<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-09-19T15:58:04Z</responseDate><request verb="GetRecord" identifier="oai:dspace.mit.edu:1721.1/68893" metadataPrefix="dim">https://dspace.mit.edu/server/oai/request</request><GetRecord><record><header><identifier>oai:dspace.mit.edu:1721.1/68893</identifier><datestamp>2024-05-15T04:35:51Z</datestamp><setSpec>com_1721.1_7582</setSpec><setSpec>com_1721.1_7581</setSpec><setSpec>col_1721.1_131023</setSpec></header><metadata><dim:dim xmlns:dim="http://www.dspace.org/xmlns/dspace/dim" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.dspace.org/xmlns/dspace/dim http://www.dspace.org/schema/dim.xsd">
   <dim:field mdschema="dc" element="contributor" qualifier="advisor" lang="en_US">Linda T. Elkins-Tanton.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="author" lang="en_US">Springmann, A.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="other" lang="en_US">Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="department">Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="accessioned">2012-01-30T17:01:19Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="available">2012-01-30T17:01:19Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="copyright" lang="en_US">2011</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="issued" lang="en_US">2011</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="uri">http://hdl.handle.net/1721.1/68893</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="oclc" lang="en_US">773577042</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Cataloged from PDF version of thesis.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Includes bibliographical references (p. 31-34).</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="abstract" lang="en_US">In this thesis we investigate the solidification of early magma oceans on the Earth and the formation of a deep dense layer at the core-mantle boundary. We also study the concentrations and densities of the last layers of the solidified magma ocean and how they create a deep dense layer after solid-state overturn. The deep dense layer that forms in our model matches the bulk physical properties of the D" layer observed by other workers. This layer is also sufficiently dense that the bulk of its material is not reentrained by the mantle after the onset of convection, and that this layer is enriched in incompatible elements such as samarium and neodymium regardless of distribution coefficients used for incompatible elements in mantle minerals such as perovskite. However, we found that this probable D" layer is more enriched in samarium than is to be expected for a planet's mantle which evolves from an initially chondritic composition.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="statementofresponsibility" lang="en_US">by Alessondra Springmann.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="degree" lang="en_US">S.M.</dim:field>
   <dim:field mdschema="dc" element="format" qualifier="extent" lang="en_US">34 p.</dim:field>
   <dim:field mdschema="dc" element="language" qualifier="iso" lang="en_US">eng</dim:field>
   <dim:field mdschema="dc" element="publisher" lang="en_US">Massachusetts Institute of Technology</dim:field>
   <dim:field mdschema="dc" element="rights" lang="en_US">M.I.T. theses are protected by &#xd;
copyright. They may be viewed from this source for any purpose, but &#xd;
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permission. See provided URL for inquiries about permission.</dim:field>
   <dim:field mdschema="dc" element="rights" qualifier="uri" lang="en_US">http://dspace.mit.edu/handle/1721.1/7582</dim:field>
   <dim:field mdschema="dc" element="subject" lang="en_US">Earth, Atmospheric, and Planetary Sciences.</dim:field>
   <dim:field mdschema="dc" element="title" lang="en_US">Terrestrial magma ocean solidification and formation of a candidate D" layer</dim:field>
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   	&lt;Title>Terrestrial magma ocean solidification and formation of a candidate D&amp;quot; layer&lt;/Title>
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   	&lt;PublicationDate>2011&lt;/PublicationDate>
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        	&lt;DisplayName>Springmann, A.&lt;/DisplayName>
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    &lt;Keyword>Earth, Atmospheric, and Planetary Sciences.&lt;/Keyword>
   	&lt;Abstract>In this thesis we investigate the solidification of early magma oceans on the Earth and the formation of a deep dense layer at the core-mantle boundary. We also study the concentrations and densities of the last layers of the solidified magma ocean and how they create a deep dense layer after solid-state overturn. The deep dense layer that forms in our model matches the bulk physical properties of the D&amp;quot; layer observed by other workers. This layer is also sufficiently dense that the bulk of its material is not reentrained by the mantle after the onset of convection, and that this layer is enriched in incompatible elements such as samarium and neodymium regardless of distribution coefficients used for incompatible elements in mantle minerals such as perovskite. However, we found that this probable D&amp;quot; layer is more enriched in samarium than is to be expected for a planet&amp;apos;s mantle which evolves from an initially chondritic composition.&lt;/Abstract>
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