U–Pb detrital zircon age patterns of Cenozoic clastic sedimentary rocks in Trinidad and its implications

2014 ◽  
Vol 307 ◽  
pp. 7-16 ◽  
Author(s):  
Xiangyang Xie ◽  
Paul Mann
2020 ◽  
Vol 123 (3) ◽  
pp. 331-342
Author(s):  
T. Andersen ◽  
M.A. Elburg ◽  
J. Lehmann

Abstract Detrital zircon grains from three samples of sandstone from the Tswaane Formation of the Okwa Group of Botswana have been dated by U-Pb and analysed for Hf isotopes by multicollector LA-ICPMS. The detrital zircon age distribution pattern of the detrital zircons is dominated by a mid-Palaeoproterozoic age fraction (2 000 to 2 150 Ma) with minor late Archaean – early Palaeoproterozoic fractions. The 2 000 to 2 150 Ma zircon grains show a range of epsilon Hf from -12 to 0. The observed age and Hf isotope distributions overlap closely with those of sandstones of the Palaeoproterozoic Waterberg Group and Keis Supergroup of South Africa, but are very different from Neoproterozoic deposits in the region, and from the Takatswaane siltstone of the Okwa Group, all of which are dominated by detrital zircon grains younger than 1 950 Ma. The detrital zircon data indicate that the sources of Tswaane Formation sandstones were either Palaeoproterozoic rocks in the basement of the Kaapvaal Craton, or recycled Palaeoproterozoic sedimentary rocks similar to the Waterberg, Elim or Olifantshoek groups of South Africa. This implies a significant shift in provenance regime between the deposition of the Takatswaane and Tswaane formations. However, the detrital zircon data are also compatible with a completely different scenario in which the Tswaane Formation consists of Palaeoproterozoic sedimentary rock in tectonic rather than depositional contact with the other units of the Okwa Group.


2020 ◽  
pp. 1-17
Author(s):  
Bo Hui ◽  
Yunpeng Dong ◽  
Feifei Zhang ◽  
Shengsi Sun ◽  
Shuai He

Abstract The Yangtze Block in South China constitutes an important Precambrian landmass in the present East Asian continent. The Neoproterozoic sedimentary successions of the Hengdan Group in the NW Yangtze Block record essential information for deciphering the Neoproterozoic tectonics along the NW margin. However, its depositional age, provenance and tectonic properties remain uncertain. Here, a combined analysis of detrital zircon U–Pb dating and geochemistry is performed on representative samples from the Hengdan Group. Concordant dating results of samples from the bottom and upper parts constrain the maximum depositional age at c. 720 Ma. Detrital zircon age patterns of samples reveal a uniformly pronounced age peak at c. 915–720 Ma, which is consistent with the magmatic pulses in domains at the NW end of the Yangtze Block. In addition, these samples display left-sloping post-Archaean Australian shale (PAAS)-normalized rare-earth element patterns and variable trace element patterns, resembling sediments accumulated in a basin related to an active continental margin geodynamic setting. Provenance analysis reveals that the main sources featured intermediate to felsic components, which experienced rapid erosion and sedimentation. These integrated new investigations, along with previous compilations, indicate that the Hengdan Group might have been deposited in a fore-arc basin controlled by subduction beneath the Bikou Terrane. Thus, such interpretation further supports proposals for subduction-related tectonics along the western margin of the Yangtze Block during the early Neoproterozoic.


Geology ◽  
2005 ◽  
Vol 33 (8) ◽  
pp. 637-640 ◽  
Author(s):  
G. Gutiérrez-Alonso ◽  
J. Fernández-Suárez ◽  
Alan S. Collins ◽  
I. Abad ◽  
F. Nieto

Abstract The 40Ar/39Ar age data on single detrital muscovite grains complement U-Pb zircon ages in provenance studies, as micas are mostly derived from proximal sources and record low-temperature processes. Ediacaran and Cambrian sedimentary rocks from northwest Iberia contain unmetamorphosed detrital micas whose 40Ar/39Ar age spectra suggest an Amazonian–Middle American provenance. The Ediacaran sample contained only Neoproterozoic micas (590–783 Ma), whereas the Cambrian sample contained three age groups: Neoproterozoic (550–640 Ma, Avalonian–Cadomian–Pan African), Mesoproterozoic- Neoproterozoic boundary (ca. 920–1060 Ma, Grenvillian-Sunsas), and late Paleoproterozoic (ca. 1580–1780 Ma, Rio Negro). Comparison of 40Ar/39Ar muscovite ages with published detrital zircon age data from the same formations supports the hypothesis that the Neoproterozoic basins of northwest Iberia were located in a peri-Amazonian realm, where the sedimentary input was dominated by local periarc sources. Tectonic slivering and strike-slip transport along the northern Gondwanan margin affected both the basins and fragments of basement that were transferred from Amazonian to northern African realms during the latest Neoproterozoic–earliest Cambrian. Exhumation and erosion of these basement sources caused shedding of detritus to the Cambrian basins, in addition to detritus sourced in the continental mainland. The apparent dominance of Rio Negro–aged micas in the Cambrian sandstone suggests the presence of unexposed basement of that age beneath the core of the Ibero-Armorican Arc.


2018 ◽  
Vol 722 ◽  
pp. 69-105 ◽  
Author(s):  
Wei Lin ◽  
Philippe Rossi ◽  
Michel Faure ◽  
Xian-Hua Li ◽  
Wenbin Ji ◽  
...  

2012 ◽  
Vol 150 (3) ◽  
pp. 455-478 ◽  
Author(s):  
CHRISTOPHER J. ADAMS ◽  
NICK MORTIMER ◽  
HAMISH J. CAMPBELL ◽  
WILLIAM L. GRIFFIN

AbstractDetrital zircon U-Pb ages for 30 Late Jurassic and Cretaceous sandstones from the Eastern Province of eastern New Zealand, combined with previously-published geochronological and palaeontological data, constrain the time of deposition in the Pahau and Waioeka terranes of the Cretaceous accretionary margin of Zealandia, and their adjacent cover strata. The zircon age patterns also constrain possible sediment source areas and mid-Cretaceous geodynamic models of the transition from basement accretionary wedge to passive-margin cover successions. Pahau Terrane deposition was mainly Barremian to Aptian but continued locally through to late Albian time, with major source areas in the adjacent Kaweka and Waipapa terranes and minor inputs from the inboard Median Batholith. Waioeka Terrane deposition was mainly Albian, with distinctive and exclusive sediment sources, principally from the Median Batholith but with minor inputs from the Western Province. Alternative tectonic models to deliver such exclusive Median Batholith and Western Province-derived sediment to the mid-Cretaceous Zealandia continental margin are: (1) the creation of a rift depression across Zealandia or (2) sinistral displacement of South Zealandia with respect to North Zealandia, to expose Western Province rocks directly at the Zealandia margin. Detrital zircon age patterns of Cretaceous cover successions of the Eastern Province of eastern New Zealand demonstrate purely local sources in the adjacent Kaweka and Waipapa terranes. Cretaceous zircon components show a decline in successions of late Early Cretaceous age and disappear by late Late Cretaceous time, suggesting the abandonment or loss of access to both the Median Batholith and Western Province as sediment sources.


2011 ◽  
Vol 62 (4) ◽  
pp. 299-307 ◽  
Author(s):  
Ion Balintoni ◽  
Constantin Balica ◽  
Antoneta Seghedi ◽  
Mihai Ducea

Peri-Amazonian provenance of the Central Dobrogea terrane (Romania) attested by U/Pb detrital zircon age patterns The Central Dobrogea Shield is a part of the Moesia, a Paleozoic composite terrane located southward of the North Dobrogea Alpine orogen. The two geological units are separated from each other by a trans-lithospheric discontinuity, the Peceneaga-Camena transform fault. Along this fault, remnants of a Variscan orogen (i.e. North Dobrogea), recycled during the Alpine orogeny come in contact with two lithological entities of the Central Dobrogea Shield, unaffected by the Phanerozoic orogenic events: the Histria Formation, a flysch-like sequence of Ediacaran age very low-grade metamorphosed and its basement, the medium-grade metamorphosed Altîn Tepe sequence. Southward, along the reverse hidden Palazu fault, the Histria Formation meets South Dobrogea, formed of quite different geological formations. Detrital zircon from the Histria Formation yielded U/Pb LA ICP MS ages that show provenance patterns typical of peri-Amazonian terranes. Such terranes were sourced by orogens ranging from Paleoarchean to Neoproterozoic. The ages between 750 and 600 Ma differentiate the Amazonian sources from the Baltican and Laurentian sources, since they are lacking from the last ones. The youngest ages of 587 and 584 Ma suggest for the Histria Formation a maximum late Ediacaran deposition age. At the same time, the continuity of the Ordovician sediments over the Palazu fault revealed by drill-cores favours a Cambrian junction between Central and South Dobrogea.


Sign in / Sign up

Export Citation Format

Share Document