NETGOLD - Lyndhurst, Tas, 1985 (P785), magnetic line data, AWAGS levelled

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. These line dataset from the NETGOLD - Lyndhurst, Tas, 1985 survey were acquired in 1987 by the TAS Government, and consisted of 1545 line-kilometres of data at 125m line spacing and 60m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.

总磁强度（Total Magnetic Intensity, TMI）数据用于表征由地壳中成岩矿物成分差异所引发的地球磁场强度变化。磁异常可分为正异常（磁场强度高于正常值）与负异常（磁场强度低于正常值），具体类型取决于岩石的磁化率。该数据集通过标准流程进行预处理，以确保所记录的响应仅源自地下岩石。经处理后得到的数据集可通过解译揭示地下地质构造。经处理的数据由GA的地球物理学家进行质量核验，以确保GA发布的最终数据符合使用要求。本次提供的测线数据集源自1985年开展的NETGOLD——塔斯马尼亚州林德赫斯特（Lyndhurst, Tas）勘测项目，由塔斯马尼亚州政府于1987年完成采集，总测线长度达1545测线公里，测线间距为125米，飞行离地高度为60米。为约束数据中的长波长分量，项目采用独立数据集——全澳航空地球物理调查（Australia-wide Airborne Geophysical Survey, AWAGS）航空磁测数据——对本次勘测数据的基准面进行校正。本次勘测数据已基本基于AWAGS数据集完成平差处理。