Alkali basalt volcanism along a subduction-related magmatic arc: The case of Puyuhuapi Quaternary volcanic line, Southern Andes (44deg20minS)Entry ID: 159-96_03
Abstract: In Southern Chile, plate configuration is characterized by ridge-ridge-trench
collision in correspondence of Taitao peninsula (Chile triple junction). The
different converging rates of Nazca and Antarctic plates favored the formation
of a forearc sliver (Chiloe block) limited to west by a dextral transcurrent
fault system, Known as Liquine-Ofqui fault system (LOFS). During the Quatenary
time, a ... series of monogenetic volcanic centers, as Puyuhuapi volcanic centers
(PVC), formed along the LOFS. The PVC lavas have a primitive character; two
groups and can be distinguihed. Group-1 rocks show a K-AlKaline affinity and
are nepheline normative with olivine and plagioclase as dominant phases.
Group-2 lavas have Na-affinity with olivine and hyperstene in the norm; olivine
is the most abundant mineral phase. In contrast with overall alkaline affinity
of PVC, the products from the neighboring central composite volcanoes are
generally calcalkaline with the exception of the lavas from Maca Volcano, which
show tholeiitic affinity.
Start Date: 1998-02-01Stop Date: 1998-05-02
ISO Topic Category
Quality A set of 16 samples from PVC was analyzed for major elements; 8 samples were
selected for trace elements analyses. Whole-rock major elements determination
were carried out by XRF using a Philips 1480 X-ray spectrometer. Na2O and MgO
contents were determined by AAS, and FeO by the titration method. Volatile
components were determined as ignition loss at 1000 deg C on 110 deg C-dried
powders, assuming a total oxidation of Fe2+ into Fe3+. Trace elements were
analyzed by a VG Elemental Plasma Quad 2 Plus Inductively Coupled Plasma
Spectrometer. Analyses of the mineral phases were carried out by a Jeol
JXA-8600 electron microprobe.
Access Constraints Data is available for public access.
Use Constraints Data is available for public use.
Data Set Progress
Role: DIF AUTHOR
Email: djorquer at inach.cl
Luis Thayer Ojeda 814 Providencia
Role: TECHNICAL CONTACT
Phone: 2 678 4299
Email: ogozfer at dgf.uchile.cl
Departamento de Geofisica Universidad de Chile Casilla 27116
Gonzalez-Ferran, O., Innocenti, F., Lahsen, A., Manetti, P., Mazzuoli, R.,
Omarini, R. and Tamponi, M., 1996. Alkali basalt volcanism along a subduction
related magmatic arc: The case of Puyuhuapi Quaternary volcanic line, Southern
Andes (44deg20minS). XIII Congreso de Geologia Argentino y III Congreso de
exploracion de Hidrocarburos. Organizado por Asociacion Geologica Argentina e
Instituto Argentiino del Petroleo y del Gas. Actas III: 549-565. Buenos Aires,
13 - 18 de Octubre.
Creation and Review Dates
DIF Creation Date: 2005-03-23
Last DIF Revision Date: 2005-04-27