Unknown
PANGAEA
In:
Supplement to: Matsumoto, Ryo; Borowski, Walter S (2000): Gas hydrate estimates from newly determined oxygen isotopic fractionation (aGH-IW) and d18O anomalies of the interstitial waters: Leg 164, Blake Ridge. In: Paull, CK; Matsumoto, R; Wallace, PJ; Dillon, WP (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 164, 1-8, https://doi.org/10.2973/odp.proc.sr.164.206.2000
Publication Date:
2024-01-09
Description:
The d18O values of interstitial waters from Site 994 and Site 997 sediments, Blake Ridge, western Atlantic, tend to decrease with depth from 0.3 per mil to -0.5 per mil Standard Mean Ocean Water in the upper 200 mbsf, then fluctuate with significant positive spikes of Delta = 0.2 per mil - 0.5 per mil in the gas hydrate zone (200 to 450 mbsf), and finally increase from -0.4 per mil to -0.2 per mil toward 700 mbsf. Positive shifts of d18O IW in the gas hydrate zone are probably caused by the dissociation of gas hydrates originally contained in sediment cores. Gas hydrates recovered from the sites are enriched in 18O, d18O ranging between 2.7 per mil and 3.5 per mil. d18O values of gas hydrates and ambient interstitial waters give an oxygen isotopic fractionation factor of 1.0034-1.0040 at 12°-16°C and ~31 MPa (3 km below sea level). Based on this fractionation and observed isotopic anomalies in the gas hydrate zone, gas hydrates occupy 6% to 12% of pore-space volume within Blake Ridge sediments.
Keywords:
164-994; 164-997; COMPCORE; Composite Core; DEPTH, sediment/rock; DSDP/ODP/IODP sample designation; Event label; Isotope ratio mass spectrometry; Joides Resolution; Leg164; Nicaraguan Rise, North Atlantic Ocean; Ocean Drilling Program; ODP; Sample code/label; South Atlantic Ocean; δ18O, water
Type:
Dataset
Format:
text/tab-separated-values, 68 data points
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