CADIC   02618
CENTRO AUSTRAL DE INVESTIGACIONES CIENTIFICAS
Unidad Ejecutora - UE
capítulos de libros
Título:
Hyperpycnal-flow deposits in Oligocene-Miocene clinothems of the Austral basin, Tierra del Fuego, Argentina
Autor/es:
PONCE, J.J.; OLIVERO, E.B.; MARTINIONI, D.R.
Libro:
Sediment Transfer from Shelf to Deepwater - Revisiting the Delivery Mechanisms. AAPG Hedberg Research Conference Guidebook.
Referencias:
Año: 2008; p. 24 - 48
Resumen:
The Upper Oligocene-Miocene deposits of the
foreland Austral Basin of Tierra del Fuego accumulated just in front of the
adjacent fold and thrust belt. They represent the youngest foredeep fill that
consists of a more than 600 m
thick, superbly exposed, sub-horizontal, clastic succession. It comprises five
depositional sequences (SI-SV), bounded by unconformities
(dI-dV). The basal sequence (SI) includes two members: A,
mudstone dominated, deposited by cohesive flows; and B, glauconite-rich,
sandstone dominated, deposited by episodic turbidity currents. The remaining
sequences (SII-SV) are composed of complex arrangements of fine
conglomerates, coarse- to fine-grained sandstones, and mudstones that were
deposited mainly by hyperpycnal flows. The basal unconformities of the SI to
SIV involve minor hiatuses, while that of the SV is a major order
unconformity. These foredeep depositional sequences constitute clinothems that
developed in accordance with two types of clinoform geometries. Type a clinoforms
present a wedge shaped geometry and characterize the foredeep infill during the
compressional tectonic regime. Regarding this clinoform type, SI is
situated closer to the orogen and shows variations in the bedding dip with
development of internal unconformities. SII to SIV are situated
towards the foreland and are characterized by subhorizontal conformable beds of
large lateral extension. Type b clinoforms, with sigmoidal geometry,
show a clear northeast progradation related to a progressive foredeep fill
under tectonic quiescence. This clinoform type characterizes the deposits in SV.
The recognition of hyperpycnites and different types of clinoform geometries in
these sequences incorporates new concepts in reservoir prospects, which are
critical for the evaluation of the petroleum system in the Austral Basin.