DOI: 10.5285/74df4192-7c80-4ffa-b890-4b344cfc1bef
title: High resolution aeromagnetic line data in the Ross Sea Rift collected for the ANDRILL pre-site survey (2008-09 season)

description: A high resolution survey was flown opportunistically by BAS at the end of the AGAP aerogeophysical campaign during the 2008-09 Antarctic field season with NSF support from McMurdo. The main purpose was to collect data on the ice shelf for a radar pre-site survey for a major planned international ANDRILL drilling campaign at Coulman High. Due to lack of appropriate funding levels from several countries this ANDRILL drilling project has been postponed (https://www.icdp-online.org/projects/world/antarctica/coulman-high/) but the site remains nevertheless a potentially interesting target for future geoscience studies. The Coulman High project aimed to explore the range of paleo-environments, ecosystems and tectonic events that affected the Ross Sea region as it transitioned from the warm, high-CO2 Greenhouse world typical of the Eocene into the lower-CO2 and highly variable Icehouse conditions of the Oligocene and early Miocene. The aeromagnetic data released here can be used together with more extensive pre-existing international datasets to help study rift-related magmatism, faulting and sedimentary basins in the region.
description: The ANDRILL aeromagnetic dataset includes all channels from raw through to levelled and microlevelled products. This survey forms part of the ANDRILL-UK Coulman high project investigation. Information about this project can be found at http://www.andrill.org/static/CH_Science.html. Channel naming follows SCAR/ADMAP2 data release protocols. Key data processing steps are described below, and a definition of all channels is in the table. Note in the database split by line the sections are defined as follows L= main survey grid lines, T=main survey tie lines. Magnetic data channels and processing flow: MagR- Raw magnetic total field intensity data (nT). TCorr-Corrections applied for tip tank events. MagR_TCorr- MagR corrected for tip tank events. RefField- Geomagnetic reference field value for which the magnetic data has been compensated. IGRF model 2005 as implemented in Geosoft (nT). MagRT- Raw magnetic value adjusted for Tip tank events and geomagnetic reference field values. MagRT= MagR_TCorr- RefField. BCorr- Low pass filtered (60 minute) magnetic base station correction. MagBRT- calculated as MagBRT= MagRT- Bcorr. MagF- Final mag value before levelling. No additional corrections applied so MagF=MagBRT MagL- Statistically levelled mag data. MagML- Microlevelled magnetic data following technique of (Ferraccioli et al., 1998). Basic channel description: Line name Line Number Flight ID Sequential flight number x x projected meters* y y projected meters* Lon Longitude WGS 1984, Lat Latitude WGS 1984, Height_WGS1984 Aircraft altitude (meters) in WGS 1984, Date Date of flight in time format e.g. 2006/01/08 Time Time (UTC) of flight e.g. 23:52:42.0 *Projected coordinates (x and y) are in Lambert conic conformal with two standard parallels defined as follows: Latitude of false origin: -74.018118 Longitude of false origin: 179 Latitude of 1st standard parallel -72.66666666667 Latitude of 2nd standard parallel -75.33333333333 False easting 1444000 False northing 1123000 Positioning for the ANDRILL HRAM survey uses kinematic differential GPS.