Search results for "Continent"

Inverse modeling of past lead atmospheric deposition in South Greenland

2015

The aim of this study is to model atmospheric lead fluxes in two different paleoenvironmental records located in southern Greenland. Fifty five sediment samples collected from the Lake Igaliku sedimentary sequence were analyzed for lead and aluminum concentrations, and lead isotopic compositions. The second archive consists in a previously published dataset, obtained from a minerogenic peat deposit, located at Tasiusaq, 16 km northwest from Lake Igaliku. A flux model fitted to both dataset produces similar results, allowing past anthropogenic atmospheric deposition to be reconstructed. This original method can be easily adapted for other studies where natural inputs dominate over discrete a…

Chapter 5.2 The Ancient Gneiss Complex of Swaziland and Environs: Record of Early Archean Crustal Evolution in Southern Africa

2007

Publisher Summary This chapter discusses the record of early Archean crustal evolution in Southern Africa. Southern Africa preserves one of the most complete and detailed records of early Precambrian crustal evolution, and the Ancient Gneiss Complex (AGC) of Swaziland and the related rocks along the southern margin of the 3.5–3.2 Ga Barberton Greenstone Belt (BGB) have played a prominent role in models for the early evolution of continental crust. The AGC is separated from the BGB by a large granitoid sheet-like pluton some 3 Ga in age and known as the Mpuluzi Batholith. In northwest Swaziland, however, small inliers of AGC gneisses occur in faulted and sheared contact with BGB rocks, and t…

Detrital and igneous zircon ages for supracrustal rocks of the Kyrgyz Tianshan and palaeogeographic implications

2014

Abstract We report detrital zircon ages for Precambrian and early Palaeozoic metasediments from the Tianshan orogen in Kyrgyzstan, an important component of the Central Asian Orogenic Belt and compare these with published ages from the Chinese Tianshan and the Tarim craton. These data provide information on possible source terrains and suggest that Precambrian basement is widespread in the Tianshan and may, at least in part, represent continental fragments rifted off the Tarim craton during the early history of the Central Asian Orogenic Belt. Distinct differences in the Precambrian zircon age distribution between the North and Middle Tianshan of Kyrgyzstan support earlier ideas that these …

Composition, structure and evolution of the early Precambrian lower continental crust: constraints from geological observations and age relationships

1986

African linkage of Precambrian Sri Lanka

1991

New age and isotopic data show that the high-grade basement rocks of Sri Lanka were not linked to the Archaean granulite domain of southern India but experienced their main structural and metamorphic development during the Pan-African event some 950 to 550 Ma ago. This occurred when West Gondwana and East Gondwana collided to form one of the longest collisional structures in the Supercontinent — the Mozambique belt that extends from Mozambique to Ethiopia and Sudan. A major tectonic boundary, interpreted as a thrust zone, divides the Highland/Southwestern Complex in the central part of Sri Lanka from the Vijayan Complex in the E and SE. The former is interpreted to represent the remnant of …

Zircon ages and Hf isotopic compositions of plutonic rocks from the Central Tianshan (Xinjiang, northwest China) and their significance for early to …

2014

We present new zircon ages and Hf-in-zircon isotopic data for plutonic rocks and review the crustal evolution of the Chinese Central Tianshan (Xinjiang, northwest China) in the early to mid-Palaeozoic. The Early Ordovician (ca. 475–473 Ma) granitoid rocks have zircon eHf(t) values either positive (+0.3 to +9.5) or negative (−6.0 to −12.9). This suggests significant addition of juvenile material to, and coeval crustal reworking of, the pre-existing continental crust that is fingerprinted by numerous Precambrian zircon xenocrysts. The Late Ordovician–Silurian (ca. 458–425 Ma) rocks can be assigned to two sub-episodes of magmatism: zircon from rocks of an earlier event (ca. 458–442 Ma) has neg…

Italian familial defective apolipoprotein B patients share a unique haplotype with other Caucasian patients.

2001

Familial defective apolipoprotein (apo) B-100 together with familial hypercholesterolemia are the two common genetic conditions that cause hypercholesterolemia. Familial defective apolipoprotein B-100 is due to mutations around codon 3500 of the apo B gene. The most-characterized mutation is a G>A transition at nucleotide 10,708 that results in the substitution of arginine by glutamine at codon 3500 (Apo B Arg3500Gln). Two other mutations are caused by a C>T transition, one at nucleotide 10,800 (Apo B Arg3531Cys) and the other at nucleotide 10,707 (apo B Arg3500Trp). In the present study we describe three new Italian cases of familial defective apolipoprotein B-100 (Apo B Arg3500Gln), one f…

Depositional ages and provenance of the Neoproterozoic Damara Supergroup (northwest Namibia): implications for the Angola-Congo and Kalahari cratons …

2017

Abstract The Damara Orogen is composed of the Damara, Kaoko and Gariep belts developed during the Neoproterozoic Pan-African Orogeny. The Damara Belt contains Neoproterozoic siliciclastic and carbonate successions of the Damara Supergroup that record rift to proto-ocean depositional phases during the Rodinia supercontinent break up. There are two conflicting interpretations of the geotectonic framework of the Damara Supergroup basin: i) as one major basin, composed of the Outjo and Khomas basins, related to rifting in the Angola-Congo-Kalahari paleocontinent or, ii) as two independent passive margin basins, one related to the Angola-Congo and the other to the Kalahari proto-cratons. Detrita…

Interactions of earthworms with Atrazine-degrading bacteria in an agricultural soil

2006

FR2116; In the last 10 years, accelerated mineralization of Atrazine (2-chloro-ethylamino-6-isopropylamino-s- triazine) has been evidenced in agricultural soils repeatedly treated with this herbicide. Here, we report on the interaction between earthworms, considered as soil engineers, and the Atrazine-degrading community. The impact of earthworm macrofauna on Atrazine mineralization was assessed in representative soil microsites of earthworm activities (gut contents, casts, burrow linings). Soil with or without earthworms, namely the anecic species Lumbricus terrestris and the endogenic species Aporrectodea caliginosa, was either inoculated or not inoculated with Pseudomonas sp. ADP, an Atr…

Interdisciplinarity in The Second Sex: Between Phenomenology and Psychoanalysis

2015

This chapter analyzes Simone de Beauvoir’s way of combining different theoretical frameworks, in particular, those of phenomenology and psychoanalysis. To elucidate the nature of Beauvoirian interdisciplinarity, I will examine Beauvoir’s discussion of penis envy and her application of Helene Deutsch’s views. I will argue that the combination of psychoanalysis and phenomenology in The Second Sex brings about an inner tension, of which those interested in applying Beauvoir’s interdisciplinary approach should be aware. nonPeerReviewed