Fort Dummer Slate Quarry EarthCache
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An Earthcache in Ft Dummer State Park. For more information visit www.earthcache.org
The park is open from Memorial Day to Labor Day, when you may need to pay a small day use fee, but do get the most bang for your buck by visiting the other caches already in the park. In the off season, it’s open to public use for hiking, skiing, or snowshoeing. Check the Vt State Parks website for more info. www.vtstateparks.com
The listed coord’s are where you will find the answers you need to log this earthcache.
CAUTION - this is a quarry, with the possibility of falling rock, and deep water at the site. Please use caution and good sense.
To claim the find, email me the answers to these questions: (Put the cache name in the subject line.)
1. Vermont is known for producing many variations of slate. Which colors of slate do you see around you?
2. How many years ago was this slate formed?
3. Take an elevation reading where you are standing. Estimate the total elevation difference, from water’s edge to the top of the quarry above and across from you.
4. At what angle are the layers of most of the slate at this location? (Remember, it all started as flat mud).
5. Post a pic of you and/or your GPS at the quarry, OR - include in your email your observations of the area.
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VERMONT GEOLOGY
Vermont's geologic structure parallels the Appalachian chain, which runs from Alabama to Newfoundland. Its oldest rocks, of Precambrian age, are in the Green Mountains. The body of rocks to the east formed on a separate continent across the Iapetus Ocean, which closed for good during the Devonian Period about 400 million years ago.
Vermont produces granite, marble and slate from these various rocks as well as talc and soapstone from its metamorphosed lavas. The quality of its stone makes Vermont a producer of dimension stone out of proportion to the size of the state.
HOW WAS SLATE FORMED?
Slate is formed by the effects of heat and pressure on shale or mudstone. The source of the heat and pressure is usually from depth of burial or tectonic plate collisions, where shale is put under tremendous directional pressure. The pressure causes an alignment of the constituent minerals in the shale, creating a foliated or platy texture, characteristic of certain metamorphic rocks.
Slate is a metamorphic rock, usually formed from a fine sedimentary clay such as shale. It is formed under low heat and low pressure, resulting in a rock that is easily split into thin slabs that have great strength and are very durable
VERMONT SLATE QUARRIES
As reported in 1845, some of the first slate to be quarried in VT came from the Devonian Littleton Formation, prominent in Windham County, and the nearby Devonian Northfield Formation. This quarry, and others in the area, are part of this Formation.
Vermont slate is renowned for it’s green, gray, black, red, and mottled (mixed coloration) slate. These colors were formed as a result of varying cooling temperatures and chemical reactions during the metamorphism of shale. It is estimated that slate formed between 450 and 650 million years ago, during the Paleozoic Era. This transition from shale to slate is responsible for a sturdy and strong stone that can be broken into flat continuous pieces. Thus, it is currently used for blackboards, roofing, flooring, mantels, tabletops, and even monuments, headstones, and memorials.
Information from Vermont Geological Survey; see: (visit link)
About the Park:
Fort Dummer State Park was named after Fort Dummer, the first permanent white settlement in Vermont. Built in 1724, the Fort was initially the gateway to the early settlements along the banks of the Connecticut River. The Park overlooks the original site of Fort Dummer, which was flooded when the Vernon Dam was built in 1908. This site, now underwater, can be seen from the northernmost scenic vista on the Sunrise Trail. There is a historical marker at the junction of Cotton Mill Hill and Rt. 142.
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