Detrital zircon provenance of Upper Jurassic–Upper Cretaceous forearc basin strata on the Insular terranes, south-central Alaska

2018 ◽  
Author(s):  
M. Reid ◽  
E.S. Finzel ◽  
E. Enkelmann ◽  
W.C. McClelland
Keyword(s):  
Detrital Zircon ◽  
Upper Cretaceous ◽  
Upper Jurassic ◽  
Forearc Basin ◽  
South Central

Initiation and evolution of forearc basins in the Central Myanmar Depression

2019 ◽  
Vol 132 (5-6) ◽  
pp. 1066-1082 ◽  
Author(s):  
Fulong Cai ◽  
Lin Ding ◽  
Qinghai Zhang ◽  
Devon A. Orme ◽  
Honghong Wei ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Upper Cretaceous ◽  
Upper Triassic ◽  
Forearc Basin ◽  
The West ◽  
Zircon Age ◽  
Shallow Marine ◽  
Western Margin ◽  
Forearc Basins ◽  
Structural High

Abstract The forearc basin in Myanmar is significant in understanding the development of continental forearc basins. We present stratigraphic, sandstone petrographic, and U-Pb detrital data from Upper Cretaceous–Eocene strata of Chindwin and Minbu sub-basins in the Central Myanmar Depression. The Upper Cretaceous lower Kabaw Formation consists of turbiditic conglomerate, sandstone, and mudstone in the Minbu sub-basin. The composition of conglomerates are mainly schist and subordinate quartz. Prominent detrital zircon age probability peaks are between 260 and 223 Ma, similar with that of Upper Triassic Pane Chaung turbidites and Kanpetlet schist on the West Burma plate. In the upper Kabaw Formation, turbiditic volcanic-rich sandstones have major age populations ranging from 103 to 70 Ma in both Minbu and Chindwin sub-basins. The Paleocene slope environment Paunggyi Formation, which overlies the Kabaw Formation, mainly consists of conglomerate, sandstone, mudstone, and tuff beds in the Minbu sub-basin. In contrast, the Paunggyi Formation in the Chindwin sub-basin is composed of sandstone and mudstone; major detrital zircon age populations from the Paunggyi Formation are between 100 and 60 Ma. Eocene strata in both basins are composed mainly of shallow marine to delta sandstone and mudstone. Major detrital zircon age populations are 100–36 Ma and 600–500 Ma. The Late Cretaceous–Eocene ages from Upper Cretaceous–Eocene strata overlap with igneous crystallization ages from the Western Myanmar Arc. We propose that the Chindwin and Minbu sub-basins developed as parts of a forearc basin along the west flank of Western Myanmar Arc (present coordinate). The forearc basin initiated in Albian time atop the continental West Burma plate due to the formation of a structural high along the western margin of West Burma plate.

scholarly journals Protolith age of the Altar and Carnero complexes and latest Cretaceous–Miocene deformation in the Caborca–Altar region of northwestern Sonora, Mexico

2019 ◽  
Vol 36 (1) ◽  
pp. 95-109 ◽  
Author(s):  
Carl E. Jacobson ◽  
César Jacques-Ayala ◽  
Andrew P. Barth ◽  
Juan Carlos García y Barragán ◽  
Jane N. Pedrick ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Detrital Zircon ◽  
Middle Jurassic ◽  
Upper Cretaceous ◽  
Age Distribution ◽  
Upper Jurassic ◽  
Late Eocene ◽  
Detrital Zircons ◽  
Normal Faults ◽  
Second Phase

In the Caborca–Altar area of northwest Sonora, variably deformed and metamorphosed sedimentary and volcanic rocks crop out in a northwest-southeast–trending belt (El Batamote belt) at least 70 km long. We obtained detrital zircon U-Pb ages from two distinctive components of the belt near Altar, here termed the Altar complex and Carnero complex. Zircon ages for metasandstone and metaconglomerate matrix from the Altar complex indicate a Late Cretaceous maximum age of sedimentation, with at least part of the complex no older than 77.5 ± 2.5 (2σ). Pre-Cretaceous detrital zircons in the complex were derived largely from local sources, including Proterozoic basement, the Neoproterozoic–Cambrian miogeocline and the Jurassic arc. The detrital zircon ages and lithologic character of the Altar complex suggest correlation with the Escalante Formation, the uppermost unit of the Upper Cretaceous El Chanate Group. In contrast, one sample from the Carnero complex yielded a Middle Jurassic maximum depositional age and a detrital zircon age distribution like that of the Jurassic eolianites of the North American Cordillera. The Carnero complex may correlate with the Middle Jurassic Rancho San Martín Formation but could also be a metamorphosed equivalent of the Upper Jurassic Cucurpe Formation, Upper Jurassic to Lower Cretaceous Bisbee Group, or El Chanate Group derived by recycling of Jurassic erg sandstones. The Late Cretaceous age for the Altar complex protolith contradicts models that relate deposition of the entire El Batamote protolith to a basin formed by oblique slip along the Late Jurassic Mojave-Sonora megashear. Instead, the belt is best explained as an assemblage of Middle Jurassic to Upper Cretaceous formations deformed and locally metamorphosed beneath a northeast-directed Laramide thrust complex. Potassium-argon and 40Ar/39Ar ages confirm previous inferences that deformation of El Batamote belt occurred between the Late Cretaceous and late Eocene. A second phase of deformation, involving low-angle normal faults, occurred during and/or after intrusion of the ~22-21 Ma Rancho Herradura granodiorite.

scholarly journals Detrital zircon geochronology and Hf isotope geochemistry of Mesozoic sedimentary basins in south-central Alaska: Insights into regional sediment transport, basin development, and tectonics along the NW Cordilleran margin

Geosphere ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 1125-1152 ◽  
Author(s):  
Cooper R. Fasulo ◽  
Kenneth D. Ridgway ◽  
Jeffrey M. Trop
Keyword(s):  
Detrital Zircon ◽  
Lower Cretaceous ◽  
Sedimentary Basins ◽  
Upper Jurassic ◽  
Detrital Zircons ◽  
Hf Isotope ◽  
Published Data ◽  
Convergent Margin ◽  
South Central ◽  
Detrital Zircon Ages

Abstract The Jurassic–Cretaceous Nutzotin, Wrangell Mountains, and Wellesly basins provide an archive of subduction and collisional processes along the southern Alaska convergent margin. This study presents U-Pb ages from each of the three basins, and Hf isotope compositions of detrital zircons from the Nutzotin and Wellesly basins. U-Pb detrital zircon ages from the Upper Jurassic–Lower Cretaceous Nutzotin Mountains sequence in the Nutzotin basin have unimodal populations between 155 and 133 Ma and primarily juvenile Hf isotope compositions. Detrital zircon ages from the Wrangell Mountains basin document unimodal peak ages between 159 and 152 Ma in Upper Jurassic–Lower Cretaceous strata and multimodal peak ages between 196 and 76 Ma for Upper Cretaceous strata. Detrital zircon ages from the Wellesly basin display multimodal peak ages between 216 and 124 Ma and juvenile to evolved Hf compositions. Detrital zircon data from the Wellesly basin are inconsistent with a previous interpretation that suggested the Wellesly and Nutzotin basins are proximal-to-distal equivalents. Our results suggest that Wellesly basin strata are more akin to the Kahiltna basin, which requires that these basins may have been offset ∼380 km along the Denali fault. Our findings from the Wrangell Mountains and Nutzotin basins are consistent with previous stratigraphic interpretations that suggest the two basins formed as a connected retroarc basin system. Integration of our data with previously published data documents a strong provenance and temporal link between depocenters along the southern Alaska convergent margin. Results of our study also have implications for the ongoing discussion concerning the polarity of subduction along the Mesozoic margin of western North America.

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