10.1594/PANGAEA.876354Fryer, Patricia BPatricia BFryerHussong, Donald MDonald MHussongPANGAEA1982Event labelIdentificationDEPTH, sediment/rockDepth, top/minDepth, bottom/maxPositionDeposit typeQuantity of depositSizeSubstrate typeSediment typeCommentDescriptionUniform resource locator/link to imageDredge, rockPiston corerVisual descriptionKK77Kana KeokiNOAA and MMS Marine Minerals Geochemical Database (NOAA-MMS)1977-04-02T00:00:00/1977-07-06T00:00:00Dataset10.2973/dsdp.proc.60.103.198210.7289/V52Z13FT10.7289/V53X84KN237 data pointstext/tab-separated-valuesCreative Commons Attribution 3.0 UnportedA detailed geophysical and geological survey of the Mariana Trough, an actively extensional back-arc basin, was conducted in 1976 and 1977 to provide data for selection of drilling sites for DSDP Leg 60. These surveys revealed large-scale bathymetric trends, sediment distribution, crustal seismic veolocity structure, and earthquake activity that suggest the basin is opening around an axial spreading center tectonically similar to the slowly spreading Mid-Atlantic Ridge. There are, however, significant differences in the character of the trough, such as poorly defined magnetic anomalies, extreme bathymetric relief, and the frequent occurrence of low-magnitude earthquakes but absence of larger seismic events. Seafloor spreading in the Mariana Trough may be characteristic of the initial opening stages of any oceanic rift system, whether or not it is in a back-arc setting.From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.141.866177.3471.75748.4025Pacific Oean