Interstadial

Marine isotope stages are sometimes subdivided into stadials and interstadials by minor climate fluctuations within the overall stadial or interstadial, which are indicated by letters. The odd-numbered interstadial MIS 5, also known as the Sangamonian interglacial, contains two periods of relative cooling, and so is subdivided into three interstadials (5a, 5c, 5e) and two stadials (5b, 5d). A stadial isotope stage like MIS 6 would be subdivided by periods of relative warming, and so in that case the first and last subdivisions would be stadials; MIS 6a, 6c and 6e are stadials while 6b and 6d are interstadials.