UST Textures (Brain Rock)

Everything you ever wanted to know about Unidirectional Solidification Textures (also known as Brain Rock).Many thanks to Doug Kirwin and Dr Alan Wilson for contributing so many photographs and so much background information. Special thanks to Nicole Richards Guillou for making the beautiful cut-away animation at 4:02. Index: 0:00 What are USTs 0:29 Doug Kirwin 0:42 Metallurgy definition 0:55 Geological context 1:34 Characteristics 2:26 Minerals 2:44 Variants 3:43 Sizes 4:02 Shapes 5:39 History 6:25 Formation processes models 7:25 Magmatic model 8:42 Hydrothermal model 9:54 Model issues 12:24 Fluid inclusions 14:41 Vein relationships 14:52 Mineralization relationships 15:30 Timing Relationships 16:59 The Ridgeway exception 19:01 Crenulations 20:13 Exploration Implications Literature referenced in the video: Wilson A.J. (2003). "The geology, genesis and exploration context of the Cadia gold-copper porphyry deposits, New South Wales, Australia".Thesis for PhD. University of Tasmania. November 2003. Müller A., Kirwin D. & Seltmann R. (2023). "Textural characterization of unidirectional solidification texturesrelated to Cu–Au deposits and their implication for metallogenesis and exploration". Mineralium Deposita (2023) 58:1211–1235. Seo J. H. Kim Y. Lee T. & Guillong M. (2021). "Periodically Released Magmatic Fluids Create a Texture of Unidirectional Solidification (UST) in Ore-Forming Granite: A Fluid and Melt Inclusion Study ofW-Mo Forming Sannae-Eonyang Granite, Korea" Minerals 11: https:// doi. org/ 10. 3390/ min11 080888 Kirwin D.J. (2005). "Unidirectional solidification textures Associated With Intrusion-Related Mongolian Mineral Deposits". In: Seltmann R, Gerel O, Kirwin DJ (eds) eodynamics and Metallogeny of Mongolia with a Special Emphasis on Copper and Gold Deposits. Centre for Russian and Central Eurasian Mineral Studies, IAGOD Guidebook Series 11, London, pp 63–84 Kirwin D.J. (2006). Unidirectional solidification textures, miarolitic cavities and orbicles: field evidence for the magmatic to hydrothermal transition in intrusion-related mineral deposits. Presentation at SEEGF conference October 2006. Shannon j.R., Walker B.M., Carten R.B. & Geraghty E.P. Unidirectional solidification textures and their significance in determining relative ages of intrusions at the Henderson Mine, Colorado. Geology. v.10. pp. 293-297, June 1982. Sinclair W.D. (2007) "Porphyry Deposits". Mineral Deposits of Canada - A Synthesis of Major Deposit Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods (pp.223-243)Edition: Special Publication 5Publisher: Geological Association of Canada, Mineral Deposits Division. Yasuda H., Morishita k. Yoshia M & Narumi T. (2020) "Transformation from Ferrite to Austenite during/after Solidification in Peritectic Steel Systems: an X-ray Imaging Study". ISIJ International, Vol. 60 (2020), No. 12, pp. 2755–2764 https://doi.org/10.2355/isijinternational.ISIJINT-2020-486