干旱区生态环境知识资源中心(Arid): Scoria Cone Construction Mechanism, Lathrop Wells Volcano, Southern Nevada

Arid

DOI	10.2172/838906
报告编号	LA-UR-04-8750
来源ID	OSTI_ID: 838906
	Scoria Cone Construction Mechanism, Lathrop Wells Volcano, Southern Nevada
	G. Valentine; D. Krier; F. Perry; G. Heiken
英文摘要	Scoria cones are commonly assumed to have been constructed by the accumulation of ballistically-ejected clasts from discrete and relatively coarse-grained Strombolian bursts and subsequent avalanching such that the cone slopes are at or near the angle of repose for loose scoria. The cone at the hawaiitic Lathrop Wells volcano, southern Nevada, contains deposits that are consistent with the above processes during early cone-building phases; these early deposits are composed mainly of coarse lapilli and fluidal bombs and are partially welded, indicating relatively little cooling during flight. However, the bulk of the cone is comprised of relatively fine-grained (ash and lapilli), planar beds with no welding, even within a few tens of meters of the vent. This facies is consistent with deposition by direct fallout from sustained eruption columns of relatively well-fragmented material, primarily mantling cone slopes and with a lesser degree of avalanching than is commonly assumed. A laterally extensive fallout deposit (up to 20 km from the vent) is inferred to have formed contemporaneously with these later cone deposits. This additional mechanism for construction of scoria cones may also be important at other locations, particularly where the magmas are relatively high in volatile content and where conditions promote the formation of abundant microlites in the rising mafic magma.
出版年	2005
报告类型	Technical Report
语种	英语
国家	美国
来源学科分类	45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE ; BOMBS ; CONES ; CONSTRUCTION ; DEPOSITION ; FALLOUT ; FALLOUT DEPOSITS ; MAGMA ; WELDING
URL	http://www.osti.gov/scitech/servlets/purl/838906
资源类型	科技报告
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/268882
推荐引用方式 GB/T 7714	G. Valentine,D. Krier,F. Perry,et al. Scoria Cone Construction Mechanism, Lathrop Wells Volcano, Southern Nevada,2005.