The Jurassic Period was a span of time from approximately 201 million years ago to 145 million years ago. The Jurassic is part of the Mesozoic Era of Earth’s history, which is regarded as the “Age of Dinosaurs.”
Stable isotopes provide a tool for exploring ancient environments. For today’s A to Z installment, we present a recent application of stable isotopes to understand What the world was like during the Jurassic Period.
Alberti, M, Fursich, F.T., Abdelhady, A.A., and Andersen, N., 2017, Middle to Late Jurassic equatorial seawater temperatures and latitudinal temperature gradients based on stable isotopes of brachiopods and oysters from Gebel Maghara, Egypt: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 468, p. 201-313.
Brachiopods and oysters are shelled organisms that live on the ocean floor. The shells of these animals are made of calcium carbonate minerals. The carbonate part of these minerals preserve the isotopic ratio carbon in carbon dioxide that was dissolved in the ocean (reflecting ocean respiration) and the isotopic ratios of oxygen of the water itself (which reflects temperature).
By collecting and analyzing shell material for isotopes of carbon and oxygen, the authors are able to investigate just how warm the ocean at the Equator was during the Jurassic and also (through comparison with the work of other scientists) the difference in temperature from the Equator to the poles.