@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 {305,
	title = {Influence of rock fabric on fracture attribute distribution and implications for groundwater flow in the Nashoba Terrane, eastern Massachusetts},
	journal = {Journal of Structural Geology},
	volume = {30},
	year = {2008},
	note = {Accession Number: 2009-050694; Language: English; Coden: JSGEDY; Collation: 14; Publication Types: Serial; Updated Code: 200928; Reviewed Item: Analytic},
	month = {2008/04/01/},
	pages = {464 - 477},
	publisher = {Elsevier : Oxford, International},
	address = {International},
	abstract = {Attributes (i.e. trace-length, spacing, termination and orientation) of joints and foliation-parallel fractures (FPFs) are used to assess the influence of lithology and fabric on fracture type and distribution in metamorphic and igneous rocks of the Nashoba terrane, Massachusetts. Orientations of NE-SW and NW-SE trending joints are consistent throughout the region, whereas FPFs are sub-parallel to the axis of the terrane. Joint spacing generally decreases to the northeast across the terrane reflecting lithologic changes from metamorphic to igneous rock types. Although trace-length and spacing frequency distributions of both joints and FPFs are best described by lognormal functions, FPFs possess narrower fracture spacing than joints. Median fracture trace-lengths of all FPFs are comparable to those of all steep joints, but the median fracture spacing is half that of all steep joints. Trace-lengths of FPFs vary as a function of the degree of development of foliation. Fracture attributes and groundwater flow models suggest that FPFs may significantly increase fracture connectivity and potential for groundwater recharge. FPFs may account for as much as 30\% of flow in fracture networks suggesting that in addition to joints, FPFs play a significant role in groundwater hydraulics that may include imparting flow anisotropy on the groundwater system.},
	keywords = {$\#$StaffPubs, foliation, fractures, ground water, Hydrogeology 21, joints, massachusetts, movement, Nashoba terrane, preferred orientation, statistical distribution, structural analysis, Structural geology, style, terranes, United States},
	isbn = {01918141},
	url = {http://www.sciencedirect.com/science/article/pii/S0191814107002362},
	author = {Alex K Manda and Stephen B Mabee and Donald U Wise}
}
