Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements
If protoplanets formed from 10 to 20 kilometer diameter planetesimals in a runaway accretion process prior to their oligarchic growth into the terrestrial planets, it is only logical to ask where these planetesimals may have formed in order to assess the initial composition of the Earth. We have use...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20120002071 2023-05-15T13:43:16+02:00 Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements Saba, Jack L. Zwally, H. Jay Yi, Donghui Robbins, John Li, Jun Unclassified, Unlimited, Publicly available December 05, 2011 application/pdf http://hdl.handle.net/2060/20120002071 unknown Document ID: 20120002071 http://hdl.handle.net/2060/20120002071 No Copyright CASI Geophysics GSFC.CP.5738.2011 American Geophysical Union (AGU) 2011 Fall Meeting; 5-9 Dec. 2011; San Francisco, CA; United States 2011 ftnasantrs 2019-07-21T00:54:41Z If protoplanets formed from 10 to 20 kilometer diameter planetesimals in a runaway accretion process prior to their oligarchic growth into the terrestrial planets, it is only logical to ask where these planetesimals may have formed in order to assess the initial composition of the Earth. We have used Weidenschilling's model for the formation of comets (1997) to calculate an efficiency factor for the formation of planetesimals from the solar nebula, then used this factor to calculate the feeding zones that contribute to material contained within 10, 15 and 20 kilometer diameter planetesimals at 1 A.V. as a function of nebular mass. We find that for all reasonable nebular masses, these planetesimals contain a minimum of 3% water as ice by mass. The fraction of ice increases as the planetesimals increase in size and as the nebular mass decreases, since both factors increase the feeding zones from which solids in the final planetesimals are drawn. Is there really a problem with the current accretion scenario that makes the Earth too dry, or is it possible that the nascent Earth lost significant quantities of water in the final stages of accretion? Other/Unknown Material Antarc* Antarctic Ice Sheet NASA Technical Reports Server (NTRS) Antarctic |
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Open Polar |
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NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Geophysics |
spellingShingle |
Geophysics Saba, Jack L. Zwally, H. Jay Yi, Donghui Robbins, John Li, Jun Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements |
topic_facet |
Geophysics |
description |
If protoplanets formed from 10 to 20 kilometer diameter planetesimals in a runaway accretion process prior to their oligarchic growth into the terrestrial planets, it is only logical to ask where these planetesimals may have formed in order to assess the initial composition of the Earth. We have used Weidenschilling's model for the formation of comets (1997) to calculate an efficiency factor for the formation of planetesimals from the solar nebula, then used this factor to calculate the feeding zones that contribute to material contained within 10, 15 and 20 kilometer diameter planetesimals at 1 A.V. as a function of nebular mass. We find that for all reasonable nebular masses, these planetesimals contain a minimum of 3% water as ice by mass. The fraction of ice increases as the planetesimals increase in size and as the nebular mass decreases, since both factors increase the feeding zones from which solids in the final planetesimals are drawn. Is there really a problem with the current accretion scenario that makes the Earth too dry, or is it possible that the nascent Earth lost significant quantities of water in the final stages of accretion? |
format |
Other/Unknown Material |
author |
Saba, Jack L. Zwally, H. Jay Yi, Donghui Robbins, John Li, Jun |
author_facet |
Saba, Jack L. Zwally, H. Jay Yi, Donghui Robbins, John Li, Jun |
author_sort |
Saba, Jack L. |
title |
Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements |
title_short |
Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements |
title_full |
Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements |
title_fullStr |
Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements |
title_full_unstemmed |
Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements |
title_sort |
analysis of antarctic ice-sheet mass balance from icesat measurements |
publishDate |
2011 |
url |
http://hdl.handle.net/2060/20120002071 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_source |
CASI |
op_relation |
Document ID: 20120002071 http://hdl.handle.net/2060/20120002071 |
op_rights |
No Copyright |
_version_ |
1766186460349726720 |