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Titel |
Assessing Cryovolcanic Resurfacing of Titan: Implications for Detection of Active Cryolavas |
VerfasserIn |
A. G. Davies, D. L. Matson, J. C. Castillo-Rogez, C. Sotin, T. V. Johnson |
Konferenz |
EGU General Assembly 2009
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 11 (2009) |
Datensatznummer |
250024468
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Zusammenfassung |
Cryovolcanism has been proposed for resurfacing Saturn’s moon Titan (see references in [1]).
We have quantitatively examined the constraints on cryovolcanic resurfacing, and the
likelihood of detection of active flows by instruments on the Cassini spacecraft. If the surface
of Titan has an age of order 0.5 Ga, then the entire satellite is resurfaced in this time by a net
rate of areal coverage of only 0.17 km2 year-1 (53 cm2 s-1), erasing most impact
craters. In comparison with Earth, this coverage rate is less than the average rate for
many contemporaneous terrestrial volcanic flows. For example, at Kilauea volcano,
Hawai’i, the average coverage rate for a flow is of order ~1 m2 s-1: on Titan, this rate
would cover the entire surface ~200 times in 0.5 Ga, if the activity was distributed
evenly. If the flows were 1 m thick, the total volume erupted in this time would still
only be 0.4% of the volume of a 50 km thick crust. At the other end of the flow
effusion-rate scale, the largest eruptions on Earth emplaced massive basalt flows, each
~10-100 m thick (e.g., Deccan Traps, India). Areal coverage rates would have
been of order ~1000 m2 s-1. This coverage rate would cover the entire surface of
Titan in less than 3000 years, an unfeasible scenario. The analogue comparisons
suggest that only a relatively very small amount of effusive activity (e.g., much less
than current activity at Kilauea) is required to resurface Titan in 0.5 Ga. If so, the
detection of active eruptions may be very difficult with the Cassini Visible-Infrared
Mapping Spectrometer (VIMS) and the Composite Infrared Spectrometer (CIRS). If
activity is confined to specific locations, then the chances of detection increase:
our modelling of cryolavas [2] suggests that the signature of such activity can be
detected by CIRS (and possibly VIMS) if the extent and areal coverage rates are
high enough. This work was performed at the Jet Propulsion Laboratory-California
Institute of Technology, under contract to NASA, with support from the NASA Outer
Planets Research Program. References: [1] Davies et al., 2009, LPSC-40 abstract
1906. [2] Davies et al., 2008, DPS-40 abstract 34.05 (BAAS vol. 40, no. 3, 2008). |
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