7 C apabilit y S t a t emen t R egolith Logging T he spec tr al da t a c ol lec t ed b y the HyL ogger TM can be used t o as ses s the cla y t ype and crys t al linit y as w el l as dep th o f o xida tion when dril ling thr ough deep w e a ther ed la t eritic r egolith pr o fles as seen in loca tions such as Aus tr alia A frica and par ts o f Br a zil t he cla y as semblage and crys t al linit y al lo ws the geologis t t o de t ermine wha t par t o f the pr o fle the s ample is fr om f or e xample the upper s apr olitic s amples ar e domina t ed b y highly crys t al line kaolinit e with minimal smec tit e i n c on tr as t the lo w er s apr olit e is char ac t erised b y a s tr ong smec tit e signa tur e with minor kaolinit e i n addition the smec tit e phase can giv e an indica tion o f wha t the primary r ock t ype w as be f or e w e a thering f or e xample mon tmoril lonit e a l smec tit e t ypical ly r esults fr om w e a thering o f f elsic r ocks non tr onit e f e smec tit e t ypical ly r esults fr om w e a thering o f ma fc r ocks s aponit e m g smec tit e is t ypical ly a w e a thering pr oduc t o f ultr ama fc r ocks t he char ac t eris tics o f the cla y miner als in tr anspor t ed o v erbur den ar e o f t en dis tinc t t o the r esidual basemen t cla ys F or e xample the kaolinit e in the tr anspor t ed pr o fles is t ypical ly signifcan tly lo w er crys t al linit y than the kaolinit e observ ed in the upper s apr olit e in t erv als t his capabilit y can al lo w a mor e objec tiv e de t ermina tion o f the base o f the tr anspor t ed o v erbur den in cases wher e this is dif fcult t o log visual ly and ther e f or e as sis ts with selec ting suit able geochemical s amples a spec tr al par ame t er can be calcula t ed fr om the spec tr a t o r epr esen t in t ensit y o f ir on o xide do wn hole which can pr o vide use ful in f orma tion on dep th o f o xida tion kaolinit e crys t al linit y smec tit e pr opor tion and t ype de fne base o f tr anspor t ed o v erbur den base o f o xida tion Al l fgur es c our t esy o f AusSpec In t erna tional