Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/8161
AuthorsMollo, S.* 
Putirka, K.* 
Iezzi, G.* 
Scarlato, P.* 
TitleThe control of cooling rate on titanomagnetite composition: implications for a geospeedometry model applicable to alkaline rocks from Mt. Etna volcano
Issue Date2013
Series/Report no./165 (2013)
DOI10.1007/s00410-012-0817-6
URIhttp://hdl.handle.net/2122/8161
KeywordsTitanomagnetite; cooling rate
Subject Classification04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology 
AbstractIn this study, we have investigated the control of cooling rate on the composition of titanomagnetite formed from a trachybasaltic melt. Results show that disequilibrium growth conditions exert a primary control on the abundance, texture, and composition of the crystals. As the degree of cooling is increased, titanomagnetites show immature textures and are progressively enriched in Al ? Mg and depleted in Ti. Thus, early-formed titanomagnetite nuclei do not re-equilibrate with the melt over faster cooling rates; instead, their compositions are far from equilibrium. On the basis of the different intra-crystal redistribution rates for Ti, Al, and Mg, we have calibrated a geospeedometer that represents the first quantitative description of the effect of cooling rate on titanomagnetite composition. This model was tested using the compositions of titanomagnetites in lava and dike samples from Mt. Etna volcano whose crystallization conditions resemble those of our experiments. Cooling rates calculated for lava samples are comparable with those measured in several volcanic complexes. At Mt. Etna, compositional variations of titanomagnetite grains from the innermost to the outermost part of a dike testify to progressively higher degrees of cooling, in agreement with numerical simulations of thermal gradients in and around magmatic intrusions.
Appears in Collections:Papers Published / Papers in press

Files in This Item:
File Description SizeFormat 
01_Mollo et al._2012_CMP.pdf927.56 kBAdobe PDFView/Open
Show full item record

Page view(s)

93
Last Week
0
Last month
1
checked on Aug 16, 2017

Download(s)

21
checked on Aug 16, 2017

Google ScholarTM

Check

Altmetric