Landmark landform / geomorphic summary of an area Still the reigning best graphical models for a a region.

( adapted from Peterson, 1981; Fig. 1 )

( adapted from Peterson, 1981; Fig. 2 ) F - basin floor (LS) (= bolson floor) P - piedmont slope (LS)

( adapted from Peterson, 1981; Fig. 3 ) Basic Landform elements of Basin & Range terrain – southwestern US bolson, semi-bolson Landscape : A - alluvial fan B - ballenas F - alluvial flat M - mountains (LS) P - fan piedmeont (LS) S - fan skirt Y - playa

Generalized landscape model for bolsons in US Basin & Range.

A - alluvial fan V - interfan valley P - fan piedmont ( adapted from Peterson, 1981; Fig. 7 ) Drainageway Types. 1 - interfan - valley drainageway 2 - fanhead trench 3 - onfan drainageway 4 - interfan-valley drainageway ( with on-fan tributaries )

( adapted from Peterson, 1981; Fig. 4 ) F - fan remnant - eroded fan remnant sideslope I - inset fan

( adapted from Peterson, 1981; Fig. 6 ) B - ballena I - inset fan P - fan piedmont (LS)

LS: badlands LF: ballenas, ballons Badlands, SD Schoeneberger

a - ( relict surface remnants with young eroded sideslopes ) b - pediment ( footslope ) c - inset fan d - (inset-fan remnants) e - younger inset-fan surface ( adapted from Peterson, 1981; Fig. 8 ) Common, Progressive Sequence of : dissection, alluviation, redissection, realluviation Time:

( adapted from Peterson, 1981; Fig. 10 ) A - fan apron BF - basin floor P - fan piedmont

( adapted from Peterson, 1981; Fig 11 ) 1 - original fan surface 2 - first gullying sequence ( or its remnants of pediments, footslopes ) 3 - second gullying sequence ( or its remnants of pediments, footslopes ) 4 - third gullying sequence ( or its remnants of pediments, footslopes ) Landscape Evolution : Typical Erosion Sequences of Fan Piedmonts Generalized (Erosional) Evolution of Divides a – relict fan-piedmont surface (1) b - asymmetric, relict fan piedmont surface and new, encroaching pediments c - ridgeline remnants of pediments 2 & 3 d - late stage erosion of “c”

( adapted from Peterson, 1981; Fig. 12 ) BF - basin floor I - inset fan P - (dissected) fan piedmont S - fan skirt

( adapted from Peterson, 1981; Fig. 13 ) Landscape : semi-bolson B - ballenas F - (axial stream) flood plain I - inset fans M - mountains (LS) P - fan piedmont ( and eroded fan remnants ) S - fan skirts T - (axial) stream terrace

Hillslope Evolution : backwearing side slopes and pedimentation ( adapted from Peterson, 1981; Fig. 16 ) S = stable summit a = base level P = pediment ( = erosional surface ) ps = pedisediment Time: 0 stream

( adapted from Peterson, 1981; Fig. 15 ) Hillslope Evolution & Hillslope - Profile Positions: - 2 dimensional - backwearing slope convergence - divide lowering summit (divide) lowering begins

( adapted from Peterson, 1981; Fig. 17 ) c = crest m = summit b = backslope f = footslope t = toeslope x = drainageway Variations of hillslope-profile positions in southwestern US Landscapes 2 dimensional hillslope-profile positions vs. 3 dimensional geomorphic components I = interfluve C = crest S = side slope H = head slope N = nose slope B = base slope C S N B N S I