Kearsley, A. T.

Miljkovic, K.

Taylor, E. A.

Tsembelis, K.

English

Open Research Online (The Open University)

Open Research OnlineThe Open University’s repository of research publicationsand other research outputsFurther development of a Hugoniot for YorkshireSandstoneConference or Workshop ItemHow to cite:Taylor, E. A.; Tsembelis, K.; Kearsley, A. T. and Miljkovic, K. (2007). Further development of a Hugoniot forYorkshire Sandstone. In: Bridging the Gap II: Effect of Target Properties on the Impact Cratering Process, 22-26 Sep2007, Saint-Hubert, Quebec, Canada, pp. 119–120.For guidance on citations see FAQs.c© 2007 The AuthorsVersion: Version of RecordCopyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyrightowners. For more information on Open Research Online’s data policy on reuse of materials please consult the policiespage.oro.open.ac.ukFURTHER DEVELOPMENT OF A HUGONIOT FOR YORKSHIRE SANDSTONE.  E. A. Taylor1, K. Tsembelis1, 2*, A. T. Kearsley2 and K. Miljkovic1, 1Department of Physics and Astronomy, Centre for Earth Plane-tary Space and Astronomical Research, The Open University, Walton Hall, Milton Keynes, MK7 6AA, U. K. (e.a.taylor@open.ac.uk; kostas@tsembelis.com; k.miljkovic@open.ac.uk). 2Physics and Chemistry of Solids, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, U.K. 3Department of Mineralogy, Natural History Museum, London SW7 5BD, U.K.(a.kearsley@nhm.ac.uk).                                                                    * Now at Atomic Energy of Canada Ltd, Chalk River Labs, ON, Canada.  Introduction:  In order to improve our understand-ing of the shock response of Yorkshire sandstone, par-ticle impact tests were carried out using the Open Uni-versity’s All Axis Light Gas Gun [1, 2], and 1-D plate impact shock studies implemented using the University of Cambridge’s Plate Impact Facility [3]. Preliminary measurements of the crater depth and diameter have been carried out, using a range of techniques. Predic-tion of the pressures generated on impact requires ap-propriate material data, preferably measured for the material (particularly relevant for geological materials where there can be material variability). This paper reports on the  development of a Hugoniot for York-shire sandstone, building on previous work [4, 5, 6]. A range of hydrocodes and analytical techniques were used [7, 8], supported by published data on sandstones and related rocks and minerals [9, 10, 11, 12]. Tech-niques to estimate the shock-driven heating of the tar-get were applied [13]. This work is a precursor to in-vestigating the possibility of shock-driven DNA modi-fication of microbial organisms in sandstone targets, which could occur at lower pressures than those previ-ously established to cause extinction [14, 15]. Future studies may also look at impact-driven changes to sub-surface habitats, noting that shock processing of rocks may make them more colonisable [16]. Before any conclusions can be drawn for these large structures, the different responses for the strength and gravity dominated regimes must be established. Sandstone Properties: The measured Hugoniot values are reported in Ref. 4. The bulk density was measured to be 2.24 g/cm3. The composition of the sandstone was established using low vacuum backscat-tered electron images to obtain modal mineral analyses (i.e. % of whole rock by area ~ volume) for five repre-sentative areas of a polished section taken from the edge of the target (example shown in Figure 1). All areas were very similar in their major mineral contents (quartz ca. 60%), and porosity (10-16%), but variable in the minor mineral contents. The results are reported in Table 1. Noting that the ratio of chlorite to K feld-spar is estimated to be 5:1, and  that the ratio of SiO2 to albite is estimated to be 9:1, we set the composition of the Yorkshire sandstone (for the purposes of devel-oping a “composite” synthetic Hugoniot) to be: quartz (59%), pore space (14%), chlorite (9%), kaolinite (8%), albite (7%), Fe and Ti oxides (3%) and K feld-spar (2%).       Figure 1. Backscattered electron image of the Yorkshire sandstone sample.  Table 1. Composition of Yorkshire sandstone sample Material Proportion (%) Error (st.dev.) “Bright” (metal oxides) 2.90 1.98 Chlorite and K feldspar 10.52 2.99 Silica and albite 65.28 2.85 Kaolinite 8.02 1.81 Pore space 13.60 2.18 TOTAL 100.32 N/A  01020304050607080901000.2 0.25 0.3 0.35 0.4 0.45V, g/ccP, GPaAhrens and Johnson Coconino (Elastic phase) [9]Ahrens and Johnson Coconino (Low P phase) [9]Ahrens and Johnson Coconino (Mixed region) [9]Ahrens and Johnson Coconino (High P phase) [9]Taylor et al.Yorkshire sandstone [4]de Carli quartz with high pressure release [6]Ahrens and Johnson Quartz [10]Interpolation - synthetic Hugoniot [6]direct measurements Figure 2.  P-V curve for Yorkshire sandstone. A trilinear Hugoniot was derived from these data [6]. Workshop on Impact Cratering II (2007) 8067.pdf Figure 3. Profile of central region of the impact crater, pro-duced by 1 mm spherical particle stainless steel projectile, impacting at 4.8 km/s at 30° to the horizontal.   Figure 4. Distribution of impact residue  Further Development of a Sandstone Hugoniot: Based on previous work, as shown in Figure 2, where the P-V curve was based on an interpolation between ex-perimentally measured data for Yorkshire Sandstone and a high pressure quartz data set., we now construct a “com-posite” synthetic Hugoniot from mineral data. Shock data for serpentine are used as the closest available analogue for K feldspar. All other data are from pub-lished experimental tests. A simple pressure-dependent crush-up model, following the approach of Ref. 13, is also developed.  Hydrocode Simulations and Analytical Calcula-tions: A series of 1-D, 2-D and 3-D simulations are presented. The tri-linear (and a bi-linear, with a range fits reflecting the data in this intermediate regime) Hugoniot, as defined in Us-up space, are used in two hydrocodes (AUTODYN and CAV_KO). A new com-posite Hugoniot, based on data for the constituent min-erals is also used as input to the hydrocode simula-tions. Both sets of results are compared with analytical results based on the planar impact approximation (CAV_SHOCK).  Further Work:  Strength and failure models for sandstone will be need to be implemented before a better understanding of the cratering processes. We plan to explore application of the Johnson-Holmquist 2 damage model, as previously used by the two of the authors to explore cratering and penetration in soda lime glass [17].  The objective is to characterise more fully the pressures generated on impact, and to draw broad conclusions on the pressure bounds for any changes observed in the microbial specimens. A con-straint on the modeling will be provided by crater pro-file data, as shown in Figure 3. Plate data for water saturated sandstone are needed, noting recently re-ported results on survivability of microbial life differ-ing between dry, and saturated, sandstone [18]. Model-ling of larger scale impacts – a longer term aim – must consider gravity-driven effects, and other aspects, be-fore any conclusions can be drawn about pressures experienced by any microbial life and changes in habi-tability driven by shock effects. The derived Hugoniot will be used to estimate release temperatures via ana-lytical calculations of waste heat generated [13].  Ini-tial observations suggest that material may have been emplaced downrange, possibly both from ejecta, and also down fracture systems (Figure 4). A detailed map of the impactor-bearing residue will need to be pro-duced.  References: [1] Taylor, E. A. et al. (2006), Proc. 57th ARA Meeting, Italy, Sept. 2006. [2] McDonnell, J. A. M. (2006), Int. J. Impact Engng., 33, 410-418. [3] Bourne, N. K. et al. (1995), Meas. Sci. Technol., 6, 1462-1470. [4] Taylor, E. A. et al. (2005), Proc. Shock Compression Condensed Matter 2005, 1488-1491. [5] Taylor, E. A. et al., Presented at 1st Conf. Impact Cra-tering Solar System, Netherlands, May 2006. [6] Milk-ović, K. et al. (2007),  submitted to Proc. Shock Com-pression Condensed Matter 2007. [7] Tsembelis, K., CAV_SHOCK software and CAV_KO software, ob-tained via http://www.shockphysics.com. [8] Century Dynamics Inc. (2003) AUTODYN Theory Manual.. [9] Ahrens, T. J., and Johnson, M. L (1995), Shock Wave Data for Rocks, AGU Ref. Shelf 3. [10] Ahrens, T. J., and Johnson, M. L. (1995), Shock Wave Data for Minerals, AGU Ref. Shelf 2. [11] Anderson, W. W. et al (1995), DNA-TR-95-32. [12] Ahrens, T. J. et al (1995), AFOSR-TR-95-0493. [13] Sharp, T. G. and deCarli, P. S. (2006), Meteorites Early Solar System II, Univ. Arizona Press, 653-677. [14] Stöffler, D. (2007) et al, Icarus, 186 (2), 585-588. [15] Burchell, M. J. et al (2004), Mon. Not R. Astron. Soc., 352, 1273-1278. [16] Cockell, C.S. et al. (2002), MAPS, 37, 1287-1298. [17] Taylor, E. A. et al (1999), Int. J. Impact Engng., 23 (10), 895-904. [18] Migaiski, M. et al. (2007), LPSC XXXVIII #1286.  Workshop on Impact Cratering II (2007) 8067.pdf

Further development of a Hugoniot for Yorkshire Sandstone

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Further development of a Hugoniot for Yorkshire Sandstone

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