Subkilometer Martian volcanoes: Properties and possible terrestrial analogs

Kilometer to subkilometer cones with large central craters are the most numerous volcanic structures in the northern plains of Mars. Based on examination of more than 12,000 high resolution Viking orbiter images, most of these very small cones are located in parts of Eastern Acidalia and Utopia‐Isidis‐Elysium Planitia. Measurements of base and pit diameter for some 2000 well‐resolved features show small variations in the histogram of base diameters between and within regions but remarkable similarity in the distribution of crater/cone diameter ratios. This suggests that the small cones had a similar origin with only minor variations in local conditions. The Acidalia cones are generally larger, more widely distributed, and occur on a greater variety of terrains than those in Utopia‐Isidis‐Elysium. Based on morphology, distribution, and the crater/cone ratio histograms, the smallest Martian cones may be similar to Icelandic pseudocraters. Somewhat larger, steeper cones with smaller crater/cone ratios which also occur in Eastern Acidalia may be analogs of terrestrial cinder cones.