3 days ago
Woo! Science: The Worcester area holds clues to the Earth's distant past
Woo! Science is a column of science news and newsmakers in Worcester and the region. Got a science news idea? Email Margaret Smith at msmith@
So, dig.
Literally. Maybe.
As we go about our day, on the streets and roads of Worcester, all around us, the hills, the rivers, the valleys and even the earth under the pavement has a story to tell us.
But exploration means taking good care, and respecting the land. Rocks, minerals, fossils and findings that took over a billion years to make can be completely messed up in a few minutes by humans running out the cosmic clock.
As it happens, Worcester sits neatly in a veritable treasure of time, as far west as New York state, as far north as Maine, and dipping into the lower New England states.
Marty Christiansen, collections management specialist at the EcoTarium science and nature museum, said, "Most of the stone under Worcester was born in the Mesoproterozoic Era." Eras are a way scientists classify significant time periods, The Mesoproterozoic Era, part of the Precambrian period, takes us back to a time of some of the earliest known, surviving geologic records. We're talking some 4.6 billion years ago, with the Mesoproterozoic Era going back to about 1.2 billion years.
So, the time when Earth was starting to become the lovable planet that we call home. In these parts, Christiansen said, "We don't have many good fossils here, but it is some of the oldest surviving stone on the planet." Christiansen said, "The geology underneath Worcester was shaped by the continent collision that formed the Appalachian Mountain range.
It's also a place of former mines for graphite, lead, coal and garnet, known in popular culture as a birthstone for January, and originating in silicate materials with colors ranging from orange to purple, and even colorless forms.
And you can find delightful stones, minerals and other amazing things, some very particular to their own region. "In western Massachusetts, obviously, quartz, lots and lots of quartz around here," said Sara Furbush, president of the Worcester Mineral Club. The club hosts expeditions to look for geological wonders in the area, but also to cultivate interest in mineralogy, geology, paleontology, gemology, lapidary, jewelry making, and more.
As for Worcester, Furbush said, "There are 31 minerals you can find in the Worcester area." Respect to that.
Your basic rock comprises one or more minerals, while minerals are basically the building blocks of rocks, with an orderly internal structure and characteristic chemical composition, crystal form, such as quartz, feldspar, mica, amphibole, olivine, and calcite.
Rocks are classified in three categories, and there are examples of all three throughout the region:
igneous rocks, or rocks formed by volcanic activity, such as granite, pumice, and pegmatite, which Furbush said has been found throughout New England, with large crystals within;
sedimentary rocks, which can even contain matter from dead plants, animal skeletons, along with sand and dirt, such as shale, and coal, literally a fossil fuel;
metamorphic rocks, which start out as one type of rock, and changed through pressure and heat within the Earth, such as slate.
One helpful tool for learning is a database created by the Virginia-based Hudson Institute of Mineralology. "You can basically look in any locality, or any town, and it will tell you minerals that have been found in the area," Furbush said. "In Worcester, there has been coal, graphite, silver. Now, whether you are going to find them nowadays or not is a different story."
Calcite, fluorite, graphite, garnet and other minerals have turned up in the area, Furbush said.
And then there is a rock crystal with a unique look, and story. Chiastolite bears a brown marking resembling a cross. It has been found in Lancaster's George Hill area, as well as in Sterling, Clinton and Boylston. They can appear as little bumps among boulders and rocks.
But when a rock or mineral has a compelling look, it can draw many seekers on a quest. "We really know of one place, and that place is getting over dug-out, and overmined," said Furbush.
So, how to strike a balance? Furbush said responsible rock and mineral clubs have guidelines and rules, among them: "Don't take everything, but take enough, as you may never return to this location," Furbush said. "You want to leave stuff for other people to find. If you dig holes, you fill it back in."Furbush said, "It's very 'take care of the land,' and whatnot. But people who don't know these things, they go, and it's creating chaos. Boulders that have been smashed to smithereens."
As a cautionary tale, Furbush cited the example of the New England Forestry Foundation's Hartnett Manhan Memorial Forest in Easthampton, a town in Western Massachusetts. "It's public land. A river ran through it, and it was great, a great place to bring kids on a hot day." Nearby is the site of a former button factory, and buttons would turn up in the water.
"You could find buttons. You could find really cool specimens. But people have been going there, and just destroying the place. There were holes dug everywhere. Trees were knocked down, cut down. The river beds were pushed back. And it got so bad that they closed it, and now it's gone for everyone."
Christiansen evoked the traditional Girl Scout principle: "Leave only footprints. Do not disturb the area. Not to disturb the natural position of rocks, but instead, appreciate them without disturbing the area."
What's special about the region's character is well worth protecting. "In a lot of New England, the glaciers scraped and passed over. A lot of our lakes were glacially formed." Along the way, glaciers not only carved the character of much of landscape; they picked up and dropped off gifts of the Earth's harvest that would delight humans eons later.
Furbush said favorite finds include rodanite, a bright pink rock found in western Massachusetts. "And then you go up to Keene, New Hampshire, and you can find beautiful tourmalines ... go over to Rhode Island, and you are finding amethyst ... so, a very unique area."
Christiansen said the area is also home to "glacial erratics," that is, objects and materials that started someplace else, but which were carried great distances by glaciers that had run over the tops of mountains. These include some boulders. "You get a lot of the big ones, that were dropped off with the glacier melt," said Christiansen.
Places such as Purgatory Chasm and Millstone Hill, in Worcester's Green Hill Park, bear witness to the work of the glaciers.
This article originally appeared on Telegram & Gazette: Woo! Science: In Worcester area, you're never too old to 'rock'
