Did Cooling Oceans Trigger Ordovician Biodiversification? Evidence from Conodont Thermometry

  title={Did Cooling Oceans Trigger Ordovician Biodiversification? Evidence from Conodont Thermometry},
  author={Julie A. Trotter and Ian S. Williams and Christopher R. Barnes and Christophe L{\'e}cuyer and R. S. Nicoll},
  pages={550 - 554}
The Ordovician Period, long considered a supergreenhouse state, saw one of the greatest radiations of life in Earth's history. Previous temperature estimates of up to ∼70°C have spawned controversial speculation that the oxygen isotopic composition of seawater must have evolved over geological time. We present a very different global climate record determined by ion microprobe oxygen isotope analyses of Early Ordovician–Silurian conodonts. This record shows a steady cooling trend through the… 

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Abstract Stable isotopic values were measured on micrite, sparry calcite, dolomite, inarticulated brachiopods, and conodonts from the Lange Ranch section (central Texas) of the Lower Ordovician