Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks
A refined model for the wide-angle reflection-refraction profile 88-3 that crosses the foreland basin of the Appalachian orogen is presented. The two major layers of the cratonic crust have velocities of 6.2 and 6.7 km·s -1 with low gradients. Near the exposed North American craton, the 6.7 km·s -1...
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crcansciencepubl:10.1139/e98-043 2023-12-17T10:44:48+01:00 Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks Jackson, H R Marillier, F Hall, J 1998 http://dx.doi.org/10.1139/e98-043 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-043 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 35, issue 11, page 1222-1237 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1998 crcansciencepubl https://doi.org/10.1139/e98-043 2023-11-19T13:39:26Z A refined model for the wide-angle reflection-refraction profile 88-3 that crosses the foreland basin of the Appalachian orogen is presented. The two major layers of the cratonic crust have velocities of 6.2 and 6.7 km·s -1 with low gradients. Near the exposed North American craton, the 6.7 km·s -1 velocity appears at the shallow depth of 13 km and the M discontinuity at greater than 40 km depth. Towards the orogen, a southeastward-dipping ramp is developed at mid-crustal levels at the top of the 6.7 km·s -1 layer. Near the Appalachian Front lower-crustal velocities typical of the Grenville are replaced with a velocity of 7.2 km·s -1 . The collinear reflection profile confirms the southward-dipping ramp, the shallowing M discontinuity, and the lateral changes in the lower crust. Refraction profiles combined with reflection and gravity data are used to distinguish the Grenville lower-crustal block. The Grenville lower-crustal block is defined as a pattern of lower-crustal and upper-mantle reflectivity, with associated velocities, and a more negative gravity anomaly than lower-crustal blocks of the Appalachian terranes. The Grenville block terminates northwest of the coast of Newfoundland near the Appalachian Front. Thus, this lower-crustal province does not underlie the Humber tectono-stratigraphic zone. This is different than the relationship of the edge of the Grenville lower-crustal block to surface zones in New England. A thick-skinned tectonic style with basement-involved deformation appears to be typical of the Newfoundland Appalachians; in contrast, a thin-skinned structural style is observed in New England. The change in structural styles occurs in the bend of the Appalachian orogen across the Gulf of St. Lawrence. Article in Journal/Newspaper Newfoundland Canadian Science Publishing (via Crossref) Ramp The ENVELOPE(166.433,166.433,-77.633,-77.633) Canadian Journal of Earth Sciences 35 11 1222 1237 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Jackson, H R Marillier, F Hall, J Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks |
topic_facet |
General Earth and Planetary Sciences |
description |
A refined model for the wide-angle reflection-refraction profile 88-3 that crosses the foreland basin of the Appalachian orogen is presented. The two major layers of the cratonic crust have velocities of 6.2 and 6.7 km·s -1 with low gradients. Near the exposed North American craton, the 6.7 km·s -1 velocity appears at the shallow depth of 13 km and the M discontinuity at greater than 40 km depth. Towards the orogen, a southeastward-dipping ramp is developed at mid-crustal levels at the top of the 6.7 km·s -1 layer. Near the Appalachian Front lower-crustal velocities typical of the Grenville are replaced with a velocity of 7.2 km·s -1 . The collinear reflection profile confirms the southward-dipping ramp, the shallowing M discontinuity, and the lateral changes in the lower crust. Refraction profiles combined with reflection and gravity data are used to distinguish the Grenville lower-crustal block. The Grenville lower-crustal block is defined as a pattern of lower-crustal and upper-mantle reflectivity, with associated velocities, and a more negative gravity anomaly than lower-crustal blocks of the Appalachian terranes. The Grenville block terminates northwest of the coast of Newfoundland near the Appalachian Front. Thus, this lower-crustal province does not underlie the Humber tectono-stratigraphic zone. This is different than the relationship of the edge of the Grenville lower-crustal block to surface zones in New England. A thick-skinned tectonic style with basement-involved deformation appears to be typical of the Newfoundland Appalachians; in contrast, a thin-skinned structural style is observed in New England. The change in structural styles occurs in the bend of the Appalachian orogen across the Gulf of St. Lawrence. |
format |
Article in Journal/Newspaper |
author |
Jackson, H R Marillier, F Hall, J |
author_facet |
Jackson, H R Marillier, F Hall, J |
author_sort |
Jackson, H R |
title |
Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks |
title_short |
Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks |
title_full |
Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks |
title_fullStr |
Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks |
title_full_unstemmed |
Seismic refraction data in the Gulf of Saint Lawrence: implications for the lower-crustal blocks |
title_sort |
seismic refraction data in the gulf of saint lawrence: implications for the lower-crustal blocks |
publisher |
Canadian Science Publishing |
publishDate |
1998 |
url |
http://dx.doi.org/10.1139/e98-043 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-043 |
long_lat |
ENVELOPE(166.433,166.433,-77.633,-77.633) |
geographic |
Ramp The |
geographic_facet |
Ramp The |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Canadian Journal of Earth Sciences volume 35, issue 11, page 1222-1237 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e98-043 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
35 |
container_issue |
11 |
container_start_page |
1222 |
op_container_end_page |
1237 |
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1785563957664153600 |