The zircon-age distribution in metamorphic rocks of the Taratash block, Southern Urals (an initial provenance signal)

2017 ◽  
Vol 72 (5) ◽  
pp. 314-319 ◽  
Author(s):  
Al. V. Tevelev ◽  
V. M. Mosejchuk ◽  
Ark. V. Tevelev ◽  
B. B. Shkursky
Keyword(s):  
Age Distribution ◽  
Southern Urals ◽  
Metamorphic Rocks ◽  
Zircon Age

scholarly journals Distribution of zircon age values in metamorphic rocks within the Taratash block of the Southern Urals (initial provenance signal)

2017 ◽  
pp. 15-19
Author(s):  
Al. V. Tevelev ◽  
V. M. Mosejchuk ◽  
A. V. Tevelev ◽  
B. B. Shkursky
Keyword(s):  
Southern Urals ◽  
Detrital Zircons ◽  
Metamorphic Rocks ◽  
The Southern Urals ◽  
Zircon Age ◽  
Lower Riphean ◽  
Kolmogorov Smirnov ◽  
Definition Of ◽  
Isotope Dating ◽  
Smirnov Test

The article establishes and realizes an idea of definition of the initial provenance signal for the Southern Urals Taratash block using isotope dating of the zircons in the Archean and Early Proterozoic magmatic and metamorphic rocks. The work takes into account 132 data for which the discordance did not exceed 10%. We obtained a probability density diagram for zircon ages, which we used firstly for comparison with detrital zircons ages from the sandstones of lower riphean Ay suite, and secondly, with density of the zircon ages in the metamorphic rocks of the Aleksandrovsky block located to the east. The similarity of distributions was verified by means of the Kolmogorov-Smirnov test.

Enigmatic provenance signature of sandstone from the Okwa Group, Botswana

2020 ◽  
Vol 123 (3) ◽  
pp. 331-342
Author(s):  
T. Andersen ◽  
M.A. Elburg ◽  
J. Lehmann
Keyword(s):  
South Africa ◽  
Detrital Zircon ◽  
Sedimentary Rock ◽  
Age Distribution ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Significant Shift ◽  
Zircon Age ◽  
Three Samples ◽  
Isotope Distributions

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.

Discussion of ‘Metamorphic P–T and retrograde path of high-pressure Barrovian metamorphic zones near Cairn Leuchan, Caledonian orogen, Scotland’

2014 ◽  
Vol 151 (4) ◽  
pp. 758-763 ◽  
Author(s):  
K. Aoki ◽  
B. F. Windley ◽  
S. Maruyama ◽  
S. Omori
Keyword(s):  
High Pressure ◽  
Granulite Facies ◽  
Geological Structure ◽  
Metamorphic Rocks ◽  
New Paradigm ◽  
Zircon Age ◽  
Tectonic Model ◽  
High Pressure Granulite ◽  
Future Publication ◽  
Western Ireland

K. Aoki, B. F. Windley, S. Maruyama & S. Omori reply: First, we thank Viete, Oliver & Wilde for their interesting and thought-provoking comments on the timing of the high-pressure granulite facies (HGR) metamorphism recorded in metamorphic rocks at Cairn Leuchan, Scotland, published by Aoki et al. (2013). Based on new metamorphic data of garnetites and garnet-amphibolites at Cairn Leuchan and new zircon U–Pb ages of amphibolitized eclogite at Tomatin, we suggested in our publication that the HGR metamorphism was retrograde after eclogite facies before the c. 470 Ma ‘Barrovian metamorphism’. Viete, Oliver & Wilde however speculate that the HGR metamorphism at Cairn Leuchan may have occurred at c. 1000 Ma, as a result of their new U–Pb zircon age of the Cowhythe Gneiss at Portsoy and from previous studies of the geological structure and geochronology. We are grateful for this opportunity to describe, albeit in a preliminary manner, our new understanding and tectonic model of the Caledonian orogen in Scotland and western Ireland of which the Barrovian metamorphism is a key component. A reply to a comment is not the correct place to propose an entirely new paradigm for such a classic orogen, but we will present our model more fully in a future publication.

scholarly journals Supplemental Material: Detrital zircon geochronology and Hf isotope geochemistry of Mesozoic sedimentary basins in south-central Alaska: Insights into regional sediment transport, basin development, and tectonics along the NW Cordilleran margin

2020 ◽  
Author(s):  
C.R. Fasulo ◽  
et al.
Keyword(s):  
Detrital Zircon ◽  
Isotope Geochemistry ◽  
Age Distribution ◽  
Sedimentary Basins ◽  
Alaska Range ◽  
Zircon Age ◽  
Detrital Zircon Geochronology ◽  
South Central ◽  
Cordilleran Margin ◽  
Detrital Zircon Ages

Supplemental Figure S1. Normalized distribution plot of detrital zircon ages from the Kahiltna assemblage of the central Alaska Range (Hampton et al., 2010), the Wellesly basin (this study), and the Kahiltna assemblage of the northwestern Talkeetna Mountains (Hampton et al., 2010). Note that the detrital zircon age distribution of ages older than 500 Ma has 10× vertical exaggeration.

DEFORMATIONS AND THE SEQUENCE OF THE STRUCTURES FORMATION IN THE NORTHERN PART OF THE ZONE OF DEVELOPMENT OF MAKSUTOVO METAMORPHIC COMPLEX (SOUTHERN URALS)

2018 ◽  
pp. 17-26
Author(s):  
B. G. Golionko ◽  
A. V. Ryazantsev
Keyword(s):  
Structural Evolution ◽  
Southern Urals ◽  
Strike Slip ◽  
Metamorphic Rocks ◽  
Metamorphic Complex ◽  
The Third ◽  
Deformation Stage ◽  
Third Stage ◽  
Western Border ◽  
Definition Of

Composition and structural evolution of the Maksutovo metamorphic complex in the its northern part has been examined. The early folds 77) plunging in the SE direction have been established to be developed only in the rocks of the Maksutovo metamorphic complex. The problem of the definition of the geodynamic nature of the 7Л deformation stage, marked by the folds 77), has not been solved yet. Tectonic inclusions of the metamorphic rocks adjacent to the western border of the Main Uralian Thrust without traces of 7Л deformation stage must not be considered as parts of the Maksutovo metamorphic complex. 7Л1 deformation stage expressed in formation of thrusts and 77. west vergent folds is connected with late Paleozoic continental collision. The third stage of deformation 7JIII is marked by development of 77) folds with steep hinges associated with post collision strike slip movements

scholarly journals Resolution of the age structure of the detrital zircon populations of two Lower Cretaceous sandstones from the Weald of England by fission track dating

1984 ◽  
Vol 121 (4) ◽  
pp. 269-277 ◽  
Author(s):  
A. J. Hurford ◽  
F. J. Fitch ◽  
A. Clarke
Keyword(s):  
Detrital Zircon ◽  
Lower Cretaceous ◽  
Fission Track ◽  
Age Distribution ◽  
The Other ◽  
Fission Track Dating ◽  
Zircon Age ◽  
Zircon Fission Track ◽  
Geological Implications ◽  
Fission Track Ages

AbstractModes in the frequency of distribution of fission track ages obtained from detrital zircon grains may prove characteristic of individual sandstone bodies, supporting the identification of the sources from which a particular flow of sedimentary detritus was derived and thus allowing new inferences to be made concerning palaeogeography. A computer program has been written and used to identify modes in the zircon fission track age distribution within two Lower Cretaceous sandstone samples from the Weald of southern England. Pronounced modes appear in one rock around 119 Ma, 160 Ma, 243 Ma and 309 Ma and in the other around 141 Ma, 175 Ma, 257 to 277 Ma and 394 to 453 Ma. The geological implications of these quite dissimilar zircon age spectra are discussed. It is concluded that they support the palaeogeographical models of Allen (1981) and indicate that the provenance of the first sample, from the Top Ashdown Sandstone member at Dallington in East Sussex, was almost entirely southerly, while that of the second, from the Netherside Sand member at Northchapel in West Sussex, was more varied, but predominantly westerly and northerly.

scholarly journals Revisiting the Intermediate Sediment Repository Concept Applied to the Provenance of Zircon

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 233
Author(s):  
Manuel Francisco Pereira ◽  
Cristina Gama
Keyword(s):  
Detrital Zircon ◽  
Age Distribution ◽  
Age Groups ◽  
Source Rocks ◽  
Beach Sand ◽  
Density Estimator ◽  
Zircon Age ◽  
Potential Source ◽  
Sedimentary System ◽  
Siliciclastic Rocks

This paper revisits the intermediate sediment repository (ISR) concept applied to provenance, using a comparison of the detrital zircon population of Holocene beach sand from the southwest Portuguese coast with populations from their potential source rocks. The U–Pb age of detrital zircon grains in siliciclastic rocks allows for the interpretation of provenance by matching them with the crystallization ages of igneous source (protosource) rocks in which this mineral originally crystallized or which was subsequently recycled from it, acting as ISRs. The comparative analysis of the Precambrian, Paleozoic, and Cretaceous ages using recent statistical tools (e.g., kernel density estimator (KDE), cumulative age distribution (CAD), and multidimensional scaling (MDS)) suggests that the zircon age groups of Carboniferous, Triassic, and Pliocene-Pleistocene ISRs are reproduced faithfully in Holocene sand. Furthermore, the recycling of a protosource (Cretaceous syenite) in a sedimentary system dominated by ISRs is evaluated. It is argued that the ISR concept, which is not always taken into account, is required for a better understanding of the inherent complexity of local provenance and to differentiate sediment recycling from first- cycle erosion of an igneous rock.

scholarly journals Rapid endogenic rock recycling in magmatic arcs

2020 ◽  
Author(s):  
Junyong Li ◽  
Ming Tang ◽  
Cin-Ty Lee ◽  
Xiaolei Wang ◽  
Zhi-Dong Gu ◽  
...  
Keyword(s):  
Subduction Zones ◽  
Pressure Ratio ◽  
Age Distribution ◽  
Magmatic Zircon ◽  
Arc Magmatism ◽  
Thrust Faults ◽  
Yangtze Block ◽  
Zircon Age ◽  
Deep Crust ◽  
O Isotopes

Abstract In subduction zones, materials on Earth’s surface can be transported to the deep crust or mantle, but the exact mechanisms and the nature of the recycled materials are not fully understood. Here, we report a set of migmatites from western Yangtze Block, China. These migmatites have similar bulk compositions as forearc sediments. Zircon age distribution and Hf–O isotopes indicate that the precursors of the sediments were predominantly derived from juvenile arc crust itself. Using phase equilibria modelling, we show that the sediments experienced high temperature-to-pressure ratio metamorphism and were most likely transported to deep arc crust by intracrustal thrust faults. By dating the magmatic zircon cores and overgrowth rims, we find that the entire rock cycle, from arc magmatism, to weathering at the surface, then to burial and remelting in the deep crust, took place within ~ 10 Ma. Our findings highlight thrust faults as an efficient recycling channel in compressional arcs and endogenic recycling as an important mechanism driving internal redistribution and differentiation of arc crust.

Sign in / Sign up

Export Citation Format

Share Document