Detrital zircon age constraints for the Winton Formation, Queensland: Contextualizing Australia's Late Cretaceous dinosaur faunas

2013 ◽  
Vol 24 (2) ◽  
pp. 767-779 ◽  
Author(s):  
Ryan T. Tucker ◽  
Eric M. Roberts ◽  
Yi Hu ◽  
Anthony I.S. Kemp ◽  
Steven W. Salisbury
2014 ◽  
Vol 397 (1) ◽  
pp. 209-223 ◽  
Author(s):  
Andrew Morton ◽  
Dirk Frei ◽  
Martyn Stoker ◽  
David Ellis

2017 ◽  
Vol 54 (2) ◽  
pp. 69-85 ◽  
Author(s):  
David Malone ◽  
John Craddock ◽  
Kacey Garber ◽  
Jarek Trela

The Aycross Formation is the basal unit of the Absaroka Volcanic Supergroup in the southern Absaroka Range and consists of volcanic sandstone, mudstone, breccia, tuff and conglomerate. The Aycross was deposited during the waning stages of the Laramide Orogeny and the earliest phases of volcanism in the Absaroka Range. U-Pb geo-chronology using laser ablation multicollector inductively coupled plasma mass spectrometry LA-ICP-MS was performed on detrital zircons collected from an Aycross sandstone bed at Falls Campground east of Togwotee Pass. The detrital zircon age spectrum ranged fom ca 47 to 2856 Ma. Peak ages, as indicated by the zircon age probability density plot are ca. 51, 61, and 72 Ma. Tertiary zircons were the most numerous (n = 32), accounting for 42% of the zircon ages spectrum. Of these 19 are Eocene, and 13 are Paleocene, which are unusual ages in the Wyoming-Idaho-Montana area. Mesozoic zircons (n = 21) comprise 27% of the age spectrum and range in age from 68–126 Ma; all but one being late Cretaceous in age. No Paleozoic zircons are present. Proterozoic zircons range in age from 1196–2483 Ma, and also consist of 27% of the age spectrum. The maximum depositional age of the Aycross Formation is estimated to be 50.05 +/− 0.65 Ma based on weighted mean of the eight youngest grains. The Aycross Formation detrital zircon age spectrum is distinct from that of other 49–50 Ma rocks in northwest Wyoming, which include the Hominy Peak and Wapiti Formations and Crandall Conglomerate. The Aycross must have been derived largely from distal westerly source areas, which include the late Cretaceous and Paleocene Bitteroot Lobe of the Idaho Batholith. In contrast, the middle Eocene units further to the north must have been derived from erosion of the Archean basement-cored uplift of the Laramide Foreland in southwest Montana.


Author(s):  
Jared T. Gooley ◽  
Marty Grove ◽  
Stephan A. Graham

ABSTRACT The Mount Diablo region has been located within a hypothesized persistent corridor for clastic sediment delivery to the central California continental margin over the past ~100 m.y. In this paper, we present new detrital zircon U-Pb geochronology and integrate it with previously established geologic and sedimentologic relationships to document how Late Cretaceous through Cenozoic trends in sandstone composition varied through time in response to changing tectonic environments and paleogeography. Petrographic composition and detrital zircon age distributions of Great Valley forearc stratigraphy demonstrate a transition from axial drainage of the Klamath Mountains to a dominantly transverse Sierra Nevada plutonic source throughout Late Cretaceous–early Paleogene time. The abrupt presence of significant pre-Permian and Late Cretaceous–early Paleogene zircon age components suggests an addition of extraregional sediment derived from the Idaho batholith region and Challis volcanic field into the northern forearc basin by early–middle Eocene time as a result of continental extension and unroofing. New data from the Upper Cenozoic strata in the East Bay region show a punctuated voluminous influx (>30%) of middle Eocene–Miocene detrital zircon age populations that corresponds with westward migration and cessation of silicic ignimbrite eruptions in the Nevada caldera belt (ca. 43–40, 26–23 Ma). Delivery of extraregional sediment to central California diminished by early Miocene time as renewed erosion of the Sierra Nevada batholith and recycling of forearc strata were increasingly replaced by middle–late Miocene andesitic arc–derived sediment that was sourced from Ancestral Cascade volcanism (ca. 15–10 Ma) in the northern Sierra Nevada. Conversely, Cenozoic detrital zircon age distributions representative of the Mesozoic Sierra Nevada batholith and radiolarian chert and blueschist-facies lithics reflect sediment eroded from locally exhumed Mesozoic subduction complex and forearc basin strata. Intermingling of eastern- and western-derived provenance sources is consistent with uplift of the Coast Ranges and reversal of sediment transport associated with the late Miocene transpressive deformation along the Hayward and Calaveras faults. These provenance trends demonstrate a reorganization and expansion of the western continental drainage catchment in the California forearc during the late transition to flat-slab subduction of the Farallon plate, subsequent volcanism, and southwestward migration of the paleodrainage divide during slab rollback, and ultimately the cessation of convergent margin tectonics and initiation of the continental transform margin in north-central California.


2009 ◽  
Vol 166 (1) ◽  
pp. 137-146 ◽  
Author(s):  
Andrew C. Morton ◽  
Kenneth Hitchen ◽  
C. Mark Fanning ◽  
Greg Yaxley ◽  
Howard Johnson ◽  
...  

2009 ◽  
Vol 45 (2) ◽  
pp. 131-146 ◽  
Author(s):  
E. R. Phillips ◽  
R. A. Smith ◽  
P. Stone ◽  
V. Pashley ◽  
M. Horstwood

SynopsisDetrital zircon populations within the Llandovery to Wenlock sandstones of the southern Midland Valley of Scotland indicate that the recycled orogenic provenance for these sedimentary rocks was essentially bimodal, comprising a younger Lower Palaeozoic component and an older predominantly Mesoproterozoic component. The Lower Palaeozoic contribution is dominated by Arenig/Llanvirn (c. 475 Ma) zircons interpreted as having been derived from a volcanic-plutonic source located within the Midland Valley terrane. The dominant Mesoproterozoic component within the sandstones is c. 1000 Ma and is thought to represent detritus shed from a Grenvillian (c. 1000–1800Ma) basement to the Midland Valley terrane. The scarcity of Archaean zircons precludes the Grampian metamorphic terrane Dalradian Supergroup as a supplier of sediment to the Ordovician–Silurian basins located along the southern margin of the Midland Valley. The age profiles of detrital zircon populations do not fit with a simple model of unroofing of a volcanic-arc complex. Rather they point to the periodic uplift of fault-bound, dismembered blocks of volcanic and plutonic rocks during a prolonged (Llandovery through to at least early Devonian) period of sinistral strike-slip deformation, and it was this which controlled basin development, sedimentary facies distribution and deformation along the southern side of the Midland Valley terrane.Appendices 1 & 2 can be found at http://www.geolsoc.org.uk/SUP18370


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