The Role of Orbital Forcing in Periodic and Non-Periodic Climate Change During the Late Oligocene and Early and Middle Miocene

Original Message-----

From: Poore, Richard Z

Sent: Thursday, July 12, 2001 8:56 AM

To: Weller, Margaret

Subject: summary for Zachosl award

Science Summary: This proposal requests support for a study to test a new hypothesis on the origin of intermittent transient glaciations of the early and middle Miocene (the Mi-events) and possibly the late Oligocene. New findings suggest that the largest of the glaciations (Mi-1) at the Oligocene/Miocene boundary coincided with a rare congruence of an extended low-amplitude orbital obliquity node with a period of low orbital eccentricity. The study focus on developing isotope records that will test the prediction that similar climate anomalies occur at 18.2 and 27 Ma when orbital calculations indicate extended low-amplitude obliquity nodes also correspond with intervals of low eccentricity.