Upwarping sentence example
- These were followed by a period of minor tilting and faulting in early Mesozoic, by a moderate upwarping in Tertiary, and by a moderate uplift in post-Tertiary time.
- The crystalline belt of the middle Appalachians, 60 or 80 m- wide, is to-day of moderate height because the Tertiary upwarping was there of moderate amotint.
- Thus interpreted, the Appalachian forms of to-day may be ascribed to three cycles of erosion: a nearly complete Mesozoic cycle, in which most of the previously folded and faulted mountain masses were reduced in Cretaceous time to a peneplain or lowland of small relief, surmounted, however, in the north-east and in the south-west by monadnocks of the most resistant rocks, standing singly or in groups; an incomplete Tertiary cycle, initiated by the moderate Tertiary upwarping of the Mesozoic peneplain, and of sufficient length to develop mature valleys in the more resistant rocks of the crystalline belt or in the horizontal strata of the plateau, and to develop late mature or old valleys in the weaker rocks of the stratified belt, where the harder strata were left standing up in ridges; and a brief post-Tertiary cycle, initiated by an uplift of moderate amount and in progress long enough only to erode narrow and relatively immature valleys.
- The more resistant rocks, even though dissected by Tertiary erosion, retain in their summit tiplands an indication of the widespread peneplain of Cretaceous tinie, now standing at the altitude given to it by the Tertiary upwarping and post-Tertiary uplift; and the most resistant rocks surmount the Cretaceous peneplain as unconsumed monadnocks of the Mesozoic cycle.