@book {339, title = {A Bibliography of Massachusetts Minerals 1796 - 1948}, series = {Special Department Publication}, number = {2}, year = {1950}, publisher = {Dept. of Geology and Mineralogy, U-Mass}, organization = {Dept. of Geology and Mineralogy, U-Mass}, address = {Amherst, MA}, keywords = {$\#$Collecting, $\#$EducationalResources, $\#$MassGeology, $\#$MineralResources, $\#$Minerals, collecting, fossil, localities, mineral, rock hunting}, author = {Johansenn, Warren I} } @conference {369, title = {Latest Paleozoic through Mesozoic faults in north-central Massachusetts and their correlations with New Hampshire}, booktitle = {Geological Society of America - Northeastern section}, year = {2016}, publisher = {Geological Society of America}, organization = {Geological Society of America}, address = {Albany, NY}, abstract = {

Several faults in south-central New Hampshire can be extended into Massachusetts (MA) as a result of detailed mapping in both states since publication of the MA state bedrock geologic map in 1983. Many of these faults delineate and/or cut Devonian metamorphic isograds in the Silurian Merrimack Belt in northern MA, and juxtapose chlorite-grade rocks in the Nashua sub-belt (NSB) between lithologically similar middle- to upper amphibolite-facies rocks on either side.

Recent mapping in the NSB, combined with previous studies, suggest it may represent a graben initially formed during latest Paleozoic transtension contemporaneous with formation of the Narragansett Basin in southeastern MA and RI. Mylonites along the Silver Hill-Wekepeke Fault (Robinson, 1981), bounding the western edge of the NSB, show east-side-down normal motion and west-side down normal motion along the Clinton-Newbury Fault Zone (CNFZ; Goldstein, 1994) which bounds the NSB{\textquoteright}s southeastern margin. A possible extension of the Flint Hill fault system (NH) forms the eastern edge of the NSB offsetting the CNFZ with normal west-side down motion near Ayer, MA. Late brittle normal faults in the NSB are abundant.\ Late, low-To, west-side-down shear zones in the Nashoba Terrane and similar rocks to the south may also be related to down-dropping of the NSB.

AFT ages were collected across north-central MA to constrain its late uplift history. A ~127 Ma AFT age in the NSB is discontinuous with AFT ages in the belts adjoining it, with ~182-144 Ma ages west across the Wekepeke fault and ~160-167 Ma east across the CNFZ. To the west, the brittle southern extension of the Pinnacle Fault in NH (Stodge Meadow Pond fault of Peterson, 1984) follows the western edge of the Fitchburg plutons in MA while a well-exposed west-side down brittle normal fault system, possibly the southward extension of the Campbell Hill Fault (NH), is developed along their eastern edge. AFT ages of ~144-136 Ma immediately west of the Pinnacle Fault in MA are discontinuous with ~117-115 Ma ages immediately to the east within the Fitchburg plutons. A single ~106 Ma age in the plutons west of the Campbell Hill Fault in MA is discontinuous with ~128-123 Ma ages to the east of it. The discontinuities amongst AFT ages across these faults suggest that they may have been active through the Cretaceous.

}, keywords = {$\#$Bibliography, $\#$StaffPubs, AFT, apatite, apatite fission track, brittle, Campbel Hill, Clinton Newbury, Cretaceous, extension, fault, fault zone, fault zones, faults, fission track, Fitchburg, Fitchburg Plutons, Flint Hill, I-290, Johnny Appleseed, Jurassic, merrimack, mesozoic, Nashua Trough, Normal Faults, Oakdale formation, Permian, Pinnacle, Rt 2, Sterling, Stodge Meadow Pond, Triassic, Wachusett, Wekepeke, Worcester Formation}, doi = {10.1130/abs/2016NE-272576}, url = {https://gsa.confex.com/gsa/2016NE/webprogram/Paper272576.html}, author = {Kopera J.P. and Roden-Tice, M.K. and Robert P Wintsch} } @proceedings {268, title = {Age-constraints on fabric reactivation in the Tusas Range, northern New Mexico, using electron-microprobe monazite geochronology; implications for the nature of regional approximately 1400 Ga deformation}, volume = {34}, year = {2002}, note = {Accession Number: 2004-044516; Conference Name: Geological Society of America, 2002 annual meeting; Denver, CO, United States; Conference Date: 20021027; Language: English; Coden: GAAPBC; Collation: 1; Collation: 180; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200413; Monograph Title: Geological Society of America, 2002 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2002/10/01/}, pages = {180 - 180}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {A key issue in constructing models for the southward growth of Laurentia during the Proterozoic is distinguishing the effects of approximately 1650 Ma and approximately 1400 Ma tectonism. These events share similar styles of deformation and metamorphism, making it difficult to assign structures, fabrics, and metamorphic phases to a particular event. The fundamental geometry of this orogen in the southwestern United States is defined in many areas by fold-fault pairs and isolated synclines of thick approximately 1700 Ma quartzite. In-situ EMP chemical dating of monazite, combined with detailed structural analysis, indicates that such synclines within the Tusas Range of northern New Mexico (locally F (sub 3) ) were substantially modified, if not developed, during approximately 1400 Ma tectonism. Monazite grains from the Ortega quartzite in the central Tusas Range display a shape preferred orientation parallel to the axial-planar fabric of these folds (S (sub 3) ), with overgrowth rims preferentially developed in the X direction of strain. These monazite grains have either >1700 Ma cores or approximately 1650 Ma cores with approximately 1400 Ma overgrowth rims, or are entirely approximately 1400 Ma in age. Field and microstructural observations show that the upright, east-west trending F (sub 3) and S (sub 3) are reactivations of older, northwest-trending fabrics and structures. The presence of approximately 1650 Ma overgrowth rims on monazite grains from the central and northern Tusas Range implies that these folds and fabrics may have nucleated prior to approximately 1400 Ma tectonism. Previous studies have shown an increase in approximately 1400 Ma monazite ages from north to south within the range, consistent with a similar increase in metamorphic grade. This gradient suggests that the central and northern Tusas may have been at progressively shallower crustal levels during approximately 1400 Ma tectonism, thus increasing the preservation of older fabrics, structures, and metamorphic monazite from south to north within the range. These observations support the hypothesis that approximately 1400 Ma tectonism locally reactivated and utilized pre-existing structures and fabrics, but had also profoundly shaped the geometry and metamorphic character of the orogen.}, keywords = {$\#$StaffPubs, dates, deformation, electron probe data, fabric, folds, geochronology, Geochronology 03, geometry, in situ, Laurentia, Mesoproterozoic, metamorphism, monazite, New Mexico, northern New Mexico, orogeny, Ortega Group, overgrowths, phosphates, Precambrian, preferred orientation, proterozoic, reactivation, Southwestern U.S., strain, structural analysis, Structural geology 16, synclines, tectonics, Tusas Mountains, United States, upper Precambrian, zoning}, isbn = {00167592}, url = {http://silk.library.umass.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true\&db=geh\&AN=2004-044516\&site=ehost-live\&scope=site}, author = {Joseph P Kopera and Williams, Michael L. and Jercinovic, Michael J.} } @article {309, title = {Microprobe monazite geochronology; new refinements and new tectonic applications}, journal = {Abstracts with Programs - Geological Society of America}, volume = {35}, year = {2003}, note = {Accession Number: 2004-076942; Conference Name: Geological Society of America, Northeastern Section, 38th annual meeting; Halifax, NS, Canada; Conference Date: 20030327; Language: English; Coden: GAAPBC; Collation: 2; Collation: 22-23; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200422; Monograph Title: Geological Society of America, Northeastern Section, 38th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2003/03/01/}, pages = {22 - 23}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {

High-resolution compositional mapping and dating of monazite on the electron microprobe is a powerful addition to microstructural and petrologic analysis and an important tool for tectonic studies. Its in-situ nature and high spatial resolution offer an entirely new level of structurally and texturally specific geochronologic data that can be used to put absolute time constraints on P-T-D paths, constrain the rates of sedimentary, metamorphic, and deformational processes, and provide new links between metamorphism and deformation. New analytical techniques have significantly improved the precision and accuracy of the technique and new mapping and image analysis techniques have increased the efficiency and strengthened the correlation with fabrics and textures. Microprobe geochronology is particularly applicable to three persistent microstructural-microtextural problem areas: (1) constraining the chronology of metamorphic assemblages; (2) constraining the timing of deformational fabrics; and (3) interpreting other geochronological results. In addition, authigenic monazite can be used to date sedimentary basins, and detrital monazite can fingerprint sedimentary source areas, both critical for tectonic analysis. Although some monazite generations can be directly tied to metamorphism or deformation, at present, the most common constraints rely on monazite inclusion relations in porphyroblasts that, in turn, can be tied to the deformation and/or metamorphic history. Microprobe mapping and dating allow geochronology to be incorporated into the routine microstructural analytical process, resulting in a new level of integration of time (t) into P-T-D histories. The Legs Lake exhumational shear zone in Saskatchewan is a classic example. Monazite can be tied to decompressional metamorphic reactions in the upper plate and to prograde reactions and shear fabrics in the footwall, firmly constraining the timing of regional exhumations with a long multiphase tectonic history.

}, keywords = {$\#$StaffPubs, age;, electron probe data;, geochronology;, Geochronology; 03, Igneous and metamorphic petrology; 05A, metamorphic rocks;, metamorphism;, methods;, monazite;, P-T-t paths;, phosphates;}, isbn = {00167592}, url = {http://silk.library.umass.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true\&db=geh\&AN=2004-076942\&site=ehost-live\&scope=site}, author = {Williams, Michael L. and Jercinovic, Michael J. and Mahan, Kevin and Joseph P Kopera} } @article {310, title = {Monazite geochronology of Proterozoic quartzites; a powerful tool for understanding reactivation of continental lithosphere in the Southwestern United States}, journal = {Abstracts with Programs - Geological Society of America}, volume = {34}, year = {2002}, note = {Accession Number: 2004-069830; Conference Name: Geological Society of America, Northeastern Section, 37th annual meeting; Springfield, MA, United States; Conference Date: 20020325; Language: English; Coden: GAAPBC; Collation: 1; Collation: 26; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200421; Monograph Title: Geological Society of America, Northeastern Section, 37th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2002/03/01/}, pages = {26 - 26}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {

The influence of approximately 1.65 vs. 1.4 Ga tectonism on the evolution of the Proterozoic orogenic belt in the southwestern United States has been an issue of considerable debate. This belt was assembled at approximately 1.75-1.65 Ga, but recent work has highlighted a significant reactivation of the orogen at 1.4 Ga. The discovery of abundant monazite in regionally extensive, 1-2 km thick quartzites found throughout the orogenic belt may provide important new constraints on its tectonic history. These quartzites define the present regional geometry of exposed Proterozoic rocks and are believed to strongly influence local structure. Preliminary results of in-situ microprobe dating of monazite from the Ortega Quartzite in the Tusas Mountains in northern New Mexico suggest an increasing influence of 1.4 Ga tectonism from north to south within the range. Monazite from the Jawbone Syncline within northernmost part of the range consistently yields ages of 1.75 to 1.72 Ga. These monazite grains are interpreted to be mostly detrital in origin, with REE and age zoning reflecting the history of the source terranes. Monazite from an anticline immediately to the south has 1.72-1.75 Ga detrital cores with 1.67-1.68 Ga rims, implying that initial fold formation occurred during the approximately 1.67-1.65 Ga Mazatzal Orogeny. Monazite from the middle and southern Tusas Mountains is predominantly 1.4 Ga in age. This suggests that a previously documented gradient in deformation and metamorphism from north to south may reflect a multistage tectonic history for the range, with an increasingly intense overprint of 1.4 Ga tectonism to the south. Monazite has also been found in several Proterozoic quartzites in Colorado, allowing the possibility to compare and correlate deformation and metamorphism across the region. Monazite dating in thick quartzites represents a powerful tool by which the effects of approximately 1.65 and 1.4 Ga tectonism can be separated, leading to a better understanding of the evolution and stabilization of Proterozoic crust in the southwestern United States and may be an important new technique in deconvoluting the tectonic histories of other orogenic belts.

}, keywords = {$\#$StaffPubs, absolute age;, continental lithosphere;, crust;, deformation;, Geochronology; 03, Jawbone Syncline;, lithosphere;, Mazatzal Orogeny;, metamorphic rocks;, metamorphism;, monazite;, New Mexico;, orogeny;, Paleoproterozoic;, phosphates;, Precambrian;, Proterozoic;, quartzites;, Southwestern U.S.;, tectonics;, Tusas Mountains;, United States;, upper Precambrian;}, isbn = {00167592}, url = {http://silk.library.umass.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true\&db=geh\&AN=2004-069830\&site=ehost-live\&scope=site}, author = {Joseph P Kopera and Williams, Michael L. and Jercinovic, Michael J.} } @article {311, title = {Monazite geochronology of the Ortega Quartzite: documenting the extent of 1.4 Ga tectonism in northern New Mexico and across the orogen}, journal = {Abstracts with Programs - Geological Society of America}, volume = {34}, year = {2002}, note = {Accession Number: 2003-041318; Conference Name: Geological Society of America, Rocky Mountain Section, 54th annual meeting; Cedar City, UT, United States; Conference Date: 20020507; Language: English; Coden: GAAPBC; Collation: 1; Collation: 10; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200313; Monograph Title: Geological Society of America, Rocky Mountain Section, 54th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2002/04/01/}, pages = {10 - 10}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {

Preliminary results of in-situ microprobe dating of monazite from the Ortega Quartzite suggest an increasing influence of 1.4 Ga tectonism from north to south within the in the Tusas Mountains of northern New Mexico. Monazite from the Jawbone Syncline within northernmost part of the range consistently yields ages of 1.75 to 1.72 Ga. These monazite grains are interpreted to be mostly detrital in origin, with REE and age zoning reflecting the history of the source terranes. Monazite from an anticline immediately to the south has 1.72-1.75 Ga detrital cores with 1.67-1.68 Ga rims, implying that initial fold formation occurred during the approximately 1.67-1.65 Ga Mazatzal Orogeny. Monazite from the middle and southern Tusas Mountains is predominantly 1.4 Ga in age. This suggests that a previously documented gradient in deformation and metamorphism from north to south may reflect a multistage tectonic history for the range, with an increasingly intense overprint of 1.4 Ga tectonism to the south. The discovery of abundant monazite in regionally extensive, 1-2 km thick quartzites found throughout the Proterozoic orogenic belt of the southwestern United States may provide important new constraints on the region{\textquoteright}s tectonic history, specifically, the extent and influence of 1.4 Ga tectonism on the formation and modification of fundamental large-scale structures. These quartzites define the present regional geometry of exposed rocks within the Proterozoic Mazatzal Province, and are believed to strongly influence local structure. In addition to northern New Mexico, monazite has also been found in several Proterozoic quartzites in Colorado, allowing the possibility to compare and correlate deformation and metamorphism across the region. Monazite dating in thick quartzites represents a powerful tool by which we can better understand the evolution and stabilization of Proterozoic crust in the southwestern United States, and may be an important new technique in deconvoluting the tectonic histories of other orogenic belts.

}, keywords = {$\#$StaffPubs, anticline, deformation;, folds;, monazite;, New Mexico;, orogeny;, Ortega Group;, phosphates;, Precambrian;, Proterozoic;, Structural geology; 16, tectonics;, Tusas Mountains;, United States;, upper Precambrian;}, isbn = {00167592}, url = {http://silk.library.umass.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true\&db=geh\&AN=2003-041318\&site=ehost-live\&scope=site}, author = {Joseph P Kopera and Williams, Michael L. and Jercinovic, Michael J.} } @article {312, title = {Monazite geochronology of the Proterozoic Ortega Quartzite; documenting the extent of 1.4 Ga tectonism in the Tusas Range and beyond}, journal = {New Mexico Geology}, volume = {24}, year = {2002}, note = {Accession Number: 2004-009303; Conference Name: New Mexico Geological Society spring meeting; Socorro, NM, United States; Conference Date: 20020405; Language: English; Coden: NMGED2; Collation: 1; Collation: 59; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200403; Monograph Title: New Mexico Geological Society spring meeting; abstracts; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2002/05/01/}, pages = {59 - 59}, publisher = {New Mexico Bureau of Mines and Mineral Resources : Socorro, NM, United States}, address = {United States}, keywords = {$\#$StaffPubs, absolute age;, dates;, deformation;, electron probe data;, geochronology;, Geochronology; 03, ion probe data;, mass spectra;, metamorphic rocks;, metamorphism;, monazite;, New Mexico;, orogeny;, Ortega Group;, phosphates;, Precambrian;, Proterozoic;, quartzites;, spectra;, Structural geology; 16, tectonics;, Tusas Mountains;, United States;, upper Precambrian;}, isbn = {0196948X}, url = {http://silk.library.umass.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true\&db=geh\&AN=2004-009303\&site=ehost-live\&scope=site}, author = {Joseph P Kopera and Williams, Michael L. and Jercinovic, Michael J.} } @Map {360, title = {Bedrock geologic map of the Ayer 7.5{\textquoteright} quadrangle, Worcester and Middlesex Counties, Massachusetts}, publisher = {Massachusetts Geological Survey}, edition = {15-01}, abstract = {

Editing and review are still underway. \ This map should be available in winter 2015/2016

}, keywords = {Ayer, ayer granite, Ayer Granodiorite, Ayer Quadrangle, Berwick, Campbell Hill Fault, chelmsford granite, Clinton Newbury Fault, Devens, Harvard Conglomerate, merrimack, Oakdale formation, pin hill, Shepley{\textquoteright}s Hill, Shirley Fault, tadmuck brook schist, Worcester Formation}, author = {Kopera J.P.} } @Map {245, title = {Preliminary bedrock geologic map of the Westford quadrangle, Massachusetts}, year = {2009}, publisher = {Massachusetts Geological Survey}, edition = {OFR-09-01}, abstract = {Bedrock Geologic Map contains brittle fracture data Mapping still in progress. For interim fracture database, please contact Joe Kopera }, keywords = {$\#$BedrockMaps, $\#$MGSPub, Acton, amphibolite, ayer granite, Berwick formation, Boxborough, calc-silicates, Carlisle, Chelmsford, chelmsford granite, Clinton-Newbury Fault, Concord, diorite, gneiss, Groton, LITTLETON, magnetite, marble, migmatite, Nashoba Formation, phyllonite, tadmuck brook schist, Tyngsborough, Westford}, author = {Joseph P Kopera and D.C. Alvord and Richard H Jahns and M.E. Willard and W.S. White} } @Map {247, title = {Progress report of bedrock geologic mapping of the Lowell quadrangle, Massachusetts}, year = {2010}, publisher = {Massachusetts Geological Survey}, edition = {PM-09-01}, abstract = {

Maps in Progress are not distributed to the public. If you would like to see a copy of this map, please contact Joseph Kopera at jkopera[at]geo[dot]geo[dot]umass[dot]edu

}, keywords = {$\#$BedrockMaps, $\#$MGSPub, Berwick formation, Chelmsford, Clinton-Newbury Fault, Dracut, Dracut diorite, Dracut gabbro, Dracut pluton, gabbro, Jahns, Lowell, Methuen, nashoba, Nashoba Formation, Tewksbury, Tyngsborough}, author = {Richard H Jahns and Joseph P Kopera} }