nature. N.p., n.d. Web. 11 Feb. 2014. <>.

Robinson, Michael A., Stewart K Sandberg, and Kirkpatrick Melissa D.,. "Using transient electromagnetic soundings to map the thickness of the Gray Delta, Maine, and correction of data using coil calibration to improve resolution. ." Geological Society of America Abstracts with Programs 33.1 (2000): 1. Print.

Weddle, Thomas K., Gray Quadrangle, Maine, 1:24,000, Augusta, ME: Natural Resources Information and Mapping, Maine Geological Survey, 1997.

"Surficial Geologic History of Maine." Maine Geological Survey. N.p., 6 Oct. 2005. Web. 11 Feb. 2014. <>.

"River Point Conservation Area." The Town of Falmouth . The Town of Falmouth , n.d. Web. 11 Feb. 2014. <>.

Wednesday, January 1, 2014

Maine's Pinatubo: Unearthing a Natural Disaster

Soon J.D. Irving Limited may be freed to start thinking about how to take 22 million tons of copper ore out of the ground in northern Maine. The Maine legislature may relax laws regulating the mining of metals in Aroostook County. While Irving consider strategies for extracting copper and zinc, as well as relatively small amounts of gold and silver, I have been thinking about how the metal rich rock, called sulfide ore, got there in the first place. It all occurred about 500 million years ago when a series of islands, not too unlike the Philippine islands, were forming off the coast of North America.

The best lens from which to consider what went into creating the ancient ore might be to consider a more recent event. Twenty-one years previous to the bill being passed, Mount Pinatubo was cooling off after a long summer of letting off steam. In the summer of 1991, the Philippine Sea Plate subducted beneath the Eurasian plate, releasing 10 billion tons of magma in a volcanic eruption. As the magma neared the surface, it released chemicals that refused to join with others to form minerals. Valuable metals, like zinc and copper and dangerous ones like cadmium and lead, were distributed as ash across the Philippine region. Far from a rain of wealth, the ashfall is thought to have significantly shortened human lifespan on nearby islands. Sulfur combined with oxygen in the atmosphere to form sulfur dioxide gas, which in turn joined with moisture in the atmosphere to form sulfuric acid. Aircraft throughout the Northern Hemisphere experienced corrosion damage from the acid for years afterward. It is with good reason that the eruption of Mount Pinatubo was regarded as a natural disaster.

Five hundred million years ago no one was around to experience the ash or acidity of eruptions that formed the islands that would become the metal-rich rock in northern Maine. The islands and the ore formed as two oceanic plates in a proto-Atlantic ocean collided. One plunged beneath, bringing loads of ocean water with it. As the water and the rock descended, both heated. The water would have rushed through subterranean rock, dissolving unmatched elements along the way. The scalding liquid would have picked up sulfur, then metals. It would wend its way upward, cooling as it went. As its temperature dropped the dissolved sulfur, submerged and lacking its partner oxygen, would seek out other mates, finding them in the unmatched metals that flowed alongside. The sulfur/ metal pairs, sulfides, solidified and were stored underground preventing life's exposure to corrosive acids or dangerous metals.

In the next decade J.D. Irving may decide it is worth unearthing the metal-bearing sulfides of Aroostook County. But the price of digging up a natural disaster must be paid. Payment can be rendered in advance if the mining company works to prevent the spread of sulfur and metals into the environment. It can be paid after the fact by the citizens of Maine, in the form of clean up costs. Or, it can be paid by sacrificing the beauty and balance of northern Maine's natural ecosystem. Regardless, the cost must be rendered, and it's best to consider this before the bill comes due.

Beck, Fredrick. "A History of Non-Ferrous Metal Mining and Exploration in Maine." Geological Society of Maine. N.p., n.d. Web. 1 Jan. 2014. <>.

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