Table Of ContentLecture Notes ni
Earth Sciences
Edited by Somdev Bhattacharji, Gerald M. Friedman,
Horst .J Neugebauer and Adolf Seilacher
51
Volker H. Jacobshagen ).dE(
ehT System Atlas fo Morocco
Studies on sti Geodynamic Evolution
galreV-regnirpS
Berlin Heidelberg NewYork London Paris oykoT
Editor
Prof. Dr Volker H. Jacobshagen
Frele Unlversltat Berhn
FB Geowissenschaften, Instltut fur Geologle
Altensteinstrasse 34a, D-1000 Berhn 33, FRG
ISBN 3-540-19086-4 Sprmger-Verlag Berhn Heidelberg New York
ISBN 0-387-19086-4 Springer-Verlag New York Berlin Heidelberg
yrarbtL Congress of nohachbuP-nt-gmgolataC system/ Atlas the of evoluhon Data Geodynamlc
H Volker Morocco / Jacobshagen, ed p cm -(Lecture notes ni scrences, earth )51 the of "One
the on conference a was book this of sources cJmanydoeg m organtzed system, Atlas the of aspects
Berltn ni 1986" by Kontlnentalrander"-Pref akhver the Forschungsgruppe "Mobrhtat
ISBN 0-387-19086-4 U( S )
1 Geology-Morocco-Atlas Mountains 2 Geology-Morocco-Antt-Atlas Mountains 3 Geo-
dynamics .I Volker Jacobshagen, II Senes
QE339 MSG36 1988 556 4'4-dc 91 88-12329
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ECAFERP
ehT mia of this volume is to reflect the current state of geoscien-
tific activity focused no the cimanydoeg evolution of the Atlas metsys
dna to discuss wen results dna ideas. ehT volume provides a selection
of papers no the geological history, structural development, dna geo-
physical data of Morocco. It saw ton possible to cover all areas of
geoscientific interest, however, ew hope to shed emos light no the
major cimanydoeg problems.
enO of the sources of this book saw a conference no the cimanydoeg
aspects of the Atlas system, organized in Berlin in 6891 yb the For-
schergruppe "Mobilit~t aktiver Kontinentalr~nder". ehT financial sup-
port for this project is being provided yb the Deutsche -egsg~!:thcsroF
meinschaft dna yb the Freie Universit~t dna the Technische Universi o
t~t of Berlin (West). Furthermore ew are very glad to mention that ew
evah received a great rebmun of publications yb authors from different
countries ohw did not take part in the Berlin conference.
It should eb noted that, at present, a lot of international geo-
scientific activity is concerned with Morocco. This is not only eud
to the fascinating complexity of naccoroM geology dna the beautiful
outcroups, that yam provide the yek to ynam general problems, but also
testifies to the liberal dna prescient science politics of the -coroM
nac authorities, most of all the Ministery of Energy dna Mining in
Rabat. Therefore, no behalf of all the authors from abroad, I take
the opportunity to express our deepest gratitude to ruo host country,
especially to the leaders of the Division ed la G~ologie, the general
director .rD .M Bensaid dna the directors .M inamhaD dna .M .aduommaH
sknahT are, furthermore, eud to Springer Verlag (Berlin-Heidelberg-
weN York) for offering the opportunity to publish a evisneherpmoc
emulov dna especially to .rD gnagfloW Engel for his patience dna help-
ful advices.
.V negahsbocaJ
CONTENTS
INTRODUCTION
JACOBSHAGEN, V.: Geodynamic evolution of the Atlas System,
Morocco: an introduction 3
ANTI-ATLAS 11
WALLBRECHER, E.: The Anti-Atlas system tan overview 31
WALLBRECHER, E.: A ductile shear zone in the Panafrican
basement on the northwestern margin of the West-Afri-
can craton (Sirwa dome, central Anti-Atlas) 91
BASSIAS, Y., WALLBRECHER, E. and WILLGALLIS, A.: Tectono-
thermal evolution of the Late Panafrican orogeny in
the Central Anti-Atlas (Southern Morocco) 43
BRABERS, P.M.: A plate tectonic model for the Panafrican
orogeny in the Anti-Atlas, Morocco 16
BUGGISCH, .W and FLOGEL, E.: The Precambrian/Cambrian
boundary in the Anti-Atlas (Morocco). Discussion ~nd
new results 18
SDZUY, K. and GEYER, G.: The base of the Cambrian in
Morocco 19
BUGGISCH, .W and SIEGERT, R,: Paleogeography and facies
of thed~r~s terminaux'~(uppermost Lower Cambrian,
Anti-Atl as/Morocco) 107
BUGGISCH, W.: Diagenesis and very low-grade metamor-
phism of the Lower Cambrian rocks in the Anti-Atlas
(~4orocco)
123
HIGH DNA MIDDLE ATLAS
129
SCHAER, J.-P.: Deformation of igneous dikes in and
around the Tichka granite, High Atlas - Morocco 131
LORENZ, J.C.: Synthesis of Late Paleozoic and Trias-
sic redbed sedimentation in Morocco 139
EMRAW J.E.: Jurassic carbonate facies of the Central
and Eastern High Atlas rift, Morocco 169
BRECHBQHLER, Y.A., BERNASCONI, R. and SCHAER,J.-P.:
Jurassic sediments of the Central High Atlas of
Morocco: Deposition, burial and erosion history 201
FROITZHEIM, N., STETS, J. and WURSTER, P.:
Aspects of !qestern High Atlas tectonics 219
,I~,EGAHSBOCAJ V , BREDE, R , HAUPTMA~IH, M HEINITZ,W
and 7YLKA, R : Structure and post-Palaeozoic evo-
lution of the central High Atlas
245
lV
FRAISSINET, C., ZOUINE, E.M., MOREL,J.-L., POISSON, A.,
ANDRIEUX, J. dna FAURE-MURET, A.: Structural evolution
of the southern and northern Central High Atlas in
Paleogene and Mio-Pliocene times 273
,YANSERD .R du: Recent data no the geology of the Middle-
Atlas (Moro, cco) 392
HERBIG, H.-G.: Synsedimentary tectonics in the Northern
Middle Atlas (Morocco) during the Late Cretaceous dna
Tertiary 123
,ZRA/,!HCS .G dna WIGGER,P.J. Geophysical studies of the
earth's crust and upper mantle in the Atlas system of
Morocco 933
CIOZONEC BASINS 953
G~RLER, K., ,HCADMLEH F.-F., ,SREMEAG P., HEISSIG, K.,
HINSCH, W., =RELD#M K., ,SNAHZRAWHCS .I~ dna ZUCHT, .M
The uplift of the central High Atlas as deduced from
Neogene continental sediments of the Ouarzazate pro-
vince, Morocco 163
,HCADMLEH F.-F.: ehT ostracode fauna of the Ait Kandoula
region: systematic description 504
ST~BLEIN, G.: Geomorphological aspects of the Quaternary
evolution of the Ouarzazate basin, Southern Morocco 334
SCHMIDT, K.-H.: Rates of scarp-retreat: a means of dating
neotectonic activity 544
SESEHTNYS 463
,AGLED-DNARUD .M and OLIVIER,Ph.: Evolution of the Aiboran
block margin from Early Mesozoic to Early Miocene time 465
,NEGAHSBOCAJ V., G~RLER, K. dna GIESE, P.: Geodynamic evo-
lution of the Atlas System (Morocco) in post-Palaeozoic
times 184
Introduction
CIMANYDOEG NOITULOVE FO EHT SALTA ,METSYS :OCCOROM
NONIATCUDORTNI
Volker negahsbocaJ
Institut fur Geologie, Freie Universit~t Berlin,
Altensteinstr. 43 ,A 0OOl-D Berlin 33
ehT Atlas metsyS
ehT northwestern margin of Africa, neewteb eht Atlantic naecO dna
eht Lesser Syrtis, is characterized yb high mountain ranges, eht ele-
vation of which stnuomrus 000.3 m in the western part. Jbel lakbuoT
(4.165 )m in eht High Atlas is eht highest mountain of North Africa.
esehT ranges have neeb synchronously uplifted since eht Miocene. yehT
differ, however, both in structure dna geological history. ehT -erhgaM
bides consisting of eht Rif dna Tell Atlas along eht Mediterranean
coast era a typical Alpidic negoro with xelpmoc eppan structures. ehT
segnar in their southern foreland, called eht Middle dna High Atlas,
era anorogenic intracratonic mountain belts separated yb elevated pla-
teaus. ehT eastern prolongation of eht High Atlas is formed yb the -aS
narah dna Tunisian Atlas. ehT Anti-Atlas, which however, lies south of
eht High Atlas in ,occoroM originated yb simple gnimodpu of the Pre-
nairbmac tnemesab of eht arahaS craton. sA all these ranges era -oeg
graphical andgeological related to hcae other they have neeb deman
eht Atlas system yb .M RETHCIR (1970).
,suhT ew find a mobile zone in eht southern foreland of eht -erhgaM
bide orogen, which in southern occoroM extends pu to 005 mk into the
African plate. sA eht southern border of this enoz diverges erom dna
erom from eht sediberhgaM to eht southwest, ew yam emussa that its -oeg
logical evolution cannot eb solely decuded from eht Mediterranean oro-
,seseneg tub smees to eb erom .xelpmoc
Geotectonic subdivision of occoroM
ehT Moroccan segment of the Atlas system is relatively well known.
For na overview, the publications of DRAHCIM (1976), TREBUOHC and
TERUM-ERUAF (1962, 1971, 1973) and TERUM-ERUAF and TREBUOHC (1971) are
recommended. The geotectonic subdivision of the Moroccan Atlas system
is nwohs in fig. 1 dna is briefly described here:
SEA
0
0
0
\
,,x o on o o o o ~ o re=l o ~ I • :~$~Z1
acI((cib~$o£ ii;iC~i~ ~~ '~' SETUAH XUAETALP
"v
,,x
"t"
*OOZ
~!iiiiiiii!!iiiiy ' ....
[3 ,°=tnoou-.R
...... ~ c=zoea=e
tsoP n- oinycroH :revoc
[~ reppU ciozoretorP
r,ppU ci0zn,eC se0,,n0tav f--I pi,te,u,
nairbmacerP
[~ reppU cioznoeC snisab (~ hgiH dne elddiM seltk
Fig. I: Geotectonic sketch-map of the Atlas system
of Morocco, based no DRAHCIM (1976)
ehT narrow arc of the Rif orogen in the north is overthrust towards
the S no na Upper Cenozoic marginal trough. oT the ,WS the orogenic
belt is bordered yb the hills dna plains of the naccoroM Meseta. Its
Variscan tnemesab is exposed in large areas from under a cover of
flat-lying Mesozoic dna Palaeogene sediments. oT the ,ES the ateseM
dna the Rif are bordered yb the High dna the Middle Atlas. Both ranges
developed from early Mesozoic rift grabens which originated in cor-
relation to the opening of the Western Tethys dna of the North Atlan-
tic .naecO
Rifting saw deinapmocca yb mafic volcanism, which culminated in the
reppU Triassic/Liassic dna in the Dogger. emoS intrusions, however, are
of Cretaceous dna even Palaeogene age. ehT structure of the High dna
Middle Atlas generally correspond to each other, both gniwohs a base-
tnem of Palaeozoic or Precambrian rocks that is covered yb thick Trias-
sic dna Jurassic sediments. Prevailing structures era steep faults, -om
noclines dna strike-slip faults. In places, especially in the central
dna eastern High Atlas, overthrusts, xob folds dna even overturned
folds exist. However, essential criteria of orogens such as: ophiolites,
nappes, flysches, regional msihpromatem dna granitoids are not devel-
oped. Both ranges are deinapmocca yb a wef small Cenozoic basins. ehT
Middle Atlas forks off from High Atlas in a northeastern direction, -ne
closing the so-called High Plateaus of Oran. ehT Variscan tnemesab of
these plateaus is covered yb Mesozoic sediments, which are in the
southwest overlain yb the Cenozoic of the Haute .ayuoluoM
ehT High Atlas is separated from the Anti-Atlas yb the ssuoS dna
the Ouarzazate basins ("sillon pr~africaine"). sA suggested yb OSSUR
dna OSSUR (1934), ynam geologists believe that the High Atlas is bor-
dered to the S yb na important fault zone, nwonk sa the South Atlas
Marginal Fault zone ("accident sud-atlasien"). Although several authors
doubt that this fault really exists, others have already introduced
it to plate tectonic concepts. emoS of meht even believe it to eb the
northwestern boundary of the African plate (e.g. YEWED etal., 1973).
ehT Anti-Atlas saw formed yb wide-spanned gnimodpu of marginal parts
of the Sahara craton. Precambrian rocks form the core of major semod
("boutonnieres") in the axial zone of the range. Normally, this base-
tnem is covered yb poorly deformed sediments of tsomreppU Proterozoic
or Lower Palaeozoic age. In the Tafilalt region (Southeast Morocco),
the Anti-Atlas dips to the E beneath demrofednu Cretaceous stnemides
of the Sahara platform.
