Journal ArticleDOI
Preservation of ancient and fertile lithospheric mantle beneath the southwestern United States.
Cin-Ty A. Lee,Cin-Ty A. Lee,Qing-Zhu Yin,Roberta L. Rudnick,Roberta L. Rudnick,Stein B. Jacobsen +5 more
TLDR
It is suggested that depleted mantle is intrinsically less dense than fertile mantle (due to iron having been lost when melt was extracted from the rock), which allows the depleted mantle to form a thicker thermal boundary layer between the deep convecting mantle and the crust, thus reducing tectonic activity at the surface.Abstract:
Stable continental regions, free from tectonic activity, are generally found only within ancient cratons—the centres of continents which formed in the Archaean era, 4.0–2.5 Gyr ago. But in the Cordilleran mountain belt of western North America some younger (middle Proterozoic) regions have remained stable, whereas some older (late Archaean) regions have been tectonically disturbed, suggesting that age alone does not determine lithospheric strength and crustal stability. Here we report rhenium–osmium isotope and mineral compositions of peridotite xenoliths from two regions of the Cordilleran mountain belt. We found that the younger, undeformed Colorado plateau is underlain by lithospheric mantle that is 'depleted' (deficient in minerals extracted by partial melting of the rock), whereas the older (Archaean), yet deformed, southern Basin and Range province is underlain by 'fertile' lithospheric mantle (not depleted by melt extraction). We suggest that the apparent relationship between composition and lithospheric strength, inferred from different degrees of crustal deformation, occurs because depleted mantle is intrinsically less dense than fertile mantle (due to iron having been lost when melt was extracted from the rock). This allows the depleted mantle to form a thicker thermal boundary layer between the deep convecting mantle and the crust, thus reducing tectonic activity at the surface. The inference that not all Archaean crust developed a strong and thick thermal boundary layer leads to the possibility that such ancient crust may have been overlooked because of its intensive reworking or lost from the geological record owing to preferential recycling.read more
Citations
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Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography
TL;DR: In this article, a 3D model of the northern Ordos block and its surrounding areas was constructed by surface wave tomography, which reveals significant intracratonic heterogeneities.
Journal ArticleDOI
Upper mantle structure beneath the eastern Colorado Plateau and Rio Grande rift revealed by Bouguer gravity, seismic velocities, and xenolith data
TL;DR: In this article, a large region of low uppermost mantle density is modeled underlain by a low-density upper mantle province that does not trend along upper crustal tectonic boundaries but, rather, is correlated with regions of middle to late Tertiary magmatism.
Journal ArticleDOI
Permian plume-strengthened Tarim lithosphere controls the Cenozoic deformation pattern of the Himalayan-Tibetan orogen
TL;DR: Guo et al. as mentioned in this paper reprocessed high-resolution magnetic data that show a 300-400-km-diameter radial pattern of linear anomalies emanating from a central region characterized by mixed positivenegative anomalies.
Journal ArticleDOI
Juvenile subcontinental lithospheric mantle beneath the eastern part of the Central Asian Orogenic Belt
TL;DR: In this paper, two groups of spinel lherzolites were identified, namely spinel harzburgite and spinel websterite, and they were shown to represent ancient lithospheric mantle that experienced high-degree melt extraction and subsequent extensive silicate metasomatism.
Journal ArticleDOI
A geochronological review of magmatism along the external margin of Columbia and in the Grenville-age orogens forming the core of Rodinia
T. Johansson,Bernard Bingen,Hannu Huhma,Tod E. Waight,Rikke Vestergaard,Alvar Soesoo,Grazina Skridlaite,Ewa Krzemińska,Leonid Shumlyanskyy,Marc Holland,Christopher S. Holm-Denoma,Wilson Teixeira,Frederico Meira Faleiros,Bruno Vieira Ribeiro,Joachim Jacobs,Cheng-Cheng Wang,Robert J. Thomas,P.H. Macey,Christopher L. Kirkland,Michael I. H. Hartnady,Bruce M. Eglington,Stephen J. Puetz,Kent C. Condie +22 more
TL;DR: A total of 4344 U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia as discussed by the authors .
References
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TL;DR: In this paper, the authors compared the relative abundances of the refractory elements in carbonaceous, ordinary, and enstatite chondritic meteorites and found that the most consistent composition of the Earth's core is derived from the seismic profile and its interpretation, compared with primitive meteorites, and chemical and petrological models of peridotite-basalt melting relationships.
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Composition and development of the continental tectosphere
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Os, Sr, Nd, and Pb isotope systematics of southern African peridotite xenoliths: Implications for the chemical evolution of subcontinental mantle
TL;DR: Isotope analyses of Os, Sr, Nd, and Pb elements were caried out on twelve peridotite xenoliths from the Jagersfontein, Letseng-la-terae, Thaba Patsoa, Mothae, and Premier kimberlites of southern Africa, to investigate the timing and the nature of melt extraction from the continental lithosphere and its relation to the continent formation and stabilization.
Journal ArticleDOI
Proterozoic crustal history of the western United States as determined by neodymium isotopic mapping
TL;DR: In this article, three age provinces have been delineated, each generally northeast-southwest trending, having decreasing crystallization ages and increasing initial e nd values with increasing distance southeastward from the Archean craton.