<mods:mods xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ID="etd1699" xsi:schemaLocation="http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd">
<mods:titleInfo>
<mods:title>BUILDING THE CONTINENTAL LITHOSPHERE: THE HISTORY OF THE CONTIGUOUS U.S. AS PRESERVED IN CRUST AND LITHOSPHERIC MANTLE STRUCTURES</mods:title>
</mods:titleInfo><mods:name type="personal">
<mods:namePart>Hopper, Emily </mods:namePart>
<mods:role>
<mods:roleTerm type="text">creator</mods:roleTerm>
</mods:role>
</mods:name>
<mods:originInfo>
<mods:copyrightDate>2016</mods:copyrightDate>
</mods:originInfo>
<mods:physicalDescription>
<mods:extent>xx, 235 p.</mods:extent>
<mods:digitalOrigin>born digital</mods:digitalOrigin>
</mods:physicalDescription>
<mods:note>Thesis (Ph.D. -- Brown University (2016)</mods:note>
<mods:name type="personal">
<mods:namePart>Fischer, Karen</mods:namePart>
<mods:role>
<mods:roleTerm type="text">Director</mods:roleTerm>
</mods:role>
</mods:name>
<mods:name type="personal">
<mods:namePart>Forsyth, Donald</mods:namePart>
<mods:role>
<mods:roleTerm type="text">Reader</mods:roleTerm>
</mods:role>
</mods:name>
<mods:name type="personal">
<mods:namePart>Hirth, Greg</mods:namePart>
<mods:role>
<mods:roleTerm type="text">Reader</mods:roleTerm>
</mods:role>
</mods:name>
<mods:name type="personal">
<mods:namePart>Parman, Stephen</mods:namePart>
<mods:role>
<mods:roleTerm type="text">Reader</mods:roleTerm>
</mods:role>
</mods:name>
<mods:name type="personal">
<mods:namePart>Wagner, Lara</mods:namePart>
<mods:role>
<mods:roleTerm type="text">Reader</mods:roleTerm>
</mods:role>
</mods:name>
<mods:name type="corporate">
<mods:namePart>Brown University. Geological Sciences</mods:namePart>
<mods:role>
<mods:roleTerm type="text">sponsor</mods:roleTerm>
</mods:role>
</mods:name>
<mods:genre authority="aat">theses</mods:genre>
<mods:abstract>The lithosphere, the plate in ‘plate tectonics’, preserves a record of past and present tectonic processes in its internal structures and its boundary with the underlying asthenosphere. This dissertation uses scattered waves, largely common conversion point stacked Sp converted waves locally supplemented with a more formal wavefield migration, to image such structures in the crust and lithospheric mantle of the contiguous U.S. In the tectonically youngest western U.S. (Chapter 1), a shallow, sharp velocity gradient at the base of the lithosphere suggests a boundary defined by ponded melt. The lithosphere thickens with age of volcanism, implying the lithosphere is a melt-mitigated, conductively cooling thermal boundary layer. Beneath older, colder lithosphere where melt fractions are much lower, the velocity gradient at the base of such a layer should be a diffuse, purely thermal boundary. This is consistent with observations in the eastern U.S. (Chapter 2), where the boundary is locally sharp in areas of inferred enhanced upwelling only; and in the cratonic interior (Chapter 5), where the boundary is transparent to Sp waves. However, observations from the eastern U.S. indicate further complexity. Variations in current lithospheric thickness linked to Proterozoic rift boundaries suggest tectonic inheritance is significant at a lithospheric scale (Chapter 2). The preservation of relict tectonic structures like this gives insight into mechanisms of ancient deformation, with observations presented here emphasizing the importance of lateral accretion. A crustal suture in the southeastern U.S. generated by the final collision in the formation of the Appalachians is observed as a long, low-angle, dipping structure, accommodating several hundred kilometers of shortening (Chapter 3). The geometry of this feature is confirmed using an independent dataset and a wavefield migration technique that more accurately retrieves dips (Chapter 4). Ancient lateral accretion within the lithospheric mantle is preserved as dipping structures associated with relict subducted slabs from Paleoproterozoic continental accretion (Chapter 5). These observations suggest that lateral accretion is integral to the cratonic root formation process.</mods:abstract>
<mods:subject>
<mods:topic>Receiver functions</mods:topic>
</mods:subject>
<mods:subject>
<mods:topic>Wavefield migration</mods:topic>
</mods:subject>
<mods:subject>
<mods:topic>Asthenosphere</mods:topic>
</mods:subject>
<mods:subject xmlns:xlink="http://www.w3.org/1999/xlink" authority="FAST" authorityURI="http://id.worldcat.org/fast" valueURI="http://id.worldcat.org/fast/1111306"><mods:topic>Seismology</mods:topic></mods:subject><mods:subject xmlns:xlink="http://www.w3.org/1999/xlink" authority="FAST" authorityURI="http://id.worldcat.org/fast" valueURI="http://id.worldcat.org/fast/1764670"><mods:topic>Lithosphere</mods:topic></mods:subject><mods:subject xmlns:xlink="http://www.w3.org/1999/xlink" authority="FAST" authorityURI="http://id.worldcat.org/fast" valueURI="http://id.worldcat.org/fast/1242475"><mods:geographic>North America</mods:geographic></mods:subject><mods:recordInfo>
<mods:recordContentSource authority="marcorg">RPB</mods:recordContentSource>
<mods:recordCreationDate encoding="iso8601">20160629</mods:recordCreationDate>
</mods:recordInfo>
<mods:language xmlns:xlink="http://www.w3.org/1999/xlink"><mods:languageTerm type="code" authority="iso639-2b">eng</mods:languageTerm><mods:languageTerm type="text">English</mods:languageTerm></mods:language><mods:identifier xmlns:xlink="http://www.w3.org/1999/xlink" type="doi">10.7301/Z0DJ5D22</mods:identifier><mods:accessCondition xmlns:xlink="http://www.w3.org/1999/xlink" type="rights statement" xlink:href="http://rightsstatements.org/vocab/InC/1.0/">In Copyright</mods:accessCondition><mods:accessCondition type="restriction on access">Collection is open for research.</mods:accessCondition><mods:typeOfResource xmlns:xlink="http://www.w3.org/1999/xlink" authority="primo">dissertations</mods:typeOfResource></mods:mods>