GEOLOGICACARPATHICA,FEBRUARY2018,69,1,71–88 doi:10.1515/geoca-2018-0005
SedimentaryprocessesandarchitectureofUpp erCretaceousdeep-seachanneldeposits:
acasefromtheSkoleNappe,PolishOuterCarpathians
PIOTRŁAPCIK
InstituteofGeologicalSciences,JagiellonianUniversity,Gronostajowa3a,30-063Kraków,Poland;piotr.lapcik@doctoral.uj.edu.pl (ManuscriptreceivedJuly4,2017;acceptedinrevisedformDecember12,2017)
Abstract:D e e p -
s e a c h a n n e l s a r e o n e o f t h e a r c h i t e c t o n i c e l e m e n t s , f o r m i n g t h e m a i n c o n d u i t s f o r s a n d a n d g r a v e l ma teriali n t h e t u r b i d i t e d e p o s i t i o n a l s y s t e m s . D e e p -
s e a c h a n n e l f a c i e s a r e m o s t l y r e p r e s e n t e d b y s t a c k i n g o f t h i c k -
beddedm a s s i v e s a n d s t o n e s w i t h a b u n d a n t c o a r s e - g r a i n e d m a t e r i a l , r i p p e d -
u p c l a s t s , a m a l g a m a t i o n a n d l a rges c a l e erosionalstructures.TheManasterzQuarryoftheRopiankaFormati on(UpperCretaceous,SkoleNappe,Carpathians)containsasuccessionofatleast31mofthick-beddedhigh- densityturbiditesalternatedwithclast-richsandydebrites,whichareinterpretedasaxialdepositsofadeep- seachannel.Thesectionstudiedincludes5or6storeyswithdebritebasallagdepositscoveredbyamalgamatedturb iditefills.Thethicknessofparticularstoreysvariesfrom2.5to13m.Verticalstackingofsimilarfaciesthroughthewhole thicknessofthesectionsuggestahierarchicallyhigherchannel-
fillorach annelco mplex set,withanaggradation rateh igherthanitslater almig ration.Such channelaxisfaci escannot aggradewithoutsimultaneousaggradationofleveeconfinement,whichwasdistinguishedinanassociatedsectionlocatedtotheNWf romtheManasterzQuarry.Lateraloffsetofchannelaxisfaciesintochannelmarginorchannelleveefaciesisestimatedatlesst han800m.TheManasterzQuarrysectionrepresentsmostlythefillingandamalgamationstageofchannelformation.Th edescribedchannelarchitecturalelementsoftheRopiankaFormationarelocatedwithintheso-
calledŁańcutChannelZone,whichwaspreviouslythoughttobeOligocenebutmayhavebeenpresentalreadyintheLateCretaceous.
Keywords:Carpathians,sedimentaryprocesses,architecturalelements,deep- seachannel,massivesandstone,turbidite,debrite.
Introduction
Thea r c h i t e c t u r a l e l e m e n t s c o n c e p t i s w i d e l y a c c e p t e d f o r analysisofdeep-
seadepositionalenvironments(Mutti& Normark1 9 8 7 ) . Accordingt o t h i s c o n c e p t , s e d i m e n t a r y bodiesaredist inguishedaspartsofahierarchicallyorganizeddeep-
seafanmodel.Ahighvarietyofarchitecturalelements arec o n d i t i o n e d b y m a t e r i a l d e p o s i t e d , s i z e a n d l a t i t u d i n a l positiono f d e p o s i t i o n a l s y s t e m , s e a l e v e l c h a n g e s , t e c t o n i c regimeandsedimentaryprocesses(e.g., Stow&Mayall2000;Mulder2011;Cossuetal.2015;Shanmugam20 16).Architec-
turalelementsareusuallydistinguishedinverywellexposed depositionals y s t e m s t h r o u g h a n a l y s i s o f f a c i e s a s s o c i a t i o n s (e.g.,Gardneretal.2003;Prélate tal.2009;Hub bardetal. 2014;B a y l i s s & P i c k e r i n g 20 15 a , b ; P i c k e r i ng e t a l . 2 01 5) . However,t h i s c o n c e p t w a s s o f a r n o t a p p l i e d t o n u m e r o u s formations,includingtheRopiankaF ormation(Turonian–
Paleocene)intheSkoleNappe(PolishCarpathians).Thisfor- mation,upto1.6kmthick,containsasuccessionofdeep- seadepositswithnumerousfaciesassociationssuggestingoc cur-
renceofdifferentarchitecturalelements(e.g.,Bromowicz1974;
Kotlarczyk1978,1988;Łapcikinpress),whichremainalmostu n d e t e r mined.Tectonicd e f o r m a t i o n a n d p o o r e x p o - sureoftheRopiankaFormationmakedifficultiesincorrela -tionsoffaciesandarchitecturalelementsoverlongerdistances.
Nonetheless,largeoutcropswithhighcontributionofthick- beddeds a n d s t o n e s g i v e a c h a n c e t o d i s t i n g u i s h s u c h bodiesi n s o m e p l a c e s , f o r e x a m p l e , i n t h e S ł o n n e s e c t i o n , whereŁapcik(inpress)distinguishedover1 40mthicklobecomplex.
Inthispaper,deep-seachannel-fillanditsinternalarchitec- turea r e p r e s e n t e d i n s t r u c t u r e l e s s a n d g r a d e d t h i c k -
b e d d e d sandstonesfromtheManasterzQuarry,inreferences toasso-
ciateds e c t i o n s . M o r e o v e r,d e p o s i t i o n a l p r o c e s s e s a r e i n t e r-
pretedonthebasisofsedimentarystructuresandtheinternala rchitectureofthechannel-fill.
Geologicalsetting
Thiss t u d y i s f o c u s e d o n t h e R o p i a n k a F o r m a t i o n ( a f t e r Kotlarczyk1978),alsoknownastheInoceramianBeds (Uhlig1888),whichisreferredtosand-
richdepositsinthenorthernparto f t h e S k o l e N a p p e ( a l s o k n o w n a s t h e S k y b a N a p p e ) . Thef o r m a t i o n c o m p r i s e s a s u c c e s s i o n o f t u r b i d i t y c u r r e n t , debrisf l o w, s l u m p , p e l a g i c a n d h e m i p e l a g i c d e p o s i t s o f t h e Turon ian–
Palaeoceneageuptoabout1.6kmthick(e.g.,Kotlarczyk1978,19 88).TheSkoleNappeisthemostexternalmajortectonicunitinthe
PolishCarpathians(Fig.1A). DepositsoftheSkoleNap peaccumulatedinaseparate
www.geologicacarpathica.com
LowerCretaceousUpperCretaceousPaleogeneNeogene ChwaniówSsMb RopiankaFm(InoceramianBeds)VariegatedHieroglyphicShaleFmFormation MeniliteFm
A
72 ŁAPCIK
GEOLOGICACARPATHICA,2018,69,1,71–88 sub-
basin(e.g.,Kotlarczyk1988),however,someauthorsregardpart oftheSkoleBasinastheCarpathianmarginalzonewhichco rre spon dst o t heb as in sl ope (e .g., Jankow ski e t al . 2012).Sedim entationintheOuterFlyschCarpathiansstartedintheLateJuras sic.TheCarpathiansevolvedfromariftbasin(sincet h e L a t e J u r a s s i c ) t o a r e m n a n t f o r e l a n d b a s i n i n t h e Oligocene(Gol onkaetal.2006;Nemčoketal.2006;Ślączkaetal.2006,2012;Gąga łaetal.2012)andultimatelyduringtheMiocenet h e b a s i n w a s f o l d e d a n d t h r u s t e d u p o n t h e C a r-
pathiansForedeep.DuringtheTuronian–
Paleocenetimes,thesedimentsoftheSkoleBasinarethoughttohave beenderivedfromthesouthernpartoftheUpperSilesiaan dMałopolskablockst o t h e n o r t h ( K s i ą ż k i e w i cz1 9 6 2 ; B r o m o w i c z 1 9 7 4 ;
Salata&Uchman2013)andfromthesideoftheSubsilesianRi dge(WęglówkaRidge)to thesouth(Książkiewicz 196 2).Thep e t r o g r a p h i c v a r i e t y o f t h e s o u r c e a r e a w a s r e p e a t e d l y mentionedi n t h e l i t e r a t u r e ( e . g . , S a l a t a & U c h m a n 2 0 1 3 ; Salata2014;Łapciketal.2016andre ferencestherein).
FourlithostratigraphicmembersoftheRopiankaFormationwere d i s t i n g u i s h e d b a s e d o n r e p e a t e d c a r b o n a t e - s i l i c i c l a s t i c deposits(Fig.1B;Kotlarczyk1978).Eachmember(
excludingtheWolaK o r z e n i e c k a M e m b e r ) c o n t a i n s c a r b o n a t e -
r i c h successionwhichpassesintosiliciclasticdominated depositstowardsthetop.Moreover,adecreasingcontribu tionofcar-
bonatematerialfromtheproximalareatothenorthtothedis- talareatothesouthoftheSkoleBasinisobserved(Kotlarczyk
N
Rzeszów Carpathian MaMioceneofthe RzeszówBay
Foredeep
study
area Poland
Carpathians
5.33
23.03
Miocene M.
L.
B
KrosnoBeds
SkoleNappe
Przemyśl 33.9
Oligocene U.
L.
U.
KliwaSs
StrwiążGlobigerinaMarlMb PopieleMb BachórzShale-
Eocene– LowerMiocene
Cretaceous– Paleocene 10km
Eocene M.
L.
56
Paleocene
SandstoneMb NienadowaMarlMbWi daczówG r e e n S h a l e M bT RShMb+Vsh+ChSMb
VariegatedShale BabicaClay
WolaKorzenieckaMb
NS e c t i o n 5 0
ChannelaxisfaciesW ęgierkaMarl
66
C
72.1WęgierkaMarl LeszczynyMb
!
Manasterz-Rzeki Maastrichtian
40404050
?
Thick-beddedsandstones Thin-tomedium-
beddedflyshThin-tomedium- beddedflysh
withalternationsofbluish- whitemarlstones
83.686.3 89.8
Campanian
Santonian
Coniacian Turonian
Kropivnik Marl
HolovniaSil iceousMarl
WiarMb
CisowaMb
? 93.9
4641 100.5
16
Cenomanian DołheRadiolarianShale KuźminaSandstone
ManasterzSection
43
Manasterz
113
Albian
Aptian SpasShale
0 150300m 35
ManasterzQuarrySection
125 129.4 132.9 139.8 145
Barremian Hauterivian Valanginian Berriasian
BełwinMudstone
UPPERCRETACEOUSDEEP-SEACHANNELDEPOSITS(SKOLENAPPE,POLISHOUTERCARPATHIANS) 7 3
GEOLOGICACARPATHICA,2018,69,1,71–88 Fig.1.Geographicalandstratigraphiclocationofstudiedarea.A—
locationmapofthestudiedareaintheSkoleNappe.BasedonKotlarczyk(1988)a n d m o d i f icationsb y G a s i ń s k i & U c h m a n ( 2 0 0 9 a n d r e f e r e n c e s t h e r e i n ) ; B — l o c a t i o n o f t h e M a n a s t e r z -
R z e k i , M a n a s t e r z a n d ManasterzQuarrysectionswithsomeindicatorsoftheorientationofbedsasmeasuredinthefieldandpredicti onofspatialdistributionoffacies;C—
stratigraphiccolumnoftheSkoleNappe.BasedonKotlarczyk(1988),Rajchel(1990),Rajchel&Uchman(1998),Ślączka& Kaminski(1 998),withfurthercorrectionsbasedonfurtherdatabyGedl(1999)andKotlarczyketal.
(2007).Theinvestigatedintervalindicatedby„!”.ThetimescaleisafterGradsteinetal.(2012).TRShMb—TrójcaRedShaleMember,VSh—
VariegatedShale,ChSMb—ChmielnikStripedSandstoneMember.
1978).Someareasshowdominationofmasstransportdepo- sitstypicalofslopeareas(Burzewski1966;Bromowicz1974;Kotlar czyk1978,1988;Dżułyńskietal.1979;Gerochetal.1979
;Malata2001;Jankowskietal.2012;Łapciketal.2016).Foraminiferid assemblagespointtodepositionoftheRopiankaFormationinbathyaldept hsbelowandabovethecalcitecom-
pensationdepth(Uchmanetal.2006).ThelithostratigraphyoftheR o p i a n k a F o r m a t i o n i s s t i l l d e b a t e d ( e . g . , M a l a t a 1 9 9 6
; Jankowskietal.2012).
Methodology
Thef i e l d w o r k w a s b a s e d o n s e d i m e n t o l o g i c a l a n d f a c i e s analysisofsandydominatedthick-
beddeddeposits.Thetex-
turea n d p r i m a r y s t r u c t u r e o f t h e s e d e p o s i t s w e r e d e s c r i b e d duringdetailedprofiling.Grain-
sizeanalysiswasconducted ino r d e r t o d e t e r m i n e t h e d e p o s i t i o n a l p r o c e s s e s o f t h e thick-
beddedsandstonesandestimatethethicknessofama l- gamatedb e d s . F i f t y s a m p l e s w e r e t a k e n f o r g r a i n - s i z e a n d petrographica n a l y s i s w h i c h w a s c o n d u c t e d a s d e s c r i b e d i n Łapcik(inp r e s s).T h e s a m p l e s f o r g r a i n - s i z e a n a l y s i s w e r e collectedf r o m 4 –
5 c m t h i c k l a y e r s w i t h d i fferentd i s t a n c e intervalsde scribedfurtherinthetext. Theorientationofthelongeraxi sof103mudstoneandmarlstoneclasts,orientationofgrainsandpe bblesimbricationandorientationoftheaxisofflutecastsfromtheM Qsectionweremeasuredbymeanof ageologicalcompassino rdertodeterminedirectionofpalaeo-
transport.T h e l a s t s t a g e o f t h e s e d i m e n t o l o g i c a l a n d f a c i e s analysisofthethick-
beddedsandstoneswasdistinguishingthechannelelements.
Thesectionsstudied
ThestudieddepositsbelongtotheinternallydeformedHusó wThrustSh ee t( Wdowi ar z1949) ,whi ch is th es ec ond t hrusts h e e t f r o m t h e n o r t h e r n m a rgino f t h e C a r p a t h i a n s .Themajorityofresearchwasfocusedonsandydeposit sinthewellexposedManasterzQuarry(MQ).Additionalsediment o-
logicalstudywasconductedintwoassociatedsections.
DescriptionofthewholeManasterzsectionispresentedbelowinthestra tigraphicorder.
TheManasterz-Rzekisection
Theoldestpartofthesectionstudiedislocatedinasmall gorgeo f a n u n n a m e d s t r e a m , a t r i b u t a r y o f t h e H u s ó w k a Streama t M a n a s t e r z -
R z e k i ( F i g . 1 C ) . T h e s e c t i o n i s r e p r e -
sentedb y f i v e i s o l a t e d o u t c r o p s c o n t a i n i n g t h i n - t o t h i c k -
beddeds a n d s t o n e s , s i l t s t o n e s , m u d s t o n e s a n d m a r l
s t o n e s (Fig.2 ) . B e d s a r e d i p p i n g t o t h e S W a t a n g l e s o f 4 0 ° –
5 0 ° (Fig.1C).Thecontributionofeachfaciesclassinparti cularoutcropsispresentedinFigure3.Sandstonesarequartz-domi- nated,veryfine-tomedium-
grained,withabundantparallel, convoluteandcross- laminationsunderlinedbycarbonized
plantdetritus.Medium-andthick-
beddedsandstonesaregradedorstructurelessatthebasalpart.
Solemarksarenume-
rouswithahighcontributionofthetracefossilsOphiomorphaandTh alassinoides.Somethin-
beddedsandstonesrichinplantdetritusshowchaoticstructure ,whichprobablyresultedfromb i o t u r b a t i o n ( t h e t r a c e f o s s i l S c o l i c i a i s p r e s e n t ) . Sandstonesarealternate dwith greymudstones,which oftenincludethinlayers ofparallelandcross-
laminatedsiltstones.Thelatestlithologyisrepresentedbybl uish-
whitemarlstoneswiths a n d s t o n e a l t e r n a t i o n s , w h i c h a r e 0 . 2 –
1 c m t h i c k . Abundantbioturbationstructureswithinmarlsto nesaredomi-natedbyPlanolitesandChondrites.
TheManasterz-Rzekisectionbeginsasthin-
beddedflyschwithabundantalternationofmarlstones(Fig.2).
Contributionofmarlstonesdecreasesinthemiddlepartofthese ctionwithsimultaneoussignificantincreaseinmedium- andthick-
beddedsandstones(Fig.3).Thetopofthesectionisagainrepresented bythin-
beddedflyschwithabundantalternationofmarlstonessimilarl o o k i n g t o t h e b o t t o m p a r t o f t h e s e c t i o n . T h e t o t a l thi cknessoftheManasterz-
Rzekisectionis116mwitha2 8 m -
t h i c k m i d d l e p a r t s h o w i n g n u m e r o u s m e d i u m a n d thicksandstonebeds.TheManasterz-
RzekisectionbelongstotheCampanianWiarMember(Fig.1B;K otlarczyk1978).
TheManasterzsection
Higherpartofthesectioncropsoutingorgesofunname dtributarieso f t h e M l e c z k a R i v e r,s o u t h o f M a n a s t e r z -
R z e k i , wherebedsdiptotheWandSW(Fig.1C).Thelowerpar tofthesectionisrepresentedbythin-
beddedflyschwithalterna-
tionofmarlstonesshowingsimilarappearancetothetopand bottompartoftheManasterz-
Rzekisection(Fig.2).Tothetopofthesection,thecontribution ofmarlstonesdecreaseswith simultaneousi n c r e a s i n g o f m u d s t o n e s ( F i g . 2 ) . T h e h i g h e r partofthesection containsamedium-andthick-beddedsand-
stoneinterval.Thesesandstonesaredominatedbyfractionallygrade da nd p a r a l l e l l a m i n a t e d pa rt s w i t h ab un d a n t , c l a s t s of coal.However,someofthemedium-andthick-
beddedsand-
stonesarestructurelessattheirbase.Abovethesandyinterval,packag esoffine-
grained,structureless,muddysandstoneswithclastsofmu dstoneandmarlstonearealternatedwithuptotensofcentime tresthick,siltyandsandycalcareous,struc-
turelessmudstoneswithdispersedquartzpebbles.Thistypeofdeposi tisabundantintheexternal(northern)partoftheSkoleNappeandt heyareknownasthe WęgierkaMarl(Baculites Marl).T
hisunitisincludedintheLeszczynyMember(upperMaastrichti an–
lowerP a l a e o c e n e ).T h e M a n a s t e r z s e c t i o n i s 375mt hick(Fig.2).Tectonicdeformationsleaveuncertaintyifthethick- beddedsandstoneintervalintheManasterzsectioncorrespondstothesi milaroneintheManasterz-Rzekisection(Fig.1C).
TheManasterzQuarrysection
Thehighestpartofthesectionstudiedisexposedinasmallquarry atManasterzwherebedsareinclinedtothesouth-west
[m]
38
Site2 Manasterz-Rzekisection
Site4
[m]
97
11 6[m]
Site5
151
Manasterzsection
374
115
37 96
36 95
94 35
11 4
11 3
11 2
150
149
142
370
339
337
93
34
92
33
111
110
106
105
336
335
32 91 csv.ff
31 90
104
103
334
331
[m]16
Site1 89
Mudstone
102 176
88
15
Sandy/siltymudstoneM arlstone
61 175
Site3 Sandstone
14
13
75
[m]
73
Convolutelamination Cross-lamination 55 Parallellamination
Verythin-
beddedsiltstoneorsand stone
39
174
173
12
11
10
9
0 csv.ff 72
71
70
Site2 [m]
39 csv.
8
7
2
0 csv.ffm
160
159
158
157
152
csv.ffm
Fig.2.LithologicalcolumnsoftheRopiankaFormationattheManasterz.LogsrefertotheManasterz-RzekiandtheManasterzsections.
Frequency(%)Frequency(%)
TotalthicknessN u m b e r ofbedsTotalthicknessN u m b e r ofbedsTotalthickness 60
50 40 30 20 10 0
Numberofbeds
Marlstone Mudstone Siltstone Thin-bedded sandstone Medium- beddedsandsto ne
Thick- beddedsands
Site1 Site2 Site3 tone
60 50 40 30 20 10
0 Site4 Site5 Total
Fig.3.FaciesclassabundanceintheManasterz-Rzekisection.
atanglesof30–
40°.Thequarryis85mlongandupto12mhigh.Theoutcropcon sistsof31moffullysandstonesectionwherey e l l o w i s h - o r a n g e , g r a d e d a n d s t r u c t u r e l e s s , a m a l g a - matedsandstonesarefine-tocoarse-
grainedwithlocallyabundantd i s p e r s e d q u a r t z g r a v e l , m u d s t o n e a n d m a r l s t o n e cobblesa n d b o u l d e r s ( F i g . 4 ) . M u d s t o n e c l a s t s a r e u s u a l l y veryp o o r i n m i c r o f a u n a , h o w e v e r,s o m e c o n t a i n a b u n d a n t bryozoans.Thesandstonesarequartzarenites,whichcontain minoradmixtureofsiliceousgrains,muscovite,sericite,glau- conite,biotite,feldspar,micaschists,pyriteconcretions,gr a-
nite,gneissandcoal.Aminorcontributionofbiogenicmaterialisr e p r e s e n t e d b y a b r a d e d b i v a l v e s h e l l s , s i l i c e o u s s p o n g e spiculesandagglutinatedbenthicforaminiferte sts.Thecon-
tributionofaccessorycomponen tsneverexceedsafewp er-
centintotal.Quartzgrainsarealmostalwayswellround ed.Polymineralicg r a i n s a r e l i m i t e d t o t h e l a rgestf r a c t i o n s o f 0.25–
2mm.Thesandstonecontainsvariableamountsofcar- bonate,silicaandclaymineralscementandpassesfromhardlit hifiedtoalmostloosesand.TheMQsandstonefaciessig- nificantlyd i fferf r o m t h e t h i c k -
b e d d e d s a n d s t o n e i n t e r v a l s fromtheManasterz- RzekiandManasterzsections.AdetaileddescriptionoftheMQs ectionispresentedin“Material studied”.
Inasimilarstratigraphicposition,totheNWofthequarry,thin- t o m e d i u m-
beddeds a n d s t o n e s a l t e r n a t e d w i t h g r e y mudstonesarepre sent(Figs.1C,2).Thesedepositsareverysimilartotheseinthe lowerpartoftheManasterzsectionandtheyr e p r e s e n t a l a t e r a l f a c i e s e q u i v a l e n t o f t h e M a n a s t e r z section.
Materialstudied TheManasterzQuarryfacies
Themajorityofresearchwasfocusedonthewellexpose dMQsandydeposits.Sedimentologicalandfaciesanaly sesofthestructurelessandgradedsandstonesallowedtodistingui shtwooroptionallythreefacies,descriptionsandinterpretationso fwhicharepresentedbelow.
Facies1
ThemajorityofdepositsintheMQsectionarerepresentedb yf ine -t oco ar se-
gra in ed,gr adedo rm ac ros copi ca ll ys tr uc -
turelesssandstoneswithquartzgravelandclastsofmudstonea ndmarlstone.Theirbeddingispoorlyexpressedbecause ofabundantamalgamationandpaucityofsedimentarystruc- tures.Theamalgamationsurfacesareunevenandmarked byabruptg r a i n -
s i z e c h a n g e s ( F i g . 5 A ) , w h i c h t e n d t o d e c l i n e la terallyinthescaleofmetres.Someofthesandstonesshowcru delamination,whichisunderlinedbyparallelorientatio nofcoarsegrainsandpebblesandveryrareimbrication.Clastsar esimilartomudstonesandmarlstonesfromtheManaster zandManasterz-
Rzekisectionsandaremostlyorientedparalleltothebedding(Fig.5 B).Clastsofmudstoneareusuallyseveraltensofcentimetresl ongandafewcentimetresthick,whereas,clastsofmarlsto nearemostlyroundedtosub-
roundeda n d d o n o t e x c e e d 2 0 c m i n d i a m e t e r.M a r l s t o n e s containa b u n d a n t C h o n d r i t e s ,P l a n o l i t e s a n d s o m e
76
Ł A P CI G
E OL O GI C A C A R P AT HI C A, 20
SW
Turbidite
?
AmalgamationzonesandscoursD ebrite
NE
MudstoneandmarlstonecobblesandbouldersInv erseandnormalgrading
ThalassinoidesandOphiomorpha
Debritesbasallagdeposits#6? ?
? Debritesbasallagdeposits#5
?
MA21-8
MA11-6
Areamostlycovered
?
?
?
Statisticaldataof
?measuredclastsorientation:
N N
Debritesbasallagdeposits#4
?
Debritesbasallagdeposits#3?
?
Debritesbasallagdeposits#2
MAN11-18
Debrisbasallagd eposits2only
n=69
Total n=103
Samplestatistics:
Meanvector1.31
Vectormagnitue(length)9.14%
012 3 4 5 m
Fig.4.InterpretationoftheManasterzQuarrysectionwithdistinguishingofthechannelelementsandstatisticaldataofmeasuredclastorientation.
UPPERCRETACEOUSDEEP-SEACHANNELDEPOSITS(SKOLENAPPE,POLISHOUTERCARPATHIANS) 7 7
GEOLOGICACARPATHICA,2018,69,1,71–88 unidentifiedb i o t u r b a t i o n s t r u c t u r e s . S e v e r a l e r
o s i o n a l i n c i-sionsu p t o 1 . 5 m d e e p a n d 2 . 5 –
6 . 5 m w i d e , w i t h m a rginsinclineda t a n g l e s f r o m 3 0 ° t o a l m o s t 9 0 ° o c c u r w i t h i n t h e massivesandstones.Theyarefill edwithsandstonewithquartzpebblesa n d s h e l l d e b r i s . Theses t r u c t u r e s a r e c o n s i d e r e d a s mega-
flutes.Someofthemarefilledexclusivelywithcoarse-
grainedm a t e r i a l , w h e r e a s o t h e r s c o n t a i n c o a r s e -
g r a i n e d depositsi n t h e l o w e r p a r t w h i c h i s c o v e r e d b y m e d i u m - t o fine-
grainedmacroscopicallystructurelesssandstone(Fig.5C).Howev er,coarse-grainedlayerscanoccurinmultiplelevelsinonem e g a - f l u t e . P a r t i c u l a r c o a r s e -
g r a i n e d l a y e r s m a y s h o w normalorinversetonormalgr ading.Mostofthemega-
flutesarepartlycoveredbyrecentdebrisortheyarepartlytruncatedby recenterosion.Therefore,theirtotalwidthwasimpossibletoest imate.Moreove r,smalle r,severalcentimetresthick sc oursareabundantwithinthemacroscopicallystructurele ssandgradedsandstone(Fig.5A).Themeasuredmeanaxi softhes c o u r s a n d g r a i n i m b r i c a t i o n i n d i c a t e N – S a n d N W – S E orientations.
Ino r d e r t o d e t e r m i n e t h e d e p o s i t i o n a l p r o c e s s o f f a c i e s 1 sandstones,twoseriesofsamplesforgrain-
sizeanalysiswerecollected(F ig.6 ).S er ie sMAN11–
16wa sco ll e ctedi n 20–
30cmintervalsfrom3.8mthickbottompartofthesection(Fig.4 ) . Th i ss a n d s t o n e i n t e r v a l r a r e l y c o n t a i n s s m a l l m ud- stonec l a s t s a n d a m a l g a m a t i o n s u r f a c e s , w h i c h d i s a p p e a r a t thedistanceof1–
3m.Clastsareorientedparalleltothebed- dingi n a d i s c r e t e h o r i z o n s . G r a i n -
s i z e a n a l y s i s s h o w e d t h a t sampledi n t e r v a l c o n t a i n s t h r e e f r a c t i o n a l l y g r a d e d a m a l g a -
matedbedswithmudcontentneverexceeding15%byweight(Fig.6).
Estimatedbedsthicknessdecreasesfrom180cmatthebo t t o m, 80 c m i n t h e m i d d l e t o 40 c m a t t h e t o p o f t h e sample dinterval(Fig.6).
Thes e c o n d s e r i e s o f s a m p l e s M A 1 1 –
6 w a s c o l l e c t e d i n 10c m i n t e r v a l s , f r o m t h e m i d d l e p a r t o f t h e s e c t i o n , w h i c h includecoarse-
grainedamalgamatedsandstone(Fig. 4).Theseriesstartsa tthebottomofanabruptcoarseningsurfaceandincludestwosuch surfaces.Theanalysisshowspresenceofthenormalgradingatth ebottomamalgamationsurfaceandtheinversetonormalgradingin theupperone(Fig.6).Thecontributionofmuddoesnotexcee d12%byweightinthewholesampleseries(Fig.6).
Interpretation:Facies1sandstonesareinterpretedas depositsofhigh-
densityturbiditycurrentsmostlyformedby layer-by- layeri n c r e m e n t a l d e p o s i t i o n ( e . g . , L o w e 1 9 8 2
; Tallingetal.2012).Rapidfalloutofgrainsfromturbulentsus- pensions u p p r e s s e d t h e f o r m a t i o n o f s e d i m e n t a r y s t r u c t u r e s (Lowe1982),however,gradingwaspreserved.Mat hematicalmodellings t u d i e s o f B a a s ( 2 0 0 4 ) s h o w e d t h a t l a c k o f Tbc
Boumaintervalsinthetopofstructurelesssandstonescannot bee x p l a i n e d b y a b r u p t d e c e l e r a t i o n o f d e n s i t y f l o w o n l y.Macroscopicallys t r u c t u r e l e s s a n d g r a d e d s a n d s t o n e b e d s a t theMQhavenosignofwaterescapestructuresand laminationint h e u p p e r p a r t , t h e y a r e w i t h i n g r a i n - s i z e l i m i t f o r r i p p l e lamination(<
0.7mm),showwidegrain-
sizedistribution(Fig.6 ) , a n d t h e y d o n o t h a v e b i o t u r b a t i o n s t r u c t u r e s . Therefore,thelaminatedtopofstructurele ssbedswaseroded
orbedformsaretoothintoberecognizedifdurationofflow wastooshortwithinplanebedandripplestabilityfields(Baas2004).
Occurrenceofamalgamationsurfaces,clastsofmud - stoneand ma rl st on eand sc oursd ir ec tl yi nd ic at es t ro ngero -sionalforcesoftheflows.Moreover,grain- sizeanalysisshowedthatamalgamationsurfacesarenotre strictedonlytomacroscopicallya b r u p t g r a i n -
s i z e c o a r s e n i n g b u t a l s o o c c u r withint h e s t r u c t u r e l e s s p a r t . T h e r e f o r e , a m a l g a m a t i o n s u r- facesaremoreabundantthanFigure4shows.
Isolateda n d l a terallyd i s c o n t i n u o u s m e g a -
f l u t e s r e f l e c t complexinternalstructureoftheconcen trateddensityflows (sensuMulder&Alexander2001)respons iblefortheirorigin.Suchflowsarefeaturedbyabruptlateraltra nsitionfromero-
sionalthroughbypasstodepositionalconditionsnearthebot- tom.Fillingsofthemega-
flutesrecordavarietyofdepositionalconditionswhichareexpressed bylateralchangesinthetex-
turea n d p r i m a r y s t r u c t u r e o f s e d i m e n t s ( e . g . , L e s z c z y ń s k i 1989andreferencestherein).Coarse- grainedflutefillingandcoarse-
graineda m a l g a m a t i o n z o n e s a r e b a s a l l a g d e p o s i t s , whichrepresentthethickestmaterialcarriedbytra ctionneartheb o t t o m ( e . g . , D ż u ł y ń s k i & S a n d e r s 1 9 6 2 ; L o w e 1 9 8 2 ; Postmae t a l . 1 9 8 8 ; S o h n 1 9 9 7
; S t r z e b o ń s k i 2 0 1 5 ) . Verticalmultipleg r a i n - s i z e c o a r s e n i n g s u r f a c e s w i t h i n s o m e m e g a - flutesindicatedepositionfromanunsteadyfluctuatingflowormultipl efi ll in gof th ef lut eb ydi fferenteve nt s.O rig in from mu ltistagef i l l i n g f r o m i n d e p e n d e n t f l o w s i s m o r e p r o b a b l e becauseparticulareventswoulderodethetopofthepre viousfillingandleavelagdepositstounderlineamalgamat ionsur-face.M o r e o v e r,p a r t i c u l a r c o a r s e - g r a i n e d l a y e r s w i t h i n t h e mega-
flutefi ll ss hownor ma lg rad ing andi nve rs et onorm al gradingfromonecoarselayertoanother(Fig.5C).Inverselyg radedcoarse-
grainedamalgamationzonesliketheonefromtheM11–
6sampledintervalimplydepositionfromhighcon-
centratedfrictionaltractionwhereinverselygradingisformedint h e b a s a l l a y e r b y s h e a r i n g a n d k i n e m a t i c s i e v i n g ( S o h n 1997;Cartignyetal.2013).Sedimentsdepositedfromtractiona rea l s o c o n f i r m e d b y r a r e o c c u r r e n c e o f c o a r s e g r a i n s a n d imbricationofpebbles.
Oneofthefeaturesofthehigh-densityturbiditesisconcen- trationofclastsindiscretehorizonslikeinsomestructurelessan dgradedsandstonesintheMQ(Tallingetal.2012).Clasttr ansportationwithinthehigh-
densityturbiditycurrentismostlyo n t h e r h e o l o g i c a l b o u n d a r y b e t w e e n t h e t u r b u l e n t dampedbotto mpartoftheflowandthemoreturbulenttoporhighlyconcentrat ed,turbulentdamped,nearbottomlayerdrivenbyturbulence fromamoredilutedtop(e.g.,Postmaetal.1988).Mostoftheelo ngatedmudstoneclastssuggesttransportationontopofthehighly concentratedbottompartoftheh i g h -
d e n s i t y t u r b i d i t y c u r r e n t , w h i c h p r e v e n t e d t h e i r fur there r o s i o n a n d a l l o w e d t h e m t o k e e p t h e i r l o n g i t u
d i n a l shape.H o w e v e r,somea u t h o r s s u g g e s t t h a t p r e s e r v a t i o n o f mudstonec la st sa nd t h e i r p lan ar conc en t r at ion to t h e t op of bedisrathertypicalofsandydebrites(e.g.,Shan mugam2006;Strzeboński2015).Thewell-
roundedmarlstoneclas tsimplyrelativelylongtractiontra nsportation.Therefore,twoimpor-
tantlydifferentshapesofclastsoflithologieswhichareeasily
78
Ł A P CI G
E OL O GI C A C A R P AT HI C A, 20
Fig.5.Sedimentologicalfeaturesoffacies1fromtheManasterzQuarrysection.A—coarse-grainedamalgamationsurfacewithsmallscalescourswithinthestructurelesssandstoneoffacies1;B—well- roundedclastsofbluish-whitemarlstoneorientedparalleltothebeddinginadiscretehorizon;C—largescourwithinthemassivesandstoneoffacies1filledwithmultiplelevelsofcoarse- grainedlayers.Particularcoarse-grainedlayersshownormalgradingorinversetonormalgradingwhichcorrespondtomultistagefillingofthescour.
lagdeposits2
Debritesbasal Channelelementturbiditefill1 00.10.50.60.1 11.1 010
UPPERCRETACEOUSDEEP-SEACHANNELDEPOSITS(SKOLENAPPE,POLISHOUTERCARPATHIANS) 7
9
GEOLOGICACARPATHICA,2018,69,1,71–88 cm
420 400
MAN11-18 Meangrainsize(mm) Meangrainsize(φ) Grains<0.054mmb yweight(%)
380 360 340 320 300 280 260 240 220 200 180 160 140 120 100 80 60 40 20 0
1 2 3 4
18
17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
0 1 0 20 3 0
sv.ffmcv.c
Meangrainsize(mm) Meangrainsize(φ) Grains<0.054mmb yweight(%)
cm50 MA1
40 30 20 10 0
6 5 4 3 2 1 sv.ffmcv.c
Meangrainsize(mm) Meangrainsize(φ)
0 10 20
Grains<0.054mmb yweight(%)
cm MA2
60 50 40 30 20 10 0
87 6 5 4 3 2 1
sv.ffmcv.c
2 3 4
Fig.6.Grain-sizetrendsandmudcontentinMAN11–18,MA11–6andMA21–8sampleseriesfromtheManasterzQuarrysection.
abradedsuggesttwodifferentsourcesofthematerialanddif- ferentd i s t a n c e o f t r a n s p o r t a t i o n . Th em a r l s t o n e s c l a s t s s u g -
geste r o s i o n inamoreproximalslopesettingandlongertransp ortation,whereas,elongatedmudstonesprobablyorigi- natedfromundercuttingoflocaloverbanks.
Therelativelysmallcontributionofmud(Fig.6)probabl ycorrespondstoflowstripping,whichcausedgrainsegregationint h e l o n g r u n c o n f i n e d f l o w s a n d b y p a s s o f m u d d y d i l u t e upperpartofthestratifieddensityflow(e.g.,Piper&Normark1983;Pe akalletal.2000;Posamentier& Walker2006;
McHargueetal.2011).Insuchacase,sedimentsoftheMQsh ouldbedepositedintherelativelydistalareatohaveenoughtimeforgrain segregationduringtransportation.
Facies2
TheM Q s e c t i o n c o n t a i n s a f e w l a y e r s o f v e r y f i n e - t o coarse-
grainedsandstoneswithabundantlargeclastsofgreyandre ddish-brownmudstoneandbluish-
whitemarlstones(Fig.7A).Thelayersare1–
2mthickandcanbetracedoverdistanceuptotensofmetres.Th eboundarybetweenfacies1andfacies2isusuallyreflectedbya changeingrain-
sizeandmudcontent.Nevertheless,somebedsoffacies1seemtopassin tostructurelessclast-
richsandstoneoffacies2withnosharpboundary.Angulart o s u b - r o u n d e d c l a s t s r e p r e s e n t t h e s a m e lithologya s i n t h e f a c i e s 1 . H o w e v e r,m a r l s t o n e s i n s o m e clasts,whic haremuchthickerandpoorlybioturbated,lith o-
logicallyresembletheWęgierkaMarl(e.g.,Burzewski1966;G erochetal.1979;Fig.7B).Clastsaremostlyorientedwiththe irlongeraxisparalleltothebeddingwithmaximumsizeupto150x60c m.However,thosewithsizeuptotensofcenti-
metresindiameterdominate.Someclastscontainincisedsand- andgravel-
sizegrainschaoticallydistributedwithintheclastsorfillingclasti cveins.Matrixisrepresentedbyfine-tocoarse-
grainedsandstonewithslightlyhighercontributionofmudt hani nf ac ies1,wh ic hl at e rallym aypa ss in to fin e- to medium-
grained,dark,muddysandstonewithabundantsmallmudstonecla stsandveinsandlensesofcleansandstonesimi-
lartofacies1.Chaoticdistributionofcoarsegrainswithinthematrix i s r e f l e c t e d b y t h e i r n e s t o r p a t c h y d i s t r i b u t i o n a n d lateralchangesintheirdensity(Fig.7C).Fine-
grainedmatrixcontainsThalassinoidesandOphiomorphapreser vedasendich-
nialfullreliefs.Moreover,someofthetracefossilscross- cutmarlstoneclastsandarefilledbythematrix(Fig.7D).
Grain-sizea n a l y s i s o f c l a s t -
r i c h l a y e r s i n c l u d e s s a m p l e s MAN117–
18fromthebottompartandMA21–8,whichwerecollectedin5–
10cmintervalsfromthemiddlepartofthesec- tion(Fig.5).SamplesMAN117–
18showrelativelymuddy (>
25%of mu d c on t e n t b yw e i g h t )f i n e -
gr a i n e d s an d s t on e s . Therei s a n i m p o r t a n t d e c r e a s e i n m e a n g r a i n -
s i z e a n d m u d contentf r o m f a c i e s 1 t o f a c i e s 2 i n t h e s a m p l e s e r i e s MAN11–18.
SamplesMA2 1– 8 sh ow a l t e r n a t i o n s o f f i n e- t o m ed i u m -
grained,graded,cleansandstoneandmuddysandstone.Layersofm u d d y f i n e -
g r a i n e d s a n d s t o n e a r e d i s c o n t i n u o u s l a t e r a l l y andch angetheirthicknessfromafewtotensofcentimetres.Theyc o
r r e s p o n d t o m a t r i x w i t h v e i n s a n d l e n s e s o f c l e a n sandstonedescribedabove.A m a l g a m a t i o n surfacesare presenta t t h e b o t t o m o f t h e l o w e r s t r u c t u r e l e s s c l e a n s a n d -stoneandabovethefine-
grainedsandstoneandstandasboundariesbetweenfacies1andfa cies2.SimilarlytoMAN11–
18,m u d d y l a y e r s a r e m u c h f i n e r- grainedt h a n i n f a c i e s 1cleansandstones.
Orientationofthelongeraxesof103clastswasmeasuredindifferentc last-
richlayers(Fig.4).Mostoftheclasts,which wereaccessib leformeasurement,areconcentratedwithinthe
lowermostc l a s t -
r i c h l a y e r.These d a t a d o n o t c o r r e l a t e w i t h orientation oferosionalstructuresandgrainimbrication, whichi n d i c a t e N W-SEa n d N -
S p a l a e o t r a n s p o r t d i r e c t i o n . Collecteddatash owthatmajorityofclastsareorientedran -
domlywithoutanyspecifictrendwhichmayindicatepalaeo- flowdirection(Fig.4).
Interpretation:Fine-tocoarse-grained,clast- rich,muddystructurelesssandstonesoffacies2areinterpreteda sdebrites.Numerous,c h a o t i c a l l y o r i e n t e d h u g e c l a s t s c o u l d b e t r a n s -
portedonlybymatrixsupporteddebrisflows(e.g.,Shanmugam2006;Strzebo ński2015).Moreover,patchyandnestdistribu-
tiono f c o a r s e -
g r a i n s i m p l y p o o r c o n d i t i o n s f o r g r a i n s e g r e - gation,w h i c h i s t h e f e a t u r e t y p i c a l o f l a m i n a r f l o w.E a c h clast-
richlayerrepresentsoneormoredebrites,whichinsomecasest e n d t o a b r u p t l y p i n c h o u t l a t e r a l l y.Abruptc h a n g e i n thickn essa n d p i n c h -
o u t o f c l a s t l a y e r s o v e r a d i s t a n c e o f severalmet resagreeswiththespatialshapetypicalofdebrites(e.g.,Amy&Tall ing2006).Insomecaselaterally disconti-
nuousmu dd y t yp e of m a t r i x w i t h v e i n s a nd l e n s e s o f c l e a n sandstonemayrepresentlargeerodedmuddyboulders,whi chwerepoorlymixedduringtransportationwithsandymatrixoft hep r e v i o u s f l o w.M o r e o v e r,t h e p o o r r o u n d n e s s o f l a rgerclastsconfirmsweakinteractionsbetweencomponent sduringtransportation.Parallelorientationofclaststothebeddinga ndoccurrenceo f v e i n s f i l l e d b y s a n d -
a n d g r a v e l -
s i z e g r a i n s implymatrixinternalshearstressduringd ebrisflowsmove-
ment.TheoccurrenceofhugebouldersofmarlstonetypicaloftheWę gierkaMarlsuggestsshelforiginofsomedebritesandtherefore ,relativelylongdistanceoftransportation.However,rareo c c u r r e n c e o f t h i n , t e n s o f c e n t i m e t r e s l o n g , u n f o l d e d mudstoneclastsimplythattherewerealsoshort- livedslideswithinternalshearlowenoughtopreventc lastdeformation andf o l d i n g . S i m i l a r l y t o f a c i e s 1 , t h e y m a y d e r i v e d f r o m undercuttingo f l o c a l o v e r b a n k d e p o s i t s . T h e e r o s i o n a l potentialofso medebrisflowsisreflectedbyunevenbottomsurfacesandi ncisionofdebritesintoturbiditic sandstone offacies1 .
Particle-sizeanalysisshowsimportantchangeingrain- sizeandmudcontributionfromdepositsofturbiditycurren tsanddebrisflowsinbothMAN1andMA2samplesseries(Fig.
6).Someo f t h e d e b r i s f l o w s w e r e p r o b a b l y t r a n s f o r m e d f r o m concentratedtohyperconcentrateddensityflowsby increasingcontributionsofcohesivemudfromdisintegrati onoferodedclasts( M u l d e r & A l e x a n d e r 2 0 0 1 ) , w h i c h a g r e e s w i t h t h e abundanceofclastsandpoorbound arybetweensomebedsoffacies1and2.
Occurrenceofclastsofmarlstonecross-
cutbybioturbationstructuresfilledwithsurroundingmatrixi mpliesbioturbationafterd e p o s i t i o n o f d e b r i t e s ( F i
g . 7 C ) . T h i s i n d i c a t e s g o o d post-
depositionale n v i r o n m e n t a l o x i c c o n d i t i o n s f o r b e n t h i c life.Preferentialoccurrenceofbioturbationstructure swithinthedebritesmayresultfromhighercontributionsofs uppliednutrientsorfromperiodsofdecreasedsedimentationrat eafterdepositionofdebrites.Nevertheless,lackofbiotur- bationstructuresatthetopoffacies1bedsmayresultfromerosion.
U P P E R C R E T A C E O U S D E E P- S E A C H A N N E L D E P O SI T S(
S K O L E N
81 G
E OL O GI C A C A R P AT HI C A, 20
Fig.7.Sedimentologicalfeatureoffacies2fromtheManasterzQuarrysection.A—clast-richsandydebrite;B—ahugeboulderofbluish-whitemarlstonesimilartotheWęgierkaMarlinthesandydebriteoffacies2;C—
sandydebritewithclastofmarlstonecross-cutbybioturbationstructuresfilledwithsurroundedmatrix.Whitearrowsshowbioturbationstructures;D—clast-rich(c)sandydebritewithsharpboundarybetweencoarse- grained(c.m)andfine-grainedmatrix(f.m).
82 ŁAPCIK
GEOLOGICACARPATHICA,2018,69,1,71–88 Facies3orlargeboulder?
InthelowerpartoftheMQsection,a1.8mthicklayerofgrey tobluish-
white,calcareousmudstonewithrarealtern a-tionof<
0.6cmthicksiltstoneispresent.Tothetopandbot-
tom,sharpboundarywithsandstoneoffacies1isobserv ed.Laterally,mudstonelayeriscontinuousoveradistanceo fatleast3m.Nevertheless,incompleteexpositiondoesnotallowd eterminationofitstruelateralsizeandcontinuity.Themud- stonei s s t r u c t u r e l e s s a n d i t s h o w s n o s i g n o f b i o t u r b a t i o n . Thesiltstoneislaminatedandrichinplantdetritus .Itshowssharpbottomboundaries.
Interpretation:G r e y,c a l c a r e o u s m u d s t o n e s a r e h e m i p e-
lagictopelagicfaciestypicalofbasinslope.Laminatedsil t-stonesa r e i n t e r p r e t e d a s d e p o s i t s o f d i l u t e l o w - d e n s i t y turbiditycurr ent sa nd corr espond to t h e TdB o u m a d iv i s i o n ,
butt h e i r o r i g i n f r o m b o t t o m c u r r e n t s c a n n o t b e t o t a l l y
excluded.U n c e r t a i n l a t e r a l c o n t i n u a t i o n a n d e x c e p t i o n a l thicknesss u g g e s t t h a t t h i s m u d s t o n e - d o m i n a t e d l a y e r m a y representa l a rgeb o u l d e r w i t h i n a d e b r i s f l o w r a t h e r t h a n acapeofthicksandsto nesfrombelow.Moreover,sometran-
sitionf ro m v er y t h i c k -
be dd e d s a nd s t o n e t ov e r y t h i c k mu d -
stonesmightbeexpected,butitisabsentinthesectionstudied.Nevertheles s,suchamudstonelayermayalsooriginatefromanabruptdecreas eofactivityinthesourcearea,whichresultedinvanishingofsanddepositi oninthestudyarea.
ManasterzQuarrysectionasachannel-fill
Deep-seachannelsareoftenthoughtasprolongationofdeep- seacanyonsorgullies,whichdistributebouldertoclay size m a terialf r o m u p p e r a n d m i d d l e s l o p e t o a b y s s a l p l a i n . Deep-
seachannelsshowmanydifferentformswithtwoendmem bersw h e r e d o m i n a t i n g p r o c e s s e s a r e e r o s i o n ( i n c i s i n g channels)oraggradation(constructivechannels)resp ectively(e.g.,Normark1970;Floodetal.1991;Hübshereta l.1997;Babonneauetal.2002).Deep-
seachannelsaredistinguishedasoneofthehierarchicalelem entswithindeep-waterdeposi-
tionalsystems.Stackingofstoreysorchannelelementsform channelc o m p l e x e s , c h a n n e l c o m p l e x s e t s a n d c h a n n e l s y s -
tems(Spragueetal.2002,2005;Abreuetal.2003).Channelsarerel ativelytemporarystructures,whichmigratelaterallybyavulsionan d l a t e r a l a c c r e t i o n . I n t h i s p ap e r t h e MQ s e c t i o n faciesa reinterpretedasdeep-seachanneldepositswithfea - turesandcharacteristicsthatarediscussedbelow.
ChannelcharacteristicsoftheManasterzQuarrysection
TheM Q s e c t i o n s h o w s t h e f o l l o w i n g f e a t u r e s t y p i c a l o f deep-seac h a nn e l f a c i e s : h i g h s a n d- t o -
mu dr a t i o , o c c u rr e n c e ofthickstructurelessandgraded sandstoneswithpaucityof sedimentarystructures,arelativelyhi ghcontributionofcoarsematerial,nu m e ro u s a m a l g a m a t i o n su r f a c e s , ab un d a n t s c ou r s andrip-
upclastsandbasallagdeposits(e.g.,Mutti&Normark1987;Shanmuga m&Moiola1988;Mayalletal.2006;McHargueetal.2011;H ubbardetal.2014).Facies
UPPERCRETACEOUSDEEP-SEACHANNELDEPOSITS(SKOLENAPPE,POLISHOUTERCARPATHIANS) 8 3
GEOLOGICACARPATHICA,2018,69,1,71–88 comparisoninthesamebasinisausefultoolfordistinguishingbetween
particularfaciesofdeep-
seachannels(McHargueetal.2011).TheMQsectionshows anextremelyhighsand-to-
mudr a t i o i n c o m p a r i s o n t o o t h e r o u t c r o p s o f t h e R o p i a n k a Formation(e.g.,Bromowicz1974;Kotlarczyk 1978).Inthe closevicinityofthestudyarea,onlyafewsmallis olatedout-
cropsw i t h f a c i ess i m i l a r t o t h e M Q s e c t i o n a r e a v a i l a b l e (Salata&Uchman2013;Łapciketal.2016).
Thismaysug-
gestthatdepositsintheMQsectionarerelatedtoachann elaxisdepositionalenvironment.
Animportantfeatureofdeep-seachannelsisthelateraltran- sitionfromchannelaxistochannelmarginandchannel- leveefacies(e.g.,Campionetal.2000;Spragueetal.2002, 2005;Gardneretal.2003;Mayalletal.2006;McHargueetal.2011;
Hubbardetal.2014).Usually,thetransitionfromchannelaxistochan nelmarginfaciesoccursatadistanceofafewhundredsofmetres(e.g.,S hanmugam&Moiola1988;Bruhn&Walker1997;Campionetal.
2000;McHargueetal.2011;Hubbardetal.2014).TheMQthic k-beddedsandstonesareestimatedto totallyp i n c h - o u t t o t h e N W a t a d i s t a n c e o f n o m o r e t h a n 800m ( F i g . 1 C ) . Theo u t c r o p s w h i c h o c c u p y s i m i l a r s t r a t i- graphicpositionstotheMQsandstonesaredominatedbythin- andm e d i u m -
b e d d e d s a n d s t o n e s a l t e r n a t e d w i t h m u d s t o n e s ands i l t s t o n e s ( F i g .2 ) . Thisf a c i esc h a ng e s ug g e s t s a l a t e r a l offsetofchannelfacies,whichpassesintocha nnelmarginorchannell e v e e f a c i e s . I n t h e c l o s e v i c i n i t y t o t h e S E , f a c i e s similartotheMQsectionareunkno wn(Guciketal.1980). Therefore,t hi ck -
beddeds ands ton es probab lyp in ch- outl at e-
rallya t a d i s t a n c e o f t e n s t o h u n d r e d s o f m e t r e s . T h e t o t a l widtho f t h e M a n a s t e r z Q u a r r y c h a n n e l s h o u l d n o t e x c e e d afewhundredsofmetres.
FormationandfillingoftheManasterzQuarrychannel Deep-
seachannelscanbefilledbyturbidites,debrites,slumpsandh emipelagicdepositswithdifferentcontributionsoftheseco mponentsbutwithagenerallydecreasingquantityofmasstra nsportdepositsdowncurrent(e.g.,Shanmugam&Moiola 1988;Dakinetal.2013;Bayliss&Pickering2015a).Channel incisionis mostlyattributed toerosionbyprevious hi gh-
densityturbiditycurrentsorthecurrentresponsiblefo rchannelfilling.However,someofthemcanbecreatedduringby passofdebrisflowswhenerosioncanreachtensofmetres(e.g., Dakinetal.2013).TheMQchannelisfilledwithmixeddepositso f h ig h-
de n s i t y t u rb i d i t y c u r r en t s a n dd e b r i s f l ow s . Numero usa m a l gamations u r f a c e s a n d a l t e r n a t i o n s o f t u r b i - ditesanddebritesimplyamultistageprocessoffillingcharac- terizedbyrepetitivetransitionsfromdepositionwithab asallagthrougherosionofthelagandtochannelfillingwithdomi- nationofstructurelessandgradedsandstones(e.g.,Cl ark&Pickering1 9 9 6 ; G a r d n e r e t a l . 2 0 0 3 ) . Thickness
o f t h e M Q channelreachesatleast31mandisinrangeofch annel-
fillthickness(e.g.,Spragueetal.2005;Mayalletal.2006;Mc Hargueetal.2011;Hubbardetal.2014).T h e lowesthierarchical ar chi te ct ur al e le me nti nch ann el se tt i ng sa re storeysorc hannelelementswiththicknessesusuallydoesnot
exceeding5m(Spragueetal.2002).Theinternalarchitectureoft h e M Q s e c t i o n a l l o w e d t o d i s t i n g u i s h s t o r e y s w i t h t w o basice l ements,w h i c h r e p e a t e d l y o c c u r w i t h i n t h e s e c t i o n . Thef i r s t b a s i c e l e m e n t i n c l u d e s d e b r i t e s o f f a c i e s 2 , w h i c h correspondtobasallagdepositsattheb ottomofaparticularstorey(e.g.,Mayalletal.2006).Occurrenc eofthesedepositsdeterminestheboundarybetweendifferentst oreyslocatedattheirbase.Facies1representsstorey-
fill,depositedaftersedi-
mentationofdebritebasallagdeposits.TheMQsectioncon- sistsoffivestorey-
fillsalternatingwiththreedebritebasallagdeposits( F i g s . 4 , 8 ) . I t i s u n c e r t a i n i f t h e c h a n n e l e l e m e n t turbiditefill5re presentstwodifferentelementsseparatedbypoorlyexposedde briteoroneverythickstorey-
fill(Figs.4,8).Thicknessofparticularstoreyvariesfrom2.5mto 8morupto1 3 m i f t h e c h a n n e l e l e m e n t 5 r e p r e s e n t s o n e c h a n n e l element(Fig.4).Thethicknessofpartic ulardebritebasallagdepositsismuchthinnerandreaches1–
2m.Thecoverofthebottompartofthesectiondoesnotallowustod istinguishthebasall a g d e p o s i t s o f t h e f i r s t s t o r e y.Alte rnativel y,d e b r i t e s mayr e p r e s e n t e v e n t d e p o s i t s , w h i c h r a n d o m l y i n t e r r u p t e d turbidites e d i m e ntationd u r i n g f o r m a t i o n o f t h e c h a n n e l -
f i l l . However,m u l t i p l e r e p e t i t i o n o f 1 ) d e p o s i t i o n o f d e b r i t e l a g deposits,2)erosionofdebritelagdepositsand3)deposition ofhigh-densityturbiditessupportsthefirstalternative.
Thick-
beddedstructurelessandgradedsandstonefaciesandtheirverticalst ackingsuggestthattheMQsectionmayrepre-
sentan a r e a n e a r t h e t h i c k e s t p a r t o f t h e ch a n n e l wh e r e t he coarsestm a t e r i a l i s s t a c k e d . M o r e o v e r,v e r t i c a l s t a c k i n g o f coupletsoffacies1andfacies2suggestsaffiliationt oalargerchannel-
fillorachannelcomplexsetwithanaggradationratehigherthanits lateralmigration.Suchchannelfaciescannot aggradew i t h o u t s i m u l t a n e o u s a g g r a d a t i o n o f l e v e e c o n f i n e- ment(McHargueetal.2011).Hence,interpretationoftheout- cropsinthesimilarstratigraphicpositiontotheNWaschannelmarginorc hannelleveeismostprobable(Figs.1C,2).
Channelformationcanbesubdividedintothreestages:
1)erosionandbypasswhenlargescaleerosionalsurfacesupt otensofmetresareformedandcappedbylagdeposits,2)chan- nelfillwhenthecoarsestmaterialisrepeatedlydepositedanderod edwithsimultaneoussedimentspilloutsidethechannel,and 3)abandonmentwhenthefinestmaterialcapsandsepa - ratest w o c h a n n e l e l e m e n t s ( e . g . , C l a r k & P i c k e r i n g 1 9 9 6 ; Gardnere t a l . 2 0 0 3 ; M a y a l l e t a l . 2 0 0 6 ; L a b o u r d e t t e e t a l . 2008;Dakinetal.2013;Bayliss&Picker ing2015a,
b).Abundanta m a l g a m a t i o n a n d s m a l l s c a l e e r o s i o n , r e l a t i v e l y lowcontributionoflagdepositsanddominationofde positsofcollapsingf l o w s i m p l y t h a t t h e M Q d e p o s i t s r e p r e s e n t t h e channelfillstage.AccordingtoMcHargueetal.
(2011),earlyfillingandamalgamationofachannelbeginsa fterstabiliza-
tionoftheequilibriumprofilebythepreviouserosionalstage.Despit
el o w e r e n e rgyo f t h e f l o w s d u r i n g t h e f i l l i n g s t a g e , erosioni s s t i l l p r o m i n e n t , e s p e c i a l l y n e a r t h e c h a n n e l a x i s . Moreover,occurrenceofclast-
richdebritesiscommonduringtheearlyamalgamationstage(McHar gueetal.2011).Mostofthemodelsassumethatthelaststageofthechan nelformationisa b a n d o n m e n t r e c o r d e d b y s e d i m e n t a t i o n o f t h i n - b e d d e d
deposits.LackoffiningandthinningupwardtrendintheMQsecti onm a y d e r i v e f r o m p o o r e x p o s u r e w h e r e a l l d e p o s i t s representon lya sm al lp ar to fa la rgerch ann el co mpl ex se t. Alternatively,t h e p r e s e n c e o f a n e a r b y s t r o n g l y d e v e l o p e d levee,mayalsoprecludedevelopm entoffiningandthinningupwardt r e n d s ( S h a n m u g a m
& M o i o l a 1 9 8 8 ) . S u c h a l e v e e mayb e r e p r e s e n t e d b y p r e v i o u s l y m e n t i o n e d f a c i e s i n t h e similarst ratigraphicpositiontotheNWoftheMQ.Itispos-
sibletospeculatethathighlyam algamateddepositsfor mingarchitectureoftheMQchannelcorrespondprobablytoa bun-
dantavulsionandlowaggradationofsecondary(inner)over- bankonthescaleofchannelele ments(Deptucketal.200 3;Posamentier&Kolla2003;McHargueetal.2011).
LocationoftheManasterzchannelintheSkoleBasin
Abundanceofmassmovementandsedimentgravityf low depositswithextrabasinalmater ialanddistributio nofmar l-
stonef a c i e s s u gg e s t t h a t s e d i m e n t a t i o n o f t h e mo s t e x t e r n a l partoftheRopiankaFormationtookplaceonthe middleorlowerb a s i n s l o p e o r c l o s e t o t h e b a s e o f t h e s l o p e ( e . g . , Burzewski1 9 6 6 ; B r o m o w i c z 1 9 7 4 ; K o t l a r c z y k 1 9 7 8 , 1 9 8 8 ; Jankowskietal.2012;Łapcik etal.2016).AnalysisofheavymineralsfromtheRopiankaFor mationshowedthatitsdepo-
sitsderivefromanimmaturepassivemarginsetting(Salata&Uch man2013).TheMQsectionrepresentsanareaofabun- dante r o s i o n a n d a b r u p t w a n i n g f l o w s , w h i c h c o r r e s p o n d t o hydraulicjumpoftheflow.Thechannel-
lobetransitionalzoneisconsideredasasiteofabundanthydraul icjumpwithcom-
monscouringanderosionalstructures(e.g.,Mutti&Normark1987
;Wynnetal.2002,Gardneretal.2003).Howeve r,thech annel-lobetransitionalzoneusuallyincludestractionstruc- tures( o f t e n l a rges c a l e ) , w h i c h a r e a b s e n t a t t h e M Q ( e . g . , Mutti&Normark1987;Wynnetal.2002).Highcontribu tionoflargeintrabasinalrip-
upclastsintheMQsectionsuggestsstrongerosionalforcesi nthepreviousflowstage.Hence,theMQc h a n n e l i s p r o b a b l y i n c i s e d i n t o m u d s t o n e - a n d m a r l-stone- richd e p o s i t s o f t h e S k o l e B a s i n s l o p e o r s u c h c l a s t s derivedfromundercutting ofthechannellevees.Th eoccur-
renceofextrabasinal,shallowwatermaterialintheMQ dep ositssuggestsa strongrelationship with theSkoleBas in shelf.Carbonatemudandshelldebriswereredeposit edintooffshoreandafterwardsslopeareasprobablybyl oweringofthes t o r m w a v e b a s e . S u c h m a t erials u g g e s t s a r e l a t i o n s h i p withcanyonsorgullieswhichcaptureditafte rredepositionbystormeventsfrommoreproximalareas.
Previouslypostulatedsimultaneousaggradationofover- bankdepositsandchannel-
fillisstronglyrelatedtocontribu-
tionofoverspilledmudfromturbiditycurrentsandwithproxi mal-to-
distalpositionofthechannel.Theheightofleveescanreach hundredsofmetresanddecreasesdowncur-
rentw i t h d e c r e asinga m o u n t s o f t h e f i n e -
g r a i n e d c o h e s i v e materialwhichstabilizeleveebanks(Da muth&Flood1985).Thelowcontributionofmudwithindepo sitsofhigh-
densityturbidityc u r r e n t i n t h e M Q s e c t i o n s u g g e s t s s p i l l o v e r a n d bypassofmoremuddypartsoftheflow.Furt herevidencefor
Fig.8.TheManasterzQuarrysectionwithdistinguishedchannelelements.A—theManasterzQuarrywithdistinguishedchannelelements.B—topoftheManasterzQuarrywithdistinguishedchannelelements. strongb y p a s s i s t h e a l m o s t c o m p l e t e lackoforganicdetritusandcoald ebrisintheMQsection.Suchmaterialiso ftena n i m p o r t a n t c o m p o n e nto f thi ck-
beddeds a n d s t o n e s i n t h e RopiankaF o r m a t i o n ( e . g . , K o t l a r c z y k
&Ś l i w o w a 1 9 6 3 ; Ł a p c i k e t a l .2 0 1 6 ; Łapcikinpress).Itisunlikelythatthesede positsa r e r e l atedt o a n o t h e r s o u r c e areathansandstonesfromthelowerpart o f t h e s e c t ion( M a n a s t e r z - Rzeki)becauses u c h m a t e r i a l i s k n o w n f r o m evenyoungerdeposits(e.g.,Ko tlarczyk
&Śliwowa1963).Therefore,themost probablescenarioisbypassoforganic detritusandcoal,whichwasdeposited ina m o r e d i s t a l a r e a , f o r e x a m ple, i n thel o b e -
l i k e d e p o s i t i o n o f t h e S ł o n n e sect ion( Ł a p c i k i n p r e s s ) .H e n c e , t h e MQchannelshouldbesituatedinrel a-
tivelyproximalareaonthelowerslopeor nearbaseoftheslope.AccordingtoGard nere ta l.
(2003),t he MQ se ct io n showsf e a t u r e s o f t h e f i l l s t a g e o f achannelsit uatedinthelowerslopeorbaseo f t h e s l o p e . T h i s a l s o s t a n d s i n agreement w i t h t h e p r o x i m a l l o c a t i o n oft h e M Q s e c t ionw i t h i n t h e s e c o n d thrusts h e e t f r o m t h e n o r t h e r n Carpathianmargin.
Palaeotransport directions andsinuosityoftheManasterzChannel DepositsoftheRopiankaFormatio nshowd ire ct io ns oft hep al ae ot ra n sportfromNW,NandNEwithdominanceof theNWdirectioninthevicinityofthes t u d y a r e a ( K s i ą ż k i e w i c z 1 9 6 2 ; Bromowicz1974).Thepalaeotransportd ataf r o m t h e M Q i n c l u d e o n l y m e a -
surementso f s c o u r o r i e n t a t i o n a n d grainim bri ca ti on wi th in th es t ruc tur e-
lessandgradedsandstones,whichindi- catet r a n s p o r t a t i o n f r o m t h e N W.
Nevertheless,directionsoftransportin adeep-
seachannelmaybevariableandarerarelyu nidirectional.Spatialdistri-
butionandorientationoflongbeltso fthick-
beddedsandstonefaciesintheexternal partoftheRopiankaFormationisconsistentwi ththepresenteddataanda ls opoi nt to th eNW–
SE axi s (Guciketal.1980). Allthese dataare premisesf o r d e p o s i t i o n o f t h i c k-bed-
dedsandstonefaciesinthevici nityo f
thes t u d y a r e a l o n g i t u d i n a l t o t h e s l o p e o f t h e S k o l e B a s i n . Mosto f t h e s e f a c i e s s u g g e s t a s t r o n g r e l a t i o n s h i p w i t h t h e ŁańcutChannelZoneproposedbyKotlarczyk&
Leśniak(1990)fortheOligocenedeposits(seealsoSalata&Uch man2012,2013).Itseemsthatthischannelzonewasalreadyactiveduring theLateCretaceous.
Thepreviouslymentionedlateralo ffsetofthefaciesfr omthechannelaxistothechannelmarginorchannelleveefrom theMQ se ct io nt ot he Ma na st er zs ec t io na ll ow ss pe cu l at io n abouts i n u o s i t y o f t h e s t u d i e d c h a n n e l . O t h e r w i s e , a x i a l o r off-
axialchannelfacieswouldbecontinuedtotheNWintheManast erzsection.Hence,thechannelfaciesoutcroppingin the MQshouldchangetheirorientationtotheNortheWtoevad et h e Ma n a s t e r z c h a nn e l l e v e e f a c i e s . N e v e r t h e l e s s , t he MQsectiondoesnotappeartohavelateralaccretionpackagesthath a v e b e e n d e s c r i b e d i no t h e r m e a n d e r i n g c h a n n e l -
f i l l deposits( e . g . , B o u m a & C o l e m a n 1 9 8 5 ; M u t t i &
N o r m a r k 1991;Abreuetal.2003;Janockoetal.2013).Unfo rtunately,coveringofthearea,tectonicdeformationsandinclin ationofbedsdoesnotallowtrackingofthechannelfacies.
InterpetationoftheManasterz-RzekiandManasterzfacies BottomandtoppartsoftheManasterz-
RzekiandtheManasterzsection
Theb o t t o m a n d t o p p a r t s o f t h e M a n a s t e r z -
R z e k i s e c t i o n showm a n y s i m i l a r i t i e s t o t h e b o t t o m p a r t o f t h e M a n a s t e r z section(Fig.2).Thin-tomedium- beddedsandstonesandmarlstoneswithabundantparallel,cro ssandconvolutelami-
nationsprobablycorrespondtochannelleveeorinter-
channeldeposits.Thedecreasingcontributionofmarlstonesinthebot- tompartoftheManasterzsectionsuggeststhatthisintervalissituat edabov et he se co ndma rl st on e-
ri ch int er va lof th e Manasterz-
Rzekis e c t i o n ( F i g s . 1 C , 2 ) .S u c h m a r l s t o n e s a r e widel yd i s t r i b u t e d i n t h e R o p i a n k a F o r m a t i o n i n t h e w h o l e marginalp a r t o f t h e S k o l e N a p p e ( e . g . , K o t l a r c z y k 1 9 7 8 , 1988;Leszczyńskietal.1995).Themarlstonesa reconsideredasc a l c i t u r b i d i t e s w it h t h e i r s ou r c e a r e a s i t ua t e d in t h e sh e l f surroundingtheSkoleBasin.Theyweredeposited bylow-den-
sityturbiditycurrentsinthemarginalpartoftheSkoleBasin,whic hprobablycorrespondstothebasinslopeandbaseoftheslope.H o w e v e r,m a r l s t o n e c l a s t s f r o m t h e M Q d e r i v e f r o m erosi ono f m a r l s t o n e s f o r m t h e o l d e r p a r t o f t h e R o p i a n k a Formation.Afterpartlylithific at ionthey,wererippe dupbyhigh-
densityt u r b i d i t y c u r r e n t s a n d r e d e p o s i t e d i n t o a m o r e distalarea.
Thick-beddedsandstonesoccurintheManasterz-
RzekiandManasterzs e c t i o n s . S t a c k i n g o f t h i c k - b e d d e d , s t r u c t u r e l e s s andgradedsandstonesoftenwit hparallellaminatedtopalter-natingw i t h t h i n -
a n d m e d i u m -
b e d d e d l a m i n a t e d s a n d s t o n e s suggestchannelo r depositi onall o b e f a c i e s . H o w e v e r,thethicknessa n d s a n d - t o -
m u d r a t i o o f t h e s e i n t e r v a l s t o g e t h e r withsparseam algamationandscourssuggestsomedistance fromtheaxisofs uchbodiesincomparisontotheMQsection.Bothsectionsrepresentpr ogradationandaggradationofsome
sand-
richb o d y.D e c r e a s i n g c o n t r i b u t i o n o f m a r l s t o n e s w i t h simultaneousincreaseinthick-
beddedsandstones(Fig.3)mayimply:1)decreasingactivityinthec arbonatesourcearea,
2)p r o g r a d a t i o n o f a s a n d b o d y w h i c h t e m p o r a r i l y b e c a m e anobstacleforcalciturbidites,or3)increasing activityinthesiliciclasticsourcearea,sedimentsfromwhichdilut edthecar-
bonatesedimentation.Therelativeproximityofthesedepositscanbe referredtothemarginalpositionofthestudyareaintheSkoleNappe(
secondthrustsheetfromtheCarpathiansmar-
gin).Tectonicd e f o r m a t i o n s o f t h e s t u d y a r e a d o n o t a l l o w certaincorrelationbetweenthesectionsstudied.Itisnotc learwhetherthetwothick-beddedintervalsoftheManasterz- RzekiandManasterzsectionsrepresentthesamesandbodyortwodiff erentsandbodies.Themaindifferencebetweenthesethick- beddeds a n d s t o n e s i s a b u n d a n c e o f c o a l d e b r i s i n t h e Manasterzs e c t i o n . H o w e v e r,t h i s i s t o o w e a k a p r e m i s e t o excludeanyalternative.Ifthetwointervalsrepresentdiff erentbodies,theintervalwithdecreasingcontributionofmarlstonesa tthebottomoftheManasterzsectionmaycorrespondtothelate raloffsetofchannelorlobefaciesoftheManasterz-
Rzekisection,a n d t h e u p p e r p a r t o f t h e M a n a s t e r z - R z e k i s e c t i o n mayc o r r e s p o n d t o c h a n n e l a b a n d o n m e n t f a c i e s o r c h a n n e l leveefacies.Thesespecul ationsalsoimplyonlateralmigra-
tiono f s a n d y b o d i e s a t t h e d i s t a n c e o f h u n d r e d s o f m e t r e s derivedprobablyfromavulsion(Fig.1C).
TheWęgierkaMarl
TheW ę g i e r k a M a r l i s w i d e l y k n o w n f r o m t h e R o p i a n k a Formationi n t h e e x t e r n a l p a r t o f t h e S k o l e N a p p e a n d i s mostlyrepresentedbypackagesoffine- grained,muddysand-
stoneswithmudstoneandmarlstoneclasts,uptotensofcenti- metresthick,andsandycalcareousmudstoneswithdispersed quartzpebblesandclastsofmarlstone.Moreover,hugemarl- stoneolistolithsarealsoknown(Burzewski1966;Kotlarczyk1 978,1988;Gerochetal.1979).Suchdepositsmostlyrepre- sents l u m p s a n d d e b r i s f l o w s o r i g i n a t i n g i n t h e m i d d l e t o lowerslopesetting.Theirabundanceands patialdistributionsuggestt h e i r c l assificationa s m a s s t r a n s p o r t d e p o s i t s c o m -
plex,whichinfluencedthebasinfloormorphology.Masstrans portdepositsoftenoccuratthebottomofchannelsand c hannelc o m p l e x e s ( C l a r k & P i c k e r i n g 1 9 9 6 ; M a y a l l e t a l . 2006;Bayliss&Pickering2015a).Inthestudyarea,th eWęgierkaM a r l f a c i e s a r e l o c a t e d a t t h e b o t t o m o f t h e M Q channelfacies.Hence,theManasterzQuarrychannelcomple xwasformedonitsfloorwithabundantdebriteswhich couldstandasconfinementoftheinitialchannelzone.Int heLeszczynyMember,theWęgierkaMarlandthick- beddedsandstonesoftenalternate(e.g.,Burzewski1966;Bro mowicz1974;Kotlarczyk1978,1988;Gerochetal.1979)butitis notclearifmassivesandstonesoftheMQsectionaresituatedonlyatthet opoftheWęgierkaMarl,oriftheyalsoborderwith the
mlaterallyand/orarecappedbythem.Someofthedebritesint h e M Q s e c t i o n c o n t a i n h u g e b o u l d e r s o f m a r l s t o n e v e r y simila rtotheWęgierkaMarl.Thissuggeststhatmasstrans - portoftheWęgierkaMarldepositsalsofilledsomechannels
