Lu-Hf Residence Time Grid (igneous)

This is an interpolated grid of Lu-Hf residence time estimates, based on (primarily zircon) Lu-Hf isotopic analyses from igneous rocks. The data provides an estimate of the duration for material residing in the crust prior to its last melting event. The point data used for the interpolation is the median magmatic residence time data from the summary Lu-Hf dataset held in the Isotopic Atlas as of February 2021. Point data added to the Isotopic Atlas after February 2021 is not represented in this grid. The grid was generated with Esri's ArcMap Spatial Analyst interpolation tool using the Natural Neighbor algorithm and 0.01 degree cell size. Two classifications are provided for this grid; a Jenks natural breaks classification with ten classes (classification 1) as per Champion (2013) http://pid.geoscience.gov.au/dataset/ga/77772, and; the same seven-class interval binning and colour scheme applied to the source point data in the Lu-Hf Isotopes - Summary Data layer (classification 2).

本数据集为镥-铪（Lu-Hf）停留时间估算值的插值网格，其构建基础为火成岩中（主要为锆石）的Lu-Hf同位素分析数据。该数据可用于估算物质在末次熔融事件发生前，在地壳中的滞留时长。用于插值的点数据，为2021年2月收录于《同位素图集》（Isotopic Atlas）的汇总Lu-Hf数据集中的岩浆停留时间中位数。2021年2月之后新增至《同位素图集》的点数据，未被纳入本插值网格。本网格由Esri公司的ArcMap Spatial Analyst空间分析工具，采用自然邻域算法生成，像元大小为0.01度。本网格提供两种分类方案：其一为遵循Champion（2013）提出的詹克斯自然断点分类法设置的10级分类（分类方案1），对应链接为http://pid.geoscience.gov.au/dataset/ga/77772；其二为与“镥-铪同位素——汇总数据图层”中源点数据一致的七级区间分箱及配色方案（分类方案2）。