12.5 Backarc and Retroarc Basins
601
EVOLUTION OF BACKARC BASIN
STAGE 3
INACTIVE BACKARC B~SIN
PELAGIC
SEDIMENTS
STAGE 2
VOLCANICLASTIC
APRON
EPICLASTIC SED IMENT
STAGE 1
NEW INTRA·ARC/ BACKARC
BASIN
SPLITTING OF ARC ,
NEW SPREADING -CENTER
REMNANT ARC
YOUNG OCEANIC
SUBAERIAL~ (INACTIVE)
BACKARC"BASIN
OCEANIC ISLAND
ARC (ACTlVE)
~H~~
~
- ----- _ -: --1--l~-----Fig. 12.29. Sedimentation model for backare areas of
oeeanie island ares in three stages of evolution. 1
Splitting of island are by rifting, and initiation of
backare spreading into aetive are and remnant are;
high influx of volcaniclasties. 2 Basin widening by
In several regions of the Andes, intramontane troughs
deve10ped between the magmatie are and the baekare thrust
belt (cf. Seet. 12.7.2). Some of them eolleeted great thieknesses of voleanic1astie material, as for example the
Altiplano ofBolivia.
Backarc Basins on Oceanic Crust
These basins tend to beeome filled after shorter time
periods than larger oeean basins due to their limited
size, nearby clastie sediment sourees, and basin eloPYRQCLAST-IC FLOWS,
ASH FALLS AND
ASH TURBIDITES
eontinued backare spreading; deposition of thiek
volcanielasite apron at base of aetive are flank and
pelagie sediment farther away. 3 Backare spreading
eeases and renewed splitting of island are rnay initiate a new basin. (After Carey and Sigurdsson 1984)
sure. Some backare regions in the western and southwestern Paeifie display different stages of basin formation resulting from the splitting of an oeeanie are.
The simp!ified model in Figure 12.29 largely refleets
observations in the baekare region of the Mariana are
whieh is eharaeterized by several older remnant ares
and basins (Carey and Sigurdsson 1984; Fryer 1996).
The evolution of such a system shows the following
stages:
601
EVOLUTION OF BACKARC BASIN
STAGE 3
INACTIVE BACKARC B~SIN
PELAGIC
SEDIMENTS
STAGE 2
VOLCANICLASTIC
APRON
EPICLASTIC SED IMENT
STAGE 1
NEW INTRA·ARC/ BACKARC
BASIN
SPLITTING OF ARC ,
NEW SPREADING -CENTER
REMNANT ARC
YOUNG OCEANIC
SUBAERIAL~ (INACTIVE)
BACKARC"BASIN
OCEANIC ISLAND
ARC (ACTlVE)
~H~~
~
- ----- _ -: --1--l~-----Fig. 12.29. Sedimentation model for backare areas of
oeeanie island ares in three stages of evolution. 1
Splitting of island are by rifting, and initiation of
backare spreading into aetive are and remnant are;
high influx of volcaniclasties. 2 Basin widening by
In several regions of the Andes, intramontane troughs
deve10ped between the magmatie are and the baekare thrust
belt (cf. Seet. 12.7.2). Some of them eolleeted great thieknesses of voleanic1astie material, as for example the
Altiplano ofBolivia.
Backarc Basins on Oceanic Crust
These basins tend to beeome filled after shorter time
periods than larger oeean basins due to their limited
size, nearby clastie sediment sourees, and basin eloPYRQCLAST-IC FLOWS,
ASH FALLS AND
ASH TURBIDITES
eontinued backare spreading; deposition of thiek
volcanielasite apron at base of aetive are flank and
pelagie sediment farther away. 3 Backare spreading
eeases and renewed splitting of island are rnay initiate a new basin. (After Carey and Sigurdsson 1984)
sure. Some backare regions in the western and southwestern Paeifie display different stages of basin formation resulting from the splitting of an oeeanie are.
The simp!ified model in Figure 12.29 largely refleets
observations in the baekare region of the Mariana are
whieh is eharaeterized by several older remnant ares
and basins (Carey and Sigurdsson 1984; Fryer 1996).
The evolution of such a system shows the following
stages: