https://bereket-haileab.geology.sites.carleton.edu/files/original/c5439c447ae6b62105ac37991cf400a4.jpg 7423d3a23ee6813fd40b63c4bba30044 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 BH250-66 Subject The topic of the resource Sillimanite Schist Description An account of the resource Major Minerals: biotite, muscovite, quartz, sillimanite Mineralogy Comments: biotite interwoven with muscovite and quartz BH250-66 is mapped as a sillimanite schist and was collected from the Black Hills of South Dakota, in the same metamorphic terrane as BH250-67 and BH250-68. While the rock is mapped as containing sillimanite, it is difficult to identify in the field, and even in thin section, the sillimanite grains are sparse and poorly developed. Some grains resemble sillimanite, but large, definitive crystals are hard to find. Despite this, the sample contains an abundance of well-aligned biotite and muscovite, creating a strongly foliated texture indicative of regional metamorphism. The schistosity is well-developed, and the quartz grains—though somewhat variable in size—exhibit undulose extinction, pointing to dynamic recrystallization. Several biotite grains host zircon inclusions with pleochroic halos, features commonly used in optical mineralogy to trace metamorphic processes. While sillimanite is difficult to confirm, the sample remains an excellent resource for teaching metamorphic textures, mineral identification challenges, and the interpretation of regional metamorphic conditions. 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: Black Hills, South Dakota, USA Source A related resource from which the described resource is derived From the rock collection of Bereket Haileab. Sample 66. Housed at Carleton College in Minnesota. Type The nature or genre of the resource 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=2ab24a0721b8438b8317ef6e12d3fba2" 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=2ab24a0721b8438b8317ef6e12d3fba2">here</a><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/11bC4L5Iij-BTWZdANuYPGFSE2THw8gW-/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1MN3VoIm7UdUREhdy9IR44B6GrVCQ2eBW/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1LkfMAhpGm4sVTPRfTpabBV-M6iav9dDA/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/17vlyQOSozarcaHZmGlzUeta311illncn/preview" allow="autoplay"></iframe> Creator An entity primarily responsible for making the resource Bereket Haileab Biotite Black Hills geology metamorphic muscovite. Metamorphic textures Regional metamorphism schist Schistosity Sillimanite schist Undulose Extinction