Publication Date:
2023-06-27
Description:
Ne, Ar, Kr, Xe, and K2O were measured in representative samples of holocrystalline basalt from DSDP Hole 504B. No hiatus in inert gas abundance is recognized at the base of the "oxic" alteration zone and the extent rather than the nature of alteration appears to determine these abundances. When the inert gas abundances are separately plotted against K2O, two distinct trends of loss emerge, one for alteration involving K-gain, the other for K-loss.
Apparent whole-rock K-Ar ages are anomalous in the upper 50 m of basement, and below 300 m sub-basement. In the intervening zone of basement, celadonization adds sufficient potassium and eliminates enough "primary" 40Ar early in the history of the basalts for "excess" 40Ar to become subordinate to radiogenic 40Ar in basalts showing potassium enrichment greater than 0.2%. Stratigraphically correct K-Ar ages are obtained, therefore, from K-enriched basalts of the oxic alteration zone.
Keywords:
69-504B; 70-504B; 83-504B; Age, 40K/40Ar Potassium-Argon; Age, dated; Age, dated standard deviation; Argon-36; Argon-40; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Krypton-84; Leg69; Leg70; Leg83; Mass spectrometry; Neon-20; Potassium oxide; Sample code/label; Sulfur, total; Xenon-132
Type:
Dataset
Format:
text/tab-separated-values, 236 data points
Permalink
