کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4677864 1634823 2011 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Volcanic outgassing of CO2 and H2O on Mars
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Volcanic outgassing of CO2 and H2O on Mars
چکیده انگلیسی

Volcanic outgassing is one of the main sources of volatiles for the martian atmosphere and degassing of the martian interior potentially influenced the early martian climate. Using a parameterized thermo-chemical evolution model and considering two end-member melting models, we self-consistently calculate the amount of CO2 and H2O outgassed during the martian evolution. Outgassing rates are found to depend primarily on a factor describing the outgassing efficiency, the bulk mantle water content, the mantle oxygen fugacity, and the local melt fraction in the magma source regions. We find that significant outgassing ceased around 3.5–2 Gyr ago, depending on the adopted melting model. A total of 0.9–1 bar CO2 is outgassed during this time period if a mantle oxygen fugacity corresponding to one log10 unit above the iron–wustite buffer is assumed. Additionally, a total of 17–61 m of water is delivered to the surface. Outgassing is most efficient in the pre-Noachian (up to 4.1 Gyr), but still significant during the Noachian, and 5–15 m of water and ∼250 mbar of CO2 are outgassed between 4.1 and 3.7 Gyr. Although this amount is probably insufficient for an appreciable greenhouse effect, pressures are found to be sufficient to stabilize transient liquid water on the surface well into the Hesperian period. Therefore, our results support the hypothesis that rather than being warm-and-wet, the martian climate was probably cold-and-wet. Outgassing is found to strongly decline during the Hesperian, and is insignificant during the Amazonian period. A simple parameterization for the outgassing of CO2 and H2O as a function of time is presented.

Research highlights
► The amount of H2O and CO2 outgassed from the martian interior is calculated.
► Less than 1 bar of CO2 is delivered to the atmosphere.
► 17–61 m of water (equivalent global layer) are delivered to the surface.
► Outgassing is found to be insufficient for an appreciable greenhouse effect.
► A parameterization for outgassing of CO2 and H2O as a function of time is presented.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 308, Issues 3–4, 15 August 2011, Pages 391–400
نویسندگان
, , , ,