The Werner Airy Basin and Hints of Highlands Volcanism
Introduction: The earliest history of the Moon is concealed or destroyed by subsequent impact cratering and volcanism. The oldest structures detectable are basins, some of which have little topographic or structural signature. In this note I reinvestigate one of the potentially oldest basins, providing evidence that it exists and contains non mare volcanism. Werner Airy Basin: In 1963 Ralph Baldwin [1, p 194] described what he called the prize discovery. This was a giant circular area west of the Altai Scarp of the Nectaris Basin, indicated by the white dashes on the image mosaic (Fig. 1) Later, Don Wilhelms [2] accepted this as a doubtful ancient impact basin that he named Werner Airy after two craters along the most convincing part of the possible basin rim. Baldwin stated that the large feature was defined by a low rim, but the circle seems to be based more on the nature of the material within it rather than elevated rim segments. Nearly all space within is covered by light plains materials, both inside craters and between them, whereas the area west and north of the putative rim has more heavily textured terrain between craters. The Clementine topographic map does onot indicate any depression here, in fact, the eastern edge of the proposed basin is one of the highest areas on the nearside.