Partitioning Pervasive Detrital Geochronologic Age Distributions in the Southern Alaskan Forearc

Finzel, Emily S.

doi:10.3389/feart.2019.00217

Cited by 4 publications

(2 citation statements)

References 95 publications

(158 reference statements)

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“…Results from large-n studies have demonstrated that in some cases small-n data sets (n = 100) may not be sufficient in accurately characterizing all the minor detrital zircon populations within and between samples (Saylor and Sundell, 2016). Detrital zircon studies of Mesozoic-Cenozoic strata in the Cook Inlet basin in south-central Alaska, however, reveal that an expanded large-n (n = 300) data set does not show a significant difference from a more limited (n = 100) data set in the presence of both major and minor age populations, given the small number of age groups present within the distribution of that specific data set (Finzel et al, 2016;Finzel, 2019). Given that our modern river samples have a variety of age groups within the overall age distribution and cover multiple regional watersheds, a large-n data set might improve our results and interpretations, especially for minor sources of sediment.…”

Section: Limitations Of the Studymentioning

confidence: 99%

Detrital zircon geochronology of modern river sediment in south-central Alaska: Provenance, magmatic, and tectonic insights into the Mesozoic and Cenozoic development of the southern Alaska convergent margin

Fasulo

Ridgway

2021

Geosphere

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New and previously published detrital zircon U-Pb ages from sediment in major rivers of south- central Alaska archive several major episodes of magmatism associated with the tectonic growth of this convergent margin. Analysis of detrital zircons from major trunk rivers of the Tanana, Matanuska-Susitna, and Copper River watersheds (N = 40, n = 4870) documents major <250 Ma age populations that are characteristic of the main phases of Mesozoic and Paleogene magmatism in the region as documented from limited U-Pb ages of igneous rocks. Key points from our detrital record include: (1) Major magmatic episodes occurred at 170, 150, 118, 95, 72, 58, and 36 Ma. The overall pattern of these ages suggests that felsic magmatism was episodic with periodicity ranging between ~14 and 32 m.y. with an average of ~22 m.y. (2) Magmatism in south-central Alaska shows similar age trends with both the Coast Mountains batholith and the along-strike Alaska Peninsula forearc basin strata, demonstrating a spatial and temporal relationship of felsic magmatism along the entire northern Cordilleran margin. (3) Topography and zircon fertility appear to influence the presence and/or absence of detrital zircon populations in individual watersheds. Results from this study indicate that regionally integrated detrital zircon populations from modern trunk rivers are faithful recorders of Mesozoic and Paleogene magmatic events along a convergent margin, but there appears to be a lag time for major rivers to record Neogene and ongoing magmatic events.

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Section: Limitations Of the Studymentioning

confidence: 99%

Detrital zircon geochronology of modern river sediment in south-central Alaska: Provenance, magmatic, and tectonic insights into the Mesozoic and Cenozoic development of the southern Alaska convergent margin

Fasulo

Ridgway

2021

Geosphere

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“…Detrital zircon (DZ) U-Pb analyses of modern river sands help define regional magmatic and metamorphic histories (Ducea et al, 2018;Finzel, 2019;Link et al, 2005;Pepper et al, 2016) and identify the impact of erosion, zircon fertility, and lithologic erodibility on provenance signatures (e.g., Amidon et al, 2005;Horton et al, 2015;Jackson et al, 2019;Malkowski et al, 2020). Zircon U-Pb ages for Andean rivers draining the Principal Cordillera, Frontal Cordillera, Precordillera, and Sierras Pampeanas (Capaldi et al, 2017(Capaldi et al, , 2019 help characterize provenance variations across hinterland, wedge-top, foreland, and broken foreland basin settings ( Figure 6), providing an opportunity to track Cenozoic erosional unroofing and sediment routing patterns.…”

Section: Source Characterization Using Modern River Detrital Zirconsmentioning

confidence: 99%

Neogene Retroarc Foreland Basin Evolution, Sediment Provenance, and Magmatism in Response to Flat Slab Subduction, Western Argentina

et al. 2020

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Understanding the effects of flat slab subduction on mountain building, arc magmatism, and basin evolution is fundamental to convergent‐margin tectonics, with implications for potential feedbacks among geodynamic, magmatic, and surface processes. New stratigraphic and geochronological constraints on Cenozoic sedimentation and magmatism in the southern Central Andes of Argentina (31°S) reveal shifts in volcanism, foreland/hinterland basin development, sediment accumulation, and provenance as the retroarc region was structurally partitioned during slab flattening. Detrital zircon U‐Pb age distributions from the western (Calingasta basin), central (Talacasto and Albarracín basins), and eastern (Bermejo foreland basin) segments of the retroarc basin system preserve syndepositional volcanism and orogenic unroofing of multiple tectonic provinces. Initial shortening‐related exhumation of the Principal Cordillera at 24–17 Ma was recorded by the accumulation of distal eolian deposits bearing Oligocene–Eocene zircons from the Andean magmatic arc. The Calingasta basin chronicled volcanism and basement shortening in the Frontal Cordillera at ~17–11 Ma, as marked by an upward coarsening succession of fluvial to alluvial fan deposits with a sustained zircon U‐Pb age component that matches pervasive Permian‐Triassic bedrock in the hinterland. An ~450 km eastward inboard sweep of volcanism at 11 Ma coincided with the inception of flat slab subduction, and subsequent thin‐skinned shortening in the Precordillera fold‐thrust belt that exhumed wedge‐top deposits and induced cratonward (eastward) advance of flexural subsidence into the Bermejo foreland basin. This foreland basin was structurally partitioned as basement uplifts of the Sierras Pampeanas transformed a fluvial megafan sediment routing network into smaller isolated alluvial fan systems fed by adjacent basement blocks.

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Heavy minerals in provenance studies: an overview

et al. 2021

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Partitioning Pervasive Detrital Geochronologic Age Distributions in the Southern Alaskan Forearc

Cited by 4 publications

References 95 publications

Detrital zircon geochronology of modern river sediment in south-central Alaska: Provenance, magmatic, and tectonic insights into the Mesozoic and Cenozoic development of the southern Alaska convergent margin

Detrital zircon geochronology of modern river sediment in south-central Alaska: Provenance, magmatic, and tectonic insights into the Mesozoic and Cenozoic development of the southern Alaska convergent margin

Neogene Retroarc Foreland Basin Evolution, Sediment Provenance, and Magmatism in Response to Flat Slab Subduction, Western Argentina

Heavy minerals in provenance studies: an overview

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