GSWA Perth Basin North Thorium Grid Geodetic

The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected 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.This radiometric thorium grid has a cell size of 0.00083 degrees (approximately 87m) and shows thorium element concentration of the Perth Basin North, WA, 2011 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2011 by the WA Government, and consisted of 93199 line-kilometres of data at 400m line spacing and 60m terrain clearance.

放射性测量法（radiometric method），亦称伽马能谱法（gamma-ray spectrometric method），通过探测地球表面附近的伽马射线自然变化量，表征钾（K）、铀（U）及钍（Th）的天然放射性衰变所产生的辐射信号。所采集的数据将通过标准化流程开展预处理，以确保记录的辐射响应仅源于地下岩石。经处理得到的数据集可通过解译，揭示地下地质构造。经处理的数据将由GA地球物理学家开展质量核查，以确保GA发布的最终数据符合使用要求。
本次发布的放射性钍网格数据像元大小为0.00083度（约87米），呈现了2011年西澳大利亚州（Western Australia，简称WA）北部珀斯盆地的钍元素浓度，单位为百万分率（parts per million，简称ppm）。该网格数据所用的原始数据集由西澳大利亚州政府于2011年采集完毕，总测线长度达93199线公里，测线间距为400米，飞行离地高度为60米。