Abstract
Observations and models of Ceres suggest that its evolution was shaped by interactions between liquid water and silicate rock. Hydrothermal processes in a heated core require both fractured rock and liquid. Using a new core cracking model coupled to a thermal evolution code, we find volumes of fractured rock always large enough for significant interaction to occur. Therefore, liquid persistence is key. It is favored by antifreezes such as ammonia, by silicate dehydration which releases liquid, and by hydrothermal circulation itself, which enhances heat transport into the hydrosphere. The effect of heating from silicate hydration seems minor. Hydrothermal circulation can profoundly affect Ceres' evolution: it prevents core dehydration via "temperature resets," core cooling events lasting ∼50 Myr during which Ceres' interior temperature profile becomes very shallow and its hydrosphere is largely liquid. Whether Ceres has experienced such extensive hydrothermalism may be determined through examination of its present-day structure. A large, fully hydrated core (radius 420 km) would suggest that extensive hydrothermal circulation prevented core dehydration. A small, dry core (radius 350 km) suggests early dehydration from short-lived radionuclides, with shallow hydrothermalism at best. Intermediate structures with a partially dehydrated core seem ambiguous, compatible both with late partial dehydration without hydrothermal circulation, and with early dehydration with extensive hydrothermal circulation. Thus, gravity measurements by the Dawn orbiter, whose arrival at Ceres is imminent, could help discriminate between scenarios for Ceres' evolution.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 123-154 |
| Number of pages | 32 |
| Journal | Journal of Geophysical Research E: Planets |
| Volume | 120 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2015 |
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Keywords
- Ceres
- core
- fracturing
- hydrothermal circulation
- thermal evolution
- water-rock interaction
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geophysics
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
Cite this
Core cracking and hydrothermal circulation can profoundly affect Ceres' geophysical evolution. / Neveu, Marc; Desch, Steven; Castillo-Rogez, Julie C.
In: Journal of Geophysical Research E: Planets, Vol. 120, No. 2, 2015, p. 123-154.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Core cracking and hydrothermal circulation can profoundly affect Ceres' geophysical evolution
AU - Neveu, Marc
AU - Desch, Steven
AU - Castillo-Rogez, Julie C.
PY - 2015
Y1 - 2015
N2 - Observations and models of Ceres suggest that its evolution was shaped by interactions between liquid water and silicate rock. Hydrothermal processes in a heated core require both fractured rock and liquid. Using a new core cracking model coupled to a thermal evolution code, we find volumes of fractured rock always large enough for significant interaction to occur. Therefore, liquid persistence is key. It is favored by antifreezes such as ammonia, by silicate dehydration which releases liquid, and by hydrothermal circulation itself, which enhances heat transport into the hydrosphere. The effect of heating from silicate hydration seems minor. Hydrothermal circulation can profoundly affect Ceres' evolution: it prevents core dehydration via "temperature resets," core cooling events lasting ∼50 Myr during which Ceres' interior temperature profile becomes very shallow and its hydrosphere is largely liquid. Whether Ceres has experienced such extensive hydrothermalism may be determined through examination of its present-day structure. A large, fully hydrated core (radius 420 km) would suggest that extensive hydrothermal circulation prevented core dehydration. A small, dry core (radius 350 km) suggests early dehydration from short-lived radionuclides, with shallow hydrothermalism at best. Intermediate structures with a partially dehydrated core seem ambiguous, compatible both with late partial dehydration without hydrothermal circulation, and with early dehydration with extensive hydrothermal circulation. Thus, gravity measurements by the Dawn orbiter, whose arrival at Ceres is imminent, could help discriminate between scenarios for Ceres' evolution.
AB - Observations and models of Ceres suggest that its evolution was shaped by interactions between liquid water and silicate rock. Hydrothermal processes in a heated core require both fractured rock and liquid. Using a new core cracking model coupled to a thermal evolution code, we find volumes of fractured rock always large enough for significant interaction to occur. Therefore, liquid persistence is key. It is favored by antifreezes such as ammonia, by silicate dehydration which releases liquid, and by hydrothermal circulation itself, which enhances heat transport into the hydrosphere. The effect of heating from silicate hydration seems minor. Hydrothermal circulation can profoundly affect Ceres' evolution: it prevents core dehydration via "temperature resets," core cooling events lasting ∼50 Myr during which Ceres' interior temperature profile becomes very shallow and its hydrosphere is largely liquid. Whether Ceres has experienced such extensive hydrothermalism may be determined through examination of its present-day structure. A large, fully hydrated core (radius 420 km) would suggest that extensive hydrothermal circulation prevented core dehydration. A small, dry core (radius 350 km) suggests early dehydration from short-lived radionuclides, with shallow hydrothermalism at best. Intermediate structures with a partially dehydrated core seem ambiguous, compatible both with late partial dehydration without hydrothermal circulation, and with early dehydration with extensive hydrothermal circulation. Thus, gravity measurements by the Dawn orbiter, whose arrival at Ceres is imminent, could help discriminate between scenarios for Ceres' evolution.
KW - Ceres
KW - core
KW - fracturing
KW - hydrothermal circulation
KW - thermal evolution
KW - water-rock interaction
UR - http://www.scopus.com/inward/record.url?scp=84924724919&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84924724919&partnerID=8YFLogxK
U2 - 10.1002/2014JE004714
DO - 10.1002/2014JE004714
M3 - Article
AN - SCOPUS:84924724919
VL - 120
SP - 123
EP - 154
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 2
ER -