Quantitative Application of Fluvial Geomorphology
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Transcript of Quantitative Application of Fluvial Geomorphology
8/9/2019 Quantitative Application of Fluvial Geomorphology
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Quantitative Application of Fluvial Geomorphology:
Preliminary Analogue Study from Modern Mahakam River,
Eat !orneo
Rian Cahya Rohmana1,2
Iqbal Fardiansyah2
Octavika Malda2
Agung Budiman2
!on"au#ani2 and $ovianto %risila&
• 1 Department of Geology UPN”Veteran”Yogyakarta,
• 2GeoPangea Research Group (GPRG,
• ! Remote "ens#ng $ Geomorphology %a&oratory' UPN”Veteran”Yogyakarta
"orreponding
author ' [email protected] ,[email protected]
Introduction
!orneo i kno#n a the larget iland in the Southeat Aia #hich drain through the longet and
$igget tropical river %appro&imately '(()*((( km in length and +()(( km #ide-. Mot of the riverare charged #ith great amount of edimentary material, reulting from e/uatorial #eathering
condition, and com$ination of climate, tectonic, $ae level change, and avulion %Schumm, *'01-.
2epite of high)reolution eimic image capa$ility that a$le to directly viuali3e paleogeography
appearance, /uantification of the fluvial morphology dimenion uing modern analogue #ill provide
further inight of channel tyle and depoitional facie geometry to the u$urface %Poamentier,
4((*-. 5hi article aim at $etter undertanding of fluvial control and morphology of Mahakam
River, !orneo uing 6andat data and field urvey %Figur! 1-. 5he morphometric meaurement aim
to predict paleo)channel hape, compoition of the ma7or lithologie, a #ell a variou parameterthat control their geometry.
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Figure *. Shuttle Radar 5opography Miion %SR5M- of !orneo 8land. Study area focue on
location highlighted $y coloured $o&e.
Mor(hom!tric M!asur!m!nt M!thod
Fluvial morphometric meaurement #ere performed from uptream to the do#ntream of the three
main river uing 6andat image. Meaurement include channel #idth %"9-, channel length %"6-,
meander $elt #idth %M!9-, meander #avelength %M6-, radiu of curvature %R"-, and inuoity
%S8- )Figur! 2*+ 5he variou tyle of fluvial morphology are related to $ed load or upended load
tranport and the cro ection of channel geometry that ho# the river #idth)depth ratio and the
inuoity %Schumm,*'01 #n Miall, 4((0 Gallo#ay, *'1*- )Figur! &*. Schumm; claification i not
necearily applica$le to e/uatorial river, hence it re/uire additional field meaurement in numerou
part of Mahakam River, uch a depth and ediment ditri$ution in order to contrain the data.
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Figure 4. Morphometric meaurement method uing landat image %courtey of Google Earth, 4(*<-.
Meaurement conit of channel #idth %"9-, channel length %"6-, meander $elt #idth %M!9-,
meander #ave length %M6-, radiu of curvature %R"-, and inuoity %S8-.
Figure <."laification of fluvial tyle, follo#ing the fluvial)geomorphological claification of
Schumm %*'0<-, given in the left column %modified after Gallo#ay, *'1*-.
tatistic o# Riv!r Mor(hology, "y(!s, and Controls
5#o ma7or channel tyle are identified #ithin the =apua, Mahakam and !arito river: %*- high)
inuoity, and %4- lo#)inuoity channel. >igh)inuoity channel are characteri3ed $y the
development of meander croll $ar %ridge and #ale-, a$andoned channel ? o&$o# lake, and
lateral accretion. Schumm; claification %*'01- ugget that meandering channel relief ha a lo# tomoderate depth : #idth ratio, #ith muddy to mi&ed)ediment dominating the inide of the channel. 8n
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addition, lo#)inuoity river can $e identified $y non)meandering croll $ar development #ith
vertical accretion, relatively traight channel and a moderate to high depth : #idth channel relief
ratio. 6o#)inuoity river are commonly filled $y coare ediment tranported a $ed load.
>o#ever, in ome area, $oth channel type are controlled $y Quatenary ediment, tructure, and
$edrock)incied morphology. 8n total, 4*< morphometric meaurement of the three river have $een
/uantified in order to predict the pro$a$ility of fluvial geometry. A tatitic e&le of channel #idth
i ho#n in Figur! -.
Figure @. General tatitic chart ho#ing #idth meaurement of =apua,Mahakam,and !arito river.
a- cumulative pro$a$ility of channel #idth $- hitogram chart that reflect ditri$ution of channel
#idth, range from 4(( to @(( m, interpreted a meandering river ytem.
Mahakam Riv!r ).ast Born!o*
5he Mahakam River i the econd longet river in !orneo %appro&imately '1( km long-. 5he middle
to uptream part of the Mahakam River are located in the 6ong 8ram area, #herea the do#ntream
part i located in Sanga)Sanga. 9e recorded * meaurement along <4*.1 km of river. Geological
map and 6andat imagery ho# a high)inuoity river ytem developed in the up to middle Mahakam
River. 8n the do#ntream area, development of the river i predominantly controlled $y incied
tructure and $edrock of the Mahakam fold thrut $elt %Figur! / and 0-.
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Figure +. "omparion $et#een 6andat imagery data %courtey of Google, 4(*<- and geological map
%GR2", *''<- of Mahakam River. ote that the river initially incied 5ertiary rock of Mahakam
Fold and 5hrut !el
Morphometric meaurement reveal that channel #idth %"9- of the Mahakam River range from
*@+ to *(<4 m %mean: <@( m, median: 41.<+ m, and mode: @04 m-, #ith meander $elt #idth %M!9-
ranging from 44 to <'< m %mean: *+4@ m, median: **0< m, mode: <0( m-, meander #avelength
%M6- range from *4*1 to **<' m %mean: @@0 m, median: <<(4 m, mode: ?A-, and radiu of
curvature %R"- range from '+ to 110 m %mean: @4* m, median: <11.+ m, and mode: <' m-.
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Figure 0. A- Meander croll of Mahakam river lie in the uptream /uaternary ediment, the
a$andoned channel or o&$o# lake are clearly o$erved from landat image. !- 6ong traight channel
repreent tructural and $edrock incied river of Mahakam Fold 5hrut !elt.
Quantitative morphometric analyi e&poe imilaritie $et#een the Mahakam and =apua river.
"ro)plot channel #idth %"9- veru inuoity %S8- yield t#o main population trend. "la of data
dominated $y $edload and upended load tranport #hich ho# a linear relationhip, #ith
meandering ytem #idth range from B *(( m to C @((m %$ounded $y the red line on Figur! -.
8nvere relationhip indicate a lo#)inuoity to traight channel %S8 C *.@-, and the uncertainty of
channel #idth to more than *((( m %Figur! a-. "ro)plot of meander #avelength %M6- veru
channel length %"6- diplay three linear population trend. 8n $ed load tranport river, the potential
meander #avelength i follo#ed $y an increae of channel length. 8n contrat, the mi&ed and
upended load channel length are uually larger than the meander #avelength %Figur! b-. 5he
radiu of curvature %R"- veru inuoity %S8- relationhip infer that mi&ed and upended river
have large value ranging from up to *.@ to @ #ith the radiu of curvature over 4(( m to C '(( m
indicating a meandering ytem. 5he radiu of curvature may have #ide range to predict from
inuoity until #e are a$le to define the ma&imum and minimum $oundarie %Figur! c-. "luter of
homogenou $ed load tranport are poi$ly aociated #ith $edrock inciion and Dtructural; river
#ithout development of meander croll, #herea pare ditri$ution i interpreted a a meandering
river ytem %Figur! d*.
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Figure 1. !athymetric urvey location in the Mahakam River, highlighted $y yello# $o&e
Figure '. a- !athymetric map of meandering river in the Muara Muntai %modified from >etina#ati,
4(('- $- ediment ditri$ution map ho#ing variou material inide the channel. 5hi indicate
mi&ed to upended load channel, an important clue that ugget channel thal#eg #a covered $y
mud plug and poi$ly turned to flo# $affle for and compartmentali3ation c- River cro)ection of
the channel coniting of ingle thal#eg #ith lo# to moderate #idth)depth ratio d- "ro)plot of
channel #idth %"9- veru depth %2- uggeting t#o population trend, and conclude that large or
#ide river tend to have large num$er of depth and depoited thick ediment.
>igh inuoity or meandering river ytem %S8 B *- are developed #ithin Quaternary ediment in the
uptream to middle area of the Mahakam River. 6o#)inuoity river %S8* to *.*- #ere initially
o$erved $y the preence of e&iting long and $ig river channel in the do#ntream area, a thechannel mot likely aociated #ith $edrock inciion and tructure. 5herefore, there i imilarity
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$et#een the Mahakam and =apua river, $oth are controlled $y $edrock and tructure in the
do#ntream area.
A((lication to ubsur#ac! Int!r(r!tation
8dentification of channel tyle i important, particularly in reervoir analyi for hydrocar$one&ploration. 5he reaon $eing interpretation of river channel tyle hold fundamental control in the
geometry and heterogeneity of fluvial reervoir. Moreover, it can $e ued for further analyi on
reervoir characteri3ation in the development tage. 9idth and thickne of fluvial and $odie are
function of the hydraulic character of the river. 6ong)term, patial or temporal change in hydraulic
character are preerved a lateral or vertical change in and $odie %reervoir- dimenion. Short)term
hydraulic change in fluvial ytem are reflected $y intra)reervoir variation in grain i3e, haline
and edimentary tructure. 5hee lithological and te&tural variation e&ercie are eentially a$le to
determine ditri$ution of poroity and permea$ility in andtone reervoir %2avi et al., *''<-. Figur!
14 ho# the e&le of morphometric identification uing high)reolution eimic time lice.
Figure *(. A- E&le of <2 time lice %<<+ m- of mid)upper Miocene meander channel ytem in
the 9et atuna !ain %Fachmi and 9ood, 4((+-, ho#ing a meander cut off and croll $ar. !- 6o#)
inouity of $edrock incied channel ytem of Hpper Miocene, 9et atuna !ain %time lice, *@0
m- %Fachmi and 9ood, 4((+-. "- !edrock incied channel of Pleitocene E ava Sea, <2 time lice
'0 m %Poamentier, 4((*-.
8n area #ith pare data and?or <2 eimic time lice #ith lo# reolution, the morphometric
/uantification of 6andat image i ueful a an analogue to identify the paleo)fluvial tyle. Modern
geomorphic feature and morphometric parameter help to predict ancient fluvial morphology and it
dimenion, lateral facie aociation, dominant lithological content %haline, and ratio- and
varia$le control of geometry %faulting and local uplift-. Quantitative morphometric of modern fluvial
ytem i a critical component to develop kno#ledge in geologic interpretation, for e&le
e/uence tratigraphy, reervoir heterogeneity and modelling, correlation trategie, drainage radiu,
and geo$odie, thu can minimi3e #ide range of uncertaintie.
R!#!r!nc!s
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2avie, R. ., Poamentier >. 9., 9ood, 6. . I "art#right, . A. %ed- 4((. Seimic
Geomorphology: Application to >ydrocar$on E&ploration and Production. Geological Society,
6ondon, Special Pu$lication, 4.
2avie, =.P., 9illiam, !. P. ., Jeell, =.P., *''<, 2imenion and Quality of Reervoir Kriginating
in 6o# and >igh Sinuoity "hannel Sytem, 6o#er "retaceou 5ravi Peak Formation, Eat 5e&a,
HSA, Geological Society, 6ondon, Special Pu$lication, v.<, p. '+)*4*.
Fachmi, M., 9ood, 6.., 4((+, Seimic Geomorphology : A Study from 9et atuna !ain,
8ndoneia, Proceeding <(th Annual "onvention I E&hi$ition, 8ndoneian Petroleum Aociation,
akarta.
>etina#ati.S., 4((', 8dentifikai !entuk 5opografi 2aar Sungai Mahakam 2engan Sitem 8nformai
Geografi , Fakulta =ehutanan Hniverita Mula#arman, Samarinda
Miall, A.2., 4((0, 5he Geology of Fluvial 2epoit : Sedimentary Facie, !ain Analyi and
Petroleum Geology, Springer.
ichol, G.., Fiher, .A., 4((, Procee, Facie and Architecture of Fluvial 2itri$utary Sytem
2epoit, ournal of Sedimentary Geology, Elevier, v.*'+, p.+)'(.
Piegay, >., Schumm, S.A., 4((<, Sytem Approache in Fluvial Geomorphology, ohn 9iley I Son.
Poamentier, >.9., 4((*, 6o#tand Alluvial !ypa Sytem : 8ncied v. Hnincied, AAPG !ulletin,
J.1+, o.*(, pp. **)*'<.