scholarly journals Ediacaran–Palaeozoic tectonic evolution of the Ossa Morena and Central Iberian zones (SW Iberia) as revealed by Sm–Nd isotope systematics

2008 ◽  
Vol 461 (1-4) ◽  
pp. 202-214 ◽  
Author(s):  
Rafael López-Guijarro ◽  
Maider Armendáriz ◽  
Cecilio Quesada ◽  
Javier Fernández-Suárez ◽  
J. Brendan Murphy ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Nd Isotope ◽  
Isotope Systematics

Non-linear dynamics, chaos, complexity and enclaves in granitoid magmas

1996 ◽  
Vol 87 (1-2) ◽  
pp. 217-223 ◽  
Author(s):  
James Flinders ◽  
John D. Clemens
Keyword(s):  
Deterministic Chaos ◽  
Interfacial Area ◽  
Two Dimensions ◽  
Mixing Processes ◽  
Nd Isotope ◽  
Natural Systems ◽  
Non Linear ◽  
The Difference ◽  
Magma System ◽  
Isotope Systematics

ABSTRACT:Most natural systems display non-linear dynamic behaviour. This should be true for magma mingling and mixing processes, which may be chaotic. The equations that most nearly represent how a chaotic natural system behaves are insoluble, so modelling involves linearisation. The difference between the solution of the linearised and ‘true’ equation is assumed to be small because the discarded terms are assumed to be unimportant. This may be very misleading because the importance of such terms is both unknown and unknowable. Linearised equations are generally poor descriptors of nature and are incapable of either predicting or retrodicting the evolution of most natural systems. Viewed in two dimensions, the mixing of two or more visually contrasting fluids produces patterns by folding and stretching. This increases the interfacial area and reduces striation thickness. This provides visual analogues of the deterministic chaos within a dynamic magma system, in which an enclave magma is mingling and mixing with a host magma. Here, two initially adjacent enclave blobs may be driven arbitrarily and exponentially far apart, while undergoing independent (and possibly dissimilar) changes in their composition. Examples are given of the wildly different morphologies, chemical characteristics and Nd isotope systematics of microgranitoid enclaves within individual felsic magmas, and it is concluded that these contrasts represent different stages in the temporal evolution of a complex magma system driven by nonlinear dynamics. If this is true, there are major implications for the interpretation of the parts played by enclaves in the genesis and evolution of granitoid magmas.

scholarly journals Trace-element and Nd-isotope systematics in detrital apatite of the Po river catchment: Implications for provenance discrimination and the lag-time approach to detrital thermochronology

Lithos ◽  
2017 ◽  
Vol 290-291 ◽  
pp. 48-59 ◽  
Author(s):  
Marco G. Malusà ◽  
Jiangang Wang ◽  
Eduardo Garzanti ◽  
Zhi-Chao Liu ◽  
Igor M. Villa ◽  
...  
Keyword(s):  
Trace Element ◽  
Lag Time ◽  
Po River ◽  
Nd Isotope ◽  
River Catchment ◽  
Isotope Systematics

Early Tertiary basalts from the Labrador Sea floor and Davis Strait region

1989 ◽  
Vol 26 (5) ◽  
pp. 956-968 ◽  
Author(s):  
D. B. Clarke ◽  
B. I. Cameron ◽  
G. K. Muecke ◽  
J. L. Bates
Keyword(s):  
Volcanic Rocks ◽  
Labrador Sea ◽  
Baffin Island ◽  
Nd Isotope ◽  
Sea Floor ◽  
West Greenland ◽  
Depleted Mantle ◽  
Davis Strait ◽  
Isotope Systematics ◽  
Seawater Exchange

Fine- to medium-grained, phyric and aphyric basalt samples from ODP Leg 105, site 647A, in the Labrador Sea show little evidence of alteration. Chemically, these rocks are low-potassium (0.01–0.09 wt.% K2O), olivine- to quartz-normative tholeiites that compare closely with the very depleted terrestrial Paleocene volcanic rocks in the Davis Strait region of Baffin Island and West Greenland. However, differences exist in the Sr–Nd isotope systematics of the two suites; the Labrador Sea samples have ε Nd values (+9.3) indicative of a more depleted source, and are higher in 87Sr/86Sr (0.7040), relative to the Davis Strait basalts (ε Nd +2.54 to +8.97; mean 87Sr/86Sr 0.7034). The higher 87Sr/86Sr in the Labrador Sea samples may reflect seawater exchange despite no petrographic evidence for significant alteration. The Labrador Sea and early Davis Strait basalts may have been derived from a similar depleted mantle source composition; however, the later Davis Strait magmas were generated from a different mantle. None of the Baffin Island, West Greenland, or Labrador Sea samples show unequivocal geochemical evidence for contamination with continental crust.

Geochemistry, zircon ages and whole-rock Nd isotopic systematics for Palaeoproterozoic A-type granitoids in the northern part of the Delhi belt, Rajasthan, NW India: implications for late Palaeoproterozoic crustal evolution of the Aravalli craton

2006 ◽  
Vol 144 (2) ◽  
pp. 361-378 ◽  
Author(s):  
PARAMPREET KAUR ◽  
NAVEEN CHAUDHRI ◽  
INGRID RACZEK ◽  
ALFRED KRÖNER ◽  
ALBRECHT W. HOFMANN
Keyword(s):  
Source Region ◽  
Magma Source ◽  
Crustal Evolution ◽  
Nd Isotope ◽  
Tectonic Environment ◽  
Granulite Metamorphism ◽  
Extensional Tectonic ◽  
Aravalli Craton ◽  
Isotope Systematics

Determination of zircon ages as well as geochemical and Sm–Nd isotope systematics of granitoids in the Khetri Copper Belt of the Aravalli mountains, NW India, constrain the late Palaeoproterozoic crustal evolution of the Aravalli craton. The plutons are typical A-type within-plate granites, derived from melts generated in an extensional tectonic environment. They display REE and multi-element patterns characterized by steep LREE-enriched and almost flat HREE profiles and distinct negative anomalies for Sr, P and Ti. Initial εNd values range from −1.3 to −6.2 and correspond to crustal sources with mean crustal residence ages of 2.5 to 2.1 Ga. A lower mafic crustal anatectic origin is envisaged for these granitoids, and the heterogeneous εNd(t) values are inferred to have been acquired from the magma source region. Zircon Pb–Pb evaporation and U–Pb ages indicate widespread rift-related A-type magmatism at 1711–1660 Ma in the northern Delhi belt and also suggest a discrete older magmatic event at around 1800 Ma. The emplacement ages of the compositionally distinct A-type granitoid plutons, and virtually coeval granulite metamorphism and exhumation in another segment of the Aravalli mountains, further signify that part of the Aravalli crust evolved during a widespread extensional event in late Palaeoproterozoic time.

The reliability of ∼2.9 Ga old Witwatersrand banded iron formations (South Africa) as archives for Mesoarchean seawater: Evidence from REE and Nd isotope systematics

2015 ◽  
Vol 111 ◽  
pp. 322-334 ◽  
Author(s):  
Sebastian Viehmann ◽  
Michael Bau ◽  
Albertus J.B. Smith ◽  
Nicolas J. Beukes ◽  
Elton L. Dantas ◽  
...  
Keyword(s):  
South Africa ◽  
Banded Iron Formations ◽  
Nd Isotope ◽  
Iron Formations ◽  
Isotope Systematics
Sign in / Sign up

Export Citation Format

Share Document