Detrital zircon geochronology and processes in accretionary wedges

Žák, Jiří; Svojtka, Martin; Hajná, Jaroslava; Ackerman, Lukáš

doi:10.1016/j.earscirev.2020.103214

Cited by 32 publications

(11 citation statements)

References 150 publications

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“…A common approach is the comparison of age distribution patterns and maximum ages of deposition inferred for the youngest grains in a distinct sample. This methodology, when applied for each of the subunits forming paleo-duplexes, is known to enable an efficient tracking of the source of accreted material as well as identification of age gaps and potential episodes of tectonic erosion (e.g., Cawood et al, 2012;Žák et al, 2020). Complex also pointed to transient periods of duplexing during the entire Franciscan subduction history that lasted >100 m.y.…”

Section: Evidence For Mass Transfer and Crustal Recyclingmentioning

confidence: 99%

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

2021

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Several decades of field, geophysical, analogue, and numerical modeling investigations have enabled documentation of the wide range of tectonic transport processes in accretionary wedges, which constitute some of the most dynamic plate boundary environments on Earth. Active convergent margins can exhibit basal accretion (via underplating) leading to the formation of variably thick duplex structures or tectonic erosion, the latter known to lead to the consumption of the previously accreted material and eventually the forearc continental crust. We herein review natural examples of actively underplating systems (with a focus on circum-Pacific settings) as well as field examples highlighting internal wedge dynamics recorded by fossil accretionary systems. Duplex formation in deep paleo–accretionary systems is known to leave in the rock record (1) diagnostic macro- and microscopic deformation patterns as well as (2) large-scale geochronological characteristics such as the downstepping of deformation and metamorphic ages. Zircon detrital ages have also proved to be a powerful approach to deciphering tectonic transport in ancient active margins. Yet, fundamental questions remain in order to understand the interplay of forces at the origin of mass transfer and crustal recycling in deep accretionary systems. We address these questions by presenting a suite of two-dimensional thermo-mechanical experiments that enable unravelling the mass-flow pathways and the long-term distribution of stresses along and above the subduction interface as well as investigating the importance of parameters such as fluids and slab roughness. These results suggest the dynamical instability of fluid-bearing accretionary systems causes either an episodic or a periodic character of subduction erosion and accretion processes as well as their topographic expression. The instability can be partly deciphered through metamorphic and strain records, thus explaining the relative scarcity of paleo–accretionary systems worldwide despite the tremendous amounts of material buried by the subduction process over time scales of tens or hundreds of millions of years. We finally stress that the understanding of the physical processes at the origin of underplating processes as well as the forearc topographic response paves the way for refining our vision of long-term plate-interface coupling as well as the rheological behavior of the seismogenic zone in active subduction settings.

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Section: Evidence For Mass Transfer and Crustal Recyclingmentioning

confidence: 99%

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

2021

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“…The youngest detrital zircons are commonly used to evaluate the maximum depositional ages of the host sediments and may approximate the timing of sediment deposition if syn‐sedimentary igneous activity is continuous in the source region, as exemplified for sediments in the arc‐flanking basins of convergent plate margins (Cawood et al., 2012; Dickinson & Gehrels, 2009; Žák et al., 2020). This is applicable to the mélange matrix samples, because magmatic activity in their source region, that is, the Yili‐Central Tianshan Block, was relatively continuous during the Paleozoic (Figure 10a).…”

Section: Discussionmentioning

confidence: 99%

“…Accretionary orogens that formed at sites of ongoing oceanic subduction along convergent margins and ultimately evolved into a collisional phase subsequent to oceanic closure are often accompanied by considerable continental growth (e.g., Aitchison & Buckman, 2012; Cawood et al., 2009). Accretionary complexes (or accretionary prisms/wedges and subduction‐accretion complexes) are key elements of accretionary and collisional orogens and, if present, are commonly regarded as excellent archive of subduction‐accretion and collision events in ancient orogens (Cawood et al., 2009; Kusky et al., 2020; Žák et al., 2020). The Central Asian Orogenic Belt (CAOB; Figure 1a) in northeast Eurasia is a typical accretionary orogen formed by multiple accretion of microcontinents, island arcs, oceanic plateaus, and accretionary complexes in the Paleo‐Asian Ocean (e.g., Buckman & Aitchison, 2004; Coleman, 1989; Gao et al., 2018; Kröner et al., 2007; Schulmann & Paterson, 2011; Sengör et al., 1993, 2018; Wan et al., 2017, 2018; Windley et al., 2007; Xiao et al., 2015).…”

Section: Introductionmentioning

confidence: 99%

Paleozoic Subduction‐Accretion in the Southern Central Asian Orogenic Belt: Insights From the Wuwamen Accretionary Complex of the Chinese South Tianshan

Wang

Klemd

et al. 2022

Tectonics

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Accretionary orogens that formed at sites of ongoing oceanic subduction along convergent margins and ultimately evolved into a collisional phase subsequent to oceanic closure are often accompanied by considerable continental growth (e.g., Aitchison & Buckman, 2012;Cawood et al., 2009). Accretionary complexes (or accretionary prisms/wedges and subduction-accretion complexes) are key elements of accretionary and collisional orogens and, if present, are commonly regarded as excellent archive of subduction-accretion and collision events in ancient orogens (Cawood et al., 2009;Kusky et al., 2020;Žák et al., 2020). The Central Asian Orogenic Belt (CAOB; Figure 1a) in northeast Eurasia is a typical accretionary orogen formed by multiple accretion of microcontinents, island arcs, oceanic plateaus, and accretionary complexes in the Paleo-Asian Ocean (e.g., Buckman

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“…1a, b). This complex formed during the Cadomian orogeny, as part of a long-lived subduction/accretionary system along the northern Gondwana periphery and now underlies much of the Teplá-Barrandian Unit (e.g., Hajná et al 2013Hajná et al , 2018Žák et al 2020). The accretionary complex is composed of basalt-bearing mélanges with a block-in-matrix fabric (Belts 1-3), a chert-graywacke mélange (Belt I), and coherent, bedded units without cherts and basalts (Belts II-III; Fig.…”

Section: Geological Settingmentioning

confidence: 99%

“…1). The Bohemian Massif is otherwise well-known for abundant quartz-sulfide or carbonate-quartz Au deposits (Morávek and Pouba 1987;Zachariáš et al 2013Zachariáš et al , 2014Němec and Zachariáš 2017) hosted by late Neoproterozoic-early Cambrian volcanosedimentary complexes of the Teplá-Barrandian Unit (~ 630-520 Ma; Sláma et al 2008;Drost et al 2011;Hajná et al 2018;Žák et al 2020) and arious units metamorphosed during the Variscan orogeny (ca. 400-300 Ma;Franke 2006;Kroner and Romer 2013;Edel et al 2018;Schulmann et al 2022 and references therein).…”

Section: Introductionmentioning

confidence: 99%

Multi-stage metal enrichment and formation of gold mineralization in black shales: the role of high heat flow in a rift setting

et al. 2023

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Black shales may serve as an important source of metals such as Co, Ni, or As, largely due to anoxic to euxinic conditions in association with high concentrations of sulfur leading to efficient scavenging and transport of metals from seawater into the seafloor sediment. We report on an unusual type of Au mineralization newly discovered in Ediacaran trench-slope black shales in the Bohemian Massif, Czech Republic. The Au enrichment is related to the formation of a quartz–sulfide vein system and a progressive evolution of ore-forming fluids with decreasing temperature, from Sb- to As-rich to final precipitation of native gold from silica and Au-bearing low-temperature hydrothermal colloidal solutions. The hydrothermal nature of these solutions is also documented by Li contents and isotope compositions which differ markedly between barren black shales and those carrying significant late-stage quartz-rich veins. The structural relationships and orientation of the associated quartz veins point to a close connection between vein emplacement and high heat flow in response to Ordovician rifting, and breakup of the northern margin of Gondwana, and opening of the Rheic Ocean. This triggered metal and sulfur remobilization, including Au, from the associated Neoproterozoic–Cambrian volcanosedimentary successions. The documented Au mineralization and its association with the Ordovician rift-related magmatic activity is different from the widespread Variscan Au occurrences in the Bohemian Massif. Our study thus provides a new genetic model potentially important for future exploration of Au also in other terrains underlain by a rifted Cadomian basement.

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Detrital zircon geochronology and processes in accretionary wedges

Cited by 32 publications

References 150 publications

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

Paleozoic Subduction‐Accretion in the Southern Central Asian Orogenic Belt: Insights From the Wuwamen Accretionary Complex of the Chinese South Tianshan

Multi-stage metal enrichment and formation of gold mineralization in black shales: the role of high heat flow in a rift setting

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