Abstract This chapter reviews major advances in studies of long-term landform evolution in the last few decades of the twentieth century. These include in particular the development of the etchplanation concept, which evolved into a dynamic approach linking inheritance, environmental change and contemporary processes, realization of the importance of weathering mantles in deciphering landscape evolution over long timescales, recognition of varying ancient landforms, especially in the Southern Hemisphere, and insights into preglacial landscapes at high latitudes that survived successive glaciations.

From the mantle plume model it would be expected that one to a few kilometers of regional, domal lithospheric uplift occurred 5–20 m.y. before the onset of flood basalt volcanism. This uplift resulted from heat conduction out of and dynamic support by the hot, buoyant, rising plume head. Field evidence for such uplift would comprise sedimentary sequences that reflect progressive basin shallowing before volcanism or (in the case of differential uplift along faults) widespread conglomerates derived from the basement rocks and underlying the first lavas. Local uplifts and subsidences cannot be used to invoke or rule out plume-caused uplift. Over large areas of the Late Cretaceous Deccan flood basalt province, the base of the lava pile is in the subsurface. Basalt-basement contacts are observed along the periphery of the province and in central India (the Satpura and Vindhya ranges), where substantial post-Deccan uplift is evident. Here, extensive horizontal Deccan basalt flows directly overlie extensive low-relief planation surfaces cut on various older rocks (Archean through Mesozoic) with different internal structures. Locally, thin, patchy Late Cretaceous clays and limestones (the Lameta Formation) separate the basalts and basement, but some Lameta sediments are known to have been derived from already erupted Deccan basalt flows in nearby areas. Thus, the eruption and flowage of the earliest Deccan basalt lava flows onto extensive flat planation surfaces developed on varied bedrock, and the nearly total absence of basement-derived conglomerates at the base of the lava pile throughout the province, are evidence against prevolcanic lithospheric uplift (both regional and local), and thereby the plume head model. There has been major (∼1 km) post-Deccan, Neogene uplift of the Indian peninsula and the Sahyadri (Western Ghats) Range, which runs along the entire western Indian rifted margin, well beyond the Deccan basalt cover. This uplift has raised the regional Late Cretaceous lateritized surface developed on the Deccan lava pile to a high elevation. This uplift cannot reflect Deccan-related magmatic underplating, but is partly denudational, is aided by a compressive stress regime throughout India since the India-Asia collision, and is possibly also related to active eastward flow of the sublithospheric mantle. The easterly drainage of the Indian peninsula, speculated to be dome-flank drainage caused by the plume head, predates the uplift. Field evidence from the Deccan and India is in conflict with a model of plume-caused regional uplift a few million years before the onset of volcanism.

Abstract Welcome to the Appalachian landscape! Our field trip begins with a journey across Fall Zone (Fig. 1 ), named for the falls and rapids on streams flowing from the consolidated rocks of the Appalachians onto the unconsolidated sediments of the Coastal Plain. The eastern U.S. urban centers are aligned along the Fall Zone, the upstream limit of navigation. Typically, the rocks west of the Fall Zone are part of the Piedmont province. This province exposes the metamorphic core of the Appalachian Mountains exhumed by both tectonics and erosion. At least four major phases of deformation are preserved in Piedmont rocks, three Paleozoic convergent events that closed Iapetus, followed by Mesozoic extension that opened the Atlantic Ocean. A record of Cretaceous to Quaternary exhumation of the Appalachians is preserved as Coastal Plain sediments. Late Triassic and Jurassic erosion is preserved in the syn-extensional fault basins, such as the Newark basin, or is buried beneath Coastal Plain sediments (Fig. 1 ). The trip proceeds northwest across the Fall Zone and Piedmont and into the Newark basin. Late Triassic and Jurassic fluvial red sandstone, lacustrine gray shale, and black basalt were deposited in this basin. The Newark basin is separated from the Blue Ridge by a down to the east normal fault that locally has contemporary microseismicity. The Blue Ridge represents a great thrust sheet that was emplaced from the southeast during the Alleghenian orogeny (Permian). The summits of the Blue Ridge are commonly broad and accordant. Davis (1889) projected that accordance westward to the summits of the Ridge and Valley to define his highest and oldest peneplain—the Schooley peneplain. North and west of the Blue Ridge is the Great Valley Section of the Ridge and Valley Province (Fig. 1 ). Where we cross the Great Valley at Harrisburg, it is called the Cumberland and Lebanon valleys. This section is underlain by lower Paleozoic carbonate, shale, and slate folded and faulted during the lower Paleozoic Taconic orogeny. The prominent ridge on the west flank of the Great Valley is Blue or Kittatinny Ridge. It is the first ridge of the Ridge and Valley Province; the folded and faulted sedimentary rocks of the Appalachian foreland basin, deformed during the Alleghenian orogeny. Drainage during most of the Paleozoic was to the northwest, bringing detritus into the Appalachian foreland basin. The drainage reversed with the opening of the Atlantic Ocean and southeast-flowing streams established courses transverse to the strike of resistant rocks, like the Silurian Tuscarora Sandstone holding up Blue Mountain. West and north of the Ridge and Valley is the Allegheny Plateau, that part of the Appalachian foreland that was only gently deformed during Alleghenian shortening. Our trip will traverse that part of the plateau called the Pocono Plateau which is underlain by Devonian to Penn-sylvanian sandstone. At the conclusion of our trip, we will reverse our transverse of the Appalachians by traveling from the Pocono Plateau to the Ridge and Valley, to the Great Valley, to the Newark Basin, to the Piedmont, and then to one of the great Fall Zone cities—Philadelphia—via the Lehigh and Schuylkill rivers.