https://bereket-haileab.geology.sites.carleton.edu/files/original/a4fa0637f553bf0b8a4dcf4e75e386e0.jpg 4541fd6593b966cb160663b09d03541e https://bereket-haileab.geology.sites.carleton.edu/files/original/e59151e8502db747658a3dd2bb97d8c5.jpg 8c69d2e4c418e23054e53a40d10bcb55 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Metamorphic Rocks Subject The topic of the resource This collection includes slates, phyllites, schists, gneisses, eclogites, marbles, quartzites, skarns, granulites, and mylonites. Creator An entity primarily responsible for making the resource Bereket Haileab Source A related resource from which the described resource is derived Housed in Anderson Hall, Carleton College. Format The file format, physical medium, or dimensions of the resource Thin sections, thin section scans, hand samples, hand sample images, photomicrographs, chemical analyses (major elements, trace elements and REE analyses for selected samples). Thin section Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource BH250-118c Subject The topic of the resource Amphibolite Description An account of the resource Major Minerals: amphibole, biotite, orthoclase BH250-118, BH250-118b, and BH250-118c are samples collected from the Morton Gneiss in Morton, Minnesota. The Morton Gneiss is one of the oldest known rocks in North America and is a widely studied example of high-grade metamorphic rock. It is prominently exposed in southwestern Minnesota, particularly around the town of Morton, from which it takes its name. Here, active quarries reveal striking outcrops of the gneiss, displaying its distinctive banding. Historically, the rock was quarried for use in tabletops, building walls, and tombstones, and quarrying continues today under the ownership of a company based near St. Cloud. The site has also been of academic interest, with recent Carleton College graduate Emma Watson (Class of 2023) completing her comprehensive thesis on the Morton Gneiss. The Morton Gneiss is Archean in origin, with its protolith (original rock) forming around 3.6 billion years ago. Since its formation, it has undergone multiple episodes of metamorphism and deformation, most notably during the Penokean orogeny (~1.85 billion years ago) and later thermal/metamorphic overprinting during the Proterozoic. It is a banded, migmatitic gneiss, showing evidence of both solid-state metamorphism and partial melting (migmatization). The rock features interlayered felsic bands (BH250-118), mafic bands (BH250-118b), and amphibolite (BH250-118c), each representing different compositions, origins, and metamorphic histories. Amphibolite (BH250-118c) is present as lenses or layers within the Morton Gneiss and represents metamorphosed mafic rocks that may have originated as basaltic or gabbroic intrusions, or as volcanic sediments. Amphibolite in this setting is dominated by hornblende and plagioclase, typically lacking quartz. It can occur conformably with the gneissic layering or as discordant bodies, suggesting emplacement as dikes during or before metamorphism. Geologically, the Morton Gneiss is significant because it preserves a record of early Earth crustal evolution, including crust formation, tectonism, and high-grade metamorphism. It forms part of the Minnesota River Valley subprovince, which is itself a key component of the Superior Province of the Canadian Shield. Interestingly, in the past, outcrops of the Morton Gneiss were considered as potential storage sites for radioactive waste, and remnants of that period—including test wells and excavated pits—can still be seen in certain locations. Coverage The spatial or temporal topic of the resource, the spatial applicability of the resource, or the jurisdiction under which the resource is relevant Location: Granite Falls, Minnesota, USA 44°49'7.94"N, 95°33'52.44"W Creator An entity primarily responsible for making the resource Bereket Haileab Source A related resource from which the described resource is derived From the rock collection of Bereket Haileab. Sample 246. Housed at Carleton College in Minnesota. Type The nature or genre of the resource Thin section Relation A related resource <iframe width="100%" height="480" src="https://drive.google.com/file/d/1tbGznYh1FAhOfRKxgkRgQ41QQxxTq42t/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/13xiGU89DDm8VQ1dU4WuQePR0lxDxCqWA/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/1tnMHw5oIbopk88dP7o6nbT_yZUUeRPN7/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/1vs9q7m9Uxitd8soiisAWUOcpXp5UFoNQ/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/1YYrDK3R59iryYxQBJWIrX0ts_Iysu1b-/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/1v3F5vz19z_LijXjMH9b0bH26cgqHF6sL/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/1U5ets6zsvvNbK4-Ix5Oq7-SjWXZ1FKxV/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/1wP1dBGW3zLn2i409RlmanQMfl-qgRR2-/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/1FHy8p7Y2S3QIDGfPCQgYlTy5LjvO-3tX/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/1bD4xkklyf0aZQyNIcuEKp41_RLVsJtyd/preview" allow="autoplay"></iframe> amphibolite Amphibolitized Intrusion Archean Gneiss Banded Gneiss Canadian Shield Felsic Gneiss gneiss Granitic Protolith High-Grade Metamorphic Rock Leucosome Veins Mafic Gneiss metamorphic Metamorphosed Mafic Rock Migmatitic Gneiss Minnesota Minnesota River Valley Subprovince Morton Morton Gneiss Partial Melting Features Penokean Orogeny Proterozoic Overprinting Quartz-K-feldspar-Plagioclase-Biotite Radioactive Waste Test Site