The Maz Metasedimentary Series (Western Sierras Pampeanas, Argentina). A relict basin of the Columbia supercontinent?

2021 ◽  
pp. 1-13
Author(s):  
C. D. Ramacciotti ◽  
C. Casquet ◽  
E. G. Baldo ◽  
R. J. Pankhurst ◽  
S. O. Verdecchia ◽  
...  

Abstract The Maz Metasedimentary Series is part of the Maz Complex that crops out in the sierras of Maz and Espinal (Western Sierras Pampeanas) and in the Sierra de Umango (Andean Frontal Cordillera), northwestern Argentina. The Maz Complex is found within a thrust stack of Silurian age, which later underwent open folding. The Maz Metasedimentary Series mainly consists of medium-grade garnet–staurolite–kyanite–sillimanite schists and quartzites, with minor amounts of marble and calc-silicate rocks. Transposed metadacite dykes have been recognized along with amphibolites, metagabbros, metadiorites and orthogneisses. Schist, quartzite and metadacite samples were analysed for SHRIMP U–Pb zircon dating. The Maz Metasedimentary Series is polymetamorphic and records probably three metamorphic events during the Grenvillian orogeny, at c. 1235, 1155 and 1035 Ma, and a younger metamorphism at c. 440–420 Ma resulting from reactivation during the Famatinian orogeny. The sedimentary protoliths were deposited between 1.86 and 1.33–1.26 Ga (the age of the Andean-type Grenvillian magmatism recorded in the Maz Complex), and probably before 1.75 Ga. The main source areas correspond to Palaeoproterozoic and, to a lesser magnitude, Meso-Neoarchaean rocks. The probable depositional age and the detrital zircon age pattern suggest that the Maz Metasedimentary Series was laid down in a basin of the Columbia supercontinent, mainly accreted between 2.1 and 1.8 Ga. The sedimentary sources were diverse, and we hypothesize that deposition took place before Columbia broke up. The Rio Apa block, and the Río de la Plata, Amazonia and proto-Kalahari cratons, which have nearby locations in the palaeogeographic reconstructions, were probably the main blocks that supplied sediments to this basin.

2013 ◽  
Vol 150 (6) ◽  
pp. 1103-1126 ◽  
Author(s):  
DETA GASSER ◽  
ARILD ANDRESEN

AbstractThe tectonic origin of pre-Devonian rocks of Svalbard has long been a matter of debate. In particular, the origin and assemblage of pre-Devonian rocks of western Spitsbergen, including a blueschist-eclogite complex in Oscar II Land, are enigmatic. We present detrital zircon U–Pb LA-ICP-MS data from six Mesoproterozoic to Carboniferous samples and one U–Pb TIMS zircon age from an orthogneiss from Oscar II Land in order to discuss tectonic models for this region. Variable proportions of Palaeo- to Neoproterozoic detritus dominate the metasedimentary samples. The orthogneiss has an intrusion age of 927 ± 3 Ma. Comparison with detrital zircon age spectra from other units of similar depositional age within the North Atlantic region indicates that Oscar II Land experienced the following tectonic history: (1) the latest Mesoproterozoic sequence was part of a successor basin which originated close to the Grenvillian–Sveconorwegian orogen, and which was intruded byc. 980–920 Ma plutons; (2) the Neoproterozoic sediments were deposited in a large-scale basin which stretched along the Baltoscandian margin; (3) the eclogite-blueschist complex and the overlying Ordovician–Silurian sediments probably formed to the north of the Grampian/Taconian arc; (4) strike-slip movements assembled the western coast of Spitsbergen outside of, and prior to, the main Scandian collision; and (5) the remaining parts of Svalbard were assembled by strike-slip movements during the Devonian. Our study confirms previous models of complex Caledonian terrane amalgamation with contrasting tectonic histories for the different pre-Devonian terranes of Svalbard and particularly highlights the non-Laurentian origin of Oscar II Land.


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.


2020 ◽  
Author(s):  
Ícaro Dias da Silva ◽  
Manuel Francisco Pereira ◽  
Emílio González Clavijo ◽  
José R. Martínez Catalán ◽  
Juan Gómez Barreiro ◽  
...  

<p>Synorogenic basins could be linked to a wide variety of sedimentary environments, from continental to deep-marine, in distinct geodynamic settings. The sedimentary evolution of synorogenic basins is mainly controlled by the existence of relief rejuvenation and denudation within and in the surroundings areas. Accumulation of sediment in such basins could react to changes in tectonic settings. Successive extensional or contractional events that are common during the formation of an orogenic belt can induce variations on basin depth, basin depocenter migration and/or repetition of sedimentation-erosion cycles.</p><p>Detrital zircon age fingerprinting of sedimentary basins has proven to be a very sensitive tool for analyzing large and local scale changes in source-terranes, contributing to refine regional paleogeographic models. Recognition of potential source areas could be done by using statistically robust techniques. Kolmogorov-Smirnoff test (K-S) and Multidimensional Scaling (MDS) has been successfully applied to define the fingerprints of sedimentary rocks using detrital zircon age populations and compare with those from potential terrane sources. Comparative statistical analysis of detrital zircon age populations from particular sources and basin strata may be useful to prove sedimentary provenance and distance from source areas, to identify intra-basin sediment recycling and to track multi-source mixing along drainage systems.</p><p>During the Late Devonian-Carboniferous amalgamation of Pangea extensive marine sedimentation occurred in the Variscan orogen on both Laurussia and Gondwana collision margins. Remains of such synorogenic basins are currently located in different sectors of the European Variscan belt, including Iberia.</p><p>Recent provenance studies conducted in SW Iberia Variscan basins have distinguished the contribution of three distinct terrane sources “Gondwana-”, “Laurussia-” and “Variscan magmatic arc-” types, in some cases admitting sediment recycling and mixing of sources. Statistical analysis of detrital zircon age population from NW Iberia Variscan basin allowed us to distinguish two major sources a “Middle Ordovician-Silurian magmatic episode”-type and a “Gondwana”-type. These two types appear to correspond to source areas belonging to the nearby autochthonous and allochthonous units. Gondwanan-type source includes six sub-types whose contributions varied throughout synorogenic basins evolution, indicating that where sedimentary recycling seems to have been relevant.</p><p>Provenance studies on Variscan basins proved to be essential to test if whether or not NW Iberia and SW Iberia synorogenic basins have developed in geographical proximity of Paleozoic Laurussian- or Gondwanan-terrane sources. The differences found between the sources of NW and SW Variscan basins suggest that they would be geographically separated and influenced by independent drainage systems. This finding has provided a better understanding of the framing of Iberia synorogenic basins in paleographic models of Pangea amalgamation.</p><p>Acknowledgements: This study was supported by SYNTHESIS3 project DE-TAF-5798, by “Estímulo ao Emprego Científico – Norma Transitória” by CGL2016-78560-P (MICINN) and by FCT- project UID/GEO/50019/2019 - Instituto Dom Luiz.</p>


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.


2017 ◽  
Vol 54 (2) ◽  
pp. 104-124 ◽  
Author(s):  
David Malone ◽  
John Craddock ◽  
Jessica Welch ◽  
Brady Foreman

We report the results of U-Pb ages from detrital zircon populations in the lower Eocene synorogenic Willwood Formation in the northern Absaroka Basin, Wyoming. Zircons (n=229) were extracted from three sandstone beds and one ash layer in the Willwood Formation at the base of Jim Mountain in the North Fork Shoshone River Valley. K-S statistical analysis indicates that the three sandstones, which were sampled from the base, middle, and top of the formation, have identical age spectra, indicating that the sandstone provenance remained the same during the duration of Willwood deposition. The zircon age spectra are dominated by Archean zircons (61%), with peak ages at 3270 and 2770 Ma. These sandstones also have very early Paleoproterozoic zircons (∼2450 Ma), which likely were derived from the Tobacco Root Mountains. The final significant age peak is ∼70 Ma, which is likely associated with the Cretaceous Tobacco Root batholith. The Jim Mountain ash, which occurs at the top of the succession, just beneath the allocthonous volcanic rocks of the Heart Mountain slide, has a maximum depositional age of ∼50 Ma. Between 49–50 Ma, as Eocene volcanism in the northern Absaroka Range became more prominent, stratovolcanoes grew and disrupted sediment transport into the Absaroka basin. Lower Wapiti sandstones to the southwest show a mix of Eocene, recycled Proterozoic and Archean grains. The coeval Crandall Conglomerate, which was dismembered by the emplacement of the Heart Mountain slide in the northern Absaroka Range, has a distinct detrital zircon age spectrum. Thus these stream systems that deposited the Crandall did not share the headwaters with the streams that supplied sediment to the Absaroka basin.


2021 ◽  
pp. jgs2021-070
Author(s):  
Isabel C. Zutterkirch ◽  
Christopher L. Kirkland ◽  
Milo Barham ◽  
Chris Elders

Detrital zircon U-Pb geochronology has enabled advances in the understanding of sediment provenance, transportation pathways, and the depositional age of sedimentary packages. However, sample selection and processing can result in biasing of detrital zircon age spectra. This paper presents a novel approach using in-situ detrital zircon U-Pb measurements on thin-sections to provide greater confidence in maximum depositional ages and provenance interpretations. New U-Pb age data of 310 detrital zircon grains from 16 thin-sections of the Triassic Mungaroo Formation from two wells in the Northern Carnarvon Basin, Australia, are presented. Whilst detrital zircon age modes are consistent with previous work, there are some differences in the relative proportions of age modes, which is partly attributed to a lack of small grains in hand-picked grain mounts. The relative sample bias is quantified via grain size comparison of dated zircon (in thin-sections or hand-picked mounts) relative to all zircons identified in bulk-mounts and thin-sections. The youngest age mode (∼320 – 195 Ma) is consistent with an active margin to the north, likely South West Borneo and/or Lhasa terrane. The dated zircons reveal a maximum depositional age of 197 Ma for the upper part of Mungaroo Formation, suggesting deposition continued into the Early Jurassic.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5628911


Geology ◽  
2021 ◽  
Author(s):  
Shanan E. Peters ◽  
Craig R. Walton ◽  
Jon M. Husson ◽  
Daven P. Quinn ◽  
Oliver Shorttle ◽  
...  

Rock quantity and age are fundamental features of Earth’s crust that pertain to many problems in geoscience. Here we combine new estimates of igneous rock area in continental crust from the Macrostrat database (https://macrostrat.org/) with a compilation of detrital zircon ages in order to investigate rock cycling and crustal growth. We find that there is little or no decrease in igneous rock area with increasing rock age. Instead, igneous rock area in North America exhibits four distinct Precambrian peaks, remains low through the Neoproterozoic, and then increases only modestly toward the recent. Peaks in Precambrian detrital zircon age frequency distributions align broadly with peaks in igneous rock area, regardless of grain depositional age. However, detrital zircon ages do underrepresent a Neoarchean peak in igneous rock area; young grains and ca. 1.1 Ga grains are also overrepresented relative to igneous area. Together, these results suggest that detrital zircon age distributions contain signatures of continental denudation and sedimentary cycling that are decoupled from the cycling of igneous source rocks. Models of continental crustal evolution that incorporate significant early increase in volume and increased sedimentation in the Phanerozoic are well supported by these data.


2019 ◽  
Vol 156 (12) ◽  
pp. 2117-2124
Author(s):  
Nikolay Bonev ◽  
Petyo Filipov ◽  
Raya Raicheva ◽  
Massimo Chiaradia ◽  
Robert Moritz

AbstractWe focused on the Pirin–Pangeon–Thasos carbonate sequence of the Rhodope thrust system, combining Sr isotopes from marble with U–Pb dating of detrital zircons from interlayered schists with outcrop near the villages of Ilindentsi and Petrovo in Bulgaria. The youngest zircon age at Ilindentsi is 266 Ma, i.e. Middle Permian, while the youngest zircon at Petrovo yielded an age of 290 Ma, i.e. Early Permian. Strontium isotopes range from 0.707420 to 0.707653, and are consistent with a Middle Permian maximum depositional age. Middle Permian sedimentation of this carbonate platform most likely occurred along the Eurasian margin rather than the Gondwana margin.


2021 ◽  
Author(s):  
Mahyra Tedeschi ◽  
Humberto Reis ◽  
Laura Stutenbecker ◽  
Matheus Kuchenbecker ◽  
Bruno Ribeiro ◽  
...  

<p>Detrital zircon records are prone to several sources of bias that can compromise sediment provenance investigations based on U-Pb ages. High-temperature metamorphism (>850 ºC) is herewith addressed as a natural cause of bias since U-Pb zircon data from rocks submitted to these extreme, often prolonged conditions, frequently display protracted apparent concordant geochronological U-Pb records. The resulting spectrum can originate from disturbance of the primary U-Pb zircon system, likewise from subsequent recrystallization and crystallization processes during multiple and/or prolonged metamorphic events. Consequently, a high-grade metamorphosed igneous rock can exhibit a zircon age spectrum similar to that produced by polymict sedimentary rocks, thereby inducing provenance misinterpretations if this rock becomes a source for a sediment. A polymict sedimentary source that undergoes such high temperatures could potentially generate an even more intricate spectrum. Archean, Neoproterozoic and Paleozoic metamorphic rocks from the literature, dated by different techniques (SIMS and LA-ICP-MS), are employed as examples to demonstrate the resulting complications.  The compilation shows that (1) high-temperature metamorphism may generate age peaks of unclear or lacking geological meaning, and (2) the interpretation of detrital zircon age spectra depends on the timing of the metamorphic event (pre- or post-depositional). When high-temperature metamorphic rocks are eroded in uplifted areas, the youngest population of a detrital spectrum represents the maximum depositional age through metamorphic zircon from the source. If a sedimentary succession was subjected to high-temperature metamorphic conditions after deposition, its youngest zircon population more likely records the metamorphism, and the maximum depositional age, as well as older sources cannot be directly accessed. To evaluate the presence of high-temperature metamorphism-related bias in a given detrital zircon sample, we suggest a workflow for data acquisition and interpretation, combining a multi-proxy approach with: in situ U-Pb dating coupled with Hf analyses to retrieve the isotopic composition of the sources, and the integration of a petrochronological investigation to typify fingerprints of the (ultra)high-temperature metamorphic event.</p>


2020 ◽  
Vol 57 (12) ◽  
pp. 1411-1427
Author(s):  
Stephen E. Box ◽  
Chad J. Pritchard ◽  
Travis S. Stephens ◽  
Paul B. O’Sullivan

Mesoproterozoic and Neoproterozoic basins in western North America record the evolving position of the Laurentian craton within two supercontinents during their growth and dismemberment: Columbia (Nuna) and Rodinia. The western-most exposures of the Columbia rift-related Belt–Purcell Supergroup are preserved in northeastern Washington, structurally overlain by the Deer Trail Group and depositionally overlying the Neoproterozoic Windermere Supergroup. It has been disputed whether the Deer Trail Group is correlative with the Belt–Purcell Supergroup, or younger. To help resolve the uncertain correlation of these units and their bearing on supercontinent evolution, we characterized the detrital zircon age populations of units from the Deer Trail Group, the Windermere Supergroup, and the Belt–Purcell Supergroup in northeastern Washington. These data show that the western part of the Columbia supercontinent (now located in Australia and eastern Antarctica) remained attached to western Laurentia and continued to supply 1600–1500 Ma detrital zircon grains to the Belt–Purcell Supergroup until after ca. 1391 Ma. The Deer Trail Group is younger than the Belt–Purcell strata, with the basal unit younger than ca. 1362 Ma and a middle unit younger than ca. 1300 Ma. The Deer Trail Group has a pre-Grenville-age provenance from the southwestern USA and possibly east Antarctica. The Buffalo Hump Formation is younger than the Deer Trail Group, with Grenville-age (ca. 1112 Ma) detrital zircon grains and a detrital zircon signature like that of the overlying Neoproterozoic Windermere Supergroup. We interpret the Deer Trail Group to have been deposited during the rift-demise of supercontinent Columbia and before the Grenville-age assembly of the supercontinent Rodinia.


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