Final Announcement

Meeting Location and Date

The Differentiation:  Building the Internal Architecture of Planets conference will be held May 7–10, 2018, at the Hilton Pasadena hotel in Pasadena, California.

Purpose and Scope

The second topical conference in the LPI's The First Billion Years initiative focuses on planetary differentiation, which created the basic architecture of the planets and established the initial chemical and physical conditions for all subsequent stages of planetary evolution. Planetary differentiation was a dynamic period of time. The first planetary crusts formed from melted silicates and ices, possibly as part of global-scale magma oceans. Metal rain separated silicates, ices, and metal phases, which produced iron-rich cores and resulted in at least transient magnetic dynamos on some planets and meteorite parent bodies. Volatiles outgassed from planetary interiors created the earliest planetary atmospheres and possibly oceans, and likely influenced early planetary habitability. Isotopic data show that these events may have occurred on timescales of approximately 10 million years or less, indicating they overlapped with the period of planetary accretion.

Understanding these processes requires input from many types of investigations including petrologic, isotopic, trace element, and paleo-magnetic analysis of samples; geophysical probes of deep planetary structure; and experimental and numerical simulations. We seek input from all of these communities at this topical conference, with a focus on interdisciplinary discussion. The scope of this conference includes both rocky and ice-rich objects.


This topical conference will draw on current knowledge in dynamics and chemistry to forge a new synthesis in our understanding of planetary differentiation. This begins with determining how accretional dynamics and compositional variations in the solar system led to the initial, primitive planetary compositions. It also requires understanding the physical and chemical processes that controlled differentiation from an unmodified body into an object with a core, mantle, crust, and (in some cases) atmosphere or ocean. Equally important is for the community to explore how differentiated bodies were altered as a result of late bombardment, and how these factors may have ultimately influenced habitability.

Science questions to be addressed at this topical conference include but are not limited to:

What is our current understanding of internal differentiation in bodies across the solar system based on available (chemical, geophysical, isotopic, petrologic) observations of meteorites and planets?

What are the timescales on which differentiation occurred on different objects and in different parts of the solar system?

What is the temporal overlap between accretion and differentiation, and how does that overlap influence the results of planetary differentiation?

What types of vertical and horizontal chemical stratification are created by magma ocean solidification? What are the structures and compositions of the earliest planetary crusts?

What is the nature of the transition from differentiation to sub‐solidus mantle convection, and what controls whether the initial convective style is mobile lid or stagnant lid?

What factors control the presence or absence of chemical equilibrium between core and mantle during core formation?

What processes control the onset time and early strength of a magnetic dynamo? How does this influence atmosphere and ocean preservation and the possibility of early planetary habitability?

How do these processes differ on volatile-rich and volatile-poor objects?

What factors control the development of fully differentiated versus partially differentiated objects?

How are these processes influenced by basin‐forming impacts?

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