https://bereket-haileab.geology.sites.carleton.edu/files/original/be627a5a1d8ac8c8c62c9721d0203712.jpg bfc15653cc8a94c5529f5517737cb203 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 BH250-238c Subject The topic of the resource Shale 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, California, USA 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 238c. Housed at Carleton College in Minnesota. Type The nature or genre of the resource Hand sample Relation A related resource <iframe width="100%" height="480" src="https://drive.google.com/file/d/1ukHDvpfLMUshINZd-cNTk8AFB0V5fd5I/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/1hvGuyrnRzy6tnuosZThQOCw1dp3w4on0/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/17Z7GSGNy6t5nxe0NMvVU4MNIbCFMdgBQ/preview" allow="autoplay"></iframe> Description An account of the resource The laminated siltstones (BH250-238b) and shales (BH250-238c) of the lower Kingston Peak Formation in Death Valley are commonly found directly above the underlying Beck Spring Dolomite, marking an important stratigraphic and environmental transition in the late Precambrian basin. The contact typically records a change from shallow-water carbonate platform deposition of the Beck Spring Dolomite into deeper-water siliciclastic sedimentation represented by laminated mudstones, siltstones, and eventually diamictite-bearing (BH250-238 and BH250-239) intervals of the Kingston Peak. These finely laminated siltstones and shales represent quieter intervals of sedimentation that contrast strongly with the coarser diamictites interbedded higher in the section. Their thin bedding suggests settling of suspended clay and silt in low-energy offshore basins. When viewed together with the diamictites, they record repeated environmental shifts: calm background sedimentation interrupted by energetic pulses of glacial debris flows, iceberg rafting, or slope failure. Thus, the transition upward from the Beck Spring Dolomite into lower Kingston Peak mudrocks and diamictites captures the progressive breakdown of a stable carbonate shelf and the onset of tectonically active, climatically unstable Cryogenian conditions that ultimately became associated with Snowball Earth glaciation. Beck Spring Dolomite carbonate to clastic transition Cryogenian Cryogenian climate Death Valley Death Valley stratigraphy diamictite fine-grained sedimentary rocks Fissile shale glacial deposits iceberg rafting Kingston Peak Formation laminated siltstone mudstone Neoproterozoic Neoproterozoic basin evolution Pahrump Group Paleoenvironments shale siliciclastic transition Snowball Earth