I.W.D. Dalziel 2007 The Ellsworth Mountains, first mapped under the leadership of Campbell Craddock, pose critical geological enigmas, solved and unsolved. The isolation of the mountains, their abrupt structural terminations and Paleozoic stratigraphic affinities are explained by rotation from the cratonic margin during Gondwanaland breakup. The mechanism remains obscure. The absence of intense folding associated with the Cambro-Ordovician Ross orogeny can be ascribed to local extension along a subducting margin. Yet tantalizing questions regarding possible Precambrian connections to Laurentia remain, and the cause of the post-Permian Gondwanide folding is controversial. The elevation (~5000m) is high for an early Mesozoic fold belt. Thermal uplift could have been initiated during Jurassic-Cretaceous block rotation and Weddell Sea opening and continued into the Cenozoic. The history of glaciation provides input for models of ice loading and unloading. Measurements of present-day uplift test these models and help assess change in the mass of the ice sheet and hence in global sea level. application/pdf 10.3133/ofr20071047SRP004 en U.S. Geological Survey The Ellsworth Mountains: critical and enduringly enigmatic reports