Geology of the Northwest African Continental Margin

709 Pages·1982·126.698 MB·English

by  U. von Rad K. Hinz M. Samthein E. Seibold (eds.)

aT
136 120
4169m
~+ ~+~
:-+~ Tp
-::..-=_-
Tml
Front Cover Figure Ku. ""--~- Kap TP253m
TP313m
Geological sketch map of Northwest 416/370
Africa and its continental margin, ~~~ p-a ~~~..L~ Kap
modified and updated from various rp689m
sources by U.v.Rad. Base map (azi
muthal projection), depth contours
(in km) and onshore geology modified 415
from Tectonic Map of Africa 2794m
1:5 000 000 (A.S.G.A./UNESCO, 1968) ~_~ Tp-Q
and L. Jansa (In.Rep. DSDP, Vol. 41, ~~t:: Tpa
1978); bathymetry modified and gener
alized after Hinz et al., Ranke et
al., toVissmann (all, this Vol.). Li
thological and stratigraphic columns
of DSDP Sites after Initial Reports
of the Deep Sea Drilling Project.
Note: Leg 79 Sites 544-547 have not
been incorporated in this figure (see
Hinz, Winterer et al., this Vol.) .
TP1079m
Lithological symbols:
g
1
1 shells (coquina); 2 foraminiferal 137 138 397 369
nanno oozei J nanno ooze; 4 nanno 5361m 5288m 2900m
chalk; 5 limestone; 6 marl; 7 marl -=---=-:. ? ::'-='.':' Tm ~-+-"!" Q
stone; 8 clay, shale: 9 coal, lig TI :..;;:....: To ~_..L
nfiintee : sa1n0d s; il1t2y /ssaanndd (ys tocnlaey) :: 1113 csoialtrs/e ~-:;'-:-.F-~-:~.- ~ KKKuca eb -~=="='-:.-.-.=- =:. TKTieul< ~.~.."...-3. .~y.~­~ Tp
--- Kce
sand (stone)/conglomerate: 14 turbi TP401m
TP442m
dite; 15 dolomite; 16 siliceous (ra
diolarian, diatom) ooze: 17 porcel 140 139
3047rn
lanite, chert: 18 volcaniclastic
~ ~ Q 51A-1
sandstone/conglomerate: 19 basalt :~: Tp
(oceanic basement): 20 basalt (sill). 1:':
Tp
~:1~ Tmu
Stratigraphical abbreviations:
Q Quaternary: Tp Pliocene: Tm Miocene :t~~ Tmm
(Tmu Tmm Tml = upper, middle, lower ._-...; :: Tpa ~~Tml
·:';·.·;:::.·i;;; Kma
Miocene); To Oligocene: Te Eocene; TP651m TP665m
Tpa Paleocene; Tl lower Tertiary; Ku
upper Cretaceous: Kma Maastrichtian; 12 141 368
Kcp Campanian: Kco Coniacian: Kt Tu 4557m 4148m 3367m
:::.=-:;
ronian: Kce Cenomanian: Kab Albian; i~-~!Q/TP ~p
~~~I!
Kap Aptian: Kba Barremian; Kh Haute -=.. ..- --Te -=-.== ?TI _ ~ Tm
rivian; Kv Valanginian: Kb Berria
TP218m ?To
sian: Kl lower Cretaceous: Ju upper TP 298m "'=-... :=.
Jurassic (Kimmeridgian/Tithonian): 366 367 ~::. ... _ Te
T/K Paleogene/upper Cretaceous (un 2!~~Q ~~~Q --::A:. .-..:.C =:=-
diff.) .
~=...L.= Tp -_-_- Tpa
Geographical abbreviations: ~;5Tm ~~: Tm
A.B. Atlas Basin: A.C. Agadir Canyon: ~~.. -.= - Te • v v v KI
Ag Agadir: A.-T.B. Aaiun-Tarfaya Ba ~.3--,- TI TP985m
sin; Cas. Casablanca; C.Can. Cayar ~.~~ Ku
= 13
Canyon; CONC.BK. Conception Bank: -;-:::=; Kce 4585m
CD..RB.. CDaopu kRkhaliar; BCas.Sin. : CEa yEars sSaeoaumiroau;n t; -~-=:: KI I~.:;~ ?Kap
E.B. Essaouira Basin; FU Fuerteven ~-=-=- Ku
tura; G.C. Gran Canaria; Gibr. Gi ~~--_=-.:.:-L
braltar; GOR.BK. Gorringe Bank; ~:=-=~ Ku
TP1153m
S.A.B. South Atlas (Agadir) Basin; TP463m
LA Lanzarote: M.P. Mazagan Plateau;
S Safi; T Tizi n'-Test Fault; TE Te
nerife; T.P. Tafelny Plateau.
~.~• • ~ ?Kh
TP3330m
30 25 (2
35
30
o
:so
..,', ,~
...~ ~ or
+ +
30
+ +
,,"'- + +
... + + + +
... ~ + -I- + + +
~ + + + + + +
+ + + 6~S\N+ + + +
.137 + + l\NOOUF -I- + + + + +
.138 + + + + + + + + + + +
25 + + + + + + + + + + + +
+++~ +++++++
++++ ~~\ ++++++++++++++++
+ ~~+ + + + + + + + + +
+ + + + + + + + + +
+~'+
. + + + + + + + + + + + + +.
~+ + + + + + + + + + + + + 25
~ + + + + + + + + + T+ ++ + +
'"' 1..'9" + -<. + + + + + + + + + + + + +
+i
~~ +~~ + + + + + + + + + + + + + + + + + + + + + + + + + +
+ +,::,Q:; '$".;:,' + + + + + + + + + + + + + +
'+ +~O ,,+ + + + + + + + + + + + + +
«-~ +<v +++
'V +~+++
+ + + + + + Unfolded Mesozoic-Cenozoic
20 : + + I + + + + I ~~ coastal basins
\ + + + +MAURETANIA
...... ++++++
Tertiary volcanic islands
.+++++
'. +++++ 20
\+ + + + + I:.':: :':.: :1 Alpine fold belts and
".+++++ foredeeps
'. + + + + •••• 0' •
+ + + +
SENE~·
.+ + + + Variscan and Alpine fold belts
: + + + + ~ (Atlas Mountains)
:+ + + +
\+ + + + ~
. + + + Variscan fold belts
... .t + + +
+ + +
~
Precambrian crystalline massifs
+++++ ~
with(post-)Paleozoic platform
~.+++ ~ cover
+ + 15
OSDP/IPOD Site
. + + + water depth(m) •
'+ + + o 1 @ Commercial Shelf
+ + + "!+ -I- 2 Well SPANSAH
+ + + ~...,.. 3 5IA-I(CONOCO,1969)
+ + + + + 4
GAMBIA + + + + + + 5
+ +. + + + + + 6
AB. PLAI N tOVE + + + + + 500 7
B +++++ 89
10
+ BASIN + + + + + + + +
11
10 + + + LIBERIA
+ + + 12
+ + + + + 13
+++++1000 ....... 14 10
UPPER VOLTA 15
+ + + + + -v--v--
","'f", 16
+ MASSIV+ + ~v\~ ~~
+ +
Fr.etown v v v 19
+ + +1500
~'-' + + + + vvv
+ + m vvvv 20
~---,~ + total penetration(m)
(,TP)
+
.13

Geology of the
Northwest African
Continental Margin
Edited by
U. von Rad K. Hinz M. Samthein E. Seibold
With 325 Figures
Springer-Verlag
Berlin Heidelberg New York 1982
Dr. Ulrich von Rad
Prof. Dr. Karl Hinz
Bundesanstalt fUr Geowissenschaften und Rohstoffe
Stilleweg 2, 3000 Hannover 51, FRG
Prof. Dr. Michael Sarnthein
Prof. Dr. Eugen Seibold
Geologisch-Paliiontologisches Institut der Universitat
OlshausenstraBe 40/60,2300 Kiel, FRG
Front cover motif: Prof. P. Wurster, Bonn
ISBN-13 :978-3-642-68411-1 e-ISBN-13 :978-3-642-68409-8
DOl: 10.1007/978-3-642-68409-8
Library of Congress Cataloging in Publication Data. Main entry under title: Geology of the
northwest African continental margin. Bibliography: p. Includes index. 1. Geology - Africa,
Northwest. 2. Continental margins - Africa, Northwest. I. Rad, Ulrich von. QE339.N67G46
556.4 81-18550 AACR2.
This work is subject to copyright. All rights are reserved, whether the whole or part of the material
is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting,
reproduction by photocopying machine or similar means, and storage in data banks. Under § 54
of the German Copyright Law where copies are made for other than private use, a fee is payable
to "Verwertungsgesellschaft Wort", Munich.
© by Springer-Verlag Berlin Heidelberg 1982.
Softcover reprint of the hardcover 1st edition 1982
The use of registered names, trademarks, etc. in this publication does not imply, even in the
absence of a specific statement, that such names are exempt from the relevant protective laws
and regulations and therefore free for general use.
2132/3130-543210
Preface
The Northwest African and the conjugate Northeast American con
tinental margins provide excellent examples of mature passive
continental margins which record in their thick sediment cover
the birth and evolution of the Atlantic Ocean Basins during
the past 200 million years. Due to a dense net of single- and
multichannel seismic reflection lines, numerous Deep Sea Drill
ing Project (DSDP) sites and petroleum exploration wells, and
the well-known onshore geology, the Northwest African margin
is one of the bes"t-documen ted margins of the world. A particu
lar advantage of this margin is that its coastal basins are
well exposed and accessible for detailed stratigraphic studies
and onshore-offshore correlations, whereas the Mesozoic-Ceno
zoic marginal basins off eastern North America underlie only
the present continental shelf and slope.
During the past decade, the Northwest African margin was stu
died in great detail, particularly by the Woods Hole Oceano
graphic Institution, Lamont-Doherty Geological Observatory,
Imperial College London, Shell Internationale Petroleum Maat
schappij (Den Haag), Kiel University, and the Bundesanstalt
fiir Geowissenschaften und Rohstoffe (BGR) at Hannover. A num
ber of important synthesis papers summarized these results;
e.g., Summerhayes et al., 1971; Dillon and Sougy, 1974;
Seibold and Hinz, 1974; Uchupi et al., 1976; Lehner and de
Ruiter, 1977 (all quoted in the references of Seibold, this
Vol.). During the late 1970's, the International Phase of Oce
an Drilling (IPOD), including its pre- and post-site surveys,
achieved a major breakthrough for our understanding of the
evolution of the Northwest African margin. GLOMAR CHALLENGER
visited this margin six times; in 1968/69 (Leg 3), in 1970
(Legs 13/14 with Sites 120,135-141), in 1975 (Leg 41, Sites
366-370), in 1976 (Leg 47A with Site 397 and Leg 50 with Sites
415/416), and, most recently, in 1981 (Leg 79). We include in
this volume a short report from the shipboard party with the
latest results of the Mazagan Slope Sites 544-547, data which
could no longer be incorporated into the other papers of our
volume, or in the front cover figure. Continued and increasing
interest in the offshore petroleum potential of the North
Atlantic continental margins helped also to stimulate new sci
entific exploration programs for the 1980's, such as the Ocean
Margin Drilling Project with GLOMAR EXPLORER.
The present volume was conceived by the German IPOD group at
Kiel in May 1979. It was agreed that the timing was appropri
ate for a comprehensive synthesis volume summarizing the major
new results on this margin in view of the pertinent literature
of the past decade. Most papers were open for discussion during
a special small symposium at Bonn-Bad Godesberg in October 1980.
The synthesis volume concentrates on geophysical, geological,
paleontological, and geochemical studies obtained during the
preparation and evaluation of DSDP Legs 14, 41, 47A, 50 and
79, as well as on the structure and Mesozoic-Cenozoic evolu-
VI Preface
tion of the onshore coastal basins and the offshore continen
tal margin. It includes also deep crustal geophysical surveys,
geological-volcanological studies of the Canary and Cape Verde
Islands, paleoenvironmental research based on Neogene to Qua
ternary cores, and a comparison of the Northwest African mar
gin with its counterpart off eastern North America.
During the past 12 years, the Deutsche Forschungsgemeinschaft
(DFG) in Bonn-Bad Godesberg has funded all METEOR cruises and
most of the German geoscientific research projects which con
centrated on Northwest Africa and its margin. We are especial
ly grateful to Dr. F. Goerlich (Secretary of the Earth Sci
ences Division of the DFG) and to Dr. H. Beiersdorf (coordi
nator of the German IPOD contribution at BGR) for their con
tinuous advice and encouragement. The Bundesminister fur
Forschung und Technologie (BMFT; Federal Minister of Hesearch
and Technology, Bonn) supported our continental margin pro
jects with R/V VALDIVIA and BGR's continental margin study
group at Hannover, the reports of which formed the nucleus of
this synthesis volume (cf. papers no.3, 4, 6, 7, 9). DFG and
BMFT together financed the Initial Contribution for the Ger
man participation in IPOD.
The JOIDES Planning Committee and the JOIDES Advisory Panel
on Passive Margins also supported our idea to compile a re
gional synthesis volume summarizing all DSDP data from the
Northwest African margin.
Dr. Hohm, Mrs. Grossi, Mrs. Schull, and Mrs. von dem Bussche
from the Springer Verlag (Heidelberg) were very helpful and
cooperative. The artwork on the front cover of the book is
from Professor P. Wurster (Bonn).
Each paper was reviewed by at least one of the editors and
one or several peers. On behalf of all authors we should
like to thank all colleagues who contributed to the quality
of the papers by careful reviews. Last but not least, we are
most grateful to all those who helped to make this volume
possible, from the captains and crews of our research ves
sels to the marine and laboratory technicians, translators,
and secretaries who went to great trouble to produce camera
ready manuscripts. In order to speed up publication and to
keep the price of the book as low as possible, we decided
to use the technique of setting the manuscripts in type
writer composition by the authors. Hence, we ask the reader
to excuse any printing errors, inconsistencies, and the less
than-perfect appearance of some of our manuscripts.
Hannover and Kiel, August 1981 Ulrich von Rad
Karl Hinz
Michael Sarnthein
Eugen Seibold
Contents
Introduction
The Northwest African Continental Margin -
An Introduction
Eugen Seibold. With 5 Figures " ... ... ...... ...... ...... 3
Structure and Geodynamic Evolution of the Continental Margin
2 Preliminary Results from DSDP Leg 79 Seaward of the
Mazagan Plateau off Central Morocco
Karl Hinz, Edward L. Winterer, Peter O. Baumgartner,
Martin J. Bradshaw, James E.T. Channel, Michel Jaffrezo,
Lubomir F. Jansa, Robert M. Leckie, Johnnie N. Moore,
Jlirgen Rullkotter, Carl Schaftenaar, Torsten H. Steiger,
Vassil Vuchev, and George E. Wiegand. With 9 Figures ... 23
3 The Continental Margin of Morocco: Seismic Sequences,
Structural Elements and Geological Development
Karl Hinz, Hans Dostmann, and Jlirgen Fritsch.
With 10 Figures ........................................ 34
4 Magnetic Anomalies in the Magnetic Quiet Zone off
Morocco
Hans A. Roeser. With 3 Figures ......................... 61
5 Atlas and Atlantic - Structural Relations
Johannes Stets and Paul Wurster. With 9 Figures 69
6 Stratigraphy, Facies and Tectonic Development of
the On- and Offshore Aaiun-Tarfaya Basin - A Review
Ulrich Ranke, Ulrich von Rad, and Gerd Wissmann.
Wit h 9 F i gu res ......................................... 8 6
7 Cretaceous-Cenozoic History of the West Saharan
Continental Margin (NW Africa): Development,
Destruction and Gravitational Sedimentation
Ulrich von Rad and Gerd Wissmann. With 12 Figures 106
8 Deep Seismic Structure (Mauritania and Central Morocco)
Winfried Weigel, Gerd Wissmann, and Pavel Goldflam.
With 18 Figures ..............................•..•..•... 132
9 Stratigraphy and Structural Features of the
Continental Margin Basin of Senegal and Mauritania
Gerd Wissmann. With 10 Figures ......................... 160
10 Bathymetry, Microphysiography and Reflectivity
Characteristics of the West African Margin Between
Sierra Leone and Mauritania
Robert D. Jacobi and Dennis E. Hayes. With 13 Figures
and 4 Tables ........................................... 182
VIII Contents
Comparison of the Northwest African and Northeast American
Margins
11 Mesozoic-Cenozoic Development of the Eastern North
American and Northwest African Continental Margins:
A Comparison
Lubomir F. Jansa and Jost Wiedmann. With 27 Figures
and 1 Table ••....•.•.•••.•.••••..••................•.• 215
Evolution of Volcanism
12 Volcanic and Chemical Evolution of the Canary Islands
Hans-Ulrich Schmincke. With 21 Figures and 3 Tables .•. 273
Cretaceous Stratigraphy, Sedimentation and Paleoenvironment
13 Cretaceous Foraminiferal and Nannoplankton
Biostratigraphy and Paleoecology Along the West African
Continental Margin
Uwe Pflaumann and Pavel Cepek. With 9 Figures and
3 Tables ............• '. • • . • . . . . . . . . . . . • . . . . . . . . . . . . . • •. 309
14 Cretaceous Radiolaria from the Northwest African
Continental Margin
Reinhard Wolfart. With 4 Figures •••..................• 354
15 Cretaceous Stratigraphy, Environment, and Subsidence
History at the Moroccan Continental Margin
Jost Wiedmann, Arif Butt, and Gerhard Einsele.
With 12 Figures and 1 Table •..•.....•.•............... 366
16 Turonian Black Shales in the MorOccan Coastal Basins:
First Upwelling in the Atlantic Ocean?
Gerhard Einsele and Jost Wiedmann. With 10 Figures and
2 Tables ..........•.•...••..•........................• 396
17 Cretaceous Coastline-Connected Mass Movements,
Southern Morocco
Gerhard Einsele. With 10 Figures •.................•... 435
18 Sedimentation in the Atlas Gulf I:
Lower Cretaceous Clastics
Manfred Behrens and Agemar Siehl. With 15 Figures ..... 427
19 Sedimentation in the Atlas Gulf II:
Mid-Cretaceous Events
Paul Wurster and Johannes Stets. With 13 Figures ...••. 439
20 Sedimentation in the Atlas Gulf III:
Turonian Carbonates
Roger Stamm and J. Thein. With 10 Figures and 1 Plate. 459
21 Cretaceous Magnetic Stratigraphy of Southwest Morocco
Klaus Krumsiek. With 10 Figures and 2 Tables .......•.. 475
22 Stratigraphy, Facies, and Significance of Late
Mesozoic and Early Tertiary Sedimentary Rocks of
Fuerteventura (Canary Islands) and Maio (Cape Verde
Islands)
Alastair H.F. Robertson and Daniel Bernoulli.
With 12 Figures ..•.•..•..•..•••.•.•.••.•....•..•••...• 498