Jarrard Richard D jarrard@mines.utah.edu Broglia Christina chris@ldeo.columbia.edu 1991 Physical properties of ODP Holes 124-768C and 124-770C (Table 1) dataset https://doi.org/10.1594/PANGAEA.761966 Jarrard Richard D jarrard@mines.utah.edu Broglia Christina chris@ldeo.columbia.edu 1991 Geophysical properties of oceanic crust at Sites 768 and 770 book chapter In: Silver, EA; Rangin, C; von Breymann, MT; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program) 124 https://doi.org/10.2973/odp.proc.sr.124.125.1991 75-90 Velocity, density, resistivity, and neutron-porosity logs were recorded in virtually the entire 222-m-thick section of basaltic back-arc crust drilled at Site 768 and through the 106-m section of MORB crust at Site 770. Our analysis of these logs and comparison with measurements on discrete cores permit determination of interlog relationships and evaluation of the reliability of each log. Crustal porosity (Phi) at the two sites is most accurately determinable from transit time (Delta t) and the inverse of velocity: Phi = 0.0054*Delta t - 0.259. Porosity is also closely related to resistivity (Ro), according to the Archie equation: Ro = (Rwas**-m where Rw is resistivity of the formation fluid, and a and m are empirically determined "constants." Both logs and cores indicate that a and m range from 2 to 6.5 and 1.2 to 1.6, respectively. Density values estimated from sonic porosity are broadly similar to, but more reliable than, density logs. Neutron-porosity logs yield values 10%-20% higher than actual porosities; this error is caused primarily by lack of proper tool eccentralization and secondarily by the presence of hydrous alteration minerals in the rocks. These in-situ geophysical properties of oceanic crust 18 Ma and 42 Ma help to bridge the in-situ measurement gap between 6 Ma and 110 Ma at other sites. Observed velocities, densities, and porosities are generally similar to predictions from crustal aging models. We infer that this correspondence is largely coincidental; observed properties here are related more to style of volcanism than to crustal aging, and crustal heterogeneity is so high that a 100-200-m-interval is not representative of larger scale geophysical properties. 121.2198 123.6684 5.1448 8.0 122.4441 6.5724 1988-12-01T14:30:00 1988-12-30T18:00:00 425.7 1259.16 not specified ODP Ocean Drilling Program https://www-odp.tamu.edu:443/ Ocean Drilling Program, Texas A&M University ODP http://www-odp.tamu.edu/ https://ror.org/01f5ytq51 124-768C 8.0 121.2198 Sulu Sea -4396.0 1988-12-01T14:30:00 1988-12-13T07:00:00 Leg124 Leg124 1988-11-01T00:00:00 1988-11-01 1989-01-04T00:00:00 1989-01-04 Joides Resolution https://www-odp.tamu.edu:443/resolutn.html Rangin, Claude Rangin, Claude Silver, Eli A Silver, Eli A Harding, Barry W Harding, Barry W Storms, Michael A Storms, Michael A doi:10.2973/odp.proc.ir.124.1990 Joides Resolution https://www-odp.tamu.edu:443/resolutn.html Drilling/drill rig DRILL 1268.5 m 525.69 m 100 cores; 915 m cored; 0 m drilled; 57.5 % recovery 124-770C 5.1448 123.6684 Mindanao Sea -4516.0 1988-12-24T08:00:00 1988-12-30T18:00:00 Leg124 Leg124 1988-11-01T00:00:00 1988-11-01 1989-01-04T00:00:00 1989-01-04 Joides Resolution https://www-odp.tamu.edu:443/resolutn.html Rangin, Claude Rangin, Claude Silver, Eli A Silver, Eli A Harding, Barry W Harding, Barry W Storms, Michael A Storms, Michael A doi:10.2973/odp.proc.ir.124.1990 Joides Resolution https://www-odp.tamu.edu:443/resolutn.html Drilling/drill rig DRILL 529.5 m 54.81 m 12 cores; 115.8 m cored; 0 m drilled; 47.3 % recovery 263 CC-BY-3.0 Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/ Sediment depth is given in mbsf. In the publication depth for Hole 124-770C is given in mbsf, but shows too high values, which seems to be the water depth (4516 m) and the sediment depth. So the water depth was subtracted. Hole 124-768C is not effected by this. Event label Event Event Sample code/label Sample label DSDP/ODP/IODP sample designation hdl:10013/epic.27914.d001 Jarrard Richard D jarrard@mines.utah.edu Sample label DEPTH, sediment/rock Depth sed m depth http://purl.obolibrary.org/obo/PATO_0001595 sediment http://purl.obolibrary.org/obo/ENVO_00002007 rock Length L http://dbpedia.org/resource/Length Depth sed [m] Density, wet bulk WBD g/cm**3 Density http://dbpedia.org/resource/Density Jarrard Richard D jarrard@mines.utah.edu WBD [g/cm**3] Density, grain Density grain g/cm**3 Density http://dbpedia.org/resource/Density Jarrard Richard D jarrard@mines.utah.edu Density grain [g/cm**3] Porosity Poros % vol http://en.wikipedia.org/wiki/Porosity porosity http://purl.obolibrary.org/obo/PATO_0000973 Jarrard Richard D jarrard@mines.utah.edu Poros [% vol] Velocity, compressional wave Vp m/s Velocity http://dbpedia.org/resource/Velocity Linear Velocity http://dbpedia.org/resource/Velocity Jarrard Richard D jarrard@mines.utah.edu Vp [m/s] supplement citable author10034 author20316 basis5 campaign3393486 campaign96 event13584 event13590 geocode1 geocode1599 geocode1600 geocode1601 geocode8128 inst34 license101 method10974 method5059 param23 param24 param26 param31 param790 pi10034 project3 ref34489 term1073131 term1073159 term21465 term29904 term38263 term41056 term43792 term43863 term43876 term43981 topotype1