Basalt density, basement age, and intrusive/extrusive relations from DSDP Legs 2 through 7, 9, and 14

• Main Authors: Salisbury, Matthew H, Christensen, Nikolas I
• Format: Dataset
• Language: English
• Published: PANGAEA 1973
• Subjects: 14-136; 14-137; 14-138; 14-141; 2-10; 3-14; 3-15; 3-18; 3-19; 4-23; 5-32; 5-36; 6-54; 6-57; 7-61; 7-63; 7-66; 9-77B; 9-79; 9-82; 9-83; 9-84; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg14; Leg2; Leg3; Leg4; Leg5; Leg6; Leg7; Leg9; North Atlantic/CONT RISE; North Atlantic/DIAPIR; North Atlantic/HILL; North Pacific; North Pacific/BASIN; North Pacific/HILL; North Pacific/Philippine Sea/RIDGE; North Pacific/PLAIN; North Pacific/RIDGE; North Pacific/VALLEY; South Atlantic/CONT RISE; South Atlantic/HILL; South Atlantic/PLAIN; South Atlantic/RIDGE; Pacific; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.711683; https://doi.org/10.1594/PANGAEA.711683

Densities of layer 2 basalt recovered during the Deep Sea Drilling Project have been found to decrease steadily with age, a finding ascribed to progressive submarine weathering in the context of sea-floor spreading. The least-squares solution for 52 density measurements gives a rate of decrease in density of (Delta p)/(Delta t) = -0.0046 g per ccm m.y. = -16 percent per 100 m.y., which is in excellent agreement with earlier estimates based on observed chemical depletion rates of dredged oceanic basalt. Weathering of sea-floor basalt, should it penetrate to any considerable depth in layer 2, will decrease layer 2 seismic refraction velocities, act as a source of geothermal heat, and substantially influence the chemistry of sea water and the overlying column of sediment.