气候变化领域集成服务门户(CCPortal): Transport, survival and modification of xenoliths and xenocrysts from source to surface

CCPortal

DOI	10.1016/j.epsl.2020.116499
	Transport, survival and modification of xenoliths and xenocrysts from source to surface
	Sasse D.; Jones T.J.; Russell J.K.
发表日期	2020
ISSN	0012821X
卷号	548
英文摘要	A wide variety of magmas entrain, transport and erupt mantle material in the form of xenoliths and xenocrysts. The host magmas are often low viscosity in nature and range from basalt to more esoteric compositions such as kimberlite, nephelinite and basanite. Here we focus on kimberlite magmas which are particularly successful at transporting deep mantle cargo to the surface, including economically important quantities of diamond. Collections of mantle-derived xenoliths and xenocrysts are critical to our understanding of the structure, stability, composition, thermal state, age, and origin of the lithosphere. However, they also inform on magma transport conditions. Through a series of scaled analogue experiments, we document the relative mechanical stability of olivine, garnet, orthopyroxene, clinopyroxene and diamond xenocrysts during magma ascent. Our experiments fluidized these mantle minerals at a constant gas flux for variable amounts of time approximating transport in a high velocity, turbulent, fluid-rich (supercritical fluid or gas, depending on depth) magma. The evolution of mineral surface features, morphology and grain size distributions is analyzed as a function of residence time. We show that on timescales consistent with magma ascent, each mantle mineral is subject to mechanical modification resulting in mass loss and reshaping (rounding) by grain size reduction and surface pitting. We further discuss the chemical consequences of producing fine particle chips that are highly susceptible to dissolution. Lastly, we utilize an empirical model that relates textural observations (e.g. impact pit size) on xenocrysts to differential particle velocities. Our approach applied to natural kimberlitic olivine and garnet xenocrysts indicates differential velocities of ∼4ms−1 – the first direct estimate for velocity in an ascending kimberlite magma. © 2020 Elsevier B.V.
关键词	abrasion attrition chemical dissolution diamond impact pits kimberlite ascent
英文关键词	Effluent treatment; Fluidization; Garnets; Grain size and shape; Mechanical stability; Morphology; Olivine; Residence time distribution; Supercritical fluids; Velocity; Volcanic rocks; Chemical consequences; Differential velocity; Grain size distribution; Grain-size reduction; Kimberlite magmas; Mantle minerals; Mineral surfaces; Particle velocities; Transport properties; basalt; clinopyroxene; garnet; kimberlite; magma; mantle; olivine; orthopyroxene; viscosity; xenolith
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202877
作者单位	Department of Earth, Ocean & Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom
推荐引用方式 GB/T 7714	Sasse D.,Jones T.J.,Russell J.K.. Transport, survival and modification of xenoliths and xenocrysts from source to surface[J],2020,548.
APA	Sasse D.,Jones T.J.,&Russell J.K..(2020).Transport, survival and modification of xenoliths and xenocrysts from source to surface.Earth and Planetary Science Letters,548.
MLA	Sasse D.,et al."Transport, survival and modification of xenoliths and xenocrysts from source to surface".Earth and Planetary Science Letters 548(2020).