Tectonic evolution of a continental magmatic arc from transpression in the upper crust to exhumation of mid-crustal orogenic root recorded by episodically emplaced plutons: the Central Bohemian Plutonic Complex (Bohemian Massif)

Lithoprobe's sponsorship has led to the acquisition of paleomagnetic data from ~20 units throughout the Paleoproterozoic Trans-Hudson Orogen (THO) of Saskatchewan and Manitoba, essentially the first such data for the region. Discussed summarily in this paper, they provide an initial framework for the THO's tectonic evolution. They show that the Archean Hearne and Superior cratons were at subtropical and subpolar paleolatitudes, respectively, at ~1875 Ma, with the Lynn Lake LaRonge arc midway between them in the Manikewan Ocean. By ~1855 Ma, this ocean was still ~5500 ± 700 km wide, and its seafloor was subducting northwestward under the Hearne craton and pericratonic Peter Lake domain margin with the coeval development of an Andean-type continental magmatic arc, the WathamanChipewyan batholith. Between ~1855 and ~1810 Ma, coalescing apparent polar wander path (APWP) segments record closing of the ocean at a rate of ~12 cm/a, trapping and accreting the several separate intervening terranes (Flin Flon, Hanson Lake, Lynn Lake LaRonge, Rottenstone, and presumably also other THO terranes). From ~1815 to ~1775 Ma, the assembled terranes drifted as a coherent craton, yielding a stillstand and hairpin in the APWP.

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Age and origin of earliest adakitic-like magmatism in Panama: Implications for the tectonic evolution of the Panamanian magmatic arc system

Lithos ◽

10.1016/j.lithos.2012.02.017 ◽

2012 ◽

Vol 142-143 ◽

pp. 226-244 ◽

Cited By ~ 19

Author(s):

Scott A. Whattam ◽

Camilo Montes ◽

Rory R. McFadden ◽

Agustin Cardona ◽

Diego Ramirez ◽

...

Keyword(s):

Tectonic Evolution ◽

Magmatic Arc

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Jurassic Arc: Reconstructing the Lost World of eastern Gondwana

Geology ◽

10.1130/g49328.1 ◽

2021 ◽

Author(s):

Elliot K. Foley ◽

R.A. Henderson ◽

E.M. Roberts ◽

A.I.S. Kemp ◽

C.N. Todd ◽

...

Keyword(s):

Detrital Zircon ◽

Tectonic Setting ◽

Magmatic Arc ◽

Continental Arc ◽

Key Factor ◽

Igneous Activity ◽

Competing Models ◽

Juvenile Crust ◽

Sedimentary Fill ◽

Continental Magmatic Arc

The tectonic setting of the Australian sector of the eastern Gondwanan margin during the Jurassic and Cretaceous is enigmatic. Whether this involved convergent tectonism and a long-lived continental magmatic arc or rift-related extension unrelated to subduction is debated. The paucity of Australian Jurassic–Cretaceous igneous outcrops makes resolving these competing models difficult. We used the detrital zircon record of the Jurassic–Cretaceous Great Australian Superbasin (GAS) as a proxy for igneous activity. We attribute the persistent magmatism recorded in GAS sedimentary fill throughout the Mesozoic to ca. 95 Ma to continuation of the established Paleozoic continental arc system. The detrital zircon record signals short (~10 m.y.) pulses of elevated Jurassic and Cretaceous magmatic activity and strongly positive εHf values, indicating juvenile crust or mantle-derived magmatism. Margin reconstruction indicates sustained continental growth at rates of at least ~55 km3 km–1 m.y.–1, mainly to the tract now represented by submerged northern Zealandia, due to the retreat of this arc system. We posit that arc retreat was a key factor in rapid crust generation and preservation, and that continental sedimentary systems globally may host cryptic records of juvenile crustal addition that must be considered in estimating crustal growth rates along convergent plate margins.

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Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS

Brazilian Journal of Geology ◽

10.1590/2317-488920150030231 ◽

2015 ◽

Vol 45 (3) ◽

pp. 431-451 ◽

Cited By ~ 5

Author(s):

Letícia Alexandre Redes ◽

Maria Zélia Aguiar de Sousa ◽

Amarildo Salina Ruiz ◽

Jean-Michel Lafon

Keyword(s):

Geochemical Data ◽

Alkaline Magmatism ◽

Alluvial Deposits ◽

Mato Grosso ◽

Microgranular Enclave ◽

Magmatic Arc ◽

Rock Types ◽

High K ◽

Continental Magmatic Arc ◽

Shrimp Zircon

The Taquaral Granite is located on southern Amazon Craton in the region of Corumbá, westernmost part of the Brazilian state of Mato Grosso do Sul (MS), near Brazil-Bolivia frontier. This intrusion of batholitic dimensions is partially covered by sedimentary rocks of the Urucum, Tamengo Bocaina and Pantanal formations and Alluvial Deposits. The rock types are classified as quartz-monzodiorites, granodiorites, quartz-monzonites, monzo and syenogranites. There are two groups of enclaves genetically and compositionally different: one corresponds to mafic xenoliths and the second is identified as felsic microgranular enclave. Two deformation phases are observed: one ductile (F1) and the other brittle (F2). Geochemical data indicate intermediate to acidic composition for these rocks and a medium to high-K, metaluminous to peraluminous calk-alkaline magmatism, suggesting also their emplacement into magmatic arc settings. SHRIMP zircon U-Pb geochronological data of these granites reveals a crystallization age of 1861 ± 5.3 Ma. Whole rock Sm-Nd analyses provided εNd(1,86 Ga) values of -1.48 and -1.28 and TDM model ages of 2.32 and 2.25 Ga, likely indicating a Ryacian crustal source. Here we conclude that Taquaral Granite represents a magmatic episode generated at the end of the Orosirian, as a part of the Amoguija Magmatic Arc.

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Geochemical Significance of Clay Minerals and Elements in Paleogene Sandstones in the Center of the Northern Margin of the Qaidam Basin, China

Minerals ◽

10.3390/min10060505 ◽

2020 ◽

Vol 10 (6) ◽

pp. 505 ◽

Cited By ~ 1

Author(s):

Guoqiang Sun ◽

Meng Wang ◽

Jiajia Guo ◽

Yetong Wang ◽

Yongheng Yang

Keyword(s):

Clay Minerals ◽

Chemical Weathering ◽

Qaidam Basin ◽

Sedimentary Environment ◽

Climatic Conditions ◽

Northern Margin ◽

Magmatic Arc ◽

Average Value ◽

Geochemical Significance ◽

Continental Magmatic Arc

The average thickness of Paleogene sandstones reaches about 3000–4000 m at the northern margin of the Qaidam Basin. However, the provenance and sedimentary environment of these sandstones are uncertain; thus, more comprehensive research is needed. Integrated research is conducted on the provenance and weathering process based on petrographic characteristics, clay minerals, and geochemical compositions of sandstones in the center of the northern Qaidam Basin. The results of lithofacies analysis show that the Paleogene sandstones were mainly derived from an active continental magmatic arc, subduction accretion, or a fold-thrust belt. The average illite content in the Paleogene clay minerals is more than 50%, followed by chlorite and smectite, which reflect climatic and environmental characteristics that were arid to semi-arid, whereas the characteristics of carbon–oxygen isotopes reveal a mainly freshwater sedimentary environment. The corrected chemical index of alteration (CIAcorr) is between 56.3 and 75.7, with an average value of 66.5. These results indicate that the provenance of the Paleogene sandstones in the center of the northern Qaidam Basin mainly formed under cold and dry climatic conditions and experienced limited chemical weathering with a small amount that underwent intermediate chemical weathering under warm and humid conditions.

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A study of retrogression in eclogites of the Oberpfalz Forest, north-east Bavaria, West Germany, and their significance in the tectonic evolution of the Bohemian Massif

Geological Society London Special Publications ◽

10.1144/gsl.sp.1989.043.01.48 ◽

1989 ◽

Vol 43 (1) ◽

pp. 507-512 ◽

Cited By ~ 6

Author(s):

P. J. O'Brien

Keyword(s):

Bohemian Massif ◽

Tectonic Evolution ◽

West Germany ◽

North East

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Interplay of Cretaceous transpressional deformation and continental arc magmatism in a long-lived crustal boundary, central Fiordland, New Zealand

Geosphere ◽

10.1130/ges02251.1 ◽

2020 ◽

Vol 16 (5) ◽

pp. 1225-1248

Author(s):

Hannah J. Blatchford ◽

Keith A. Klepeis ◽

Joshua J. Schwartz ◽

Richard Jongens ◽

Rose E. Turnbull ◽

...

Keyword(s):

New Zealand ◽

Thermal Structure ◽

Shear Zones ◽

Arc Magmatism ◽

Magmatic Arc ◽

Continental Arcs ◽

Metasedimentary Rocks ◽

Spatio Temporal ◽

Continental Magmatic Arc ◽

Lower Crustal

Abstract Recovering the time-evolving relationship between arc magmatism and deformation, and the influence of anisotropies (inherited foliations, crustal-scale features, and thermal gradients), is critical for interpreting the location, timing, and geometry of transpressional structures in continental arcs. We investigated these themes of magma-deformation interactions and preexisting anisotropies within a middle- and lower-crustal section of Cretaceous arc crust coinciding with a Paleozoic boundary in central Fiordland, New Zealand. We present new structural mapping and results of Zr-in-titanite thermometry and U-Pb zircon and titanite geochronology from an Early Cretaceous batholith and its host rock. The data reveal how the expression of transpression in the middle and lower crust of a continental magmatic arc evolved during emplacement and crystallization of the ∼2300 km2 lower-crustal Western Fiordland Orthogneiss (WFO) batholith. Two structures within Fiordland’s architecture of transpressional shear zones are identified. The gently dipping Misty shear zone records syn-magmatic oblique-sinistral thrust motion between ca. 123 and ca. 118 Ma, along the lower-crustal WFO Misty Pluton margin. The subhorizontal South Adams Burn thrust records mid-crustal arc-normal shortening between ca. 114 and ca. 111 Ma. Both structures are localized within and reactivate a recently described >10 km-wide Paleozoic crustal boundary, and show that deformation migrated upwards between ca. 118 and ca. 114 Ma. WFO emplacement and crystallization (mainly 118–115 Ma) coincided with elevated (>750 °C) middle- and lower-crustal Zr-in-titanite temperatures and the onset of mid-crustal cooling at 5.9 ± 2.0 °C Ma−1 between ca. 118 and ca. 95 Ma. We suggest that reduced strength contrasts across lower-crustal pluton margins during crystallization caused deformation to migrate upwards into thermally weakened rocks of the mid-crust. The migration was accompanied by partitioning of deformation into domains of arc-normal shortening in Paleozoic metasedimentary rocks and domains that combined shortening and strike-slip deformation in crustal-scale subvertical, transpressional shear zones previously documented in Fiordland. U-Pb titanite dates indicate Carboniferous–Cretaceous (re)crystallization, consistent with reactivation of the inherited boundary. Our results show that spatio-temporal patterns of transpression are influenced by magma emplacement and crystallization and by the thermal structure of a reactivated boundary.

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