The Southern Central Andes: Contributions to Structure and Evolution of an Active Continental Margin

260 Pages·1988·5.655 MB·English

by  L. Baeza, S. Pichowiak (auth.), Dr. Heinrich Bahlburg, Priv. Doz. Dr. Christoph Breitkreuz, Prof. Dr. Peter Giese (eds.)

Lecture Notes ni
Earth Sciences
Edited by Somdev Bhattacharji, Gerald M. Friedman,
Horst .J Neugebauer and Adolf Seilacher
71
H. Bahlburg Ch. Breitkreuz
.P Giese ).sdE(
The Southern Central Andes
Contributions to Structure dna Evolution
of na Active Continental Margin
galreV-regnirpS
Berlin Heidelberg NewYork London Paris Tokyo
srotidE
Dr. Heinrich Bahlburg
Priv. Doz. Dr. Ohristoph Breitkreuz
Institut f~r Geologie und Pal~iontolegie
Technische Berlin Universit~.t
Ernst-Reuther-Platz ,1 [3-1000 Berlin ,01 FRG
Prof. Dr. Peter Giese
Institut rJ(f Geophysikalische Wissenschaften
Freie Universit&t Berlin
Rheinbabenallee 49, D-1000 Berlin 33, FRG
ISBN 3-540-50032-4 Springer-Verlag Berlin Heidelberg New York
ISBN 0-387-50032-4 Springer-Verlag New York Berlin Heidelberg
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© Springer-Verlag Berlin Heidelberg 1988
Printed in Germany
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2132/3140-543210
tnempracsE of the amacatA Fault Zone near Antofagasta (Northern Chile):
Recent uplift of the Coastal Cordillera (view towards the north).
ECAFERP
ehT suggestion to compile dna publish this emulov dealing with emos geoscientific
smelborp of the Central sednA emac pu during a conference no "Mobility of Active
Continental Margins" held in Berlin, yraurbeF .6891 At this international ,ecnerefnoc
dezinagro yb the Berlin puor GhcraeseR "Mobility of Active Continental Margins",
colleagues from Europe, Southern dna Northern aciremA reported no their current
investigations in the Central .sednA
ehT Central sednA claim a special position in the 0007 mk long naednA niatnuom .egnar
In Northern Chile, Southern Bolivia dna tsewhtroN Argentina the Central sednA wohs
their largest width with erom than 056 mk dna gnola a esrevartoeG neewteb the Pacific
coast dna eht ocahC all typical naednA cinotcetohprom units era well developed. ,ereH
the naednA-erp evolution is yb detnemucod outcropping of Paleozoic dna nairbmaC-erp
rocks. ehT characteristic anemonehp of the naednA cycle nac eb studied along eht
entire geotraverse. ehT migration of the tectonic dna citamgam activity starting in
Jurassic dna being active till yranretauQ is clearly evidenced. Besides eht ,ayalamiH
the Central sednA wohs with 70-80 mk dna -400 lagm the largest crustal thickness
nwonk in niatnuom ranges. esehT dna ynam other interesting dna exciting geoscientific
features degaruocne a puorg of geoscientists from both West-Berlin universities
(Freie UniversitAt dna Technische UniversitAt) to focus their studies along a
geotraverse through the Central .sednA ehT realization of these studies would ton
evah been possible without eht active assistance dna close cooperation of ruo
colleagues from eht geoscientific institutions in Salta (Argentina), aL zaP dna atnaS
Cruz (Bolivia) dna Antofagasta dna Santiago (Chile). Concerning the namreG
participation, this joint dna interdisciplinary project is financially detroppus
since 2891 sa hcareseR "puorG Mobility of Active Continental Margins" yb the namreG
hcraeseR Society dna yb the West-Berlin universities sa well. A rebmun of seugaelloc
morf universities in tseW ynamreG take part in this project, too.
ehT papers presented here deal with eht period from Late nairbmacerP pu to eht
tsegnuoy anemonehp in Quaternary. ehT contributions cover the whole murtceps of
geoscientific research, geology, paleontology, petrology, geochemistry, scisyhpoeg
dna .ygolohpromoeg
In conclusion, the data published here yam help to evorpmi the picture of naednA
structure dna evolution. ehT detailed investigations carried out in the past years
,wohs that the first simple plate tectonic sledom desoporp in the beginning of eht
seventies have to devorpmi dna modified. Furthermore, the results nac eb seen sa
contribution to the international Lithospheric Project dna sa a useful data base for
eht construction of a Central naednA Transect.
lV
/2ow 007 ° 68 ° 66 &6 ° 620
I !
/-
/"
i
i
/
\./
>.
0D 200 mk
l t
Western CordiUera with
Coastal Cordillera
Late Tertiary-Quaternary volcanism
Longitudinal Valley Altiplano / Puna
~ nretsaE meUidroC
Chilean Precorditlera parts n i:a demrof yb nairbmacerP stinu
~ Preandean Depression Sierras Subandinas
Simplified pam of the main morphostructural units of the southern Central sednA
neewteb 02 ° dna 62 ° S
eW era grateful to .B ,reknuD .H ,awolG .F Jurtan, .B Kleeberg, dna .K ,ekhcseZ
Berlin, for their technical assistance in the preparation of this .emulov
ehT editors
STNETNOC
A: NAEDNA-ERP NOITULOVE ............................................................ i
I. Basement dna Paleozoic Basins
,AZEAB L. & ,KAIWOHCIP S.:
Ancient crystalline basement provinces in the North Chilean Central Andes -
relics of continental crust development since the Mid-Proterozoic .................. 3
,AZALONECA F.G., MILLER, .H & TOSELLI, A.J.:
ehT Puncoviscana Formation (Late Precambrian - Early Cambrian).- Sedimento-
fogy, tectonometamorphic history dna ega of the oldest rocks of WN Argentina ...... 52
,APMUK ~M & ,ZEHCNAS M.C.:
Geology dna sedimentology of the Cambrian Grupo Mes6n WN( Argentina) .............. 93
,AYOM C.:
Lower Ordovician in the southern part of the Argentine Eastern Cordillera ......... 55
,GRUBLHAB H., ,ZUERKTIERB .C & ZEIL, :.W
Geology of the Coquena Formation (Arenigian-Llanvirnian) in the WN Argentine
Puna: Constraints no geodynamic interpretation .................................... 17
,ZUERKTIERB C., ,GRUBLHAB .H & ZEIL, :.W
ehT Paleozoic evolution of Northern Chile: Geotectonic implications ............... 78
:B NAEDNA NOITULOVE .............................................................. 301
.I Mesozoic-Cenozoic Basins
,EKHCS~RG M., ,TDNARBELLIH A.v., PRINZ, P., QUINZIO, L.A. & WILKE, H.-G.:
Marine Mesozoic Paleogeography in Northern Chile between 12 ° - 26°S .............. 501
,SALLIUQRAM .R & SALFITY, J.A.:
Tectonic framework dna correlations of the Cretaceous-Eocene Salta Group;
Argentina ........................................................................ 911
GNOHC D., G.:
ehT Cenozoic saline deposits of the Chilean Andes ' between 18o00 dna ' 27o00
South Latitude ................................................................... 731
,ELEBA G.:
Geomorphical west-east section through the North Chilean Andes near Antofa-
gasta ............................................................................ 351
IIIV
II. Mesozoic-Cenozoic magmatism and tectonics .................................... 169
,TLEHCUB .M & TELLEZ C., C.:
The Jurassic La Negra Formation in the area of Antofagasta, Northern Chile
(lithology, petrography, geochemistry) ........................................... 171
,FARGEIR-TTIMHCS C. & PICHLER, H.:
Cenozoic ignimbrites of the Central Andes: A wen genetic model ................... 381
,EZTUG H.-J., ,TDIMHCS S. & ,KNURTS S.:
Central Andean gravity field dna its relation to crustal structures .............. 991
,REGGIW P.:
Seismicity dna crustal structure of the Central Andes ............................ 902
,RETTUER K.-J., GIESE, P., GdTZE, H.-J., ,REBUEHCS E., ,BAWHCS K., ,ZRAWHCS
.G & ,REGGIW P.:
Structures and crustal development of the Central Andes between 12 ° dna 25°S ..... 132
A: PRE-ANDEAN EVOLUTION
I: Basement and Paleozoic Basins

TNEICNA ENILLATSYRC TNEMESAB SECNIVORP NI EHT HTRON NAELIHC LARTNEC SEDNA - SCILER FO
TSUR CLATNENITNOC TNEMPOLEVED ECNIS EHT DIM CIOZORETORP
.L *azeaB & .S Pichowiak**
* otnematrapeD ed Geociencias, Universidad del Norte,
Casilla 1280, Antofagasta, Chile
** Institut for Geologie, Freie UniversitAt, Altensteinstr. 34a,
0001 Berlin ,33 Federal Republic .ynamreG
TCARTSBA
Ancient crystalline tnemesab provinces are found only rarely in the North Chilean
parts of the Central sednA dna they wohs only diffuse structural similarities eud to
multiphase tectonic dna cihpromatem reworking. Radiometric dating of supracrustal
series dna intrusive cycles point to a crustal creation history reaching back sa far
sa the Mid-Proterozoic (1460±448 :aM NELEB metabasalts; 1254+97/_94 :aM AJOHC
migmatite; 1213+28/_25; AJOHC orthogneiss). ehT oldest rock records era of mostly
low- to edarg-muidem cihpromatem volcanic-clastic secneuqes with intrusive granitic
pulses. High-grade cihpromatem rocks occur only in wef sites sa granulitic gneisses
dna migmatites. Most of the radiometric data suggest various phases of cihpromatem
formation (Brazilian, Caledonian dna Variscan events). Primary ages nwohs to eb Mid-
Proterozoic yb the depositional events of basic to intermediate volcanic dna
volcanic-clastic rocks. Amphibolitic metabasalts are of primitive type, elbarapmoc to
nredom tholeiitic rocks of BFC (continental flood basalts) affinities. Shallow seated
granitic bodies intruded the supracrustals during syn- to postkinematic stages of
various orogenic cycles. ehT oldest intrusive cycles nac eb identified sa
"Brazilian", "Caledonian" dna "Variscan" dna vary in different provinces. ehT naednA"
cycle" is responsable for the main tectonic kinematics dna continous citamgam pulses.
ehT characteristics of granitic rocks vary only slightly. lacimehcoeG data indicate
xelpmoc citamgam systems with possible crustal contaminants (transition from GPW to
GAV trace element affinities; rS i values from 0.7051 to 0.7062).
NOITCUDORTNI
naednA mountain building processes have been well investigated dna interpreted - sa a
classical elpmaxe of a young orogen in the Circumpacific region. Kinematics era
dootsrednu sa triggered yb the subduction of oceanic lithosphere at na active
continental margin at least since the Triassic-Jurassic transition (e.g. RARRAF et
al., 1970; TTUNcM et al., 1975; KAIWOHCIP et al., 1988). Most of the research
published no the Central region Andes sah focused no Mesozoic dna Cenozoic processes
Lecture Notes in Earth Sciences, Vo]. 71
H. Bahlburg, Ch, Breitkreuz, .P Giese (Eds.),
The Southern Central Andes
© Springer-Verlag Berlin Heidelberg 8891