Friday Trips |
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A-1
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Tectonic-Stratigraphic-Metamorphic
Perspective of the New England Caledonides, West-Central Massachusetts. Part 1. |
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| Leaders: Peter Robinson <Peter.Robinson@NGU.NO> with contributions from many former students and colleagues | ||
| Description: The route of this trip will follow that of the 1993 GSA Transect Trip Day 2 and also the informal trip conducted for the March 2002 Northeastern GSA Meeting in Springfield. It will begin at the Bernardston fossil locality and follow a generally southwestward path across the Pelham dome and the main body of Monson Gneiss into the granulite-facies region of south-central Massachusetts. Discussions will cover a wide spectrum of viewpoints including those of stratigraphy, paleontology, geochronology, igneous intrusions, deformation fabrics including mylonites, metamorphism, partial melting and questions of plate-tectonics. Emphasis will be on developments and concepts since 1993, on the problems related to these, and on recognition that Paleozoic thermotectonics took place in five different episodes, the Late Ordovician Taconian (455-440 Ma), the Late Silurian to Early Devonian Acadian (420- 385 Ma), the Late Devonian to Early Mississippian Quaboagian (370-350), the Late Pennsylvanian Northfieldian (305-285 Ma) and the Permian Alleghanian (270-260 Ma). Two of these are newly and perhaps recklessly named. | ||
| Starting Time and Place: 8 A.M., Hampshire Mall Parking Lot (0.5 miles west of the western intersection of Rt.9 and Rt.116 in Hadley, MA). Gather in the lot on the N side between Media Play and MacDonald's (there is no direct access to the lot from MacDonald's, which is on Rt.9). Because of logistics at several stops, including the Quabbin Reservation, it is hoped to consolidate the trip into a minimum number of vans including one or more provided by University of Massachusetts. We will then proceed in about 40 minutes directly to Stop 1 which is beside U. S. Route 5 north of Bernardston, Mass. Bring lunch and clothing to suit any weather. Several stops will involve walks, mostly on gentle ground up to about 1/2 mile. The trip will conclude with Stop 8, a large wave-washed exposure of Monson Gneiss on Quabbin Reservoir, reached by a drive through locked gates by special arrangement with the management. Return to Amherst will be west along Route 9. | ||
A-2 |
Paleozoic
Mafic Dikes on Mount Monadnock, New Hampshire |
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| Leaders: Peter J. Thompson <pjt3@cisunix.unh.edu> | ||
| Description: The purpose of this trip will be to explore cross-cutting relationships between post-Acadian metamorphosed mafic dikes and granitic dikes similar to the Fitzwilliam granite (dated at 355 Ma, Robinson and Tucker, 1996). The mafic dikes are biotite-rich microdiorites or perhaps kersantites. They contain corroded garnet xenocrysts, hornblende rimmed or replaced by biotite, and ilmenite rimmed by sphene (evidence for Alleghenian overprint?). The dikes cut all phases of Acadian folding in the Littleton Formation exposed on Mt. Monadnock. The trip will concentrate on exposures at the west foot of the mountain, but time and weather permitting, we will venture to the summit area, where a mafic dike cuts spectacular recumbent isoclinal folds. | ||
| Starting Time and Place: 8 A.M., Hampshire Mall Parking Lot (0.5 miles west of the western intersection of Rt.9 and Rt.116 in Hadley, MA). Gather in the lot on the N side between Media Play and MacDonald's (there is no direct access to the lot from MacDonald's, which is on Rt.9). Possible additional meeting point in New Hampshire will be designated by email correspondence with pre-registered participants. | ||
A-3 |
Ductile to Brittle Mesozoic Overprint of Alleghenian Structures, Rockville Area, Connecticut | |
| Leaders: Robert P. Wintsch <wintsch@indiana.edu>, Mary Roden-Tice, M.J. Kunk, and J.N. Aleinikoff | ||
| Description: This trip examines the ductile and brittle structures in high grade rocks of the Bronson Hill terrane, in the Rockville quadrangle (east of Manchester, CT). Ductile fabrics, including sheath folds and climbing veins show a strong SSE vergence. Cross cutting, and retrograde mylonites and phyllonites also show a S and E vergence. Brittle faults show thrust (south vergent), left lateral, and right lateral displacements. Cross cutting relationships establish relative ages, and U-Pb, argon 40/39, and fission track data, provide semi-quantitative age estimates for these structures as early Permian, early Triassic, and Cretaceous. An overall tectonic model of two cycles of left-lateral transpression and extension is offered, with early Triassic and early to mid Cretaceous extensions interrupted by a Middle Triassic transpressional event. | ||
| Starting Time and Place: 8:30 A.M. at the Park and Ride lot off I-84 at the Buckland St.exit. | ||
A-4
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Bedrock Geology of the Lake Sunapee Area, West-Central New Hampshire | |
| Leaders: Timothy T. Allen <tallen@keene.edu> | ||
| Description: Several important features of the Acadian orogen in New Hampshire come together in the Lake Sunapee area, including plutons associated with all four groups of the New Hampshire Plutonic Series, as well as a narrow septum of metasedimentary rocks which may be related to larger structures of the orogen. We undertook mapping in this area in an attempt to help improve understanding of the relationships between structural development, magmatism and metamorphism during the Acadian orogeny. Many of the outcrops are very complex co-minglings of multiple rock types. In addition, we found that the geology of the area is dominated by previously un-recognized Mesozoic normal faults--Lake Sunapee is a graben! | ||
| Starting Time and Place: 8:30 A.M. at the Park-and-Ride lot off Route 103-A at its intersection with Route 11 near Exit 12 of Interstate 89 in New London, New Hampshire. | ||
Saturday Trips |
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B-1 |
Monazite Geochronology and the Alleghenian Assembly of Central New England | |
| Leaders: Frank S. Spear <spearf@rpi.edu>, John T. Cheney <jtcheney@amherst.edu>, and Joseph M. Pyle <pylej@rpi.edu> | ||
| Description: This field trip will examine the geology across central to western New Hampshire from the Merrimack synclinorium across the Bronson Hill anticlinorium to the central New England metamorphic low along the Vermont-New Hampshire border. The main conclusion of this work is that monazite chronology reveals a long and protracted history for central New England metamorphism and tectonics. In New Hampshire, this history began in the Late Silurian/Early Devonian with the intrusion of the New Hampshire Magma Series plutons, and continued until the Permian. Previous petrologic studies (summarized in Spear et al., 2002) had indicated that the nappes of western New Hampshire had undergone distinct metamorphic histories. The monazite chronology bears out this conclusion. However, it was not anticipated that recrystallization in the staurolite zone of western New Hampshire (the so-called “Big Staurolite” nappe of Spear et al., 2002) had occurred in the Alleghenian rather than the Acadian. Therefore, it now appears to us that the final juxtaposition of the New Hampshire series against the Vermont series occurred at the end of the Paleozoic and not during the Acadian orogeny as has been long believed. | ||
| Starting Time and Place: 8 A.M., Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill). Possible additional meeting point in New Hampshire will be designated by email correspondence with pre-registered participants. | ||
B-2 |
Stratigraphy and Structural Geology in the Devonian Granulite Facies | |
| Leaders: Henry N. Berry IV <Henry.N.Berry@maine.gov> | ||
| Description: The Merrimack belt in central Massachusetts contains strongly deformed, metamorphosed sedimentary rocks. Similar rocks are preserved among the abundant plutons of New Hampshire and extend into central Maine, where the metamorphic intensity is less and Silurian fossils are present in the better preserved and fossil-controlled stratigraphic sections of Maine. On this trip we will see rocks in the highest grade Devonian metamorphic rocks in the Appalachians, reaching into the granulite facies. Even though the rocks have been affected by partial melting and high-grade metamorphism, relict primary stratigraphic features can be discerned. Because the stratigraphic interpretation is so vitally important, one objective of the trip is to show participants a variety of common and distinctive rock types in hopes that they may be familiar to workers from surrounding areas. The second objective is to demonstrate the critical relationships on the ground that have been used to reconstruct the sequence of structural, plutonic, and metamorphic events in this area, independent of regional stratigraphic considerations. | ||
| Starting Time and Place: 8 A.M., Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill). | ||
B-3 |
The Shelburne Falls Arc - Lost Arc of the Taconic Orogeny |
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| Leaders:Paul Karabinos <pkarabin@williams.edu>, Heather Stoll <Heather.Stoll@williams.edu>, and J. Christopher Hepburn <hepburn@bc.edu> | ||
| Description: This field trip will visit spectacular and scenic exposures in the Taconic orogen of western Massachusetts. We will explain why we believe that the Taconic orogeny resulted from the collision of Laurentia with the Shelburne Falls arc rather than the Bronson Hill arc. Participants will see the 475 Ma plutonic core of the the Shelburne Falls arc beautifully exposed along the Deerfield River and ancient pillow lavas from the forearc exposed in the Chickley River. We will visit the 479 Ma Hallockville Pond Gneiss, which intruded the Moretown Formation and Glendale Falls where a 447 Ma pluton cross cuts a Taconian thrust and thus helps date the end of faulting in this part of the orogen. We will hike along part of the Appalachian National Scenic Trail to examine the unconformity between Middle Proterozoic Laurentian basement and Late Proterozoic rift clastics in the Day Mountain thrust sheet. Time permitting, we will also see an example of a thrust between the Taconic sequence (continental slope and rise deposits) and coeval continental shelf rocks in the vicinity of Mount Greylock. | ||
| Starting Time and Place: 8:00 A.M. at Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill), or meet the trip at the “Glacial Potholes” by Mole Hollow Candle Shop in downtown Shelburne Falls. | ||
B-4 |
A Trip Through Geologic Time in the Connecticut Valley | |
| Leaders: Richard D. Little <little@gcc.mass.edu> | ||
| Description: This trip is part of the National Association of Geology Teachers - New England Section meeting, concurrent with the NEIGC, but others are welcome to attend. This excursion will start with a 45-minute presentation on local geology at Greenfield Community College followed by a visit to the college's Rock Park, featuring rare armored mud balls as well as tons of other local specimens. The trip will then depart to sites ranging from Mesozoic sedimentary and igneous rocks to glacial and Lake Hitchcock-age landforms. Lunch can be purchased at a field site. The trip will end in time for participants to attend the before-dinner talk (New Zealand Geology) by NAGT- NE President Larry Spencer at Smith College. | ||
| Starting Time and Place: 8:30 A.M. at the Greenfield Community College "Rock Park" at the rear of the main (brick) building. Park in Lot F and walk up road to Rock Park. To reach GCC: take the Greenfield Exit #26 off I-91, proceed on Rte. 2 west for 50 feet (light), turn right. Campus is 1 mi on left. | ||
B-5
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Causes and Consequences of the Triassic-Jurassic Mass Extinction as seen from the Hartford Basin | |
| Leaders: Paul E. Olsen <polsen@ldeo.columbia.edu>, Jessica H. Whiteside <jhw@ldeo.columbia.edu>, and Philip Huber <philnamy@earthlink.net> | ||
| Description: We will examine outcrops, exposures, cores, and fossils that illustrate the major features of the Triassic-Jurassic boundary and subsequent events in the Hartford basin - the source for much of what we know about continental ecosystems during this critical transition in Earth history. In addition to the physical and biological record of the boundary itself, we will focus on the post boundary events, especially the syn-basalt interval, which may have been characterized by a super-greenhouse environment, and the subsequent biotic recovery. We will see spectacular exposures of volcanic structures, including an extremely large eruptive fissure complex, as well as strata containing fauna and flora documenting the extraordinarily stressed post-boundary biota and environments, as well as the rise of dinosaurs to ecological dominance. | ||
| Starting Time and Place: 7 A.M.(leave at 7:30 A.M.), Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill). Participants should be sure to bring a lunch and water to drink. Also, $5 will be needed to gain admission to Dinosaur State Park in Connecticut. | ||
B-6 |
Late Wisconsinan Glacial History of the Connecticut River Valley and A New Drainage History of Glacial Lake Hitchcock: Varves, Landforms and Stratigraphy | |
| Leaders: Lesleigh Anderson <land@geo.umass.edu> and Julie Brigham-Grette (in absentia) <jbg92@geo.umass.edu> | ||
| Description: This trip will visit the local glacial landforms and outcrops with a focus on the history of Glacial Lake Hitchcock, timing of deglaciation, processes influencing lake sedimentation and factors influencing the drainage sequence and style of the lake. In this context, we will also reconsider how the drainage history may be related to the rate and timing of glacio-isostatic rebound. We will examine the stratigraphy and morphology of glacial, glaciofluvial and lacustrine deposits. Most stops will be repeats of the Friends of The Pleistocene Conference held in June 2000. Some stops may be muddy or require a brief walk-in. Bring or wear boots. Some small shovels will be provided. | ||
| Starting Time and Place: 8 A.M., Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill). | ||
Sunday Trips |
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C-1 |
Tectonic-Stratigraphic-Metamorphic Perspective
of the New England Caledonides, West-Central Massachusetts. Part 2. |
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| Leaders: Peter Robinson <Peter.Robinson@NGU.NO> with contributions from many former students and colleagues | ||
| Description: Continuation of Trip A-1. This part of the trip is specifically scheduled to allow interested persons to participate on a different Saturday trip, particularly B-2 lead by Henry Berry, which deals with little know aspects of stratigraphic correlation and structure in the granulite-facies region of south-central Massachusetts and northern Connecticut. With one exception, it will cover areas not on the Berry field trip and will focus on high-grade metamorphism and partial melting, and evidence for shear fabrics of the Quaboagian episode. | ||
| Starting Time and Place: 8:30 A.M at STOP 8A on Route 9. This is at a large road cut (on left, park on right) of rusty schist and amphibolite at the crest of Brimstone Hill several miles east of Quabbin Memorial Park and west of the Town of Ware. Possibly stop 8A will have been visited already on Friday, so the group may move on at 8:30 to STOP 8B (about 1 mile, outcrop on left, park on right) or STOP 9 (State Park on left on crest of Coys Hill), both of which are also on Route 9 and visible from the road, where they will be easily found by late arrivals. The trip is designed to wind down in the vicinity of Sturbridge, Mass. (about 1 hour from Cambridge) around noon for those (including the leader) planning to attend the Frondel Memorial Symposium at Harvard University in the afternoon. Later stops may be visited under the guidance of contributing co-authors. All stops are close to the road or involve very short walks. Lunch is optional. | ||
C-2 |
Basaltic Sills, Dikes, and Lavas of the Hartford Basin, Connecticut | |
| Leaders: Anthony Philpotts <anthony.phipotts@uconn.edu> and Gregory McHone <gregmchone@snet.net> | ||
| Description: Mesozoic volcanic events of Connecticut and Pangaea. We will visit some of the classic exposures of basalts in Connecticut, including the Tariffville Gorge, North Branford Quarry, and Buttress Dike at West Rock, plus an excellent new cut into the base of the Talcott Basalt in Meriden. The North Branford quarry has one of the longest quarry faces in the world, with superb exposures through the Holyoke basalt. Discussions on site will center on petrographic evidence for the evolution of basalts, and on the structures and paleogeography of these gigantic intrusions and flows. | ||
| Starting Time and Place: You should arrrive BEFORE 9:00 A.M. at the parking lot outside of the entry building at the North Branford Quarry of Tilcon, Inc. From I-91 south, take Exit 8 just north of New Haven, Ct. and head east on Rte. 80 for 5.3 miles to Rte 22. Turn left (north) on Rte. 22 and almost immediately turn right into the entrance to the quarry. All participants must travel together in the quarry with a guide from the Tilcon corporation, so do not come late! The trip will start at 9:00 A.M. and finish in the afternoon near Tariffville (a few miles west of Bradley Airport). Bring lunch, or purchase food at a mall stop scheduled before our lunch stop at Castle Craig, Meriden. | ||
C-3 |
Geochemistry and Geochronology of Middle Proterozoic and Silurian Felsic Sills in the Berkshire Massif, Massachusetts | |
| Leaders: Paul Karabinos <Paul.M.Karabinos@williams.edu>, David Morris, Michael Hamilton, and Nicole Rayner <nrayner@nrcan-rncan.gc.ca> | ||
Description: We
will traverse the Berkshire massif from east to west and visit five
excellent exposures
of felsic sills
that were
previously interpreted as syntectonic intrusives into Taconic thrusts. New
SHRIMP zircon ages indicate that the sills were intruded during two widely
separated episodes: the older group of sills intruded at ca. 1 Ga during
high-grade Grenville metamorphism, and the younger group intruded during
the Silurian at ca. 430 Ma. The new age data require a reinterpretation
of the role of the Berkshire massif during the Taconic orogeny. Rather
than being dissected by a dozen thrust faults, it seems likely that the
massif behaved as a rigid block during Paleozoic uplift. Also,
the eastern boundary of the massif may be a Silurian fault, perhaps related
to the opening of the Connecticut Valley trough, rather than a Taconic
thrust. |
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| Starting Time and Place: 8:00 A.M. at Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill), or meet the trip at the eastern intersection of Rt 20 and Rt 8, known as Bonny Rigg Corners, in Becket, Massachusetts. Each stop requires more than 1 km of hiking and some of the walks have steep sections. Participants should be prepared for the walks and bring lunch and water. | ||
C-4 |
Influences of Land Use on Water Quality and Surface Hydrology of the Mill River Watershed, Hatfield, Massachusetts | |
| Leaders: Amy L. Rhodes <arhodes@science.smith.edu> | ||
| Description: The Mill River Watershed (13,000 hectares) is a fourth-order catchment of the Connecticut River and houses many rare and endangered species. This field trip will investigate the heterogeneous topography, geology, and land use practices that range from remote, forested upland terrain to densely populated, lowland areas overlying Glacial Lake Hitchcock sediments. Discussions will center on methods to distinguish effects of non-point source pollution from mineral weathering on water chemistry, and assessment of impacts of water removal on stream hydrology (Rhodes et al., ES&T, 2001), as well as strategies that involve undergraduates in watershed-based research. | ||
| Starting Time and Place: 8:30 a.m., Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill). Bring lunch and water. Trip will include an approximately 1 km hike. | ||
C-5
|
Deerfield Basin: Evidence for evolving Mesozoic stress fields and fault types | |
| Leaders: Don Wise <dwise@geo.umass.edu> | ||
| Description: This trip will focus on brittle fracture history of the basin starting with its western hinge zone, concentrating on the central portion on the floor of the Connecticut River near Turners Falls, and ending at its eastern border fault zone. Triassic and early Jurassic history involved NNE trending en echelon extension. With time, crustal anisotropy concentrated these features along the west flank of the Bronson Hill Anticlinorium to produce the border fault and the present dominant east tilt of the basin. Late NNE-SSW compression created small scale thrust and strike-slip faults. Most but not all the stops are repeats from parts of former NEIGC trips. Some stops involve steep climbs, slippery paths, rock-hopping, and potential wet feet with part of the itin erary dependent on weather and river levels. | ||
| Starting Time and Place: 8 A.M., Umass Lot #62 off N. Pleasant Street near Geosciences (Morrill). | ||