Page 49 - Sumatra Geology, Resources and Tectonic Evolution

36 CHAPTER 4

t0 9~o 918 ~ 1~)0 ~ 14 Ch.uping. 1~2 o ~ 1~)4 o 1~6 o 1~)8 o
o g~ Limestone
;,I['BAN DA ACEH _^~ .-,
l'~ ~Uneuen LHOKSUMAWE PENANGF,_)[~ ~ ~ l~l--l")l~,/llAIkl ,,.,.,-,,.,I -r'DIAOOIf "~
~. ~ L[nit(NF) .'O~.. ~)~.~ r~-nlvll~l,~ etuu/n~t-~oo~u
... " e ~ Ujeuen (Lst) .~k..~ i
Situtup(Lst) ~ 9 Formation (NF) (~rj~~176
Formation Sembuan {,st Peusan g an Grou p
(M P, M=LT) ~,Tawa~r st)~ Formation (N F)
Formation e Kaloi Formation(Lst)(P LT) 9 9
-4~ '~ ~'~ ~O LANGSA , r)~-" I~:....:....:iiii::l Tr,asslc chert & sandstone (Ch,CI)_
"k~" ~N~" Bat~umilmil(Lst) ~ Kodiang 1"~..~ Permian and Triassic
"N k ~ ~ ~Formation (MP, T) k,,Llmestone ~ llm,-,efnntae //e{~
"~ ~\ k~ ~ Kualu(Cl)Formation (M-L~ ~ - , .... ~,~,~,,~ ~L--,a,/
' Permian (Volc)volcanic units
~ , Pangururan ~\'h '~ - K~al~(Ch.Ssl
" ' o Bryo~nBed'~ ~.~Form~on~_LT~_ r ~ ~ Permian sedimentary units (CI)
_ 2 ~ v - ',~..~ \ ~ .......... ~.:.:.:....:.:.= 2 o_
~ \ ,~-%~ c-----. ~ , ~ (Ch= chert; CI= clastics)

~ [ Silungk.ang.(C~.~D\ Telukkido "~1~ KUNDUR "
t-ormat on (M~') . apan Formation
__Cubadak(Ci)~%Formahon (LT-J) ,~Lrp~ (M-LT) ,-
Format o6 9 LUBUK~IKAPING ] %~% LINGGA 0 ~
- 0 ~ o ~ (M-LTI " \ %Tuhur Formation(CI) j.f )\,~
,~ " '~, \ (M-LT) ~ .,/q~"~ ( M - LT)
s Silun g kan g (CI, Lst) Palepat(Volc). '~/
Formation (M~St)~,Palr~natlon (EP) - ~
PADANG ~ ,~\"~:.~,~. Barisan(CI)
(' \ Tuhur(CI)""~..'r Formation
~. ~ F~ ~B~inOMUAR.ABUNG~JAMBI~. ~BtmNGKA~sandstone
-,,..,_r ' ' ~ \ /~'%-. ~a~epa~(vo~c) - ) ~-:.:.:.:-:-.~ p u
_ 2 ~ ,.~ ~ N,.,aoltCl~']~Formati0n (EP) ~ C::~r---::::::::::~ (M-LT) 2 ~ _
~ ~ Pemali Group(Ch Ss)
I:,~ s ~ Mengkarang(cI) J,.u....~v'"~:---:.i~ (MP~ ~',,,, TnN
" ~,~ '~L ) Formation EP) -Ir ! ~ ' ........ MP)
(
~?
M LP ~,
"
"~ ~'~'~k Buklt . PALEMBANG "":. o 'O
'ALEMBAI~G %Q)
(LT-J) Late Triassic to Jurassic nendo~o(Lst) /)
(M-LT) Middle to Late Triassic BENGKULU'~'~ ~. (MP) )L
- 4~ (MP) Middle Permian ~ ~. { 4~
(EP) Early Permian ~.~
(NF) No age-diagnostic fossils found "-~~

~
_60o 100 6 20o 300 4oo OOOkm
98 ~ 100 ~ 102 ~

Fig. 4.10. Distribution of Permo-Triassic rocks in Sumatra.

fenestellids, echinoids, ?cephelapods and corals (Cameron et al. Kualu Formation (Figs 4.3 & 4.4). The Kualu Formation crops out
1982a). Fontaine & Vachard (1984) report a fauna collected as small isolated exposures among Toba Tufts to the south of
from the Batumilmil Limestone at Laubuluh, a village 13 km to Medan (Cameron et al. 1982a) (Fig. 4.3) and over a much larger
the north of Tigabinanda with crinoids, bryozoa, productid area to the NW of Rantauprapat and to the south of Lake Toba
bracbiopods and rare foraminifers Nodasaria(?), Pachiploia (Clarke et al. 1982a; Aldiss et al. 1983) (Fig. 4.4). Lithologies
cukurkoyi and Multidiscus padangensis. This fauna indicates a typical of the Kualu Formation have also been encountered in
Murghabian to Dzhulfian (mid-Late Permian) age for the oil company boreholes to the SE of Rantauprapat, below Tertiary
Batumilmil Formation (Fontaine & Gafoer 1989). Triassic cono- sediments, and have been described under the name of the 'Mutus
donts (Hindeodella triassica Muller) were found by Metcalfe Assemblage' (Eubank & Makki 1981). Similar rocks also occur in
(1986) in limestones of the Batumilmil Limestone Formation at the island of Kundur off the coast of east Sumatra where they are
Sungai Wampu (Fig 4.3). This form ranges throughout the Triassic. called the Papan Formation (Cameron et al. 1982c) (Fig. 4.10).
At the type locality in the Sungai Kualu, the lithologies are thin-
bedded sandstones, wackes, siltstones and mudstones. The
Pangururan Bryozoan Bed (Fig. 4.4). The Pangururan Bryozoan mudstones are often carbonaceous and contain wood and plant
Bed on Lake Toba has already been discussed in the review of fragments. The upper part of the succession is more arenaceous,
the Carboniferous formations in Sumatra. The fauna was con- with cross-beds, load and flute casts and slump structures in the
sidered to range from Late Carboniferous to Early Permian, with sandstone units. The Papan Formation on Kundur is more
the balance of opinion favouring an Early Permian age (Aldiss conglomeratic.
et al. 1983). No other occurrences of rocks of either of these The characteristic Mid-Late Triassic bivalve Halobia sp.
ages have yet been found elsewhere in Sumatra. Unfortunately, occurs at many localities, including H. tobensis and H. kwaluana.
this fauna was not re-examined during the review of fossil of Mid-late Carnian and H. simaimaiensis of Norian age
localities in Sumatra by Fontaine & Gafoer (1989). (Fontaine & Gafoer 1989).