Middle Miocene disruption

[3] Cooling that led to the Middle Miocene disruption is primarily attributed CO2 being pulled out of the Earth's atmosphere by organic material before becoming caught in different locations like the Monterey Formation.

[5] One of the primary effects of the climatic cooling that took place during this time period was the growth of the EAIS,[6][4] termed the East Antarctic Ice Sheet Expansion (EAIE).

[8] Significant sections of ice on the Antarctic continent are believed to have started growth at the beginning of the Middle Miocene disruption and continued to expand until about 10 Ma.

[2] One of the primary indicators for the significant global ice sheet growth is the higher concentration of 18O found in benthic foraminifera from oceanic sediment cores during this time period.

[13] In the Columbia River Basalt Group (CRBG), the cessation of kaolin-producing pedogenic processes occurred at the start of the MMCT and has been used as a proxy marker for the end of the MMCO.

[24] Another hypothesis for the crash involves the shrinkage and shoaling of the Central American Seaway, limiting water mass exchange between the Atlantic and Pacific Oceans.

A primary example of these extinctions is indicated by the observed occurrence of Varanidae, chameleons, Cordylidae, Tomistominae, Alligatoridae, and giant turtles through the Miocene Climatic Optimum (18 to 16 Ma) in Central Europe (45-42°N palaeolatitude).

Two crocodilians of the genera Gavialosuchus and Diplocynodon were noted to have been extant in these northern latitudes prior to the permanent cooling step, but then became extinct between 14 and 13.5 Ma.

This Antarctic cooling, along with significant changes in temperature gradients in Central Europe as indicated by Madelaine Böhme's study on ectothermic vertebrates, provide evidence that plant and animal life needed to migrate or adapt in order to survive.