—The mid-Tertiary-age volcanoes, dikes, and sills of the Navajo volcanic field are classic and geologically-distinctive landforms of the Colorado Plateau. They are the products of structurally-controlled magma ascent, explosive eruptions, and deep post-eruptive exhumation. Igneous rock types include potassic lamprophyres, serpentinized tuffs, and exotic mafic and ultramafic intrusives. These ro...

[1] Many Hesperian outflow channels head at elevations compatible with aquifer recharge beneath the Martian south polar cap, and such channels are widely interpreted as the products of this recharge. Some outflow channels head at greater elevations that are inconsistent with southern recharge, including three systems located in Aurorae Planum and eastern Ophir Planum. These three systems have p...

We used a rapid assessment to survey American pika (Ochotona princeps) populations and documented 420 pika site occurrences in southwestern U.S.A. These included 329 sites from the Sierra Nevada (SN), California; 67 from six southwestern Great Basin (swGB) ranges, California and Nevada; 16 from three central Great Basin ranges, Nevada; and 8 from the central Oregon Cascades. Of these, 67% were ...

A controversy arises concerning relict, ubiquitous, depositional, solifluction, “string lobe” landforms in the Ridge and Valley province of Pennsylvania, reported by other investigators. distinguishment is made here defending an original interpretation particular which identified these as snowdune meltwater-eroded depressions formed within colluvium during cold phases Pleistocene Epoch. Hence, ...