Physical Sciences and Mathematics Commons^™

A Triple Oxygen Isotope Analysis Of Altered Oceanic Crust And Its Buffering Effect On The Steady State Oxygen Isotope Composition Of Seawater, Jesse P. Mcgunnigle

Earth and Planetary Sciences ETDs

The secular chemical marine sediment trend showing an increase in δ¹⁸O over geologic time has traditionally been investigated using δ¹⁸O modelling of ancient ocean compositions, ocean surface temperatures, and sample diagenetic alteration. This study presents a triple oxygen isotope mass balance for the oceans using high precision δ¹⁸O and Δ'¹⁷O measurements of altered oceanic crust. The mass balance model predicts an ice-free seawater with δ¹⁸O = -0.29‰ and Δ’¹⁷O = -0.002‰ with steady state reached at approximately (0.5 to 1)×10⁹ years. Modifications to the hydrothermal alteration and …