TY - JOUR AU - Ludman, Allan AU - Hopeck, John T. AU - Berry IV, Henry N. PY - 2017/03/16 Y2 - 2024/03/29 TI - Provenance and paleogeography of post-Middle Ordovician, pre-Devonian sedimentary basins on the Gander composite terrane, eastern and east-central Maine: implications for Silurian tectonics in the northern Appalachians JF - Atlantic Geoscience JA - atlgeo VL - 53 IS - 0 SE - Articles DO - 10.4138/atlgeol.2017.003 UR - https://journals.lib.unb.ca/index.php/ag/article/view/24514 SP - 063 - 085 AB - <p style="margin: 1em 0px; line-height: 200%; text-indent: 0.5in;"><span style="font-family: 'Minion Pro','serif';" lang="EN-CA"><span style="font-size: medium;">Recent mapping in eastern and east-central Maine addresses long-standing regional correlation issues and permits reconstruction of post-Middle Ordovician, pre-Devonian paleogeography of sedimentary basins on the Ganderian composite terrane. Two major Late Ordovician-Silurian depocenters are recognized in eastern Maine and western New Brunswick separated by an emergent Miramichi terrane: the Fredericton trough to the southeast and a single basin comprising the Central Maine and Aroostook-Matapedia sequences to the northwest. This Central Maine/Aroostook-Matapedia (CMAM) basin received sediment from both the Miramichi highland to the east and highlands and islands to the west, including the pre-Late Ordovician Boundary Mountains, Munsungun-Pennington, and Weeksboro-Lunksoos terranes. Lithofacies in the Fredericton trough are truncated and telescoped by faulting along its flanks but suggest a similar basin that received sediment from highlands to the west (Miramichi) and east (St. Croix).</span></span></p><p style="margin: 1em 0px; line-height: 200%; text-indent: 0.5in;"><span style="font-family: 'Minion Pro','serif';" lang="EN-CA"><span style="font-size: medium;">Deposition ended in the Fredericton trough following burial and deformation in the Late Silurian, but continued in the CMAM basin until Early Devonian Acadian folding. A westward-migrating Acadian orogenic wedge provided a single eastern source of sediment for the composite CMAM basin after the Salinic/Early Acadian event, replacing the earlier, more local sources. The CMAM, Fredericton, and Connecticut Valley-Gaspé depocenters were active immediately following the Taconian orogeny and probably formed during extension related to post-Taconian plate adjustments. These basins thus predate Acadian foreland sedimentation.</span></span></p><p style="margin: 1em 0px; line-height: 200%; text-indent: 0.5in;"><span style="font-family: 'Minion Pro','serif';" lang="EN-CA"><span style="font-size: medium;">Structural analysis and seismic reflection profiles indicate a greater degree of post-depositional crustal shortening than previously interpreted. Late Acadian and post-Acadian strike-slip faulting on the Norumbega and Central Maine Boundary fault systems distorted basin geometries but did not disturb paleogeographic components drastically.</span></span></p> ER -