Category Archives: Stable Isotopes

Paleogene Antarctic ocean circulation from isotopes – #365papers – 2017 – 66

#365papers for March 7, 2017

Kennett and Stott, 1990 Proteus and Proto-Oceanus: ancestral paleogene oceans as revealed from Antarctic stable isotopic results; ODP Leg 113: Proceedings of the Ocean Drilling Programs, Scientific Results, v. 113, p. 865-880.

What’s it about?

These are the published results of an ocean drilling cruise that took place in Antarctica in the late 1980’s. A core from the ocean floor was drilled and various parts of it were studied. This paper discusses geochemical results from the skeletons (tests) of single-celled organisms called foraminifera (forams) found throughout the core. From these results, the authors discuss deep ocean currents from millions of years ago.Continue reading “Paleogene Antarctic ocean circulation from isotopes – #365papers – 2017 – 66”

The Paleocene-Eocene boundary in deep ocean foraminifera – #365papers – 2017 – 65

#365papers for March 6, 2017

Thomas and Shackleton, 1996, The Paleocene-Eocene benthic forminiferal extinction and stable isotope anomalies, in Knox, Corfield, Dunay, eds., Correlation of the Early Paleogene in Northwest Europe: Geological Society Special Publication n. 101, p. 401-441.

What’s it about?

This paper examines the abundance and geochemistry of single-celled organisms called foraminiferans (forams) that were living in the oceans around 55 million years ago. Forams are still present today worldwide. They make little tiny calcite skeletons (called tests) that can be used to identify the species and then can be analyzed.

Using these foram skeletons, the authors identified the many species that lived in the ocean before and after the Paleocene-Eocene boundary and recognized some extinctions associated with the boundary. With geochemical analysis, they showed that there are some significant anomalies (rapid, unexpected changes) at the Paleocene-Eocene boundary.Continue reading “The Paleocene-Eocene boundary in deep ocean foraminifera – #365papers – 2017 – 65”

Knowing a Snail’s Diet from the Chemistry of its Shell – #3650papers – 2017 – 62

#365papers for March 3, 2017

Prendergast, Stevens, Hill, Hunt, O’Connell, and Barker, 2015, Carbon isotope signatures from land snail shells: Implications for palaeovegetation reconstruction in the eastern Mediterranean: Quaternary International, in press.

What’s it about?

This paper discusses the use of carbon isotopes in the shells of land snails to interpret what the snails were eating. To do this, they studied wild snails for which they could also measure the carbon isotopes of potential food sources.Continue reading “Knowing a Snail’s Diet from the Chemistry of its Shell – #3650papers – 2017 – 62”

Recognizing What Was Once a Safe Space Using Fossil Snails – #365papers – 2017 – 59

#365papers for February 28, 2017

Prendergast, Stevens, O’Connell, Hill, Hunt and Barker, 2016, A late Pleistocene refugium in Mediterranean North Africa? Palaeoenvironmental reconstruction from stable isotope analyses of land snail shells (Haua Fteah, Libya): Quaternary Science Reviews, v. 139, p. 94-109.

What’s it about?

There was a time in early human history when northern Africa grew arid, making life rather challenging for people. This paper is about an area where the aridity did not have such an impact, making a safe refugium for people to wait it out. The evidence that there was, in fact, a ‘safe space’ comes from isotopic analysis of fossil snails.Continue reading “Recognizing What Was Once a Safe Space Using Fossil Snails – #365papers – 2017 – 59”

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

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

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

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

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

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