Multi-Taxa Isotopic Investigation of Paleohydrology In the Lower Cretaceous Cedar Mountain Formation, Eastern Utah, U.S.A.: Deciphering Effects Of the Nevadaplano Plateau On Regional Climate

Abstract

We investigate the regional climatic effects of the formation of the ''Nevadaplano'' plateau during the Sevier Orogeny in an overall warming world. Paleohydrology was reconstructed from 590 individual measurements of phosphate O isotopes in continental faunas of the Lower Cretaceous Cedar Mountain Formation, Utah, U.S.A. Semi-aquatic (turtles, crocodiles) and terrestrial (dinosaurs) taxa are compared to coeval pedogenic carbonates to interpret changing water sources over time. Samples were grouped into four stratigraphic faunas (lower Yellow Cat, upper 19.1 to 20.3%) values generally exceed those of semi-aquatic taxa. Using mass-balance equations for modern terrestrial animals adjusted for size and inferred dinosaur physiology, ingested water is calculated for the above dinosaur groups. On a member scale, when meteoric-water values are compared with calculated dinosaur drinking water, values are equal to or lighter than meteoric water for most herbivorous groups (as low as 215.5% for ornithischians) and equal to or heavier than meteoric water for most carnivorous groups (as high as 22.0% for allosauroids). Changes in d O-enriched water (e.g., up to an average of 22.0% from an allosauroid tooth) and extremely 18 O-depleted water (e.g., 215.5% for ornithischians) in the Ruby Ranch Member. By Mussentuchit-time, delivery of the Western Interior Seaway-dominated moisture to the region, despite continued rise of the Sevier Mountains.

Niche Partitioning in Theropod Dinosaurs: Diet and Habitat Preference in Predators from the Uppermost Cedar Mountain Formation (Utah, U.S.A.)

“…Further, specimens between sites tend to show a similar minor degree of wear attributable to transportation, indicating that hydraulic transport and reworking was minimal. Most importantly for our purposes, previous isotopic analyses from this same sample demonstrate the expected variation for modern fauna, implying that biogenic signals were not lost due to diagenetic alteration 17,24 .…”

Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record

“…Top predators play a key role in shaping ecosystems 42–44 and can act as buffering agents during intervals of ecological disruption, increasing resilience against environmental change 45 , and biological invasion 46 . Current evidence suggests that small-bodied, highly cursorial tyrannosaurs with advanced sensory toolkits invaded the North American continent no later than the Albian, yet were unable to ascend to top predator roles until a combination of physiogeographic, climatic, and paleoenvironmental changes, such as transgression of the Western Interior Seaway and shrinking species ranges 8,47,48 , a global temperature maximum in the Turonian 49 , and shifts in precipitation and climate 50 likely combined to wipe out allosaurians as a stabilizing effect on Late Cretaceous ecosystems.…”

A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America

“…These regional tectonic changes, coupled with global trends, resulted in the establishment of the North American Cretaceous Western Interior Seaway (WIS; Dickinson & Snyder, 1978 ; DeCelles, 1986 ; Neilson, 1986 ; Kauffman & Caldwell, 1993 ), a large, epieric body of water that flooded much of central North America by the early Late Cretaceous. Initially, rise of the Sevier Orogeny produced a period of increasing aridity that is recorded throughout most of the Cedar Mountain Formation (e.g., Yellow Cat through Ruby Ranch members) ( Stokes, 1944 ; Young, 1960 ; Suarez et al, 2014 ; Hatzell, 2015 ). However, continued transgression of the WIS produced a dramatic climate shift in the capping Mussentuchit Member of the Cedar Mountain Formation, which records a rapidly changing paleoclimatic shift toward warmer, more humid conditions ( Cifelli et al, 1997 ; Suarez et al, 2012 , 2014 ).…”

“…Initially, rise of the Sevier Orogeny produced a period of increasing aridity that is recorded throughout most of the Cedar Mountain Formation (e.g., Yellow Cat through Ruby Ranch members) ( Stokes, 1944 ; Young, 1960 ; Suarez et al, 2014 ; Hatzell, 2015 ). However, continued transgression of the WIS produced a dramatic climate shift in the capping Mussentuchit Member of the Cedar Mountain Formation, which records a rapidly changing paleoclimatic shift toward warmer, more humid conditions ( Cifelli et al, 1997 ; Suarez et al, 2012 , 2014 ).…”