scholarly journals Reconnaissance U-Pb SHRIMP geochronology and Sm-Nd isotope analyses from the Tehery-Wager Bay gneiss domain, western Churchill Province, Nunavut

2007 ◽  
Author(s):  
O van Breemen ◽  
S Pehrsson ◽  
T D Peterson
Keyword(s):  
Nd Isotope ◽  
Shrimp Geochronology ◽  
Isotope Analyses

Rb/Sr and Sm/Nd isotope analyses of CCSD eclogites (Sulu, China): A test for the closure temperature concept

2006 ◽  
Vol 70 (18) ◽  
pp. A564
Author(s):  
J. Schneider ◽  
B.-M. Jahn ◽  
K. Okamoto ◽  
L. Tong ◽  
Y. Iizuka ◽  
...  
Keyword(s):  
Closure Temperature ◽  
Nd Isotope ◽  
Temperature Concept ◽  
Isotope Analyses

scholarly journals Nd isotope mapping of the Grenvillian Allochthon Boundary Thrust in Algonquin Park, Ontario

2019 ◽  
Vol 56 (2) ◽  
pp. 101-110 ◽  
Author(s):  
A.P. Dickin ◽  
J.W.D. Strong
Keyword(s):  
High Grade ◽  
Geographical Pattern ◽  
Precise Location ◽  
Nd Isotope ◽  
North Shore ◽  
The North ◽  
Digital Elevation ◽  
Elevation Data ◽  
Digital Elevation Data ◽  
Isotope Analyses

Over 50 new Nd isotope analyses are presented for high-grade orthogneisses from Algonquin Park and surrounding region to map major Grenvillian thrust boundaries. Nd model ages display a consistent geographical pattern that allows detailed mapping of the boundary between the Algonquin and Muskoka domains, here interpreted as the local trajectory of the Ottawan-age Allochthon Boundary Thrust (ABT). The ABT is underlain by a domain with Paleoproterozoic Nd model ages, interpreted as a tectonic duplex entrained onto the base of the main allochthon. The boundaries determined using Nd isotope mapping are consistent with field mapping and with remotely sensed aeromagnetic and digital elevation data. The precise location of the ABT can be observed in a road-cut on Highway 60, on the north shore of Lake of Two Rivers in the centre of Algonquin Park.

An application of Nd isotope mapping in structural geology: delineating an allochthonous Grenvillian terrane at North Bay, Ontario

2003 ◽  
Vol 140 (5) ◽  
pp. 539-548 ◽  
Author(s):  
A. P. DICKIN ◽  
R. H. MCNUTT
Keyword(s):  
Structural Geology ◽  
Amphibolite Facies ◽  
High Grade ◽  
Grenville Province ◽  
Nd Isotope ◽  
Bay Area ◽  
The North ◽  
Depleted Mantle ◽  
Different Types ◽  
Isotope Analyses

Fifty new Nd isotope analyses are presented from the North Bay area of the Grenville Province in Ontario. These data are used to map the extent of an allochthonous Grenvillian terrane which is an outlier of the Allochthonous Polycyclic Belt of the Grenville Province. Amphibolite facies orthogneisses from the allochthonous terrane have depleted mantle Nd model ages (TDM) below 1.8 Ga, whereas the gneisses of the structurally underlying parautochthon almost invariably have model ages above 1.8 Ga. The distribution of model ages is consistent with the distribution of distinct types of metabasic rock, used by other researchers as the criterion for recognizing rocks of the allochthonous and parautochthonous belts of the Grenville Province. The agreement between these different types of evidence demonstrates that Nd isotope mapping is a reliable and powerful tool for mapping terrane boundaries in high-grade metamorphic belts.

scholarly journals Evolução Tectono-Estratigráfica e Paleoclimática da Formação Maricá (Escudo Sul-Rio-Grandense, Brasil): um Exercício de Geologia Histórica e Análise Integrada de uma Bacia Sedimentar Neoproterozóica

2007 ◽  
Vol 34 (2) ◽  
pp. 57 ◽  
Author(s):  
ANDRÉ DE BORBA ◽  
ANDERSON MARASCHIN ◽  
ANA MARIA MIZUSAKI
Keyword(s):  
Foreland Basin ◽  
Global Scale ◽  
Source Rocks ◽  
Integrated Analysis ◽  
Santa Barbara ◽  
Volcanic Event ◽  
Nd Isotope ◽  
Shrimp Geochronology ◽  
Step Heating ◽  
Depositional Evolution

Significant improvement in the knowledge concerning the Neoproterozoic Maricá Formation of the Sul-riograndense Shield, southern Brazil, was obtained in the latest years. This contribution synthesizes recent data obtained though an integrated analysis of the lowermost unit of the “Camaquã Basin”. Stratigraphic and paleocurrent analyses, petrography, Sr and Nd isotope geology, U-Pb SHRIMP geochronology and Ar-Ar dating were applied to the sedimentary and volcanogenic record of the Maricá Formation in order to better constrain its depositional evolution. The Maricá Formation was deposited within a coastal to shallow marine setting, its detrital load being derived from the weathering of granite-gneissic, paleoproterozoic (1.76 to 2.37 Ga) source rocks, possibly located in the western La Plata craton. A syn-depositional, partially explosive, volcanic event was recognized and dated by U-Pb SHRIMP at 630.2 ± 3.4 Ma, positioning the inception of the “Camaquã Basin” at the end of the Cryogenian. Thus, the deposition of the Maricá Formation post-dates the global-scale Marinoan glaciation (660-635 Ma), possibly recording greenhouse paleoclimatic conditions. Field, petrographic and isotopic evidence supports this interpretation. The evolution of the Maricá Formation started during the collisional climax of the Brasiliano II orogenic system (Dom Feliciano orogen), thus the analyzed sedimentation could represent the infilling of a foreland basin. It is possible that correlative portions of the foreland system may be preserved in other sedimentary or metamorphic successions of the Mantiqueira Province, such as the Fuente del Puma (Lavalleja), Porongos, Brusque, Abapã (Itaiacoca), Cerro da Árvore and Passo da Capela units. The 507.3 ± 1.8 and 506.7 ± 1.4 Ma Ar-Ar step-heating ages obtained in K-feldspars from volcanogenic samples of the Maricá Formation are most likely associated with uplift and cooling below ca. 200ºC, possibly during the inception of the rift where the Camaquã Group (Santa Bárbara and Guaritas formations) accumulated.

In situ Nd isotope analyses in geological materials with signal enhancement and non-linear mass dependent fractionation reduction using laser ablation MC-ICP-MS

2015 ◽  
Vol 30 (1) ◽  
pp. 232-244 ◽  
Author(s):  
Lei Xu ◽  
Zhaochu Hu ◽  
Wen Zhang ◽  
Lu Yang ◽  
Yongsheng Liu ◽  
...  
Keyword(s):  
Laser Ablation ◽  
High Efficiency ◽  
Linear Mass ◽  
Nd Isotope ◽  
Bias Stability ◽  
Icp Ms ◽  
Non Linear ◽  
Mass Dependent ◽  
Mass Dependent Fractionation ◽  
Isotope Analyses

Combining high-efficiency cones with the addition of nitrogen in laser ablation MC-ICP-MS not only enhances the sensitivity and mass bias stability, but also suppresses the non-linear mass fractionation for Nd isotope analyses.

Use of 1012 ohm current amplifiers in Sr and Nd isotope analyses by TIMS for application to sub-nanogram samples

2013 ◽  
Vol 28 (5) ◽  
pp. 749 ◽  
Author(s):  
J. M. Koornneef ◽  
C. Bouman ◽  
J. B. Schwieters ◽  
G. R. Davies
Keyword(s):  
Nd Isotope ◽  
Isotope Analyses

Crustal formation in the Grenville Province: Nd-isotope evidence

2000 ◽  
Vol 37 (2-3) ◽  
pp. 165-181 ◽  
Author(s):  
A P Dickin
Keyword(s):  
North America ◽  
Grenville Province ◽  
Nd Isotope ◽  
Precambrian Shield ◽  
First Order ◽  
Isotope Evidence ◽  
Isotope Analyses

Ninety-eight new Nd-isotope analyses are presented for gneissic rocks from the Grenville Province. When combined with over 250 published Nd analyses and some unpublished analyses, these data can be used to establish a first-order crustal formation age map for most of the Grenville parautochthon and allochthonous polycyclic belt. In particular, the geographic extents of a juvenile Labradorian arc (Labradoria) and a juvenile 1.5 Ga arc (Quebecia) are defined, each with an area probably in excess of 100 000 km2. In addition, pre-1.75 Ga arcs are identified in Ontario (Barilia) and Labrador (Makkovikia). This work largely fills the last major gap in the continent-wide crustal formation age map of the Precambrian Shield of North America.

scholarly journals Compilation of Sm-Nd isotope analyses of igneous suites, western Churchill Province

2010 ◽  
Author(s):  
T D Peterson ◽  
S Pehrsson ◽  
T Skulski ◽  
H Sandeman
Keyword(s):  
Nd Isotope ◽  
Isotope Analyses

scholarly journals Routine high-precision Nd isotope analyses: an optimized chromatographic purification scheme

2021 ◽  
Author(s):  
Eugenia Hyung ◽  
François L. H. Tissot
Keyword(s):  
High Precision ◽  
Column Chromatography ◽  
Chromatographic Purification ◽  
Good Separation ◽  
Chromatography Method ◽  
Nd Isotope ◽  
Purification Scheme ◽  
High Yields ◽  
Isotope Analyses

We present an optimized α-HIBA column chromatography method for Nd for high-precision isotope analyses (±2–5 ppm). It produces consistently high yields (>95%) and extremely good separation of Ce, Pr and Sm from Nd.

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