g. pointbar deposits, deserted channels, and abandoned oxbow lakes), (2) and floodplain cover deposits, formed by vertical accretion of fine sediments in slow-moving floodwaters of the

basins. Cover deposits are widespread along the flanking zone from Jacobabad to Manchar Lake, in the southeast around Mirpur Khas and Umarkot, and in the delta (Holmes, GW3965 in vitro 1968). The historical Indus River sent off distributaries and small seasonal spillway channels toward its flanks and across the delta. Such smaller-scale channels are characterized by levees rather than by river bars and meander scrolls. Levees of the Ghar and Western Nara (Fig. 1) are ∼3 m high due to periodic overspill of their selleck compound banks and define these 3 km-wide paleochannels. Narrower channels and shorter wavelength meanders define former courses of the

Indus: the Khairpur at between 4 km and 8 km; Shahdapur at 5 km; and the Warah at 6 km (Fig. 1). The modern Indus is wider with larger but fewer meanders (∼14 km wavelength). Sinuosity of the paleo-Indus channels (Fig. 1 and Fig. 2) had a range from: (1) Badahri: 1.51, (2) Warah: 1.55, (3) Kandhkot: 1.65; (4) Puran: 1.81, (5) Shahdadkot: 1.99, (6) Eastern Nara: 2.05, (7) Khairpur: 2.33, and (8) Shahdadpur: 2.51. The modern Indus has sinuosity values ranging from 1.1 to 2.0 with a mean value of 1.8 (see discussion below). Paleochannels therefore had similar or sometimes greater sinuosity. The visible record of paleochannels represents only the last ∼1000 years. The remotely sensed topography of Fig. 2 perhaps captures some of the longer record of river avulsion and floodplain development and demonstrates how the floodplain aggrades through major avulsions of the trunk Indus. The large channel belt switches leaving behind 1–3 m of super-elevated channel belt deposits that shed crevasse-splay fingers

and fans interweaving with cover deposits to their sides (Fig. 2, Fig. 3, Fig. 4 and Fig. 5). An interesting feature of the imaged floodplain topography is its fan-like appearance (Fig. 2 and Fig. 5). When viewed along valley profiles (Fig. 3), these fan-like waves have a first order wavelength of 29 km, upon which is superimposed a second Arachidonate 15-lipoxygenase order set of waveforms with wavelength of ∼3.6 km. We suggest that the first order waveform reflect the avulsion frequency of the main Indus River (on the order of several centuries). Major avulsions shift the loci of floodplain deposition suddenly, leaving behind these first-order super-elevated fan lobes (see Fig. 2B). Whereas the second-order scale features perhaps relate to decadal occurrence of floods that build up intermingled crevasse deposits around the larger paleochannel features (Fig. 5). The width and depth of the modern Indus and other paleochannels are well demonstrated in both strike sections (Fig. 4) and plan view (Fig. 5).