Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and Canada
We report the calcite twinning strain results of a traverse across the Grenville orogen from Parry Sound, Ontario (NW) to Ft. Ann, New York (SE), including the younger, adjacent Ordovician Taconic allochthon. Fifty four carbonates (marbles, calcite veins, Ordovician limestone) were collected resulti...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2017-11-01
|
| Series: | Geoscience Frontiers |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987117300257 |
| _version_ | 1797719119583248384 |
|---|---|
| author | John P. Craddock Suzanne D. Craddock Alex Konstantinou Andrew R.C. Kylander-Clark David H. Malone |
| author_facet | John P. Craddock Suzanne D. Craddock Alex Konstantinou Andrew R.C. Kylander-Clark David H. Malone |
| author_sort | John P. Craddock |
| collection | DOAJ |
| description | We report the calcite twinning strain results of a traverse across the Grenville orogen from Parry Sound, Ontario (NW) to Ft. Ann, New York (SE), including the younger, adjacent Ordovician Taconic allochthon. Fifty four carbonates (marbles, calcite veins, Ordovician limestone) were collected resulting in 68 strain analyses on mechanically twinned calcite (n = 2337 grains) across the Central Gneiss Belt (CGB; 3 samples), the Central Metasedimentary Belt (CMB; 27 samples), the Central Granulite Terrane (CGT; Adirondack's; 13 samples) and the Ottawan Orogenic Lid (OOL; 11 samples). Twinning strains in the greenschist-grade OOL marbles preserve N–S shortening and U-Pb titanite ages (∼1150 Ma; n = 4) document these marbles formed during the Shawinigan (1190–1140 Ma) part of the Grenville orogen. From northwest to southeast, the Ottawan (1095–1020 Ma) twinning strain is dominantly a layer-parallel shortening fabric oriented N–S (Parry Sound), then becomes parallel to the Grenville thrust direction (NW–SE) across the CMB to the Adirondack Highlands where the sub-horizontal shortening strain becomes margin-parallel (SW–NE). Within the regional sample suite there are two areas studied in detail, the Bancroft shear zone (n = 11) and a roadcut on the southeast side of the Adirondack Mountains (Ft. Ann, NY; n = 8). Marbles from the Bancroft shear zone contain calcite grains with 2 sets of twin lamellae (e1 and e2). The better-developed e1 sets (n = 406) record a horizontal fabric oriented NW–SE whereas the younger e2 lamellae (n = 146) preserve a margin-parallel (SW–NE) horizontal fabric. Both the e1 and e2 strains record an overprint vertical shortening strain (NEV), perhaps related to extensional orogenic collapse. We also report an Ottawan orogen-aged granoblastic mylonite (1093 Ma, U-Pb zircon; 1102 Ma Ar-Ar biotite) in the Keweenaw thrust hanging wall 500 km inboard of the Grenville front and interpret the relations of Grenville-Keweenaw far-field dynamics. |
| first_indexed | 2024-03-12T09:00:09Z |
| format | Article |
| id | doaj.art-d6e51bd11329444cb40d304819f50c31 |
| institution | Directory Open Access Journal |
| issn | 1674-9871 |
| language | English |
| last_indexed | 2024-03-12T09:00:09Z |
| publishDate | 2017-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Geoscience Frontiers |
| spelling | doaj.art-d6e51bd11329444cb40d304819f50c312023-09-02T15:44:42ZengElsevierGeoscience Frontiers1674-98712017-11-01861357138410.1016/j.gsf.2017.01.006Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and CanadaJohn P. Craddock0Suzanne D. Craddock1Alex Konstantinou2Andrew R.C. Kylander-Clark3David H. Malone4Geology Department, Macalester College, St. Paul, MN 55105, USASchool of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ, USACyprus Hydrocarbons Company, Nicosia, CyprusDepartment of Earth Science, University of California, Santa Barbara, CA 93106, USADepartment of Geography-Geology, Illinois State University, Normal, IL 61790-4400, USAWe report the calcite twinning strain results of a traverse across the Grenville orogen from Parry Sound, Ontario (NW) to Ft. Ann, New York (SE), including the younger, adjacent Ordovician Taconic allochthon. Fifty four carbonates (marbles, calcite veins, Ordovician limestone) were collected resulting in 68 strain analyses on mechanically twinned calcite (n = 2337 grains) across the Central Gneiss Belt (CGB; 3 samples), the Central Metasedimentary Belt (CMB; 27 samples), the Central Granulite Terrane (CGT; Adirondack's; 13 samples) and the Ottawan Orogenic Lid (OOL; 11 samples). Twinning strains in the greenschist-grade OOL marbles preserve N–S shortening and U-Pb titanite ages (∼1150 Ma; n = 4) document these marbles formed during the Shawinigan (1190–1140 Ma) part of the Grenville orogen. From northwest to southeast, the Ottawan (1095–1020 Ma) twinning strain is dominantly a layer-parallel shortening fabric oriented N–S (Parry Sound), then becomes parallel to the Grenville thrust direction (NW–SE) across the CMB to the Adirondack Highlands where the sub-horizontal shortening strain becomes margin-parallel (SW–NE). Within the regional sample suite there are two areas studied in detail, the Bancroft shear zone (n = 11) and a roadcut on the southeast side of the Adirondack Mountains (Ft. Ann, NY; n = 8). Marbles from the Bancroft shear zone contain calcite grains with 2 sets of twin lamellae (e1 and e2). The better-developed e1 sets (n = 406) record a horizontal fabric oriented NW–SE whereas the younger e2 lamellae (n = 146) preserve a margin-parallel (SW–NE) horizontal fabric. Both the e1 and e2 strains record an overprint vertical shortening strain (NEV), perhaps related to extensional orogenic collapse. We also report an Ottawan orogen-aged granoblastic mylonite (1093 Ma, U-Pb zircon; 1102 Ma Ar-Ar biotite) in the Keweenaw thrust hanging wall 500 km inboard of the Grenville front and interpret the relations of Grenville-Keweenaw far-field dynamics.http://www.sciencedirect.com/science/article/pii/S1674987117300257Orogenic beltsStrainProterozoic |
| spellingShingle | John P. Craddock Suzanne D. Craddock Alex Konstantinou Andrew R.C. Kylander-Clark David H. Malone Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and Canada Geoscience Frontiers Orogenic belts Strain Proterozoic |
| title | Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and Canada |
| title_full | Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and Canada |
| title_fullStr | Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and Canada |
| title_full_unstemmed | Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and Canada |
| title_short | Calcite twinning strain variations across the Proterozoic Grenville orogen and Keweenaw-Kapuskasing inverted foreland, USA and Canada |
| title_sort | calcite twinning strain variations across the proterozoic grenville orogen and keweenaw kapuskasing inverted foreland usa and canada |
| topic | Orogenic belts Strain Proterozoic |
| url | http://www.sciencedirect.com/science/article/pii/S1674987117300257 |
| work_keys_str_mv | AT johnpcraddock calcitetwinningstrainvariationsacrosstheproterozoicgrenvilleorogenandkeweenawkapuskasinginvertedforelandusaandcanada AT suzannedcraddock calcitetwinningstrainvariationsacrosstheproterozoicgrenvilleorogenandkeweenawkapuskasinginvertedforelandusaandcanada AT alexkonstantinou calcitetwinningstrainvariationsacrosstheproterozoicgrenvilleorogenandkeweenawkapuskasinginvertedforelandusaandcanada AT andrewrckylanderclark calcitetwinningstrainvariationsacrosstheproterozoicgrenvilleorogenandkeweenawkapuskasinginvertedforelandusaandcanada AT davidhmalone calcitetwinningstrainvariationsacrosstheproterozoicgrenvilleorogenandkeweenawkapuskasinginvertedforelandusaandcanada |