37 CRITICAL MINERAL DEPOSITS AND ORE SYSTEMS OF THE NORTHEAST

This session will showcase new findings pertaining to critical mineral resources and hydrothermal-magmatic ore systems across the northeast. We welcome submissions involving fieldwork, geochemical, petrologic, geochronologic, and other approaches from micro- to macroscopic scales.

Tuesday, 24 March 2026
8:00 AM - 12:00 PM
CCC, Room 25

Beyond the Pinewood – Did Alleghenian Mineralization Reach out to Roxbury, Connecticut?

Paper number: 37-2
Program: Technical Sessions
Time: 8:25 AM – 8:45 AM

Authors

Abstract

Hydrothermal mineral deposits in the Western Uplands of Connecticut have been known and exploited for over 250 years. Although their mineralogies are well-known, only the hydrothermal vein systems genetically associated with the Permian Pinewood intrusive suite have a robust genetic model. This Cornubian-type system of 3 plutons and swarms of hydrothermal fissure veins form a trend of about 315 degrees over 10 km in northern Trumbull paralleling the Alleghenian tectonic convergence vector. The Pinewoodian genetic model suggests a local northwestern deepening of the Alleghenian plutons responsible for its hypothermal fissure veins.

This study examines the potential for a more distal continuation of that model based on an additional Permian syenite stock in Southbury, a number of undated quartz-rich mineral fissure veins situated as far as Roxbury, 3 quartz masses, and an albite-quartz-sulfide deposit of unknown genesis. The Pinewoodian and undated (fissure) veins all have northwest-orientated, parallel, smooth-walled, unbrecciated host-rock contacts and nearly solid quartz compositions. This is in contrast to presumably Mesozoic hydrothermal veins in the same region that are brecciated, vuggy and exhibit mixed calcite-quartz-fluorite-barite-sulfide-zeolite mineralogy. Five minerals – topaz, pyrrhotite, bismuth, arsenopyrite and siderite, chosen as indexes of different vein crystallization temperatures, show a progressive change from hypothermal in the southeast to mesothermal/epithermal in the northwest. This pattern serves as a proxy for a corresponding depth increase of their potential Alleghenian source plutons.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411146

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.