Flexing of the Indi
an lithosphere due to the continent&nd
ash;continent collision
and thrust fold lo
ading produced the G
angetic Forel
and B
asin during the Middle Miocene. The b
asin
att
ained its present configur
ation during the L
ate Qu
atern
ary. Neotectonics
and clim
ate ch
ange since the l
ast intergl
aci
al influenced the evolution of the present l
andsc
ape of the G
angetic (G
ang
a) pl
ains. The region
al geomorphic surf
aces in these pl
ains
are: (1) Upl
and Interfluve Surf
ace (T
2); (2) M
argin
al Pl
ain Upl
and Surf
ace (MP); (3) Meg
af
an Surf
ace (MF); (4) Piedmont F
an Surf
ace (PF); (5) River V
alley Terr
ace Surf
ace (T
1); (6) Active Flood Pl
ain Surf
ace (T
0). Minor geomorphic fe
atures comprise ponds,
alluvi
al ridges,
and sm
all ch
annels, which occur on the Upl
and Interfluve Surf
aces. The present contribution reviews geomorphic processes th
at sculpted the b
asin l
andsc
ape
and, then, using the blue green-stimul
ated luminescence (BGSL)
and infr
ared-stimul
ated luminescence (IRSL)
ages provides
a first order chronologic
al fr
amewor
k for the rel
ationship of m
ajor
and minor geomorphic fe
atures to clim
ate
and tectonics. Luminescence d
ating of the Upl
and Interfluve Surf
ace (T
2) shows th
at form
ation of this surf
ace st
arted before 51
ka and continued
at le
ast up to 7
ka. Deposition in the M
argin
al Pl
ain (MP) beg
an
at le
ast
at 76
ka and continued
after 32
ka br
ac
keting the evidence of
a more humid clim
ate during 50&nd
ash;40
ka. Sediment
ation on the T
2 and MP surf
aces w
as synchronous. The top of these surf
aces gives v
ari
able
ages r
anging from 48 to 7
ka, due to differenti
al erosion of
an undul
atory topogr
aphy c
aused by tectonic
activity. Age upper bound for the initi
ation
and termin
ation of the fin
al building ph
ase of G
ang
a Meg
af
an c
an be pl
aced
at
![]()
align=center border=0 SRC=/im
ages/glyphs/BQ1.GIF>26
ka and
![]()
align=center border=0 SRC=/im
ages/glyphs/BQ1.GIF>22
ka respectively. Deposition on Piedmont F
an Surf
ace continued between 8
and 3
ka. The River V
alley Terr
ace Surf
ace (T
1) of G
ang
a River shows the
activity of Y
azoo type ch
annels during 3&nd
ash;1.1
ka. The l
ast ph
ase of
active
accretion on the n
arrow, poorly developed youngest Active Flood Pl
ain Surf
ace (T
0) w
as
after 1.5
ka. The ponds of T
2 surf
ace formed due to cess
ation of fluvi
al
activity sometime during 8&nd
ash;6
ka. A prominent tectonic
activity
at 7&nd
ash;5
ka and dry clim
ate
at 5
ka produced undul
atory topogr
aphy
and high silt
ation r
ates in the l
akes
and ponds. The peripher
al bulge, southern G
ang
a Pl
ain h
as been tectonic
ally
active c
ausing deep incision of rivers
and
a 40-
ka seismic event,
and Mid&nd
ash;L
ate Holocene tectonic
activity c
an be inferred.