Geoscience Reference
In-Depth Information
Figure 10.14.
(a) The
accretion of the terranes
that make up the
Himalayas. CS, Chilien
suture; KS, Kokoxili
suture; BNS,
Banggong-Nujiang
suture; ITS,
Indus-Tsangpo (or
Yarlung-Zangpo) suture;
MCT, main central thrust;
MBT, main boundary
thrust (or fault). The
tectonic blocks are ASI,
Asian plate; KUN, Kunlun
block; QIA, Qiangtang
block; LHA, Lhasa block;
and IND, Indian plate.
(b) A reconstruction of
Tibet and the Himalayas
at 20-Ma intervals from
140 Ma to the present. The
Qiangtang block is
assumed to have sutured
to Asia at about 200 Ma.
140-120 Ma: the small
ocean basin between Asia
and the Lhasa block
closes. 100 Ma: the Lhasa
block is sutured to Asia
along the BNS. 80-60 Ma:
subduction takes place
beneath the Lhasa
continental margin
(including the possible
subduction of a volcanic
arc). 40 Ma: subduction
ceases. Continental
obduction or shortening
occurs as the Indian and
Asian plates collide.
20 Ma: MCT is the main
thrust. Present: MBT is the
main thrust. Note that the
deep geometry of the
bounding sutures
between the terranes is
purely schematic - details
are shown in other figures
in this section. (From
All egre
et al
.(1984).)
(a)
KUN
ASI
OIA
LHA
IND
