Stable Isotope Studies of the Water Cycle and Terrestrial Environments

This volume is devoted to Earth surface environmental reconstructions and environmental changes that may be deciphered and modelled using stable isotopes along with mineralogical/chemical, sedimentological, palaeontological/biological and climatological methodologies. The book is divided into two sections, both using stable isotopes (δD, δ18O, δ13C, d15N, δ34S, clumped isotopes Δ47) in various samples and phases as the main research tool. The first section is devoted to studies focusing on the distribution of isotopes in precipitation, groundwater, lakes, rivers, springs, tap water, mine water and their relationship with terrestrial environments at regional to continental scale. In relation to this, the second section includes case studies from a range of continental settings, investigating cave deposits (stalagmites, bat guano), animal skeletons (dinosaurs, alligators, turtles, bivalves), present and past soils (palaeosols) and limestones. The sections focus on the interaction between the surficial water cycle and underground water storage with deposits acting as archives of short- to long-term climatic and environmental changes. Examples from the Early Cretaceous to present time come from Europe, Asia, Africa, North and South America.
Quantification of a North American greenhouse hydrological cycle: using oxygen isotopic composition of phosphate from Early Cretaceous (Aptian–Albian) turtles
Correspondence: CAS, [email protected]; TBT, [email protected]
Correspondence: CAS, [email protected]; TBT, [email protected]
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Published:October 28, 2021
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CiteCitation
C. A. Suarez, M. N. Frucci, T. B. Tompkins, M. B. Suarez, 2021. "Quantification of a North American greenhouse hydrological cycle: using oxygen isotopic composition of phosphate from Early Cretaceous (Aptian–Albian) turtles", Stable Isotope Studies of the Water Cycle and Terrestrial Environments, A.-V. Bojar, A. Pelc, C. Lécuyer
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Abstract
The oxygen isotopic composition of turtle phosphate from Early (Aptian–Albian) Cretaceous turtles from several North American palaeolatitudes was measured to estimate the isotopic compositions of groundwater δ18Ow. In Earth's history, under greenhouse conditions, researchers have recorded an intensification of the hydrological cycle as global heat was distributed from the equator to the poles via latent heat transport. Previous studies, using pedogenic carbonate nodules, show an increased rainout effect, causing intense depletion in δ18Ow at high latitudes due to this phenomenon. This study shows the utility of another palaeo-δ18Ow proxy, turtle phosphate oxygen from turtle carapace and plastron. Turtle δ18Op was sampled from several Early Cretaceous sites. We find that turtle-derived δ18Ow values range from −3.1 ± 0.9‰ at a palaeolatitude of 29.5° N to −7.2‰ at 40° N. Turtles at the lowest latitude (Arkansas) plot off the carbonate-derived δ18Ow gradient; however, turtles at 34° N and 40° N plot within the range of carbonate-derived δ18Ow. Turtles from Arkansas (29.5° N) were likely to have been influenced by marine water and/or enriched Gulf of Mexico water vapour resulting in a deviation from the expected δ18Ow gradient. These data are encouraging steps towards using turtles to estimate palaeohydrological dynamics; however, additional analysis of lower- and higher-latitude specimens is necessary to confirm this trend.
- Albian
- Anapsida
- Aptian
- Arkansas
- carbonates
- Cedar Mountain Formation
- Chordata
- concretions
- Cretaceous
- fresh-water environment
- greenhouse effect
- ground water
- isotope ratios
- isotopes
- Lower Cretaceous
- marine environment
- Mesozoic
- morphology
- North America
- O-18/O-16
- oxygen
- paleoclimatology
- paleoenvironment
- paleohydrology
- paleolatitude
- paleomagnetism
- pedogenesis
- phosphates
- regression analysis
- Reptilia
- secondary structures
- sedimentary structures
- soils
- stable isotopes
- statistical analysis
- Testudines
- Tetrapoda
- United States
- Utah
- Vertebrata
- Holly Creek Formation
- Mussentuchit Member