https://bereket-haileab.geology.sites.carleton.edu/files/original/a08c0baf589940979ec3f5795b7be316.jpg 5e46207fd5c5f69c24632c18c6e2e297 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 and hand sample 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 BH250-191 Subject The topic of the resource Anorthosite Description An account of the resource Major Minerals: anorthite, orthopyroxene, plagioclase Minor Minerals: serpentine BH250-191 is an anorthosite sample collected near Silver Bay, Minnesota, and is part of the Mesoproterozoic Duluth Complex—a massive intrusive body. Like other anorthosites in the complex, this rock is characterized by its plagioclase-rich composition. The dominant mineral is plagioclase feldspar, typically ranging from labradorite to bytownite (An₅₀–An₈₀), comprising over 90% of the rock. The plagioclase crystals are generally euhedral to subhedral, commonly centimeter-scale, and exhibit weak to moderate zoning. BH250-191 differs from BH250-46 in that its plagioclase shows some undulose extinction, likely due to thermal heating from the intrusion of the Duluth gabbro. The sample is located near BH250-193, which marks the contact between gabbro and anorthosite. Several student projects based on BH250-193 explore the history of this contact and the effects of thermal alteration. The bulk composition of BH250-191 is high in Al₂O₃, reflecting the abundance of calcic plagioclase, and relatively low in SiO₂ (~50–55 wt%) compared to granitic rocks. K₂O and Na₂O contents are also low, consistent with the dominance of calcium-rich feldspar. The rock displays a typical cumulate texture and occurs interlayered with troctolite, gabbro, and oxide-rich layers. In this location, the anorthosite appears as a large xenolith, as seen in the accompanying photograph. 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: Northern Minnesota, Minnesota, USA Date A point or period of time associated with an event in the lifecycle of the resource Fall 2014 Source A related resource from which the described resource is derived From the rock collection of Bereket Haileab. Sample BH250-164. Housed at Carleton College in Minnesota. Contributor An entity responsible for making contributions to the resource Bereket Haileab Type The nature or genre of the resource Hand sample and thin section Relation A related resource <iframe width="100%" height="600" style="border: 0;" src="https://carleton.maps.arcgis.com/apps/instant/media/index.html?appid=37c5b06e48ef41d09b27dfec04e61861" frameborder="0" allowfullscreen="allowfullscreen">iFrames are not supported on this page.</iframe><br />View on ArcGIS Online <a href="https://carleton.maps.arcgis.com/home/item.html?id=37c5b06e48ef41d09b27dfec04e61861">here</a><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1jTpdMK1opWxUIv584syBfbWhXUgNDgi5/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1DmtVWK9sVSE45HJnY82xg_25DeUa8-SF/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1hMW1bWg8n6yb9GGufU30nKRvablJFw3V/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1_nHxt9tAvlP1beVahryd3QUEgfwWfc95/preview" allow="autoplay"></iframe>&nbsp; <br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1AEx6RaHCO-J16cc9Bi9GrvDlhCPku_KJ/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/19yYhG9OmbOD6PnfKnNSqsJpMxSXlMLRZ/preview" allow="autoplay"></iframe> <iframe width="100%" height="480" src="https://drive.google.com/file/d/19YF8ebU6iXPDhQVpED7HfoRAaWV52p2H/preview" allow="autoplay"></iframe> Creator An entity primarily responsible for making the resource Bereket Haileab Anorthite anorthosite cumulate rock Cumulate texture Duluth Complex euhedral plagioclase Gabbro-Anorthosite Contact Layered mafic intrusion Mafic Intrusive Rock Midcontinent Rift Minnesota Northern Minnesota Plagioclase feldspar Silver Bay Thermal Metamorphism Undulose Extinction xenolith