The objective of this paper is to outline the advantages of using a gradiometer over a marine magnetometer for surveying the seafloor. Marine surveys conducted with a gradiometer will minimize external interference in the field allowing the interpreter to provide quick results with confidence.

Many survey companies operating in the oil and gas industry rely heavily on a single magnetometer, which if not utilized properly can create multiple problems for archaeologists. Magnetic data with outside interference, bottom strikes, or collected during geomagnetic storms will creates data artifacts that look like real magnetic anomalies. Several shallow water surveys from 2015 are provided as examples of poorly collected data, which show how the data can inhibit an archaeologists' recommendations to operators. Operators that are required to use marine magnetometers will see the value in using gradiometers over single marine magnetometer, especially in surveys that may potentially identify shipwrecks or in areas with the potential for unexploded ordinance (UXO).

Poorly collected magnetometer data can increase interpretation costs and may require the area to be resurveyed there by delaying future projects. The adoption of the gradiometer over the magnetometer is recommended across the board for all operators. With the broad adoption of the gradiometer, archaeologists can provide better recommendations for future exploration and development to the oil and gas industry, which can prevent damage to cultural material, subsea structures, UXO and allow for a better collaboration with BOEM and BSEE.

Even though gradiometers have been in use for marine surveys for over 60 years (Wow, Cooper 1989), they are rarely used for marine surveys, especially in the well developed areas. This paper will show the results of poorly collected magnetometer data to demonstrate the need to adopt the gradiometer as the standard for marine magnetic surveys.

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