Timing of the Acadian Orogeny in northern New Hampshire

New U‐Pb geochronology constrains the timing of the Acadian orogeny in the Central Maine Terrane of northern New Hampshire. Sixteen fractions of one to six grains each of zircon or monazite have been analyzed from six samples: (1) an early syntectonic diorite that records the onset of the Acadian; (2) a schist, a migmatite, and two granites that together record the peak of the Acadian; and (3) a postkinematic pluton that records the end of the Acadian. Zircon from the syntectonic Wamsutta Diorite gives a 207Pb/206Pb age of circa 408 Ma, the time at which the boundary between the deforming orogenic wedge and the foreland basin was in the vicinity of the Presidential Range. This age agrees well with the Emsian position of the northwest migrating Acadian orogenic front and records the beginning of the Acadian in this part of the Central Maine Terrane. We propose a possible Acadian tectonic model that incorporates the geochronologic, structural, and stratigraphic data. Monazite from the schist, migmatite, Bigelow Lawn Granite, and Slide Peak Granite gives 207Pb/206U ages, suggesting the peak of Acadian metamorphism and intrusion of two‐mica granites occurred at circa 402–405 Ma, the main pulse of Acadian orogenesis. Previously reported monazite ages from schists that likely record the peak metamorphism in the Central Maine Terrane of New Hampshire and western Maine range from circa 406–384 Ma, with younger ages in southeastern New Hampshire and progressively older ages to the west, north, and northeast. Acadian orogenesis in the Presidential Range had ended by circa 355 Ma, the 207Pb/235U age of monazite from the Peabody River Granite. From 408 to perhaps at least 394 Ma, Acadian orogenesis in the Presidential Range was typical of the tectonic style, dominated by synkinematic metamorphism, seen in central and southern New Hampshire, Massachusetts, and Connecticut. From no earlier than 394 Ma to as late as 355 Ma, the orogenesis was typical of the style in parts of Maine dominated by postkinematic metamorphism

Market Structure, Entrance Conditions and Optimal Number of Banks in the Bolivian Financial System: A Concentration and Industrial Mobility Indicators Approach

This paper calculates indicators of market structure: concentration ratio, Herfindahl index, Herfindahl-Hirschman index, inverse of the Herfindahl index and the stability indicator. These indicators are used: (1) to measure indirectly the competitiveness of the bank market, (2) to define conditions of entrance of new banks to the market, and (3) to establish a criterion to estimate the optimal number of banks in the market.indicadores de concentración; estructura de mercado; número óptimo de bancos

Hastings Community (Fall/Winter 1984)

https://repository.uchastings.edu/alumni_mag/1065/thumbnail.jp

Sierra County Advocate, 1902-02-21

https://digitalrepository.unm.edu/sc_advocate_news/2881/thumbnail.jp

Sierra County Advocate, 02-21-1902

https://digitalrepository.unm.edu/sc_advocate_news/1803/thumbnail.jp

Salinic to Neoacadian Deformation within the Migmatite Zone of the Central Maine Belt in Western Maine

Detailed bedrock mapping coupled with new geochronology in the southern part of the Gilead 7.5’ Quadrangle in Western Maine has revealed at least three phases of Salinic through Neoacadian deformation. The geology of the study area is dominated by the migmatized Silurian Rangeley, Perry Mtn. (?), and Smalls Falls Formations of the Central Maine Belt (CMB), which are intruded by quartz diorites from the Piscataquis Volcanic Arc, two-mica granites, and pegmatite. All of the metasedimentary rocks are stromatic migmatites, part of the Migmatite-Granite Complex (Solar and Tomascak, 2016). The geochronology (Wheatcroft, 2017) brackets the cycle of deposition, metamorphism, migmatization, and deformation to between circa 435 Ma. to 352 Ma. D1 is represented by cryptic pre-metamorphic faults that offset and truncate the stratigraphic units. Premetamorphic faults are observed outside of the study area in a contiguous section to the north. These faults are likely Salinic in age and developed synchronous with deposition or circa 435 Ma.. D2 deformation is characterized by nappe-scale, isoclinal folding of unknown vergence where bedding, S0, is parallel to schistosity, S2. Only a few F2 folds are present in the study area and in these places bedding, S0, is antiparallel to S2 schistosity. The gray schists and quartzites above Bog Brook in the study area preserve this fabric relationship and suggest the presence of a macroscale F2 hinge zone. The extensive migmatization has obscured most of the D2 fabrics that are likely Early Acadian in age. D3 deformation is characterized by numerous open, reclined, upright to overturned, macroscopic folds with limbs striking 245, 87 and 345, 62, a calculated inter-limb angle of 83°, and a hinge line trend and plunge of 55, 60. Mesoscopic D3 folds of the composite S0/S2 fabrics are common but of diverse fold orientations due to the migmatization. The S3 axial planar cleavage is characterized by a zonal crenulation in the F3 mesoscale folds. The stratigraphic age assignment supported by lithologic correlation and new detrital zircon geochronology suggests the stratigraphy is inverted due to D2 isoclinal folding. As such the D3 folds are best characterized as antiformal synclines and synformal anticlines and are likely of Late Acadian or Neoacadian in age (pre-352 Ma.)

Annual report of Rockingham county for the year ending December 31, 1957.

This is an annual report containing vital statistics for a county in the state of New Hampshire

Unemployment insurance

Thesis (M.A.)--Boston Universit

The New Hampshire, Vol. 64, No. 41 (Apr. 26, 1974)

An independent student produced newspaper from the University of New Hampshire