(Table 1) Bulk and grain density, porosity, and p- and s-wave velocity characteristics of ODP Hole 163-990A sediments, supplement to: Cerney, Brian; Carlson, Richard L (1999): The effect of cracks on the seismic velocities of basalt from Site 990, Southeast Greenland margin. In: Larsen, HC; Duncan, RA; Allan, JF; Brooks, K (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 163, 1-7


Seismic velocities in rocks are influenced by the properties of the solid, the pore fluid, and the pore space. Cracks dramatically affect seismic velocities in rocks; their influence on the effective elastic moduli of rocks depends on their shape and concentration. Thin cracks (or fractures) substantially lower the moduli of a rock relative to the effect of spherical voids (or vesicles), and lower moduli are reflected by lower P- and S-wave velocities. The objective of this research is to determine the types and concentrations of cracks and their influence on the seismic properties of subaerially erupted basalts drilled from Hole 990A on the Southeast Greenland margin during Ocean Drilling Program Leg 163. Ellipsoidal cracks are used to model the voids in the rocks. The elastic moduli of the solid (grains) are also free parameters in the inverse modeling procedure. The apparent grain moduli reflect a weighted average of the moduli of the constituent minerals (e.g., plagioclase, augite, and clay minerals). The results indicate that (1) there is a strong relationship between P-wave velocity and porosity, suggesting a similarity of pore shape distributions, (2) the distribution of crack types within the massive, central region of aa flows from Hole 990A is independent of total porosity, (3) thin cracks are the first to be effectively sealed by alteration products, and (4) grain densities (an alteration index) and apparent grain moduli of the basalt samples are directly related.

DOI https://doi.org/10.1594/PANGAEA.804640
Related Identifier https://doi.org/10.2973/odp.proc.sr.163.106.1999
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.804640
Creator Cerney, Brian; Carlson, Richard L
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 1999
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 770 data points
Discipline Earth System Research
Spatial Coverage (-39.780 LON, 63.473 LAT); Greenland Sea
Temporal Coverage Begin 1995-09-20T17:45:00Z
Temporal Coverage End 1995-10-01T13:00:00Z