BH250-123
Title
Subject
Description
BH250-123 is a shale sample collected from Thomson Dam, Minnesota. It is a fissile, gray to black shale, locally metamorphosed to slate or phyllite. The rock is fine-grained, with planar laminations often preserved despite deformation. Its dark gray to black color is attributed to abundant organic material.
In thin section, the sample reveals a matrix composed of, Quartz, Muscovite, Chlorite
These minerals reflect low-grade regional metamorphism. The rock is strongly foliated and cleaved, with well-developed slaty cleavage observed in both hand sample, outcrop and thin sections. Folding is common near the dam, further indicating a history of intense deformation.
Geochemically, the sample exhibits high Al₂O₃ content, consistent with clay-rich protoliths and the presence of aluminum-bearing phyllosilicates.
Coverage
GPS Coordinates: 46°39'56.43"N, 92°24'19.65"W