The Mecubúri and Alto Benfica Groups, NE Mozambique: Aids to unravelling ca. 1 and 0.5Ga events in the East African Orogen

Thomas, Robert J.; Jacobs, Joachim; Horstwood, Matthew; Ueda, K.; Bingen, Bernard; Matola, R.

doi:10.1016/j.precamres.2010.01.010

Cited by 58 publications

(34 citation statements)

References 105 publications

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“…Measurement procedures followed methods described by Thomas et al (2010). A small number of zircons (sample 292) were analysed using an AttoM single-collector sector field (SC-SF) ICP-MS system (Nu Instruments, Wrexham, uK) and a New Wave Research uP193FX (193 nm), excimer ablation system (New Wave Research, uK).…”

Section: Zircon U-pb Geochronologymentioning

confidence: 99%

Tectonic interleaving along the Main Central Thrust, Sikkim Himalaya

Mottram

Argles

Harris

et al. 2014

JGS

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Geochemical and geochronological analyses provide quantitative evidence about the origin, development and motion along ductile faults, where kinematic structures have been overprinted. The Main Central Thrust is a key structure in the Himalaya that accommodated substantial amounts of the India-Asia convergence. This structure juxtaposes two isotopically distinct rock packages across a zone of ductile deformation. Structural analysis, whole-rock Nd isotopes, and u-Pb zircon geochronology reveal that the hanging wall is characterized by detrital zircon peaks at c.

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Section: Zircon U-pb Geochronologymentioning

confidence: 99%

Tectonic interleaving along the Main Central Thrust, Sikkim Himalaya

Mottram

Argles

Harris

et al. 2014

JGS

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“…The detrital zircon samples and granite sample 143-PP3 were dated using multi-collector (MC-) ICP-MS whilst granite samples R-1303 and 165-PP4 were dated using single collector sector field (SC-SF-)ICP-MS. Methods and run conditions are detailed in Thomas et al (2010). All samples were imaged using Cathodoluminscence (CL) prior to analysis.…”

Section: Geochronologymentioning

confidence: 99%

Investigating high zircon concentrations in the fine fraction of stream sediments draining the Pan-African Dahomeyan Terrane in Nigeria

Johnson

Horstwood²,

Lapworth

et al. 2012

Applied Geochemistry

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Sixteen hundred stream sediments (<150 μm fraction) collected during regional geochemical surveys in central and SW Nigeria have high median and maximum concentrations of Zr that exceed corresponding Zr concentrations found in stream sediments collected from elsewhere in the World with similar bedrock geology. X-ray diffraction studies on a sub-set of the analysed stream sediments showed that Zr is predominantly found in detrital zircon grains. However, the main proximal source rocks (Pan-African 'Older Granites' of Nigeria and their Proterozoic migmatitic gneiss country rocks) are not enriched in zircon (or Zr). Nevertheless, U-Pb LA-ICP-MS dating with cathodoluminescence imaging on detrital zircons, both from stream sediment samples and underlying Pan-African 'Older Granites' confirms a local bedrock source for the stream sediment zircons. A combination of tropical/chemical weathering and continuous physical weathering, both by 'wet season' flash flooding and 'dry season' unidirectional winds are interpreted to have effectively broken down bedrock silicate minerals and removed much of the resultant clay phases, thereby increasing the Zr contents in stream sediments. The strong correlation between winnowing index (Th/Al) and Zr concentration across the study area support this interpretation. Therefore, 'anomalous' high values of Zr, as well as other elements concentrated in resistant 'heavy' minerals in Nigeria's streams may not reflect proximal bedrock concentrations of these elements. This conclusion has important implications for using stream sediment chemistry as an exploration tool in Nigeria for primary metal deposits associated with heavy minerals.

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“…Grey markers show age against εHf from this study (diamonds -quartzite clast DJ1412.2; triangles -sandstone DJ.1433.3; circles -DJ.1405.2; crosses -igneous cobbles, undifferentiated) and are overlain with bars representing the range of potential igneous and volcanic source rocks, identified by the adjacent abbreviation, from South America, Antarctica and South Africa: AP -Antarctic Peninsula, EM -Ellsworth Mountains, Antarctica; FA -Famatinian arc, South America; HN -Haag Nunataks, Antarctica; KCKaapvaal craton, southern Africa; NC -Nampula Complex, southern Africa; RC -Rayner Complex, Antarctica; SR -Shackleton Range, Antarctica. (Data from Chernicoff et al 2010;Halpin et al 2005;Thomas et al 2010;Will et al 2010;Zeh, Gerdes & Barton, 2009. ) (Bahlburg et al 2009) but are relatively abundant in the upper parts of the Ellsworth Mountains succession ) and also from sediments and cobbles in Mesozoic sedimentary rocks from the southern Antarctic Peninsula .…”

Section: Interpretation Of the Geochronology And Hf Isotope Geochemistrymentioning

confidence: 99%

Permo-Carboniferous conglomerates in the Trinity Peninsula Group at View Point, Antarctic Peninsula: sedimentology, geochronology and isotope evidence for provenance and tectonic setting in Gondwana

et al. 2011

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-Field observations from the Trinity Peninsula Group at View Point on the Antarctic Peninsula indicate that thick, southward-younging and overturned clastic sedimentary rocks, comprising unusually coarse conglomeratic lenses within a succession of fine-grained sandstonemudstone couplets, are the deposits of debris and turbidity flows on or at the foot of a submarine slope. Three detrital zircons from the sandstone-mudstone couplets date deposition at 302 ± 3 Ma, at or shortly after the Carboniferous-Permian boundary. Conglomerates predominantly consist of quartzite and granite and contain boulders exceeding 500 mm in diameter. Zircons from granitoid clasts and a silicic volcanic clast yield U-Pb ages of 466 ± 3 Ma, 373 ± 5 Ma and 487 ± 4 Ma, respectively and have corresponding average εHf t values between +0.3 and +7.6. A quartzite clast, conglomerate matrix and sandstone interbedded with the conglomerate units have broadly similar detrital zircon age distributions and Hf isotope compositions. The clast and detrital zircon ages match well with sources within Patagonia; however, the age of one granite clast and the εHf characteristics of some detrital zircons point to a lesser South Africa or Ellsworth Mountain-like contribution, and the quartzite and granite-dominated composition of the conglomerates is similar to upper Palaeozoic diamictites in the Ellsworth Mountains. Unlike detrital zircons, large conglomerate clasts limit possible transport distance, and suggest sedimentation took place on or near the edge of continental crust. Comparison with other upper Palaeozoic to Mesozoic sediments in the Antarctic Peninsula and Patagonia, including detrital zircon composition and the style of deformation, suggests deposition of the Trinity Peninsula Group in an upper plate basin on an active margin, rather than a subduction-related accretionary setting, with slow extension and rifting punctuated by short periods of compression.

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The Mecubúri and Alto Benfica Groups, NE Mozambique: Aids to unravelling ca. 1 and 0.5Ga events in the East African Orogen

Cited by 58 publications

References 105 publications

Tectonic interleaving along the Main Central Thrust, Sikkim Himalaya

Tectonic interleaving along the Main Central Thrust, Sikkim Himalaya

Investigating high zircon concentrations in the fine fraction of stream sediments draining the Pan-African Dahomeyan Terrane in Nigeria

Permo-Carboniferous conglomerates in the Trinity Peninsula Group at View Point, Antarctic Peninsula: sedimentology, geochronology and isotope evidence for provenance and tectonic setting in Gondwana

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