Payún Matrú is a shield volcano whose foot coincides with the elevation contour and which extends mainly east-west; rising about above the surrounding terrain it covers about of land with lava and has diverse landforms. Ignimbrites cover and flatten its northern and eastern slopes, while in the west and south lava domes and coulées predominate; these have often rough surfaces and are difficult to traverse. The lower slopes are more gentle and covered by Pleistocene-Holocene lava flows. Wind erosion has created flutes, grooves and yardangs within the ignimbrites, such as in the western sector where yardangs reach heights of and widths of . The total volume of this shield is about .