Abstract Details
(2020) Isotopic Constraints on the Origin and Evolution of Martian Volatiles
Wang K
https://doi.org/10.46427/gold2020.2735
01c: Room 1, Tuesday 23rd June 00:30 - 00:33
Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.
Submitted by My Riebe on Sunday 21st June 06:50
Will it be possible in the future to use this data to quantify the amounts of water on early Mars more precisely than "less than Earth"? If not what kind of data is needed to do this?
Linking moderately volatile elements (e.g., K) to water sometimes could be controversial as the source of water and moderately volatile elements could be decoupled. However, if we assume highly volatile elements do follow the same depletion trend as the moderately volatile elements. Using our data, we could quantify the initial accreted water on Mars is ~30% of the Earth (to account for the isotopic fractionation during volatile loss).
Will it be possible in the future to use this data to quantify the amounts of water on early Mars more precisely than "less than Earth"? If not what kind of data is needed to do this?
Linking moderately volatile elements (e.g., K) to water sometimes could be controversial as the source of water and moderately volatile elements could be decoupled. However, if we assume highly volatile elements do follow the same depletion trend as the moderately volatile elements. Using our data, we could quantify the initial accreted water on Mars is ~30% of the Earth (to account for the isotopic fractionation during volatile loss).
Submitted by My Riebe on Sunday 21st June 06:50
Will it be possible in the future to use this data to quantify the amounts of water on early Mars more precisely than "less than Earth"? If not what kind of data is needed to do this?
Linking moderately volatile elements (e.g., K) to water sometimes could be controversial as the source of water and moderately volatile elements could be decoupled. However, if we assume highly volatile elements do follow the same depletion trend as the moderately volatile elements. Using our data, we could quantify the initial accreted water on Mars is ~30% of the Earth (to account for the isotopic fractionation during volatile loss).
Will it be possible in the future to use this data to quantify the amounts of water on early Mars more precisely than "less than Earth"? If not what kind of data is needed to do this?
Linking moderately volatile elements (e.g., K) to water sometimes could be controversial as the source of water and moderately volatile elements could be decoupled. However, if we assume highly volatile elements do follow the same depletion trend as the moderately volatile elements. Using our data, we could quantify the initial accreted water on Mars is ~30% of the Earth (to account for the isotopic fractionation during volatile loss).
Submitted by My Riebe on Sunday 21st June 07:01
What do we know about when Mars lost its water?
During the accretion and magma ocean stage of Mars.
What do we know about when Mars lost its water?
During the accretion and magma ocean stage of Mars.
Submitted by My Riebe on Sunday 21st June 07:02
Nabiei et al. (Nature Comm,., 2018) suggested that the ureilite parent body was a Mercury or Mars sized object. Would it be possible to test this too?
Yes, we are interested to measure ureilites and angrites in the future.
Nabiei et al. (Nature Comm,., 2018) suggested that the ureilite parent body was a Mercury or Mars sized object. Would it be possible to test this too?
Yes, we are interested to measure ureilites and angrites in the future.
Submitted by Tomohiro Usui on Sunday 21st June 23:10
I’m convinced by your talk that d41K is a great tracer for the “degree of volatile loss”. But, my understanding is that the d41K systematics assumes the uniform starting compositions of terrestrial bodies (e.g., CI-chondrites). If Mars accreted more volatile-rich building blocks and lost more volatiles during the formation, how does d41K is presented?
Yes, we assumed a uniform starting point for all four differentiated bodies. This assumption is based on the observation that they "appear" fall on the same line (K isotopes versus mass). We tried to start with different K isotopic compositions for different bodies (except Earth and Moon) and then later loss is proportional to its size; however, we can not reproduce a good correlation between K isotopes and mass for four bodies.
I’m convinced by your talk that d41K is a great tracer for the “degree of volatile loss”. But, my understanding is that the d41K systematics assumes the uniform starting compositions of terrestrial bodies (e.g., CI-chondrites). If Mars accreted more volatile-rich building blocks and lost more volatiles during the formation, how does d41K is presented?
Yes, we assumed a uniform starting point for all four differentiated bodies. This assumption is based on the observation that they "appear" fall on the same line (K isotopes versus mass). We tried to start with different K isotopic compositions for different bodies (except Earth and Moon) and then later loss is proportional to its size; however, we can not reproduce a good correlation between K isotopes and mass for four bodies.
Submitted by Larry Nittler on Monday 22nd June 20:00
Very nice presentation, Kun. The Cl/K ratio on both Mercury and Mars is chondritic (based on gamma-ray data from MESSENGER and MRO, respectively) whereas Earth is apparently depleted in Cl (e.g., work by Zak Sharp). What might this mean for the overall comparison of volatile inventories of Earth and Mars?
Haha, Larry, I knew that you would ask a question about Mercury. Thanks for the question. I wasn't aware of the comparison of Cl/K ratios between Earth, Mars and Mercury. Both Cl and K are moderately volatile elements, and their ratios may stay the same if they are both depleted in the same degree relative to CI. I need to check the Cl/K ratio of the Earth and see how constant the ratio is between different Earth's reservoirs. I don't have any direct sense or simple answer for how does Cl/K ratio mean to volatile depletion.
Very nice presentation, Kun. The Cl/K ratio on both Mercury and Mars is chondritic (based on gamma-ray data from MESSENGER and MRO, respectively) whereas Earth is apparently depleted in Cl (e.g., work by Zak Sharp). What might this mean for the overall comparison of volatile inventories of Earth and Mars?
Haha, Larry, I knew that you would ask a question about Mercury. Thanks for the question. I wasn't aware of the comparison of Cl/K ratios between Earth, Mars and Mercury. Both Cl and K are moderately volatile elements, and their ratios may stay the same if they are both depleted in the same degree relative to CI. I need to check the Cl/K ratio of the Earth and see how constant the ratio is between different Earth's reservoirs. I don't have any direct sense or simple answer for how does Cl/K ratio mean to volatile depletion.
Submitted by Wenhua Lu on Tuesday 23rd June 04:19
Nice presentation. As you mentioned that the small planetesimals are tend to lose more vapor and get heavier 41K relative to the large rocky bodies, like Earth. But the large bodies usually formed by accreted the small planetesimals which may have lost vapor, as a result, they should inherit the heavy isotopic feature. How to you think about this? or, does it means that limit vapor would lost during the formation of the large rocky bodies?
Good questions. Thanks. We think primitive meteorites (aka chondrites) are undifferentiated and unmelted, thus not losing volatiles. There are many asteroids in the asteroids belts are differentiated (like Vesta), but also many undifferentiated (like Ceres). So there are plenty undifferentiated and unmelted planetesimals could provide volatiles and dominate the K isotopic signatures (mass-balance).
Nice presentation. As you mentioned that the small planetesimals are tend to lose more vapor and get heavier 41K relative to the large rocky bodies, like Earth. But the large bodies usually formed by accreted the small planetesimals which may have lost vapor, as a result, they should inherit the heavy isotopic feature. How to you think about this? or, does it means that limit vapor would lost during the formation of the large rocky bodies?
Good questions. Thanks. We think primitive meteorites (aka chondrites) are undifferentiated and unmelted, thus not losing volatiles. There are many asteroids in the asteroids belts are differentiated (like Vesta), but also many undifferentiated (like Ceres). So there are plenty undifferentiated and unmelted planetesimals could provide volatiles and dominate the K isotopic signatures (mass-balance).
Submitted by Wenhua Lu on Tuesday 23rd June 04:20
Nice presentation. As you mentioned that the small planetesimals are tend to lose more vapor and get heavier 41K relative to the large rocky bodies, like Earth. But the large bodies usually formed by accreted the small planetesimals which may have lost vapor, as a result, they should inherit the heavy isotopic feature. How to you think about this? or, does it means that limit vapor would lost during the formation of the large rocky bodies?
Good questions. Thanks. We think primitive meteorites (aka chondrites) are undifferentiated and unmelted, thus not losing volatiles. There are many asteroids in the asteroids belts are differentiated (like Vesta), but also many undifferentiated (like Ceres). So there are plenty undifferentiated and unmelted planetesimals could provide volatiles and dominate the K isotopic signatures (mass-balance).
Nice presentation. As you mentioned that the small planetesimals are tend to lose more vapor and get heavier 41K relative to the large rocky bodies, like Earth. But the large bodies usually formed by accreted the small planetesimals which may have lost vapor, as a result, they should inherit the heavy isotopic feature. How to you think about this? or, does it means that limit vapor would lost during the formation of the large rocky bodies?
Good questions. Thanks. We think primitive meteorites (aka chondrites) are undifferentiated and unmelted, thus not losing volatiles. There are many asteroids in the asteroids belts are differentiated (like Vesta), but also many undifferentiated (like Ceres). So there are plenty undifferentiated and unmelted planetesimals could provide volatiles and dominate the K isotopic signatures (mass-balance).
Submitted by Wenhua Lu on Tuesday 23rd June 04:25
As you mentioned that the small planetesimals are tend to lose more vapor and get heavier 41K relative to the large rocky bodies, like Earth. But the large bodies usually formed by accreted the small planetesimals which may have lost vapor, as a result, they should inherit the heavy isotopic feature. How to you think about this? or, does it means that limit vapor would lost during the formation of the large rocky bodies?
Good questions. Thanks. We think primitive meteorites (aka chondrites) are undifferentiated and unmelted, thus not losing volatiles. There are many asteroids in the asteroids belts are differentiated (like Vesta), but also many undifferentiated (like Ceres). So there are plenty undifferentiated and unmelted planetesimals could provide volatiles and dominate the K isotopic signatures (mass-balance).
As you mentioned that the small planetesimals are tend to lose more vapor and get heavier 41K relative to the large rocky bodies, like Earth. But the large bodies usually formed by accreted the small planetesimals which may have lost vapor, as a result, they should inherit the heavy isotopic feature. How to you think about this? or, does it means that limit vapor would lost during the formation of the large rocky bodies?
Good questions. Thanks. We think primitive meteorites (aka chondrites) are undifferentiated and unmelted, thus not losing volatiles. There are many asteroids in the asteroids belts are differentiated (like Vesta), but also many undifferentiated (like Ceres). So there are plenty undifferentiated and unmelted planetesimals could provide volatiles and dominate the K isotopic signatures (mass-balance).
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