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Award Detail

Awardee:VERMONT STATE COLLEGES
Doing Business As Name:Castleton University
PD/PI:
  • Timothy W Grover
  • (802) 468-1289
  • Tim.Grover@castleton.edu
Award Date:08/11/2014
Estimated Total Award Amount: $ 59,713
Funds Obligated to Date: $ 59,713
  • FY 2014=$59,713
Start Date:08/15/2014
End Date:07/31/2018
Transaction Type:Grant
Agency:NSF
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Collaborative Research: RUI: Proterozoic Mountain Building and Collapse, Eastern Adirondacks, New York
Federal Award ID Number:1419852
DUNS ID:071097745
Parent DUNS ID:071088637
Program:TECTONICS
Program Officer:
  • Stephen S. Harlan
  • (703) 292-8552
  • sharlan@nsf.gov

Awardee Location

Street:62 Alumni Drive, Woodruff Hall
City:Castleton
State:VT
ZIP:05735-4454
County:Castleton
Country:US
Awardee Cong. District:00

Primary Place of Performance

Organization Name:Castleton State College
Street:62 Alumni Drive
City:Castleton
State:VT
ZIP:05735-4454
County:Castleton
Country:US
Cong. District:00

Abstract at Time of Award

Rocks of the Adirondack Mountains of New York represent a large dome-shaped uplift of the Precambrian basement of North America. These rocks record the assembly and breakup of the supercontinent, "Rodinia" that formed approximately 1 billion years ago. The formation and dispersal of this continent may have played a role in the evolution of life on Earth, the evolution of climate and the production of a snowball Earth, and in the development of important economic resources, including Rare Earth Element deposits. New data are significantly changing our understanding of the history of the Adirondack uplift. A major period of mountain-building, the 1180 million year Shawinigan orogeny, was previously unrecognized in the region, and one challenge involves recognizing and distinguishing the effects of this tectonism compared to the 1050 Million year Ottawan orogeny that was previously thought to dominate the geology of this region. The latest stages in the geologic history of the Adirondacks involved intrusion of extensive granite ("Lyon Mountain granite") and the development of shear zones that were important in the collapse of the mountains and in the uplift of the basement rocks. This research will involve modern structural, petrologic, and geochronologic analysis to characterize the geologic and tectonic history of the eastern Adirondack region, and further our understanding of mid crustal processes during mountain building and collapse. This work represents a new collaboration between the University of Massachusetts and Castleton State College, a predominantly undergraduate state college nearly adjacent to the Adirondack field area. In addition to the PIs, the research team will consist of undergraduates from Castleton State College and a graduate student from the University of Massachusetts. The graduate student will serve as a mentor for undergraduates from Castleton and a link between the two institutions. The collaboration will provide an ideal base for field research during all seasons of the year and it will provide access for Castleton undergraduates to a predominantly undergraduate state college nearly adjacent to the Adirondack field area. In addition to the PIs, the research team will consist of undergraduates from Castleton State College and a graduate student from the University of Massachusetts. The graduate student will serve as a mentor for undergraduates from Castleton and a link between the two institutions. The collaboration will provide an ideal base for field research during all seasons of the year and it will provide access for Castleton undergraduates to a research-oriented university and to research equipment. Finally, the eastern Adirondack Mountains are a popular destination for hiking, camping, and vacations. Student researchers will work to develop outreach materials and programs about the geology of the spectacular northeastern Adirondack region. This research tests the hypothesis that there is a regionally extensive shear zone in the eastern Adirondacks in the vicinity of Whitehall, New York that accommodated the eastward unroofing of the Adirondack Mountains during orogenic collapse shortly after the culmination of the Ottawan orogenic event (ca. 1050 Ma). Preliminary in-situ monazite ages constrain the extensional shearing to 1050-1026 Ma, similar to those reported for the extensional movement on the Carthage-Colton shear zone in the NW Adirondacks. These data suggest that orogenic collapse following the Ottawan orogeny resulted in the formation of a two-sided metamorphic core complex or gneiss dome structure. This project will utilize in-situ high resolution monazite geochronology, in conjunction with detailed field mapping, structural and kinematic analysis, and metamorphic petrology in order to characterize the extent, kinematics, and timing of East Adirondack shearing and to integrate the shear zone into the overall tectonic history of the Adirondack Mountains. The Grenville orogen marks the culminating collision in the assembly of the supercontinent Rodinia. Post-collisional collapse of the Himalayan-scale Grenville orogen signaled the start of a new phase of rifting, passive margin development, and in the broadest sense, the Appalachian Wilson cycle. Major changes have been proposed in the character and age of tectonic events involved in the construction and collapse of the orogen. With the coming of Earthscope-US-Array and GeoPrisms it is critical to evaluate new models for this orogen that may have had a controlling influence on the geometry and character of the proto-Atlantic margin. The proposed research will involve detailed field mapping and structural/petrographic analysis in order to establish a chronologic framework for the development and overprinting relationships of fabrics and metamorphic mineral assemblages. Rocks related to each of the major stages of Adirondack orogenesis (Elsevirian, Shawinigan, AMCG plutonism, Ottawan, etc) are all in close proximity in the eastern Adirondacks. The project involves the use of thermobarometry and psuedosection analysis to delineate the Pressure-Temperature evolution of the crust during the orogenic events with particular focus on the late-stage shearing. A major portion of the work will involve in-situ monazite geochronology in order to place timing constraints on all parts of the history. Our ultimate goal is to place new constraints on the tectonic history of the Grenville Orogen, especially on the collapse and exhumation stages, and also to add to the evolving understanding of monazite behavior during metamorphism and deformation. This work will help to place the Adirondack massif within the context of gneiss domes and provide evidence about the role that this dome played in the collapse and exhumation of the orogen.

Publications Produced as a Result of this Research

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Grover, T.W., Williams, M.L. Smith, A., Pless, C.R., Suarez, K. and Baurle, E. "Kinematic, metamorphic, and geochronologic constraints on intrusion, deformation, and metamorphism southeast of Dacy Clearing, Shelving Rock Quadrangle, eastern Adirondack Mountains, New York" Geological Society of America Abstracts with Programs, v.50, 2018, p..

Williams, M.L., Grover., T.W., Jercinovic, M.J., Pless, C.R., Regan, S.P., and Suarez, K. "Constraining the timing and character or extreme crustal melting in the Adirondack Mountains using multiscale compositional mapping and in-situ geochronology" Geological Society of America Abstracts with Programs, v.50, 2018, p..

Smith, A.M., Grover, T.W., Williams, M.L., Pless, C.R., Suarez, K., Baurle, E. "Structure, petrology, and geochronology of orthogneisses in the southern Shelving Rock Quadrangle, eastern Adirondacks, New York" Geological Society of America Abstracts with Programs, v.50, 2018, p..

Suarez, K., Williams, M.L., Grover, T.W., Valley, P.M., Walsh, G.J., Regan, S.P., and Pless, C.R. "An investigation into the correlation between Na-metasomatism and economic deposits in the Adirondack Mountains, NY" Geological Society of America Abstracts with Programs, v.50, 2018, p..

Pless, C.R., Williams, M.L., Grover, T.W., Suarez, K. and Smith, A. "Timing of partial melting using combined in-situ monazite and zircon geochronology, eastern Adirondack Highlands, NY" Geological Society of America Abstracts with Programs, v.50, 2018, p..

Grover, T.W., Williams, M.L., Regan, Sean P., Pless, Claire R., Jercinovic, M.J. "Constraints from monazite geochemistry and LA-ICP-MS zircon analyses on the nature and timing of metamorphism in the Dresden Station area, eastern Adirondacks" Geological Society of America Abstracts with Programs, v.49, 2017, p.. doi:doi: 10.1130/abs/2017AM-304262 

Suarez, Kaitlyn, Williams, M.L., Grover, T.W., and Pless, Claire R. "Constraining the timing of melting in the eastern Adirondack Mountains, NY using a combination of in-situ monazite and zircon U/Pb dating techniques" Geological Society of America Abstracts with Programs, v.49, 2017, p.. doi:doi: 10.1130/abs/2017AM-307903 

Williams, Michael L, Jercinovic, Michael J., and Grover, Timothy W. "Electron microprobe petrochronology: new data and new challenges from the Adirondack Mountains, New York" Geological Society of America Abstracts with Programs, v.49, 2017, p.. doi:doi: 10.1130/abs/2017AM-304420 


Project Outcomes Report

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

The outcomes summarized below are the result of a multifaceted research project on the geologic evolution of the eastern Adirondack Mountains. Our research included field mapping with data and sample collection, structural analysis, petrologic analysis, and geochronology using monazite and zircon, two trace minerals that contain radiogenic isotopes. Our results are interpreted within existing models for the geologic evolution Adirondack Mountains.

The rocks exposed in the eastern Adirondack Highlands today are the products of a protracted period of mountain building from approximately 1200 Ma to 970 Ma. This period of time accompanied a mountain-building event known as the Shawinigan Orogeny (1200-1140 Ma), intrusion of an unusual suite of igneous rocks known as the AMCG suite (1160-1140 Ma), a second mountain building event known as the Ottawan Orogeny (1090-1050 Ma), and finally gravitational collapse of the Himalayan scale mountain range that existed following Ottawan Orogeny (1050-970 Ma).

Our work shows that these rocks were heated to temperatures of 750-800°C and at mid to lower crustal depths at the end of the Shawinigan Orogeny at ~1155 Ma. We speculate that intrusion of the AMCG suite added a significant amount of heat to the lower crust at this point. These temperatures are high enough to cause metasedimentary rocks of pelitic composition (originally mudstones) to partially melt. Some rocks melted extensively at this time. In some cases, the melt was driven or migrated out of the host rock, in other instances the melt crystallized within the host rock upon cooling. The melt formed through a process called biotite dehydration melting. In this reaction biotite + quartz + sillimanite +/- plagioclase breaks down to form melt + garnet + K-feldspar.

Approximately 100 million years later Amazonia collided with the eastern margin of Laurentia generating the Ottawan Orogeny. This was accompanied by a period of west-verging thrusting and folding. Most AMCG rocks in the eastern Adirondacks were penetratively deformed during this phase of mountain building. The rocks in the mid to lower crust were again heated to temperatures of 750-800°C. We found that some rocks of pelitic composition melted at this time while others did not. Rocks that melted extensively in the Shawingan Orogeny and where the melt left the rocks do not contain any biotite. Therefore, even though they reach sufficient temperatures, they will not melt again. However, in rocks melted during the Shawinigan Orogeny but the melt did not leave the rock contain enough biotite to actually melt a second time. Additionally, some rocks of pelitic composition that did not melt during the Shawingan did melt during the Ottawan by a similar biotite dehydration melting reaction.

A Himalayan-scale mountain range existed at the culmination of the compressional event caused by the collision of Laurentia with Amazonia. With the cessation of the compressive stresses that created the mountain range the thick crust became gravitationally unstable and began to collapse. The results from our monazite geochronology show the culmination of the Ottawan Orogeny at approximately 1050 Ma with extensional collapse beginning shortly thereafter. We find monazite with compositionally distinct rims that are enriched in yttrium and other heavy rare earth elements. The increase in yttrium concentrations suggest that monazite was growing as garnet was breaking down. This would be the case is the rocks were uplifted during extension. We have recognized a shear zone called the East Adirondack Shear Zone that accompanied some of this uplift and extension. We believe this extensional event was accompanied by intrusion of the Lyon Mountain granite and infiltration of an unknown but significant amount of fluid. These fluids are essential in forming the numerous iron oxide apatite deposits that are found in the northeastern Adirondacks. It is noteworthy that many of these deposits also contain significant concentrations of rare earth elements (REE’s). REE’s are essential elements in the construction of a number of high-tech devices ranging from cell phones to windmill blades.

A major objective of this project was to provide academic and professional development opportunities for undergraduates at Castleton University and undergraduates and graduate students at the University of Massachusetts. We especially wanted to provide opportunities for the graduate students to mentor the undergraduates. We accomplished these objectives by having the undergraduates working with the graduate students in the field and by having the graduate students train the undergrads how to use the analytical instrumentation available at the University of Massachusetts. We also held weekly research seminars via Zoom. Each week we would discuss a paper from the geological literature as well as our research progress. Zoom allows us to share screens and therefore easily share and present our data for discussion. Eight students from Castleton University had some involvement with undergraduate student research as a direct result of this funded proposal. All eight are lead or co-authors on numerous presentations at meetings of the Geological Society of America.

 


Last Modified: 10/30/2018
Modified by: Timothy W Grover

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