Venus: Timing and rates of geologic activity

Abstract

We employ the accumulation of the impact-crater population as a geochronometer to examine the observable record of the history of Venus (<1 b.y), analyzing age relationships between craters and the different geologic units. We show that the earlier suite of units (from heavily deformed tesserae through slightly deformed regional plains) occurred during a time period an order of magnitude shorter than the subsequent period (from the end of emplacement of the wrinkle-ridge network until the present). These results imply high global rates of endogenic (volcanic) activity during the first era (comparable to that of mid-oceanic-ridge volcanism of Earth) and much lower global rates of endogenic activity (by two orders of magnitude) for the second period.