Dinosaur-Bearing Hyperconcentrated Flows of Cretaceous Arctic Alaska: Recurring Catastrophic Event Beds on a Distal Paleopolar Coastal Plain

Origin of Clay Minerals In Alluvial Paleosols, Prince Creek Formation, North Slope, Alaska, U.S.A: Influence of Volcanic Ash On Pedogenesis In the Late Cretaceous Arctic

“…In waterlogged soils, the reduced iron and gray colors in gley horizons are due in part to bacterial decomposition of organic matter at temperatures above freezing, and pH values close to 5. These pedogenic processes are consistent with current cool temperate paleoclimatic reconstructions of Late Cretaceous North Slope ecosystems (Spicer and Herman 2010;Flaig et al 2011Flaig et al , 2013Flaig et al , 2014.…”

“…Evidence for pedogenic illite-smectite formation in the Prince Creek Formation stands in stark contrast to much more modest clay mineral transformations typical of modern arctic soil-forming environments (Ping et al 1999;Borden et al 2010). Instead, the Late Cretaceous Arctic of northern Alaska was one in which rapid weathering of volcanic ash and alluvium in a seasonally wet environment resulted in a rich ecosystem with soils that supported a diverse flora and a year-round dinosaur fauna (Fiorillo et al 2010a(Fiorillo et al , 2010bFlaig et al 2014). The Late Cretaceous Prince Creek Formation, therefore, provides an exquisite example of a flourishing high-latitude ecosystem in a greenhouse world.…”

“…Furthermore, these pedogenic processes are consistent with evidence of seasonality (spring runoff in response to warmer temperatures) recognized from other aspects of the Prince Creek Formation. For example, root structures are often present in channel deposits, which suggest some form of wet-dry seasonality (Fiorillo et al 2010b;Flaig et al 2011Flaig et al , 2014. Similarly, the taphonomic pattern of the distribution of several bone beds in the Prince Creek Formation, as mortality events, has been attributed to a seasonal pattern of Late Cretaceous spring runoff from the ancestral Brooks Range (Fiorillo et al 2010b).…”

Reconstructing the paleohydrology of a cretaceous Alaskan paleopolar coastal plain from stable isotopes of bivalves

“…The study interval of the Prince Creek Formation (PCF) is an Early Maastrichtian (most recent 40 Ar/ 39 Ar age of 69.2 ± 0.5 Ma; Flaig and Fiorillo, 2015) coastal plain to deltaic succession deposited on a tidally influenced Arctic Alaskan coastal plain (Flaig et al, 2011van der Kolk et al, in press). These sediments were shed from the ancestral Brooks Range into what is now known as the Colville Basin (Flaig et al, 2011).…”

“…Flaig et al (2011) examine the facies and alluvial architecture of the PCF and determined that the PCF represents a poorly drained coastal plain to lower deltaic plain heavily influenced by marine waters influx with flashy seasonal flooding likely driven by from snowmelt in the ancestral Brooks Range. This likely contributes to the preservation of dinosaurs entombed in these seasonal flash flood deposits (Fiorillo et al, 2010;Flaig et al, 2011Flaig et al, , 2013Flaig and Fiorillo, 2015). Since stable isotopes of ancient minerals like carbonates and phosphate record the isotopic composition of the water from which it precipitated from, and since the isotopic composition of water is indicative of its source (marine, meteoric, and snowmelt) we will test these interpretations using isotopic composition of bivalves associated with the isotopic composition of phosphate and siderite from a study by Suarez et al (2013).…”