<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Jeremy Hall</dc:contributor>
  <dc:contributor>James H. Luetgert</dc:contributor>
  <dc:creator>Stephen Hughes</dc:creator>
  <dc:date>1994</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The deep structure of the Newfoundland Appalachian orogen is investigated by analyses of three intersecting seismic refraction/wide-angle reflection profiles which traverse the Gander and Dunnage zones or central mobile belt of Newfoundland. A simultaneous travel time inversion for velocity and interface was applied to the in-line seismic refraction/wide-angle reflection data and constrained by synthetic amplitude models. The results of the modeling procedure show a subhorizontally layered crust with upper crustal velocities ranging from 5.4 to 6.2 km/s, a midcrustal velocity of 6.25–6.35 km/s, and a lower crustal velocity of 6.7±0.2 km/s. The top of the lower crust is marked by a series of prominent reflections between 18 and 23 km depth which suggest a complex layered velocity interface. Strong laterally coherent Moho reflections indicate a sharp crust-mantle transition at 35 ± 3 km. The uppermost mantle has a velocity of 8.0±0.2 km/s, and a reflecting horizon at 55 km depth suggests an increase to velocities approaching 8.5 km/s. Normal moveout corrections applied to fan profiles provide constraining evidence for the reflecting horizon at the top of the lower crust and laterally continuous Moho reflections at 11–12 s two-way travel time. Comparisons with a coincident deep seismic reflection profile show that the refraction and reflection Mohos match to better than 2–3 km. Bulk Poisson's ratios of 0.23–0.24 for the whole crust calculated from&amp;nbsp;&lt;/span&gt;&lt;i&gt;P&lt;sub&gt;m&lt;/sub&gt;P&lt;/i&gt;&lt;span&gt;/&lt;/span&gt;&lt;i&gt;S&lt;sub&gt;m&lt;/sub&gt;S&lt;/i&gt;&lt;span&gt;&amp;nbsp;travel times suggest a crust dominated by quartzofeldspathic lithologies and a notable absence of voluminous mafic additions to the lower crust. The absence of a deep crustal root, coupled with the bulk intermediate composition inferred for the lower crust from the seismic refraction/wide-angle data, implies that the crust beneath central Newfoundland has undergone multiple periods of reactivation and equilibration following successive orogenic episodes.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1029/94JB00653</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Geophysical Union</dc:publisher>
  <dc:title>The seismic velocity structure of the Newfoundland Appalachian orogen</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>