Standard Wireline Sonic Waveform Data (Phase 1)
IODP-USIO logging contractor: LDEO-BRG
Hole: U1309D (Phase 1)
Expedition: 304
Location: Atlantis Massif-Mid-Atlantic Ridge (central N Atlantic)
Latitude: 30° 10.120' N
Longitude: 42° 7.113' W
Logging date: January 2, 2005
Sea floor depth (driller's): 1656 mbrf
Total penetration: 401.3 mbsf
Total core recovered: 257 m (64 % of cored section)
Oldest sediment cored: none
Lithologies: Basalt, diabase, gabbro, oxide gabbro, peridotite, troctolite
TOOL USED: DSI (Dipole Sonic Imager)
Recording mode: Monopole P&S, Lower Dipole, and Stoneley (both passes).
Remarks about the recording: none.
MONOPOLE P&S MODE: measures compressional and hard-rock shear slowness. The monopole transmitter is excited by a high-frequency pulse, which reproduces conditions similar to previous sonic tools.
LOWER DIPOLE MODE: measures shear wave slowness using firings of the lower dipole transmitter.
STONELEY MODE: measures low-frequency Stoneley wave slowness. The monopole transmitter, driven by a low-frequency pulse, generates the Stoneley wave.
Acoustic data are recorded in DLIS format. Each of the eight waveforms generally consists of 512 samples, each recorded every 10 (monopole P&S) and 40 microsec (all dipole modes), at depth intervals of 15.24 cm (6 inches). The original data in DLIS format is first loaded on a Sun system using GeoFrame software. The packed waveform data files are then converted into ASCII and finally binary format.
Each line is composed of the entire waveform set recorded at each depth, preceded by the depth value. In the general case of 8 receivers with 512 samples per waveform, this corresponds to 1 + 4x512 = 4097 columns. In this hole, the specifications of the files are:
Number of columns: 4097
Number of rows: 2337 (Pass 1)
Number of rows: 2372 (Pass 2)
The following files have been loaded (Phase 1):
DSI from FMS/DSI/GPIT/SGT (Pass 1, BHA at ~ 1710.5 mbrf)
304-U1309D-ph1_mono_p1.bin: 1700.7-2056.7 mbrf
304-U1309D-ph1-ldip_p1.bin: 1700.7-2056.7 mbrf
304-U1309D-ph1-st_p1.bin: 1700.7-2056.7 mbrf
DSI from FMS/DSI/GPIT/SGT (Pass 2, open hole)
304-U1309D-ph1_mono_p2.bin: 1695.4-2056.7 mbrf
304-U1309D-ph1_ldip_p2.bin: 1695.4-2056.7 mbrf
304-U1309D-ph1_st_p2.bin: 1695.4-2056.7 mbrf
The sonic waveform files are not depth shifted to a reference run or to the seafloor. For depth shift to the sea floor, please refer to the DEPTH SHIFT section in the standard log documentation file.