https://bereket-haileab.geology.sites.carleton.edu/files/original/b0f207b8a6e792590e9a5a9174064579.jpg cdc955957ce72563e676216ff21f071e 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 Igneous Rocks Subject The topic of the resource This collection covers both volcanic and intrusive rocks, including rhyolites, granites, diorites, andesites, basalts, gabbros, diabases, pumices, obsidians, syenites, phonolites, peridotites, carbonatites, dacites, trachyte, dunites, xenoliths, ignimbrites, and pegmatites. 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). 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 BH250-230a Subject The topic of the resource Accretionary Lapilli 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: Green Sand Beach, Hawaii, USA GPS Coordinates: 18°56'11.41"N, 155°38'47.19"W Date A point or period of time associated with an event in the lifecycle of the resource 2022 Source A related resource from which the described resource is derived From the rock collection of Bereket Haileab. Sample BH250-230a. Housed at Carleton College in Minnesota. Type The nature or genre of the resource Hand sample Creator An entity primarily responsible for making the resource Bereket Haileab Relation A related resource <iframe width="640" height="480" src="https://drive.google.com/file/d/10yjdXUYdRs-QeF2aYnk1Tpn9H0ombW2Q/preview" allow="autoplay"></iframe><iframe width="640" height="480" src="https://drive.google.com/file/d/1HAYTA5S525_ELy02h7f0gsUE2EbYbMHp/preview" allow="autoplay"></iframe> Contributor An entity responsible for making contributions to the resource Bereket Haileab Description An account of the resource Accretionary lapilli are small, rounded pellets of volcanic ash and dust that form in the atmosphere during explosive volcanic eruptions. They develop when fine ash particles collide and stick together in a moist eruption column or plume. Aggregation begins around a central nucleus—such as a glass shard or phenocryst—and as the particle is lofted by turbulent air, additional ash accretes onto it in concentric layers. Once formed, these lapilli typically fall close to the volcanic vent. Compositionally, accretionary lapilli consist mostly of fine volcanic ash, rich in glass shards. Their distinctive concentric internal structure, resembling hailstones, makes them easily recognizable in the field. They often occur in layers within pyroclastic deposits, such as tuffs and ash beds. These features are commonly well preserved and can become lithified in tephra of the same age. In the tuff deposits I studied in the Turkana Basin, many of the Plio-Pleistocene ash layers contain accretionary lapilli, providing evidence of moist eruptive conditions and proximal ash fall. Accretionary lapilli Concentric ash structures Explosive volcanic eruption Glass shard-rich ash igneous Lapilli formation Moist eruption column Phreatomagmatic Phreatomagmatic eruption indicators Pyroclastic deposits Turkana Basin tuffs volcanic Volcanic ash aggregation Volcanic hailstones Volcaniclastic textures