https://bereket-haileab.geology.sites.carleton.edu/files/original/a52c606eb4b412ceb22f3fe5320f0701.jpg bc252fcf021880cf503857ae215691eb https://bereket-haileab.geology.sites.carleton.edu/files/original/43f1782eeacab79ba04594cdc7070cdb.jpg 6678f87d14621e0bd5e97ecaca0eb0dc https://bereket-haileab.geology.sites.carleton.edu/files/original/8111cbe9940790dd68ab7f35b304206c.jpg 036de40d7460be46a094d9c0c662e531 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 BH250-180 Subject The topic of the resource Carrara Formation Shale Description An account of the resource <p>Major Minerals: clay minerals</p> <p>Mineralogy Comments: pyrolusite<br />Fossils: contains trilobite</p> <p>Carrara Formation Shale, Emigrant Pass, Death Valley.</p> <p>The Carrara Formation is a well-known sedimentary sequence extensively exposed in the Death Valley region, particularly around Emigrant Pass in the Funeral Mountains and Panamint Range. It is dominantly composed of shale, siltstone, limestone, and sandstone.</p> <p>The shale units are typically dark gray to greenish, fissile, and fine-grained, and are often interbedded with silty layersand carbonate beds.</p> <p>The Carrara Formation is also fossiliferous, particularly known for its abundant trilobites. The shale layers can preserve trilobite remains as well as trace fossils such as burrows. There is a site where geologist and amature fossil hunters come and collect fossils.</p> <p>Pyrolusite mineralization can be found in the outcrops of the Carrara shale.</p> <p>Compare this shale with BH250-178h</p> <p>Look at the chemical analysis of BH250-180: it shows high concentrations of SiO₂, Al₂O₃, and K₂O, indicating that the sample is rich in clay minerals and quartz. It is also enriched in rare earth elements (REEs), which are often associated with the clay fraction and can provide insights into provenance and diagenetic history.</p> <p>Shale, being a fine-grained sedimentary rock, is composed primarily of clay minerals, quartz, and minor amounts of other minerals. Its bulk chemistry directly reflects its mineral composition, sedimentary origin, and the processes it underwent during diagenesis.<br /><br /></p> <p><strong>REE Plot of BH250-27 Quartzite, BH250-123 Slate, and BH250-180 Shale</strong></p> <p>The chondrite-normalized rare earth element (REE) patterns of BH250-27 quartzite, BH250-123 slate, and BH250-180 shale illustrate how sedimentary maturity, mineralogical composition, and provenance influence trace-element distributions in sedimentary rocks. Although all three rocks ultimately derive from the weathering of pre-existing continental crust, they preserve markedly different REE signatures that reflect their contrasting compositions and depositional histories.</p> <p>BH250-27 quartzite exhibits the lowest overall REE concentrations. This result is expected because the rock is composed almost entirely of quartz, a mineral that incorporates very little REE into its crystal structure. During repeated cycles of weathering, transport, and sedimentary reworking, most REE-bearing minerals were removed, producing an exceptionally mature quartz-rich sediment. The resulting REE pattern is characterized by low abundances and relatively subdued fractionation compared to the finer-grained sedimentary rocks.</p> <p>BH250-123 slate contains significantly higher REE concentrations than the quartzite. Derived from fine-grained mud-rich sediments, the slate retains clay minerals, micas, and accessory phases that efficiently host and preserve rare earth elements. Its REE pattern more closely resembles that of average continental crust and demonstrates the ability of fine-grained siliciclastic sediments to concentrate trace elements during deposition.</p> <p>BH250-180 shale displays the greatest overall REE enrichment of the three samples. Shales commonly contain abundant clay minerals and very fine detrital material with large surface areas that readily adsorb and retain trace elements. As a result, shale often serves as one of the best sedimentary proxies for the average composition of the upper continental crust. The strong REE enrichment observed in BH250-180 reflects this concentration of clay-rich and accessory mineral components.</p> <p>As shown in the accompanying figure, REE abundances generally increase in the order:</p> <p><strong>Quartzite &lt; Slate &lt; Shale</strong></p> <p>This progression reflects increasing concentrations of clay minerals, micas, and accessory phases capable of hosting rare earth elements. The comparison provides an excellent example of how sedimentary maturation removes trace-element-bearing minerals from quartz-rich sands while concentrating them in finer-grained mudstones and shales. Consequently, the REE patterns of these three rocks offer a valuable illustration of the relationships among provenance, weathering, transport, mineralogy, and sedimentary maturity.</p> <p>&nbsp;</p> <iframe width="1800" height="100" src="https://docs.google.com/spreadsheets/d/e/2PACX-1vS4nyqCmZQGn3t6vX4g4nhDPwHMBaKrigt1LaY2pykWbBGXB1wNb6FYArx625I-JTtD7lyg4uz1OS1r/pubhtml?gid=1857916010&amp;single=true&amp;widget=true&amp;headers=false"></iframe> 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: Death Valley, CA, USA Nearby Geographic Features: Death Valley GPS Coordinates: 35.892483, -116.076889 Source A related resource from which the described resource is derived From the rock collection of Bereket Haileab. Sample BH250-180. Housed at Carleton College in Minnesota. 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=42b43f55e1734d0ab49af3e7a011fe1e" 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=ff95aee0ff25474da7fdd00babcaaca4">here</a><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1O699S3F6PKEdbFPa8aTR3H3eb6v4qIhk/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1_w6R6O3kcwaJdI8wkOM9r7zRhbbmiyHn/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1b4h0PJ014Yx7rU4iy7-p_nOUMyiPwTzF/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1ivXubwApOE7Rej1vZQpSAuveaktpGEsD/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1J8L6D6cnR7vRV51kFyt6AsiaF_VllotW/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1YeoaxWksGpTBhkzSv-wDK1ilmHORgKOr/preview" allow="autoplay"></iframe><br /><br /><iframe width="100%" height="480" src="https://drive.google.com/file/d/1MoLnPUvow03GF7vCiyeSejjTvwwF3HQi/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/146as0ZddWLBeU0Gzdeknw_hFuuZwPR7H/preview" allow="autoplay"></iframe> Creator An entity primarily responsible for making the resource Bereket Haileab Cambrian Carrara Formation Death Valley geology Emigrant Pass Fissile shale Fossiliferous shale Mn(OH)2 MnO2 Pyrolusite sedimentary shale Trace fossils trilobite Trilobite fossils