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| Titel |
When sink becomes source: Importance of sediment recycling in linked orogen-basin systems |
| VerfasserIn |
Brian W. Romans, Julie C. Fosdick, Stephen M. Hubbards, Andrea Fildani |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250084901
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| Zusammenfassung |
| Much of the recent research on sedimentary system dynamics has focused on extant systems
where the linkage of sediment production from eroding highlands can be directly linked to
deposition in lowlands and/or offshore basins. Studies of such systems, typically late
Pleistocene to Holocene in age, are especially valuable for quantitative constraints such as
system morphometrics (e.g., longitudinal profiles, basin volumes, etc.) and rates of processes
(e.g., erosion/denudation, sediment accumulation, etc.), which can be measured
directly or estimated with relatively high certainty. Moreover, information about
climate and tectonic forcings that are independent to the system is explicitly known
for extant systems. However, an understanding of longer-term (>105 yr) evolution
can only be gained through the investigation of ancient systems. Such systems are
either buried in the subsurface, which requires geophysical remote sensing and/or
drilling, or exposed at the Earth’s surface as outcrops as the result of uplift and
exhumation. The dynamic linkage of mountain belt and adjacent basin makes foreland
basin systems ideal natural laboratories to address long-term sedimentary system
evolution.
In this presentation, we highlight important issues and challenges that sedimentary
systems research is currently facing, with an emphasis on sediment recycling during
progressive stages of basin development. In this context, we focus on sedimentary systems in
which multiple episodes of uplift and erosion of the primary depocenter led to a
history whereby basin material was repeatedly recycled. The spatial and temporal
aspects of sediment recycling have implications for how provenance signals (based
on composition, crystallization or metamorphic age information, thermal history,
etc.) are used. Additionally, improved constraints regarding the timescales and
magnitude of sediment recycling have implications for system-scale modeling. Key
parameters such as total sediment volumes and differences in rock erodibility between
original basement source and sedimentary source must be accounted for in these
models if budget closure is to be considered. Sediment recycling has long been
considered by basin analysts and recognized using numerous provenance indicators;
however, new analytical tools allow us to further quantify the impact of recycled
source terranes. The Magallanes Basin of South America provides an appropriate
example to discuss these issues because of its long-lived convergent basin history
and proximity to distinctive source terranes. A robust and growing database of
compositional (e.g., sandstone composition, shale geochemistry), detrital age (zircon
geochronology), and time-temperature (detrital thermochronology) information is used to
help constrain source-area configuration and evolution. These data are placed within a
multi-scale stratigraphic framework that addresses basin geometry and depositional
system evolution, thereby enabling us to test geologic models based on sediment
transport pathways, maturation of sediment-sources, and post-depositional thermal
history. |
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