Figure F3. Discrete Cl– excursions within the GHSZ correlate well with other proxies of gas hydrate abundance, such as temperature anomalies in the cores (temperature distribution for Holes 1244C and 1251D; temperature deviation for Hole 1245B), as shown by Tréhu et al. (2004). Here we show that the isotopic composition of the water shows deviations to high D and 18O values. These anomalies reflect release of water enriched in the heavy isotopes as the gas hydrate is destabilized during core retrieval (Cl– and temperature anomaly profiles are modified from Tréhu et al., 2004). BSR = bottom-simulating reflector, APC = advanced piston corer, XCB = extended core barrel, T = temperature. SMOW = Standard Mean Ocean Water.