scholarly journals The missing link of Rodinia breakup in western South America: A petrographical, geochemical, and zircon Pb-Hf isotope study of the volcanosedimentary Chilla beds (Altiplano, Bolivia)

Geosphere ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 619-645 ◽  
Author(s):  
Heinrich Bahlburg ◽  
Udo Zimmermann ◽  
Ramiro Matos ◽  
Jasper Berndt ◽  
Nestor Jimenez ◽  
...  
Keyword(s):  
South America ◽  
Age Distribution ◽  
Limited Range ◽  
Detrital Zircons ◽  
Hf Isotope ◽  
Geochemical Data ◽  
Isotope Data ◽  
Final Assembly ◽  
Depositional Age ◽  
Southwestern Amazonia

Abstract The assembly of Rodinia involved the collision of eastern Laurentia with southwestern Amazonia at ca. 1 Ga. The tectonostratigraphic record of the central Andes records a gap of ∼300 m.y. between 1000 Ma and 700 Ma, i.e., from the beginning of the Neoproterozoic Era to the youngest part of the Cryogenian Period. This gap encompasses the time of final assembly and breakup of the Rodinia supercontinent in this region. We present new petrographic and whole-rock geochemical data and U-Pb ages combined with Hf isotope data of detrital zircons from the volcanosedimentary Chilla beds exposed on the Altiplano southwest of La Paz, Bolivia. The presence of basalt to andesite lavas and tuffs of continental tholeiitic affinity provides evidence of a rift setting for the volcanics and, by implication, the associated sedimentary rocks. U-Pb ages of detrital zircons (n = 124) from immature, quartz-intermediate sandstones have a limited range between 1737 and 925 Ma. A youngest age cluster (n = 3) defines the maximum depositional age of 925 ± 12 Ma. This is considered to coincide with the age of deposition because Cryogenian and younger ages so typical of Phanerozoic units of this region are absent from the data. The zircon age distribution shows maxima between 1300 and 1200 Ma (37% of all ages), the time of the Rondônia–San Ignacio and early Sunsás (Grenville) orogenies in southwestern Amazonia. A provenance mixing model considering the Chilla beds, Paleozoic Andean units, and data from eastern Laurentia Grenville sources shows that >90% of the clastic input was likely derived from Amazonia. This is also borne out by multidimensional scaling (MDS) analysis of the data. We also applied MDS analysis to combinations of U-Pb age and Hf isotope data, namely εHf(t) and 176Hf/177Hf values, and demonstrate again a very close affinity of the Chilla beds detritus to Amazonian sources. We conclude that the Chilla beds represent the first and hitherto only evidence of Rodinia breakup in Tonian time in Andean South America.

scholarly journals Age, HF-isotope systemantics of detritial zircons and the source of conglomerates of the mt. Southern Demerdzhy, Mountainous Crimea

2019 ◽  
pp. 36-61
Author(s):  
S. V. Rud’ko ◽  
N. B. Kuznetsov ◽  
E. A. Belousova ◽  
T. V. Romanyuk
Keyword(s):  
Middle Jurassic ◽  
Age Distribution ◽  
Primary Source ◽  
Upper Jurassic ◽  
Detrital Zircons ◽  
Hf Isotope ◽  
Coarse Grained ◽  
East European ◽  
Scythian Plate ◽  
Isotope Systematics

The U–Pb dating and Hf isotope systematics of detrital zircons from a sandstone interbed in the section of the upper conglomerate sequence of the Mt. South Demerdzhi were carried out. The dominant populations of detrital zircons in the studied sample characterize episodes of magmatic activity within the source of the Upper Jurassic conglomerates. Magmatism was manifested in the Vendian-Cambrian, Carbon-Triassic and Late Jurassic. The åHf values of detrital zircons of these ages indicate the insignificant role of the ancient (Archean–Early Proterozoic) continental crust in the protolith of magmatic chambers. The similarity of the detrital zircons age distribution from the Middle Jurassic and Upper Jurassic conglomerate strata suggests that they are molasses of the Cimmerian orogen. The absence of products of Middle Jurassic magmatism in molasses of the Cimmerian orogen, which we fixed, limits position of the Cimmerian orogen in the southern part of the Scythian plate. It is shown that the primary source of the Precambrian detrital zircons were mobilized within the Cimmerian orogen the crustal fragments of the Peri-Gondwanan origin, rather than the basement complexes of the East European Platform, similar to the complexes of the Ukrainian shield. The reconstruction of the main stages of the accumulation of the coarse-grained strata of the Mountaineous Crimea in the context of the tectonic evolution of the southern margin of Laurasia during the Mesozoic is presented.

scholarly journals Paleo - position of the South China Craton in the Rodinia Supercontinent: Evidence from the U - Pb age and Hf isotope of detrital zircon from the Nam Co Complex

2021 ◽  
Vol 62 (3) ◽  
pp. 1-12
Author(s):  
Keyword(s):  
South China ◽  
Detrital Zircon ◽  
Age Distribution ◽  
Detrital Zircons ◽  
East Antarctica ◽  
Hf Isotope ◽  
The South ◽  
Nam Co ◽  
Rodinia Supercontinent ◽  
South China Craton

To constrain the paleo - positions of the South China Cratons in the Rodinia Supercontinent during the Neoproterozoic, the in - situ U - Pb dating, and Hf isotope analysis of the detrital zircon from the Nam Co Complex, Song Ma Suture zone, northwestern Vietnam was performed. The U - Pb isotopic dating on detrital zircons shows that the Nam Co Complex demonstrates the major population (>50%) of around ~850 Ma while the minor population is scattered between ~1.2÷3.0 Ga. The Neoproterozoic age spectrum exhibits a large range of the εHf(t) from strongly negative to positive values ( - 17.418022÷ 14.600527), indicating that the source of the magma for this age range has been not only derived from reworking of the Archean basement rocks, but also generated from the juvenile material. The U - Pb age distribution patterns and Hf isotopic data of the detrital zircon in the Nam Co Complex are compatible with those of the South China Craton rather than those of the Indochina Craton. The data also indicate that sedimentary protoliths of the Nam Co Complex were deposited in a convergent - related basin along the southwestern margin of the South China Craton during the Neoproterozoic. Combined with the similarities of the detrital zircon age between western Cathaysia, Indochina, East Antarctica and East India, it is proved that the South China Craton was situated at the margin of the Rodinia Supercontinent and in close proximity to the Indochina, East Antarctica and East India.

scholarly journals Supplemental Material: Mantle control on magmatic flare-ups in the southern Coast Mountains batholith, British Columbia

2021 ◽  
Author(s):  
M.R. Cecil ◽  
et al.
Keyword(s):  
British Columbia ◽  
Trace Element ◽  
Hf Isotope ◽  
Geochemical Data ◽  
Location Information ◽  
Southern Coast ◽  
Coast Mountains ◽  
Isotope Data ◽  
O Isotope

<div>Includes sample location information, whole rock geochemical data, and individual zircon trace element, Lu-Hf isotope, and O isotope data.<br></div>

scholarly journals U–Pb ages and Hf-isotope data of detrital zircons from the late Neoarchean-Paleoproterozoic Minas Basin, SE Brazil

2017 ◽  
Vol 291 ◽  
pp. 143-161 ◽  
Author(s):  
Carmen I. Martínez Dopico ◽  
Cristiano Lana ◽  
Hugo S. Moreira ◽  
Lucas F. Cassino ◽  
Fernando F. Alkmim
Keyword(s):  
Detrital Zircons ◽  
Hf Isotope ◽  
Isotope Data ◽  
Se Brazil

Nature of magmatism and sedimentation at a Columbia active margin: Insights from combined U–Pb and Lu–Hf isotope data of detrital zircons from NW India

2013 ◽  
Vol 23 (3) ◽  
pp. 1040-1052 ◽  
Author(s):  
Parampreet Kaur ◽  
Armin Zeh ◽  
Naveen Chaudhri ◽  
Axel Gerdes ◽  
Martin Okrusch
Keyword(s):  
Detrital Zircons ◽  
Hf Isotope ◽  
Active Margin ◽  
Isotope Data

scholarly journals The Proterozoic Guanhães banded iron formations, Southeastern border of the São Francisco Craton, Brazil: evidence of detrital contamination

2017 ◽  
Vol 17 (2) ◽  
pp. 303 ◽  
Author(s):  
Vitor Rodrigues Barrote ◽  
Carlos Alberto Rosiere ◽  
Vassily Khoury Rolim ◽  
João Orestes Schneider Santos ◽  
Neal Jesse Mcnaughton
Keyword(s):  
Detrital Zircons ◽  
Iron Formation ◽  
Geochemical Data ◽  
Banded Iron Formations ◽  
Banded Iron Formation ◽  
Zircon Age ◽  
Shallow Marine ◽  
Eu Anomaly ◽  
Depositional Age ◽  
Iron Formations

The Guanhães banded iron formation (BIF) bearing succession occurs as tectonic slices, juxtaposed to Archean TTG granite-gneissic basement rock, developed during the Neoproterozoic-Cambrian Brasiliano collage. The succession has a maximum depositional age of ~2.18 Ga, from detrital zircons in quartzite, and consists of quartzites, schists, BIFs, gneiss and amphibolite, all metamorphosed under amphibolite facies conditions. The Guanhães BIF shows HREE enrichment and consistent positive Eu anomaly (PAAS-normalized REE+Y). Two types of contamination were observed in the samples. The first is contamination by an exotic detrital component, which resulted in low Y/Ho (<30) and Pr/Yb (SN) ratios. Evidence of such contamination, combined with inferred stratigraphic stacking data, indicates that the Guanhães BIFs were deposited on a shallow marine environment. The second type of contamination resulted in higher Eu-anomalies, positive Ce-anomalies, and higher REE+Y concentrations, possibly due to the interaction between later magmatic fluids and the Guanhães BIF. A strong Cambrian event is recorded in zircon age data. The uncontaminated samples display REE+Y distribution similar to other Precambrian BIFs, particularly those from the Morro-Escuro Sequence and the Serra da Serpentina Group, without true Ce-anomalies and Y/Ho close to seawater values (45). Geochronological and geochemical data presented in this paper strongly suggest a correlation between the Guanhães supracrustal succession and the Serra da Serpentina and Serra de São José Groups.

New geological and paleomagnetic data from Siberian Craton and implications for the post 2 Ga global paleogeography

2020 ◽  
Author(s):  
Sergei Pisarevsky ◽  
Tatiana Donskaya ◽  
Dmitry Gladkochub
Keyword(s):  
North America ◽  
Siberian Craton ◽  
Building Blocks ◽  
Detrital Zircons ◽  
Paleomagnetic Data ◽  
Geochemical Data ◽  
Geological History ◽  
Northern Margin ◽  
Tectonic History ◽  
Final Assembly

&lt;p&gt;Siberian Craton is generally recognised as one of the building blocks of two supercontinents: Mesoproterozoic Nuna (Columbia) and Neoproterozoic Rodinia. Although the exact Siberian positions in Nuna and Rodinia are debated, most workers agree that the southern part of Siberia (hereafter in present day coordinates) has been located not too far from the northern margin of Laurentia (cratonic part of North America) between ca. 1600 Ma and ca. 700 Ma. New geochronological, paleomagnetic and geochemical data from the Siberian craton obtained in recent years improved our understanding of Siberian geological history comparing to previous reviews. The progress in global Precambrian paleogeography also contributed to a re-evaluation of the Siberian tectonic history. The compilation of Siberian paleomagnetic data suggests that after the final assembly of Siberian Craton and until Ediacaran time the craton mostly occupied the low- to moderate latitudes. Most of this time western, northern and eastern Siberian edges have been passive or active oceanic margins. The southern margin Siberian margin has been probably connected with some other continent. Using new geological and paleomagnetic data, in particular recent results of the detrital zircons distributions in Siberia, Laurentia and other ancient continents, we tested several paleogeographic reconstructions of this connection. We also propose a new model of the breakup of Siberia from the remnants of Rodinia and consequent opening of the Paleo-Asian Ocean.&lt;/p&gt;

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