During the SCREECH experiment, coincident MCS reflection, wide-angle seismic reflection/refraction, magnetic, gravity, and multibeam bathymetric data were collected along three primary transects across the Newfoundland margin. Each transect reached from unambiguous continental crust seaward past a magnetic anomaly identified by Srivastava et al. (2000) as M3, and thus onto presumed oceanic crust (Fig. F1). MCS data were also collected on lines parallel and perpendicular to all transects, particularly around line 2MCS.
MCS data were acquired using the 480-channel, 6-km streamer of the Maurice Ewing. The MCS data have a sampling interval of 4 ms, a shot-spacing of 50 m, a fold of 60, a recording length of ~16 s, and a common midpoint (CMP) spacing of 6.25 m. The tuned 8540-in3 air gun array of the Maurice Ewing provided the seismic source. A CMP navigation map for SCREECH transect 2 MCS lines can be found in the "Supplementary Material" contents list.
Wide-angle data along transects 1, 2, and 3 were recorded on 29 OBS/Hs from Dalhousie University, the Geological Survey of Canada, and Woods Hole Oceanographic Institution, and they were deployed and recovered from the Oceanus. Twenty-seven of these instruments were deployed along SCREECH transect 2; the locations of instruments on the seaward portion of SCREECH transect 2 are shown on the CMP track map (see the "Supplementary Material" contents list). The wide-angle data have a shot spacing of 200 m and a sampling interval of ~10 ms.
Magnetic data were acquired throughout the SCREECH survey using a towed Geometrics G-886 marine magnetometer. Gravity data were also collected along each line using a BELL BGM-3 gravimeter with gyro-stabilizing platform.
Data acquired along SCREECH line 2MCS and the attending gridlines, hereafter called the SCREECH transect 2 survey, are the subject of this chapter (Figs. F1, F2). Line 2MCS begins at the edge of the eastern Grand Banks and then passes southeast over Flemish Pass, Beothuk Knoll, and transitional crust in the Newfoundland Basin. It ends ~60 km seaward of magnetic Anomaly M0, which is widely recognized as one of the oldest unambiguous seafloor-spreading anomalies in the basin (Tucholke et al., 1989). Line 2MCS crosses both Sites 1276 and 1277.