GSWA Widgiemooltha 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 0.00021 degrees (approximately 21m) and shows thorium element concentration of the Widgiemooltha North, WA, 2013 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2013 by the WA Government, and consisted of 92768 line-kilometres of data at 100m line spacing and 50m terrain clearance.

放射性测量法（radiometric method），亦称伽马射线能谱法（gamma-ray spectrometric method），通过采集地表附近的伽马射线自然变化数据，反演钾（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进行处理，以确保记录到的辐射响应仅源于地下岩石的辐射作用。经处理得到的数据集可通过地质解译，揭示地下地质构造特征。经处理的数据将由GA地球物理学家开展质量核验，以确保GA发布的最终数据满足使用需求。

本放射性钍元素网格的单元尺寸为0.00021度（约21米），展示了2013年西澳大利亚州（WA）威吉穆尔塔北部区域的钍元素浓度分布，浓度单位为百万分率（parts per million，简称ppm）。本网格所用数据由西澳大利亚州政府于2013年采集，数据总量达92768测线公里，测线间距为100米，采集时的地形离地高度为50米。