Map showing lava flows in the northeast part of the Phaethontis Quadrangle of Mars

The Systematic mapping of lava flow units in the Tharsis region has been compiled into a series of 16 maps at 1:2,000,000 scale. This work provides information on the sources and areal extent of the lava flows, on their eruptive sequences and relative ages, and on relations between the flows and geologic structure in the largest, most active tectonic and volcanic province on Mars. Some of the maps were made from controlled Viking photomosaics published as quarter quadrangles in the Atlas of Mars Topographic Series (U.S. Geological Survey, 1979) and tied to the Viking control net. Where these photomosaics were not available, larger scale catalog photomosaics tied to the Mariner 9 control net were used. These maps were subsequently reduced to the 1:2,000,000 scale, but slight discrepancies may occur in places between features referred to coordinates on the two types of bases.

针对塔尔西斯（Tharsis）区域的熔岩流单元开展的系统制图工作，已被整理为16幅1:200万比例尺的系列地图。本数据集涵盖了该区域熔岩流的喷发源、平面分布范围、喷发序列与相对年代，以及火星这一规模最大、活动最为活跃的构造与火山省内，熔岩流与地质构造之间的相互关联等信息。其中部分地图由美国地质调查局（U.S. Geological Survey）1979年出版的《火星地形图集》中，以四分之一四边形图幅（quarter quadrangles）形式发布的经控制点校正的维京号（Viking）摄影镶嵌图制作而成，并匹配至维京号控制网。在无此类摄影镶嵌图可用的区域，则采用了匹配至水手9号（Mariner 9）控制网的大比例尺目录摄影镶嵌图。后续这些地图均被缩制至1:200万比例尺，但在基于两种基准坐标系的地物坐标之间，部分区域可能存在细微偏差。