Compositions of Mercury's earliest crust from magma ocean models

Stephanie M. Brown, Linda Elkins-Tanton

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

The size of the Mercurian core and the low ferrous iron bearing silicate content of its crust offer constraints on formation models for the planet. Here we consider a bulk composition that allows endogenous formation of the planet's large core, and by processing the mantle through a magma ocean, would produce a low-iron oxide crust consistent with observations. More Earth-like bulk compositions require silicate removal, perhaps by a giant impact, to create the planet's large core fraction. We find that the endogenous model can produce a large core with either a plagioclase flotation crust or a low-iron oxide magmatic crust. Because a magma ocean creates a gradient in iron oxide content in the resulting planetary mantle, the parts of the mantle removed by a putative giant impact could result in either a high-iron oxide mantle in contradiction to current crustal measurements, or a low-iron oxide mantle consistent with the current understanding of Mercury. If a giant impact cannot preferentially remove shallow mantle material then the proto-Mercury must have had a bulk low iron-oxide composition. Thus a specific bulk composition is required to make Mercury endogenously, and either a specific process or a specific composition is required to make it exogenously through giant impact. Measurements taken by the MESSENGER mission, when compared to predictions given here, may help resolve Mercury's formation process.

Original languageEnglish (US)
Pages (from-to)446-455
Number of pages10
JournalEarth and Planetary Science Letters
Volume286
Issue number3-4
DOIs
StatePublished - Sep 15 2009
Externally publishedYes

Fingerprint

ocean models
Mercury
iron oxides
iron oxide
magma
crusts
crust
Earth mantle
mantle
ocean
Planets
Chemical analysis
planets
Silicates
planet
silicates
planetary mantles
oceans
Bearings (structural)
silicate

Keywords

  • core
  • crustal composition
  • giant impact
  • magma ocean
  • Mercury

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Compositions of Mercury's earliest crust from magma ocean models. / Brown, Stephanie M.; Elkins-Tanton, Linda.

In: Earth and Planetary Science Letters, Vol. 286, No. 3-4, 15.09.2009, p. 446-455.

Research output: Contribution to journalArticle

@article{5fd96714191f4da0b8f24b48e9b71ea2,
title = "Compositions of Mercury's earliest crust from magma ocean models",
abstract = "The size of the Mercurian core and the low ferrous iron bearing silicate content of its crust offer constraints on formation models for the planet. Here we consider a bulk composition that allows endogenous formation of the planet's large core, and by processing the mantle through a magma ocean, would produce a low-iron oxide crust consistent with observations. More Earth-like bulk compositions require silicate removal, perhaps by a giant impact, to create the planet's large core fraction. We find that the endogenous model can produce a large core with either a plagioclase flotation crust or a low-iron oxide magmatic crust. Because a magma ocean creates a gradient in iron oxide content in the resulting planetary mantle, the parts of the mantle removed by a putative giant impact could result in either a high-iron oxide mantle in contradiction to current crustal measurements, or a low-iron oxide mantle consistent with the current understanding of Mercury. If a giant impact cannot preferentially remove shallow mantle material then the proto-Mercury must have had a bulk low iron-oxide composition. Thus a specific bulk composition is required to make Mercury endogenously, and either a specific process or a specific composition is required to make it exogenously through giant impact. Measurements taken by the MESSENGER mission, when compared to predictions given here, may help resolve Mercury's formation process.",
keywords = "core, crustal composition, giant impact, magma ocean, Mercury",
author = "Brown, {Stephanie M.} and Linda Elkins-Tanton",
year = "2009",
month = "9",
day = "15",
doi = "10.1016/j.epsl.2009.07.010",
language = "English (US)",
volume = "286",
pages = "446--455",
journal = "Earth and Planetary Sciences Letters",
issn = "0012-821X",
publisher = "Elsevier",
number = "3-4",

}

TY - JOUR

T1 - Compositions of Mercury's earliest crust from magma ocean models

AU - Brown, Stephanie M.

AU - Elkins-Tanton, Linda

PY - 2009/9/15

Y1 - 2009/9/15

N2 - The size of the Mercurian core and the low ferrous iron bearing silicate content of its crust offer constraints on formation models for the planet. Here we consider a bulk composition that allows endogenous formation of the planet's large core, and by processing the mantle through a magma ocean, would produce a low-iron oxide crust consistent with observations. More Earth-like bulk compositions require silicate removal, perhaps by a giant impact, to create the planet's large core fraction. We find that the endogenous model can produce a large core with either a plagioclase flotation crust or a low-iron oxide magmatic crust. Because a magma ocean creates a gradient in iron oxide content in the resulting planetary mantle, the parts of the mantle removed by a putative giant impact could result in either a high-iron oxide mantle in contradiction to current crustal measurements, or a low-iron oxide mantle consistent with the current understanding of Mercury. If a giant impact cannot preferentially remove shallow mantle material then the proto-Mercury must have had a bulk low iron-oxide composition. Thus a specific bulk composition is required to make Mercury endogenously, and either a specific process or a specific composition is required to make it exogenously through giant impact. Measurements taken by the MESSENGER mission, when compared to predictions given here, may help resolve Mercury's formation process.

AB - The size of the Mercurian core and the low ferrous iron bearing silicate content of its crust offer constraints on formation models for the planet. Here we consider a bulk composition that allows endogenous formation of the planet's large core, and by processing the mantle through a magma ocean, would produce a low-iron oxide crust consistent with observations. More Earth-like bulk compositions require silicate removal, perhaps by a giant impact, to create the planet's large core fraction. We find that the endogenous model can produce a large core with either a plagioclase flotation crust or a low-iron oxide magmatic crust. Because a magma ocean creates a gradient in iron oxide content in the resulting planetary mantle, the parts of the mantle removed by a putative giant impact could result in either a high-iron oxide mantle in contradiction to current crustal measurements, or a low-iron oxide mantle consistent with the current understanding of Mercury. If a giant impact cannot preferentially remove shallow mantle material then the proto-Mercury must have had a bulk low iron-oxide composition. Thus a specific bulk composition is required to make Mercury endogenously, and either a specific process or a specific composition is required to make it exogenously through giant impact. Measurements taken by the MESSENGER mission, when compared to predictions given here, may help resolve Mercury's formation process.

KW - core

KW - crustal composition

KW - giant impact

KW - magma ocean

KW - Mercury

UR - http://www.scopus.com/inward/record.url?scp=70349171287&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70349171287&partnerID=8YFLogxK

U2 - 10.1016/j.epsl.2009.07.010

DO - 10.1016/j.epsl.2009.07.010

M3 - Article

AN - SCOPUS:70349171287

VL - 286

SP - 446

EP - 455

JO - Earth and Planetary Sciences Letters

JF - Earth and Planetary Sciences Letters

SN - 0012-821X

IS - 3-4

ER -