Ice ages boost production of new ocean crust
Lower sea levels amplify magma outpourings
![Abyssal hills](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/02/ts_sepr_osc_0.png?fit=860%2C460&ssl=1)
SEA SUMMIT Rows of thick ocean crust called abyssal hills, which run parallel to the mid-ocean rift (yellow, center) in this seafloor map, formed during ice ages when lower sea levels caused larger magma outpourings at mid-ocean ridges, new research suggests.
LarryMayer/Univ. of New Brunswick Ocean Mapping Group