GEOL 11042 Lecture 39: 39-Miocene Epoch
9 Nov 2020
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Document Summary
The miocene epoch in the cenozoic era ranges in time from about 23. 8 million years ago to 5. 3 million years ago. The miocene begins warm (although not as warm as the eocene was!) and ends cool. We can think of it as the turning point for earth"s climate, because in mid-miocene, the global cool-down begins that ultimately leads to the glacial-interglacial cycle that dominates the pleistocene epoch. Seaway: the isolation of antarctica after the drake passage opens, which initiates the permanent ice sheet formation on antarctica. The forested ecosystems gave way to grasslands with enclosed forests, and these grasslands supported a wide range of grazing and browsing mammals (niche partitioning again! The columbia river basalts are the result of flood basalt eruptions of mid-miocene age. Although not as large or long-lasting as the deccan traps or the siberian traps, they did release enough co2 to drive a warm event in the mid miocene.
