Northwestern Vermont Geoscience Tour
Southern Champlain
Valley Geoscience
Todays tour will take us further down what should be becoming familiar Route 7 but we will not be returning to the ECHO center at the end of the day as we will be camping at Button Bay State Park and having a star party at that location. We will stop and make detailed observations of roadcuts along Route 7 as we travel first to the Lake Champlain Maritime Museum (802) 475-2022, open 5/24- 10/30 from 10-5, admission $10.00 then Button Bay State Park (802) 475-2377. There are rustic lean-to's (keep out weather and bugs) for rent at $25.00 per day, with central showers, toilets and pool. You need to bring all sleeping gear, lights etc. check in/out 2:00PM. The map below will get you to the Museum and you can see where Button Bay Road is just to the south of the LCMM.
http://www.lcmm.org/museum_info/directions.htm http://www.lcmm.org/museum_info/visit.htm
Southern Champlain Valley Tour
Along the way to the Maritime Museum in Ferrisburgh and Button Bay State Park we will observe roadcuts that will show us further evidence of the effects of the Champlain thrust fault that runs in from the shoreline of Lake Champlain and crosses Route 7 in several places. We will do this because the proximity to the road provides ample references to correlate your location and the geologic formations found on your geologic map. You will also be able to see that different types of sediments created the various outcrops indicating changes in the paleo shoreline environments and water depth. Remember that heavier materials drop out first as water velocity slows as a large body of water is encountered. look for evidence of what might be sedimentary facies as you observe the roadcuts. We will use a surficial geology map to identify the formations we see along the way, plot our locations and identify rock types we have seen before on previous days of this trip. At each stop measure strike and dip, identify the rock type, note any intrusions or metamorphism and the effects of faulting. The first roadcut stop is about 1/2 mile beyond yesterdays turnoff to the Shelburne Bay Fishing access. Stay in the right lane as you approach the large roadcut that faces you and go around the jughandle and across Route 7 at the light. Continue on another 100 yards and park in the small church parking area on the left. Walk back to the green in the middle of the jughandle and begin your study of these rock exposures. Walk down the sidewalk towards the bridge over the La Platte River and identify the change of rock types as you descend. What change in deposition occurred that is evidenced in the rock outcrops? Can you see another type of rock along the La Platte river under the railroad bridge that parallels Route 7 ? See if you can get a GPS elevation change reading from the river level back to the top of the hill that may be useful in constructing a rock column. Your rock column will include dolostones quartzites and shales. Do those different rock types indicate transgressions and regressions in this paleo-coastal area? About 3 miles directly east from this location is a large limestone quarry that is not open to puplic access. see if you can locate that formation on your geologic map.
Shelburne Vermont Shelburne Vermont
Both photos above by Mark Powers
Leaving this roadcut proceed south on Route 7 until you begin to descend a long hill with a field and spectacular view of the Lake and the High Peaks of the Adirondacks to the west. Just past Horsfords Nursery on the right you will see a turnoff on the left where you will park. Walk carefully South along Route 7 on this side until you arrrive at a severely folded asea of shaley limestone that might be considered to be almost slate. This location is very near the Champlain Thrust Fault boundary as you can see on your geologic map. See if you can determine bedding planes in this location, or if not bedding planes, determine what forces created the parallel layers in this formation and why the calcite veins are where they are. Sketch the dramatic nearly 180 degree fold in the rock and examine hand samples to try and determine if it is shaley limestone or slate. Continue south on Route 7 about 4 miles until you get to Ferrisburgh and just past Greenbush road on the right. find a place to pull off of the side road so that you can examine the roadcut on the East side made of shaley limestone. This location is also very close to the fault but the appearance of the rock is different than the previous stop. Ascertain why and speculate on the abundant calcite veining deposits are here. Continue south again until you get to the first set of traffic lights for Vergennes and pull over into the rest stop just past the lights on the left. Cross the road and examine the large outcrop that shows evidence of glacial scouring. make notes about the extent of the scouring and the compass direction the glacier most have been moving. Make final reflective notes about the road cut portion of todays trip. This portion of the trip will take 3 hours.
Charlotte Vermont Ferrisburgh Vermont
Both photos above by Mark Powers
Lake Champlain Maritime Museum (LCMM)
This museum is a working museum where displays exhibit current lake discoveries and research by the museums staff of divers, archaeologists and biologists. We visit this museum to see how this dedicated group is actively looking at the human impacts on the lake both past and present and their efforts to document and preserve the history of human activities on the lake The director Art Cohn has more energy than any two people I know and he has made numerous discoveries of historic shipwrecks and has been instrumental in cataloging those wrecks before the ever thickening layer of Zebra Mussels obliterates all traces of them. He and his staff have built replicas of revolutionary war craft that turned the tide of that conflict as well as the War of 1812 on Lake Champlain and have also chronichled the use of the lake over time for commerce as Vermont's economy progressed. Beyond the archaeologic aspects, The LCMM is very interested in the biologic health of the lake and there are numerous displays about environmental awareness and the impact that human acttivities in this rural region have on the lake. The lake has a lot of interesting and odd fish species like the Bowfin and Sturgeon and the exhibit Fish Stories describes the changing habitat the lake has undergone from glacial lake to marine to the present day populations. The exhibit discusses the anthropogenic changes caused by canal building and changes in lake health due to changes in land use in the surrounding watershed. Other exhibits describe how the Lake and surrounding environment is affected by the climate of our region where the range of temperatures can range from the high 90's to -25 degrees Fahrenheit. The lake often freezes over completely and it has depths that reach to over 400 feet in places. The maritime museum has a wealth of information about those different subsurface environments and how the various thermoclines interact seasonally.
One outreach program for schools that the LCMM has developed is a really well integrated series of lessons in the 1609 Quadricentennial Curriculum that commemorates the date when Samuel de Champlain first entered the lake. This program integrates aspects of geoscience with history and is useful for a variety of grade levels. Customized tours of the facility can be arranged for the LCMM by calling the main office. Our visit that relates to geoscience will take 4 hours.
Map of New France by Samuel de Champlain from http://en.wikipedia.org/wiki/Samuel_de_Champlain
Bowfin Sturgeon
pond.dnr.cornell.edu/nyfish/Amiidae/bowfin.jpg fish.dnr.cornell.edu/.../atlantic_sturgeon.jpg
Button Bay State Park
We visit this location to see some unique formations a diverse ecosystem on the shores of the lake and to have a clear night sky for astronomical observations. This park is a nice retreat on the shores of the lake and it is named for the odd circular concretions sometimes found on the shorelines called buttons. These concretions are very fine grained silt derived mineral segregations typically found in glacial lake sediments. The glacial clay sediments that contain these sediments are referred to as varved clays. The cementing materials are typically CacO3 and FeO2 and the concretions often form concentrically around a nucleus and are flattened in the layers of sediment giving them the apearance of buttons (32). These concretions offer further evidence of our previous discussions of the stages of the development of the bodies of water that have occupied the Champlain Valley over time. Exploring the park will also reveal some deposits of fossiliferous limestone and you should identify the imbedded fossils that you can find, many of which we have already encountered on previous days trips. The park employs naturalists that can lead a naure hike along the shoreline and woodlands explaining the biological community found there and the impact that human presence in the region has had over time. the naturalists are knowledgeable about the water quality, invasive species and events that formed the land of this area. There are numerous species to observe in the park such as turtles, snakes, osprey, geese and the occasional bald eagle. Kayaks can be rented to explore the shoreline and the nearby but offshore islands. The daylight portion of this trip should take 2 hours. The naturalists can host the astronomy discussions in the evening and are able to field questions at a variety of levels or the night sky observations can be done independently.
Both photos above from http://www.selfdesignedstudent.com/2008/06/button-bay-state-park.html
Concretions Fossiliferous limestone
Both photos above http://www.anr.state.vt.us/DEC/GEO/rockkits.htm
Night sky observations at Button Bay
As you know from the drive to this area it is quite rural and there is no light pollution to interfere with viewing the night sky. During the previous days trips you probably have seen some of the most spectacular sunsets over the lake and the Adirondack mountains. Recall the reasons that we see the oranges and reds of sunsets as the white light of the sun travels through more atmosphere as the sun becomes lower on the horizon. This is also a good time to review the data that you have been taking with your GPS unit about Moon rise and set as well as the phases the Moon has been in and the relative positions of the Earth, Moon and Sun at the particular time of the year you are taking this trip. Make notes about your conclusions about those topics in your journal and make labeled diagrams to further illustrate your knowledge of those items. After the sun sets you will be able to clearly see Venus to the west and you should recall the similarities and differences to our planet and how the phases of Venus were so important in developing the heliocentric model of our solar system. Using a quick reference Sky and Telescope magazine star chart of the northern hemisphere for the appropriate time of the year or an interactive star chart (use zip code 05491 when prompted) with helpful links identify constellations and planets that you see in the sky over Button Bay and any stars that you can locate. Locate Polaris and compare its location with the north reading you take with your GPS or magnetic compass. Consider that Samuel de Champlain used an astrolabe for his navigations here in 1609. The referenced link provides a template for constructing an astrolabe that you can try to use with the accompanying instructions. Can you discern any color differences in the stars you identify? Use a Hertzprung-Russell diagram to check your perceived colors of the stars you identify. Why might the colors on the H-R diagram not be apparent? Use the diagram to ascertain other aspects of the stars you find such as size luminosity and their position on the diagram. Another observation that you can make provided the Moon is not too bright and the sky is clear is the band of stars in the Milky Way. Make a note of how this region and the constellations move over time as the night progresses. Lastly if you are patiently lying on your back stargazing note any meteors and satellites passing over and make a note of their direction of travel. Is there any regularity to the direction of either type of object ? Given that Vemont is in a relatively high latitude, how different will the night sky be 6 months from the date you are making these observations? It is unlikely that you will be on this trip when the elusive Aurora Borealis are sometimes visible but review the cause of this phenomena of the Earth's magnetic field, charged particles in the solar wind and the ionosphere. This evening activity will take 2-3 hours.
Photo by Joe Comeau http://onemansblog.com/wp-content/uploads/2007/03/AuroraBorealis.jpg
Todays tour will take us further down what should be becoming familiar Route 7 but we will not be returning to the ECHO center at the end of the day as we will be camping at Button Bay State Park and having a star party at that location. We will stop and make detailed observations of roadcuts along Route 7 as we travel first to the Lake Champlain Maritime Museum (802) 475-2022, open 5/24- 10/30 from 10-5, admission $10.00 then Button Bay State Park (802) 475-2377. There are rustic lean-to's (keep out weather and bugs) for rent at $25.00 per day, with central showers, toilets and pool. You need to bring all sleeping gear, lights etc. check in/out 2:00PM. The map below will get you to the Museum and you can see where Button Bay Road is just to the south of the LCMM.
http://www.lcmm.org/museum_info/directions.htm http://www.lcmm.org/museum_info/visit.htm
Southern Champlain Valley Tour
Along the way to the Maritime Museum in Ferrisburgh and Button Bay State Park we will observe roadcuts that will show us further evidence of the effects of the Champlain thrust fault that runs in from the shoreline of Lake Champlain and crosses Route 7 in several places. We will do this because the proximity to the road provides ample references to correlate your location and the geologic formations found on your geologic map. You will also be able to see that different types of sediments created the various outcrops indicating changes in the paleo shoreline environments and water depth. Remember that heavier materials drop out first as water velocity slows as a large body of water is encountered. look for evidence of what might be sedimentary facies as you observe the roadcuts. We will use a surficial geology map to identify the formations we see along the way, plot our locations and identify rock types we have seen before on previous days of this trip. At each stop measure strike and dip, identify the rock type, note any intrusions or metamorphism and the effects of faulting. The first roadcut stop is about 1/2 mile beyond yesterdays turnoff to the Shelburne Bay Fishing access. Stay in the right lane as you approach the large roadcut that faces you and go around the jughandle and across Route 7 at the light. Continue on another 100 yards and park in the small church parking area on the left. Walk back to the green in the middle of the jughandle and begin your study of these rock exposures. Walk down the sidewalk towards the bridge over the La Platte River and identify the change of rock types as you descend. What change in deposition occurred that is evidenced in the rock outcrops? Can you see another type of rock along the La Platte river under the railroad bridge that parallels Route 7 ? See if you can get a GPS elevation change reading from the river level back to the top of the hill that may be useful in constructing a rock column. Your rock column will include dolostones quartzites and shales. Do those different rock types indicate transgressions and regressions in this paleo-coastal area? About 3 miles directly east from this location is a large limestone quarry that is not open to puplic access. see if you can locate that formation on your geologic map.
Shelburne Vermont Shelburne Vermont
Both photos above by Mark Powers
Leaving this roadcut proceed south on Route 7 until you begin to descend a long hill with a field and spectacular view of the Lake and the High Peaks of the Adirondacks to the west. Just past Horsfords Nursery on the right you will see a turnoff on the left where you will park. Walk carefully South along Route 7 on this side until you arrrive at a severely folded asea of shaley limestone that might be considered to be almost slate. This location is very near the Champlain Thrust Fault boundary as you can see on your geologic map. See if you can determine bedding planes in this location, or if not bedding planes, determine what forces created the parallel layers in this formation and why the calcite veins are where they are. Sketch the dramatic nearly 180 degree fold in the rock and examine hand samples to try and determine if it is shaley limestone or slate. Continue south on Route 7 about 4 miles until you get to Ferrisburgh and just past Greenbush road on the right. find a place to pull off of the side road so that you can examine the roadcut on the East side made of shaley limestone. This location is also very close to the fault but the appearance of the rock is different than the previous stop. Ascertain why and speculate on the abundant calcite veining deposits are here. Continue south again until you get to the first set of traffic lights for Vergennes and pull over into the rest stop just past the lights on the left. Cross the road and examine the large outcrop that shows evidence of glacial scouring. make notes about the extent of the scouring and the compass direction the glacier most have been moving. Make final reflective notes about the road cut portion of todays trip. This portion of the trip will take 3 hours.
Charlotte Vermont Ferrisburgh Vermont
Both photos above by Mark Powers
Lake Champlain Maritime Museum (LCMM)
This museum is a working museum where displays exhibit current lake discoveries and research by the museums staff of divers, archaeologists and biologists. We visit this museum to see how this dedicated group is actively looking at the human impacts on the lake both past and present and their efforts to document and preserve the history of human activities on the lake The director Art Cohn has more energy than any two people I know and he has made numerous discoveries of historic shipwrecks and has been instrumental in cataloging those wrecks before the ever thickening layer of Zebra Mussels obliterates all traces of them. He and his staff have built replicas of revolutionary war craft that turned the tide of that conflict as well as the War of 1812 on Lake Champlain and have also chronichled the use of the lake over time for commerce as Vermont's economy progressed. Beyond the archaeologic aspects, The LCMM is very interested in the biologic health of the lake and there are numerous displays about environmental awareness and the impact that human acttivities in this rural region have on the lake. The lake has a lot of interesting and odd fish species like the Bowfin and Sturgeon and the exhibit Fish Stories describes the changing habitat the lake has undergone from glacial lake to marine to the present day populations. The exhibit discusses the anthropogenic changes caused by canal building and changes in lake health due to changes in land use in the surrounding watershed. Other exhibits describe how the Lake and surrounding environment is affected by the climate of our region where the range of temperatures can range from the high 90's to -25 degrees Fahrenheit. The lake often freezes over completely and it has depths that reach to over 400 feet in places. The maritime museum has a wealth of information about those different subsurface environments and how the various thermoclines interact seasonally.
One outreach program for schools that the LCMM has developed is a really well integrated series of lessons in the 1609 Quadricentennial Curriculum that commemorates the date when Samuel de Champlain first entered the lake. This program integrates aspects of geoscience with history and is useful for a variety of grade levels. Customized tours of the facility can be arranged for the LCMM by calling the main office. Our visit that relates to geoscience will take 4 hours.
Map of New France by Samuel de Champlain from http://en.wikipedia.org/wiki/Samuel_de_Champlain
Bowfin Sturgeon
pond.dnr.cornell.edu/nyfish/Amiidae/bowfin.jpg fish.dnr.cornell.edu/.../atlantic_sturgeon.jpg
Button Bay State Park
We visit this location to see some unique formations a diverse ecosystem on the shores of the lake and to have a clear night sky for astronomical observations. This park is a nice retreat on the shores of the lake and it is named for the odd circular concretions sometimes found on the shorelines called buttons. These concretions are very fine grained silt derived mineral segregations typically found in glacial lake sediments. The glacial clay sediments that contain these sediments are referred to as varved clays. The cementing materials are typically CacO3 and FeO2 and the concretions often form concentrically around a nucleus and are flattened in the layers of sediment giving them the apearance of buttons (32). These concretions offer further evidence of our previous discussions of the stages of the development of the bodies of water that have occupied the Champlain Valley over time. Exploring the park will also reveal some deposits of fossiliferous limestone and you should identify the imbedded fossils that you can find, many of which we have already encountered on previous days trips. The park employs naturalists that can lead a naure hike along the shoreline and woodlands explaining the biological community found there and the impact that human presence in the region has had over time. the naturalists are knowledgeable about the water quality, invasive species and events that formed the land of this area. There are numerous species to observe in the park such as turtles, snakes, osprey, geese and the occasional bald eagle. Kayaks can be rented to explore the shoreline and the nearby but offshore islands. The daylight portion of this trip should take 2 hours. The naturalists can host the astronomy discussions in the evening and are able to field questions at a variety of levels or the night sky observations can be done independently.
Both photos above from http://www.selfdesignedstudent.com/2008/06/button-bay-state-park.html
Concretions Fossiliferous limestone
Both photos above http://www.anr.state.vt.us/DEC/GEO/rockkits.htm
Night sky observations at Button Bay
As you know from the drive to this area it is quite rural and there is no light pollution to interfere with viewing the night sky. During the previous days trips you probably have seen some of the most spectacular sunsets over the lake and the Adirondack mountains. Recall the reasons that we see the oranges and reds of sunsets as the white light of the sun travels through more atmosphere as the sun becomes lower on the horizon. This is also a good time to review the data that you have been taking with your GPS unit about Moon rise and set as well as the phases the Moon has been in and the relative positions of the Earth, Moon and Sun at the particular time of the year you are taking this trip. Make notes about your conclusions about those topics in your journal and make labeled diagrams to further illustrate your knowledge of those items. After the sun sets you will be able to clearly see Venus to the west and you should recall the similarities and differences to our planet and how the phases of Venus were so important in developing the heliocentric model of our solar system. Using a quick reference Sky and Telescope magazine star chart of the northern hemisphere for the appropriate time of the year or an interactive star chart (use zip code 05491 when prompted) with helpful links identify constellations and planets that you see in the sky over Button Bay and any stars that you can locate. Locate Polaris and compare its location with the north reading you take with your GPS or magnetic compass. Consider that Samuel de Champlain used an astrolabe for his navigations here in 1609. The referenced link provides a template for constructing an astrolabe that you can try to use with the accompanying instructions. Can you discern any color differences in the stars you identify? Use a Hertzprung-Russell diagram to check your perceived colors of the stars you identify. Why might the colors on the H-R diagram not be apparent? Use the diagram to ascertain other aspects of the stars you find such as size luminosity and their position on the diagram. Another observation that you can make provided the Moon is not too bright and the sky is clear is the band of stars in the Milky Way. Make a note of how this region and the constellations move over time as the night progresses. Lastly if you are patiently lying on your back stargazing note any meteors and satellites passing over and make a note of their direction of travel. Is there any regularity to the direction of either type of object ? Given that Vemont is in a relatively high latitude, how different will the night sky be 6 months from the date you are making these observations? It is unlikely that you will be on this trip when the elusive Aurora Borealis are sometimes visible but review the cause of this phenomena of the Earth's magnetic field, charged particles in the solar wind and the ionosphere. This evening activity will take 2-3 hours.
Photo by Joe Comeau http://onemansblog.com/wp-content/uploads/2007/03/AuroraBorealis.jpg
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