Insights into crust formation and recycling in North Africa from combined U–Pb, Lu–Hf and O isotope data of detrital zircons from Devonian sandstone of southern Libya

Abstract

Combined U -Pb, Lu-Hf and O isotope data of detrital zircons from the Devonian sandstone of southern Libya provide important new boundary parameters for reconstruction of palaeosource areas and sediment transport and may lead to novel approaches to test current plate tectonic models, with important implications for our understanding of the evolution of northern Gondwana (in present-day coordinates) during the Palaeozoic. Detrital zircon U-Pb ages from Devonian sandstone of the eastern margin of the Murzuq Basin show four main age populations: 2.7-2.5 Ga (13%), 2.1-1.9 Ga (10%), 1.1-0.9 Ga (25%) and 0.7-0.5 Ga (46%). The ubiquitous occurrence of c. 1.0 Ga detrital zircons is characteristic of the Saharan Metacraton sedimentary cover sequence and provides new insights into palaeogeographic reconstructions of Gondwanaderived terranes in the Eastern Mediterranean and SW Europe. The Lu-Hf isotope data suggest that zircons crystallized within a narrow time interval from magmas with heterogeneous Hf isotope compositions. These magmas were derived by melting of pre-existing rocks, rather than being juvenile. The calculated Hf model ages range from 3.7 Ga to 1.3 Ga, with a major population between 2.8 Ga and 1.9 Ga, indicating prominent recycling of Archaean and Palaeoproterozoic crust.

Sediment provenance studies in hydrocarbon exploration and production: an introduction

“…The studies have a wide geographical diversity, from regions of frontier hydrocarbon exploration in the Arctic (Bue & Andresen 2013), North Africa (Meinhold et al 2013) and SE Asia (Naing et al 2013) to more established producing basins, such as the Norwegian Sea ) and the North Sea (Lundmark et al 2013).…”

“…The data clearly demonstrate input from two distinct sedimentary sources, easterly Uralideand westerly Greenland -Canada-derived detritus, therefore testing previous interpretations of regional sediment sources. Meinhold et al (2013) also use detrital zircons to explore sedimentary sources, in this case from the Devonian of Libya. The paper illustrates the added value of collecting different isotopic data on single minerals, in this case U-Pb, Lu -Hf and O from zircons.…”