1 New advances in geological and geophysical research on the Appalachian orogen.
We invite contributions that discuss new research on the Appalachian orogen. Submissions should include, but are not limited to, geological or geophysical studies or works comprising a combination of both methods.
Sunday, 22 March 2026
8:00 AM - 12:00 PM
CCC, Room 22/23
Traverse Across The Taconian Collision Zone: Dutchess County to Hinterland of the Manhattan prong
Paper number: 1-12
Program: Technical Sessions
Time: 11:40 AM – 12:00 PM
Authors
Abstract
The collision of the Laurentian margin with the accretionary wedge and oceanic arc occurred after deposition of basal unit of the Walloomsac Formation at about 458 Ma based on conodonts from NJ to VT. Clove Valley on the biotite to garnet isograds marks the transition to west- vergent synmetamorphic structure and destruction of features related to emplacement of the Taconic allochthons. Structures in the Pawling area are controlled by mobility of basement on ductile faults and internal detachment faults; these repeat levels of cover rocks interspersed with slivers of basement in windows. Stitching plutons of the Cortlandt Intrusive suite (CIS) (450 to 445 Ma) were intruded into this setting along the boundary between the Hudson Highlands (HH) and the Manhattan prong. Waldren (1986) and Dorfler (2015) documented an increase in tectonic loading of approximately 10 km just before intrusion of the Cortlandt complex and the Croton Falls pluton. Eastward vergence of faults develops in basement and cover coincident with extensive partial melting of basement and the intrusion of the Candlewood Granite (443 Ma) (Walsh, 2012). This signals regional retrochariage or back folding of basement and tectonic cover, after or during intrusion of the Bedford pluton across Camerons line and before the Siscowitt Granite totally engulfs Camerons line. CIS plutons of the Manhattan prong from Brookfield south to Bedford, NY lack intense contact aureoles and sharp truncation of country rocks. Rather, they have syntectonic contacts and igneous structure more compatible with temperature and pressure conditions in the country rocks.Well dated intrusions and estimates of crustal depth before,during or following intrusion may track differential crustal resposes within orogens.
Geological Society of America Abstracts with Programs. Vol. 58, No. 2
doi: 10.1130/abs/2026NE-411290
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