# Presentation: 090131

## Chip Shearer
Institute of Meteoritics
University of New Mexico

**Chip Shearer**
**Institute of Meteoritics**
**University of New Mexico**

## Rationale for Workshop 

- Rationale for Workshop

- Planetary differentiation is a fundamental early solar system process that in part dictates the evolutionary pathway followed by a planet.
-  The last 15 years have seen a dramatic refinement of our understanding of the early evolution of planetary bodies.
- timescales over which differentiation occurred.
-  increase in the sophistication of our understanding of orbital dynamics, accretion, and mechanisms of the differentiation process.
- a broader perspective of planetary differentiation derived by contrasting planetary settings (Earth, Moon, Mars, asteroids).
- The goal of this workshop was to integrate these advances into a richer understanding of the earliest stages of planetary evolution.
- Important scientific theme for lunar exploration.

## Conveners 

- Conveners

** ****Chip Shearer**
**     *****Institute of Meteoritics, University of New***
***     ******Mexico***
**Lars Borg**
**     *****Lawrence Livermore National Labs***
**Kevin Righter**
**     *****Johnson Space Center*****.  **

## Program Committee 

- Program Committee

**Craig Agnor**
***       ******University of California,Santa Cruz***
**Linda Elkins-Tanton**
***       ******Brown University***
**Walter Kiefer**
**       *****Lunar and Planetary Institute***
**Jay Melosh**
***       ******University of Arizona***
**Meenakshi Wadhwa,****   *****Arizona State University***
**Richard Walker,****   *****University of Maryland****** ***

## Workshop Sponsors 

**Workshop Sponsors **

*** ******Lunar and Planetary Institute***
** ****NASA**
** ****Mars Exploration Office **
** ****Curation and Analysis Planning  Team for Extraterrestrial Materials  (CAPTEM)**

## Summary of Workshop 

- Summary of Workshop

**Doubletree Hotel Sonoma, Sonoma County California.**
**December 7-10 2006 **
**Reception December 7**
**5 Technical Sessions December 8-10**
**Evening poster session December 8**
**85 Registered Attendees. **
**10 Students**
**Most from US, several from Europe and Asia.**
**       **

## Workshop Themes 

- Workshop Themes

** ****Early Differentiation, an overview from a**
**     ****planetary perspective.**
** ****Accretion and the initial conditions of the**
**    ****terrestrial planets.**
** ****Timescales of early planetary  differentiation.**
** ****Mechanisms of silicate differentiations.**
** ****Dynamic, isotopic, and experimental constraints**
**    ****for core formation.**

## Invited Speakers I 

- Invited Speakers I

**Early Differentiation, an overview from a planetary perspective.**
**Dave Stevenson (Caltech) **_***Early Planetary Differentiation.***_
**Mike Drake (University of Arizona) **_***The Vesta-HED***_
***	***_***meteorite connection.***_
**Lars Borg (LLNL) **_***The differentiation history of Mars inferred from the isotopic study of SNC meteorites.***_
**Chip Shearer (UNM) **_***Remnants of a magma ocean, Insights into the differentiation of the Moon and relevance to the terrestrial planets.***_
**Accretion and the initial conditions of the terrestrial planets.**
**Hal Levison (SWRI) **_***Terrestrial planet formation, Timescales and***__** **__***modeling results.***_
**Francis Nimmo (University of California,Santa Cruz)***** ***_***Observational and theortical constraints on the initial temperature structure of the terrestrial planets.***__** **_** **

## Invited Speakers II 

- Invited Speakers II

**Timescales of early planetary  differentiation.**
**T Kleine (ETH Zurich) **_**Tungsten isotope constraints on core formation in the terrestrial planets.**_
** ****Stein Jacobson (Harvard) **_**Isotopic constraints on the time scales of Earth’s differentiation.**_
** ****Mark Harrison (UCLA) **_**The Hadean Earth**_**. **
** ****Mechanisms of silicate differentiations.**
**Rick Carlson (DTM) **_**Early planetary differentiation: Unmixing and remixing planetary interiors.**_
**Mark Walter (University of Bristol) **_**Exploring the geochemical consequences of magma ocean differentiation.**_
** ****Dynamic, isotopic, and experimental constraints for core formation.**
**Nancy Chabot (JHU-APL) **_**Experimental constraints on Planetary core formation in an early magma ocean.**_

## Examples of Mars related presentations 

- Examples of Mars related presentations

**Differentiation of Mars**
** **_***The differentiation history of Mars inferred from the isotopic study of SNC meteorites.***_
_*** ***__***Timescales of the early differentiation of Mars.***_
_***Water on Mars. Behavior of water during accretion and early differentiation.***_
_***What controlled the rate of crustal differentiation on early Mars?***_
_***New, geophysically constrianed martian mantle compositions.***_
_***Siderphile element constraints on the depth and extent of melting on early Mars.***_
_***Duration of lunar differentiation and similarities to early Mars.***_

## Examples of Mars related presentations

***Comparisons between Mars and the other terrestrial planets***
_***Remnants of a magma ocean, Insights into the differentiation of the Moon and relevance to the terrestrial planets.***_
_***Early Planetary differentiation: Comparative planetology.***_
_***Redox control of S among the terrestrial planets.***_
_***Observational and theortical constraints on the initial temperature structure of the terrestrial planets.***__** **__** **_
_***Late accretional histories of the Earth, Moon, and Mars.***_
_***Giant impacts and terrestrial planet evolution.***_
_***Linked magma ocean solidification and atmospheric growth.***_
_***Mars vs Moon. The effects of length scales and initial composition on Planetary differentiation. ***_

## Examples of important results 

- Examples of important results

**Planetary differentiation is an early and rapid process.**
** ****Perhaps contemporary with CAI and chondrule formation.**
** ****Both the Moon, Mars, and EPB experienced differentiation through rapid crystallization of a magma ocean (10-50 my).**
**Secondary crustal formation (granites) and stability of water on the Earth’s surface occurred early (4.45 Ga). Is this relevant to Mars?**
**  **

## Examples of important results 

- Examples of important results

**Different styles of accretion (i.e. Moon vs Mars) will influence extent of melting and number of magma oceans.**
**Considerable differences in W and Sm isotopic systematics between Mars and Moon.**

**146****Sm ******** ****142****Nd (t****1/2**** = 103 Ma)**
**182****Hf ******** ****182****W (t****1/2**** = 9 Ma)**

## Examples of important results 

- Examples of important results

**P-T-H****2****O of magma ocean crystallization had a substantial effect on **
**Nature of primary planetary crusts.**
**Post-magma ocean additions to the mantle via late-stage accretion.**
**Atmospheric evolution.**

- Longhi, 1980

## Future observations for a better understanding planetary differentiation.

- Develop further linkages between observations and models.
- Magma ocean crystallization.
- Giant impact models.
- Multiple magma oceans.
-  Nature of planetary interiors (geophysical networks).
- Exploration and sampling of preserved primary planetary crusts.
- Moon = FANs
- 4 Vesta = basalts
- Mars = ancient terrains.