The Clean SWEEP of the Rocky Mountains – #365papers – 2017 – 50

#365papers for February 19, 2017

Chamberlain, Mix, Mulch, Hren, Kent-Corson, Davis, Horton, and Graham, 2012, The Cenozoic climatic and topographic evolution of the western North American cordillera: American Journal of Science, v. 312, p. 213-262.

What’s it about?

This paper uses a compilation of new and previously published oxygen stable isotope data from all over the Rocky Mountain region to understand the timing and uplift pattern of the Rocky Mountains. It seems that the Rocky Mountains first rose to the north, then grew southward. Continue reading

Climate Models and Eocene Isotopes, or How to Make My Head Hurt – #365papers – 2017 – 49

#365papers for February 18, 2017

Feng, Poulsen, Werner, Chamberlain, Mix, and Mulch, 2013, Early Cenozoic evolution of topography, climate, and stable isotopes in precipitation in the North American cordillera: American Journal of Science, v. 313, p. 613-648.

What’s it about?

Isotopes of oxygen and hydrogen in precipitation vary based on multiple factors, including how far from water vapor sources (usually the ocean) the precipitation is taking place, and whether or not there are mountains present, which can deflect and change patterns and amounts of precipitation. Because of this, we can use isotopes of oxygen from rocks and fossils, which reflect ancient precipitation, and understand the pattern and timing of uplifts of mountains.

This paper goes a step further, by using mathematical models to predict what oxygen isotopes of precipitation should have looked like based on a few ideas of how the Rocky Mountains may have come up. Continue reading

Two Papers, Two Authors, One Year, Same Result, But… – #365papers – 2017 – 48

#365papers for February 17, 2017

Bender, M.M., 1971, Variations in the 13C/12C ratios of plants in relation to the pathway of photosynthetic carbon dioxide fixation: Phytochemistry, v. 10, p. 1239-1244.

Smith, B.N. and Epstein, S., 1971, Two categories of 13C/12C ratios for higher plants: Plant Physiology: v. 47, p. 380-384.

Two papers, one topic.

What are these about?

Both of these papers are important first steps in our understanding of how stable isotopes can be used to understand plant physiology. Continue reading

Analyzing Salty Waters with Laser Spectroscopy – #365papers – 2017 – 47

#365papers for February 16, 2017

Skrzypek and Ford, 2014, Stable Isotope Analysis of Saline Water Samples on a Cavity Ring-down Spectroscopy Instrument: Environmental Science & Technology, v. 48, p. 2827-2834.

What’s it about?

This is a methods paper about how to analyze saline (salty) waters with the new laser-based isotope analyzers. It discusses several solutions to the problems that can arise when dealing with salty waters. Continue reading

Paleogene Mountains, Rivers, Lakes,… and Isotopes – #365papers – 2017 – 46

#365papers for February 15, 2017

Davis, Mulch, Carroll, Horton, and chamberlain, 2009, Paleogene landscape evolution of the central North American Cordillera: Developing topography and hydrology in the Laramide foreland: Geological Society of America Bulletin, v. 121, p. 100-116.

What’s it about?

This paper uses isotopes of oxygen, carbon, and strontium from multiple areas along the east edge and middle of the Rocky Mountains to explore the timing of the uplift of the Rockies, and to understand how the new mountains affected climate locally. Continue reading

The Last Glacial Maximum in Wyoming. A Story From Tooth Enamel – #365papers – 2017 – 44

#365papers for February 13, 2017

Kohn and McKay, 2012, Paleoecology of the late Pleistocene-Holocene faunas of eastern and central Wyoming, USA, with implications for LGM climate models: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 326-328, p. 42-53.

What’s it about?

This paper uses measurements of stable isotopes of carbon and oxygen from tooth enamel to interpret past mean annual precipitation and other climatic variables for two caves in Wyoming. Continue reading

How Do the Early Processes of Fossilization Affect the Chemistry of Bones and Teeth? – #365papers – 2017 – 41

#365papers for February 10, 2017

Tutken, Vennemann, and Pfretzschner, 2008, Early diagenesis of bone and tooth apatite in fluvial and marine settings: Constraints from combined oxygen isotope, nitrogen and REE analysis: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 254-268.

What’s it about?

This paper discusses how we can determine how altered a geochemical signal in a fossil bone or tooth might be, comparing bones and teeth that fossilized in both freshwater (river) and marine (ocean) environments. The authors used collagen content, nitrogen content, and the abundance of Rare Earth Elements (REEs) to attempt to estimate alteration. Continue reading

Fresh water and marine snails from 55 million years ago – #365papers – 2017 – 39

#365papers for February 8, 2017

Schmitz and Andreasson, 2001, Air humidity and lake δ18O during the latest Paleocene-earliest Eocene in France from recent and fossil fresh-water and marine gastropod δ18O, δ13C, and 87Sr/86Sr: Geological Society of America Bulletin, v. 113, p. 774-789.

What’s it about?

This paper describes oxygen isotope ratios from modern freshwater snails and how the values and patterns of intra-shell analyses relate to the overall climate of a region. These patterns are then compared with Paleocene-Eocene aged gastropods to get at ancient climate. Some marine snails were also studied to see how they compare with freshwater snails. Strontium was also used to help get at the amount and timing of precipitation and weathering  in a region. Continue reading

Snail Shells, Climate, and Weather – #365papers – 2017 – 35

#365papers for February 4, 2017

Yanes, Izeta, Cattaneo, Costa, and Gordillo, 2014, Holocene (~4.5-1.7 cal. kyr BP) paleoenvironmental conditions in central Argentina inferred from entire-shell and intra-shell stable isotope composition of terrestrial gastropods: The Holocene, v. 24, p. 1193-1205.

What’s it about?

This paper discusses the use of geochemistry (specifically stable isotopes) of fossil snail shells to understand past environments. It looks especially on comparing results from whole shell analysis (grinding the whole shell up and putting it into the mass spectrometer) against serial or intra-shell analyses, where multiple samples are collected from a single shell. Continue reading

More Tales from Land Snails – #365papers – 2017 – 34

#365 papers for February 3, 2017

Prendergast, Stevens, Barker, and O’Connell, 2015, Oxygen isotope signatures from land snail (Helix melanostoma) shells and body fluid: Proxies for reconstructing Mediterranean and North African rainfall: Chemical Geology, v. 409, p. 87-98.

What’s it about?

This paper seeks to show that what we’ve been saying we can do with the geochemistry of snail shells (especially oxygen isotopes) can actually be done. This paper shows that there is a relationship between oxygen isotopes in rainfall and those of snail body fluids. The relationship between isotopic signatures of body fluids and shells is then shown. Continue reading