https://bereket-haileab.geology.sites.carleton.edu/files/original/2e768b737e93cfe051ae12f7f27f4b5b.jpg b97601e943101a80fa6a06a7e3247777 https://bereket-haileab.geology.sites.carleton.edu/files/original/d502c7005c6c35bdae547d1fe33e1550.jpg 255dd34e185886195fd2977609e6720d 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 Sedimentary Rocks Subject The topic of the resource This collection includes sandstones, limestones, breccias, conglomerates, dolostones, shales, oolites, and BIF. 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. 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 BH250-154 Subject The topic of the resource Jacobsville Sandstone Description An account of the resource Major Minerals: quartz, muscovite, orthoclase Minor Minerals: oxides Texture: arkosic sandstone, lithic fragment, reduction spot The Jacobsville Sandstone is a sedimentary rock unit exposed extensively in the Upper Peninsula of Michigan, particularly along the shores of Lake Superior, and forms part of the Midcontinent Rift-related sedimentary sequence. It is notable for its distinctive red color, thick bedding, and broad regional extent. Mineralogically, the Jacobsville Sandstone is composed predominantly of quartz with angular to subangular grains, forming the dominant framework. It is classified as an arkosic sandstone due to its high feldspar content, including both plagioclase and K-feldspar. Additional components include lithic fragments, muscovite, and hematite, the latter being abundant as both a pigment and a cementing agent. The arkosic composition and the presence of feldspar suggest a short transport distance from the source and/or tectonic uplift, facilitating rapid erosion and deposition. Reduction Spots The red color of the sandstone results from oxidized iron (hematite) in the cement. Locally, this coloration is interrupted by pale reduction spots or zones, typically circular or patchy, and appearing greenish or grayish. These spots form from localized reducing fluids, likely introduced during diagenesis or later fluid flow events, which chemically reduce ferric iron (Fe³⁺) in hematite to ferrous iron (Fe²⁺)—a soluble or pale-colored form. In some cases, organic matter may have contributed to the reduction process. Organic residues can act as reducing agents, leaching iron and producing reduction spots where hematite is altered or removed. This unit is correlated with the Hinckley Sandstone. For more information see, BH250 – Sandstone Overview with Petrographic Notes Coverage The spatial or temporal topic of the resource, the spatial applicability of the resource, or the jurisdiction under which the resource is relevant GPS Coordinates: 46°35'20.11"N, 87°23'6.18"W Source A related resource from which the described resource is derived From the rock collection of Bereket Haileab. Sample BH250-154. Housed at Carleton College in Minnesota. Type The nature or genre of the resource Thin section and hand sample Relation A related resource <iframe width="100%" height="600" style="border: 0;" src="https://carleton.maps.arcgis.com/apps/instant/media/index.html?appid=4f616ac0f9fa45538a9eb5c1f9ae0d95" 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=4f616ac0f9fa45538a9eb5c1f9ae0d95">here</a><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1CiOdV5Qqrzykdhj429Cx3zkRSdDUOtJM/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1TIKJKNDf_ScpW7mJXQmbobXLphb0GUAz/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1x1qCM_2mgiXBbYA4ctG53KE7CObNjNwb/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1IDD5fTUugJ-bfkvbAMk3axIBWs8x_zt_/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1iA2Dvbbpwoq77kadmnLR5jKbJ_oqXqRR/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1myutH8fTdCefOvNUCI6dDAvG796X5-N3/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1lVQAGfIvtzA7USY0R4OjZ5g8IvsP8Qif/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/1OimRklf6k6IJ79Lg5u05QhqSphdB6M7X/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/1B35fPsVY_zripTmCTBt5aGuauTBEog2x/preview" allow="autoplay"></iframe> Creator An entity primarily responsible for making the resource Bereket Haileab Arkosic Sandstone Clastic sedimentary rock Feldspar-rich sandstone Hinckley Sandstone Jacobsville Sandstone Lake Superior geology Marquette Midcontinent Rift Organic reduction Proterozoic sedimentary rocks Provenance Reduction spots Sedimentary petrology Upper Peninsula Michigan