2ndd Deep-Water Circulation C Congress, 10-1 12 Sept. 2014,, Ghent, Belgiium Med dical CT-iimages off contouriite cores: An onset to processsing and data intterpretatiion Thomas Vandorpe1, David D Van Ro ooij1, Susanaa Lebreiro2, Belen B Alonso3, Anxo Menaa4, Veerle Cnu udde1 and 5 Francisco Jaavier Hernan ndez-Molina 1 2 3 4 5 Dpt. Geoloogy & Soil Science, Ghent Univerrsity, B-9000 Gheent, Belgium. Tho [email protected] @ugent.be; [email protected] nt.be; [email protected] IGME, Maadrid, Spain. [email protected] me.es Instituto dee Ciencas del Maar, CSIC, Barcelo ona, Spain. [email protected] @icm.csic.es Departameento de Xeocienccas, University off Vigo, Vigo, Spai ain. [email protected] uvigo.es Departmennt of earth sciences, Royal Hollow way University off London, London n, UK. [email protected] @rhul.ac.uk Abstra ract: Althoughh CT scans arre being usedd in scientific research sincce the late 19970’s, they arre only recently being usedd in contouriite research. M Mostly a verttical slice thrrough or an X X-radiograph of the sedim ment core is shhown, not disp playing the thhree-dimension nal variationss within the seediment core. These can bbe very imporrtant howeverr. This researrch attempts to t discern components witthin the entirre core basedd on their radiio-density valu ues, using the 3D analysis software s “Mo orpho+”, deveeloped by the UGCT (Ghennt University Centre for X-Ray X Tomoggraphy). The abundance of o each compponent is disp played througghout the seddiment core an nd will be com mpared to MSCL, XRF and grainsize datta in order to derive what information is i held within n CT scans. B By scanning muddy, m silty and a sandy conntourite coress (both compaacted and not) t), a non-exhau ustive referen ce set of CT scans s for conto ourite cores w will be created d. Key w words: CT scanning, contou urites, Gulf off Cádiz, MSCL L, XRF. den nsity values histogram (Figg. 1), a measurre for changess in density an nd average atomic num mber. Thesee com mponents are isolated and qquantified in comparison c too thee total volume of interest. CTION INTRODUC X-ray computed tom mography (C CT) is a nnondestructive ttechnique ennabling researrchers to obttain information of the internal structure of an obj bject (Brabant et al. 2011). CT-images C in n sediment ccore sections mayy display featuures not visiblle with the naaked eye or on core-picturees, such as distinct layyers, bioturbation,, cracks, annd weatherin ng effects ((e.g. Dewanckele et al. 2014) and a as such it is a tool whhich has been useed to further improve coree interpretatioons. CT imagery iin contourite research r is scaarce so far. Soome authors (e.g. Rebesco et al. a 2012 and Voigt V et al. 20013) use X-radioggraphs, whichh do not take into account the full 3D variaations within a core. Laterall variations aree of high importaance and shouuld be taken in nto account. T This research focuusses on seveeral contouritee cores from the Alboran Seaa and the Gulf of Cádiz co ontaining mudddy, silty and sanndy intervals in order to assess a what exxtra information can be obtaained from CT C scans andd to generate a prreliminary refference set of CT scans agaainst which future cores can be compared. FIG GURE 1. Histogra am of the radio-ddensity values in core GC01 (Gulff of Cádiz). C The colou urs in this histogra ram correspond to o those in Fig.2. IN NITIAL RESU ULTS The colourss within the vertical secttion (Fig. 2)) gen nerally only show the coomponent wh hich has thee hig ghest percenttage in that interval. Ho owever otherr com mponents are not fully abseent within tho ose zones, e.g.. bettween 2150 and 2550 cm m the dominan nt componentt is the t purple one while the liight blue com mponent is nott abssent (up to 20%). 2 There is as well an importantt am mount of the yellow y (up to 7.5%) component presentt (Fiig. 2). Also although neverr really visiblle in the coree image, the red co omponent is nnever totally absent a and hass som metimes perceentages up to 55% (e.g. 900m m, Fig. 2). L AND METHODS MATERIAL Over 5 m meters of sediment core GC01 (northhern Gulf of Caddíz) were sccanned with the SOMAT TON definition fflash scannerr of the Ghent G Univerrsity hospital. A 120kV step and a rotation time of 1 secoond were set by w which a x andd y-resolution of 0.2mm andd zresolution off 0.6mm wass obtained. The T images w were reconstructedd using thee “J37s meedium smoooth” algorithm. T The analyticall software paackage Morphho+ (Brabant et al., 2011) from the Ceentre for X--ray Tomographyy of the Ghentt University was w used in orrder to discern ddifferent com mponents baseed on the raddio- Based on the abunddance of th he differentt com mponents, at least 14 unitss can be distin nguished (Fig.. 2). These unitss almost exaactly match XRF-definedd  2ndd Deep-Water Circulation C Congress, 10-1 12 Sept. 2014,, Ghent, Belgiium zones (cfr. F Fe/Ca and Si//Al curves in Fig. 2). Zonne 2 (green box in Fig. 2) consists c mosttly of the grreen component and correlattes with Si/A Al values. T The variation of tthe other CT--components can c however still be used in oorder to derivee intra-zone variations. v In this case the redd component,, indicating very v high raddiodensity valuees still shows a lot of variaation. It has too be noted that X XRF measuress the chemical compositionn of the top millim metre of a spllit core, which h may not be the same throughhout the entirre horizontal slice of the ccore this measurinng point reprresents. A CT T scan measuures the radio dennsity of that entire e horizonttal slice and m may as a result ppotentially revveal more infformation on the core. RE EFERENCES S Braabant, L., Vlassenbroeck, JJ., De Witte, Y., Y Cnudde, V., Boone, M.N., M Dewancckele, J., Van Hoorebeke, H L., 2011. Thrree-Dimension onal Analysis of o HighResolution X-Ray X Compuuted Tomograp phy with Morpho+. Miscroscopy M annd Microanaly ysis 17 (2): 252-263. Deewanckele, J., De Kock, T., Fronteau, G.,, Derluyn, H., Vontobel, M., M Dierckx, L.., Van Hooreb beke, L., Jacobs, P., Cnudde, C V., 20014 Neutron raadiography and X-ray co omputed tomoography for qu uantifying weathering and a water uptaake processes inside porouss limestone used as buildingg material. Maaterials characterizattion 88: 86-999. Reebesco, M., Wåhlin, A., Labberg, J.S., Sch hauer, U., Beszczynskaa-Möller, A., L Lucchi, R.G..,, Noormets, R., Accettella, D., Zarayskkaya, Y., Diviiacco, P., in press Quaternary contouritite drifts of thee Western Spitsbergen margin. m Deepp Sea Research h Part I: Oceanograph hic Research PPapers, 79: 15 56-168. Vo oigt, I., Hen nrich, R., PPreu, B.M., Piola, A.R.,, Hanebuth, T.J.J., Schwenkk, T., Chiessii, C.M., 2013.. A submarin ne canyon aas a climate archive — Interaction of o the Antarctiic Intermediatte Water withh the Mar del Plata Canyyon (Southwest Atlantic).. Marine Geollogy 341: 46-557. RESEARCH FUTURE R Further ccomparisons to XRF, MSC CL and grain-ssize data will be carried out to t find out what w the differrent components represent annd how they can be usedd to further interppret contouritte cores. To achieve a this ggoal, contourite ssections from m various settings will be scanned in order to com mpile an initiial reference set against whichh future scanss can be compared. LEDGEMEN NTS ACKNOWL The authhors acknowleedge FWO grrant “Contourrite3D” for finan ancing this prooject, and Pro of. Dr. E. Achhten and Claire Scchepens (Radiiology unit, UZ U Gent). FIGURE 2. Variation of the com mponents (percen ntages) and XRF- measured Fe/Ca and Si/Al throug ghout sediment coore GC01. The grrey component is v section th hrough the core is given on the rig ght. The black horrizontal lines delilineate 14 zones based b on the CT not displayed iin the graphs. A vertical data. Zone 2 iss indicated in greeen because it sho ows a good correllation between th he green compone ent and the Si/Al ddata. Also the purple component and the Fe/Ca Ca data display the same trends.