{"id":6550,"date":"2016-01-06T10:10:30","date_gmt":"2016-01-06T09:10:30","guid":{"rendered":"http:\/\/karmaka.de\/?p=6550"},"modified":"2021-02-15T13:51:45","modified_gmt":"2021-02-15T12:51:45","slug":"meteorite-found-at-lake-eyre-success-of-desert-fireball-network","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=6550","title":{"rendered":"MURRILI meteorite (H5\/S2-5, 1.68 kg) fallen on Nov 27, 2015 (10:43:44.50 UTC) was found at Kati Thanda (Lake Eyre South), South Australia – Success of Desert Fireball Network"},"content":{"rendered":"

Last update: 15 February, 2021<\/strong><\/p>\n

Chasing Meteors<\/strong>
\nABC Radio National, Earshot<\/em>, 5 December 2016
\nAUDIO (MP3)<\/strong><\/a>
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“I just went out on our little veranda for a smoke and a relax after work and there is no lights out here. So all you can see is like a silhouette of a sand dune. And then all of a sudden I saw this sort of flash and ran out and went ‘Wow’. What was that? You know this broad, bright streak across the sky. It was so close, then I thought we were about to have a nuclear war.”<\/span><\/p>\n

(Liz Lamble, kitchen manager at William Creek Hotel, 123 km west-northwest of the fall location.)
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On December 31, during a three-day recovery expedition and with the permission and help of the local Arabana people Prof Phil Bland, PhD student Robert Howie and Dr Jon(athan) Paxman of Curtin University found a 1.68 kg (~13x7x6 cm) entirely fusion crusted ordinary chondrite (H5\/S2-5) which had fallen on the dry lakebed of Kati Thanda (Lake Eyre South) in the South Australian outback (29.26089\u00b0S, 137.53765\u00b0E) on November 27, 2015 (10:43:44.50 UTC). The find was possible because five cameras<\/a> of the Desert Fireball Network (e.g. William Creek, Mount Barry, Billa Kalina and Wilpoorina) had recorded the fall. The data available, including the use of a WRF (Weather Research and Forecasting) climate model, could be used to calculate the trajectory and approximate fall location of the meteorite. The triangulation by Martin Towner, Martin Cupak, Ellie Sansom, and Hadrien Devillepoix was based on the three DFN camera stations in William Creek<\/a>, Billa Calina<\/a>, and Wilpoorinna<\/a>. The meteoroid with an estimated pre-atmospheric weight of about 80 kg and an initial speed of 13.82 km\/s travelled through the atmosphere at an angle of about 70 degrees during its 72 km long luminous flight for about 6.1 seconds until it had slowed down to about 3.83 km\/s and entered the dark flight phase of its trajectory at a height of 18.24 km above the ground. The meteoroid’s preatmospheric orbit was calculated to have the following elements: a = 2.62 AU, e = 0.62; i = 3.58 deg, \u03c9 = 356.3 deg; \u03a9 = 64.63 deg, \u03bd = 3.2, q = 0.9944 AU, Q = 4.3 AU.
\nIt wasn’t until the last day of the recovery expedition, 31 December, that a tandem search effort was undertaken since during the first two days the meteorite could not be found. With a storm coming in from the north there was not much time left before Lake Eyre would be flooded from the north and any signs of the meteorite’s impact on the ground erased from the lake’s surface. Two quad bikes were used on the lake bed by Bland and Howie while a light plane with Jon(athan) Paxman on board and piloted by Trevor Wright, a publican and local tour flight operator from the nearby William Creek settlement, did the aerial observations. These aerial observations were important in the endeavor to find the exact fall location of the meteorite as told by mechatronic engineer Dr Jonathan Paxman who spotted the impact hole after about 80 minutes of aerial search. From the air Bland and Howie were guided to the impact site. In early December Martin Cupak and Ben Hartig had already headed out to the fall region to do a flyover and managed to photograph a 60 cm impact feature in the lakebed. When the quad bike team arrived at the fall side they found a ‘small salt ring’, a small depression with a diameter of about 20 cm. The meteorite was found only 218 meters from the impact location which had been determined based on the usual assumption of a spherical meteoroid in the calculation of the dark flight trajectory. The Murrili meteorite (~ 13 x 7 x 6 cm) was excavated from a depth of about 43 cm in the thick salt lake mud. Since December 30 the recovery team had been guided by former cowboy and rail worker Dean Stuart and Dave Strangways of the local Arabana people. The meteorite was named by the Arabana people and was given the name MURRILI as significant for this region of Kati Thanda. The name honors a language that is hardly spoken anymore and thus might unfortunately vanish forever. The meteorite has been 3D CT-scanned at a location of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and as ‘property of the Crown’ its main mass was handed over to the South Australian Museum (SAM) where it will be curated.
\nA mean cosmic ray exposure (CRE) age of 7.12 \u00b1 0.41 Ma (38Ar concentration) was calculated and the measured cosmogenic nuclide ratios are reported to be compatible with a small pre-atmospheric size of 15\u201320 cm. Two small wedges (137.2 g and 86.9 g) and a cut slab (38.6 g) were cut from the main mass for examination and analyses. The cut surfaces show signs of terrestrial weathering (pervasive alteration with rusty staining) due to the meteorite’s exposure to the wet lake bed for a bit more than a month. A 51.5 gm fragment was analysed for physical properties like density, porosity, and magnetic susceptibility. The bulk density of the analysed Murrili fragment is 3.47 \u00b1 0.01 g cm-3. Its grain density is 3.59 \u00b1 0.01 g cm-3. The two densities together yield a porosity of (3.4 \u00b1 0.4)% which is low for an H chondrite which could be explained by aggressive terrestrial weathering in the warm, brine-saturated mud of the lake. The magnetic susceptibility of the analysed fragment is log \u03c7 = 5.19 \u00b1 0.09 (SI units). On March 31, 2016 the meteorite was officially registered in the Meteoritical Bulletin Database as MURRILI<\/strong><\/a><\/p>\n

The recovery of the meteorite is another great success of the Desert Fireball Network (DFN)<\/strong><\/a>, a crucial project which enables the recovery of freshly fallen meteorites and must be supported by anyone having an interest in meteoritics. It is a network<\/a> of currently 32 remote camera observation stations<\/a> set up in the Australian Nullarbor Desert and a collaborative effort of Imperial College, London, Ondrejov Observatory in the Czech Republic, Curtin University in Western Australia, the Western Australian Museum and other institutions. The first find based on calculations using the DFN data was Bunburra Rockhole<\/em>, a eucrite which fell on July 21, 2007.<\/p>\n

Scientific literature:<\/strong><\/span><\/p>\n\n\n

Mineralogy, petrology, geochemistry, and chronology of the Murrili (H5) meteorite fall: The third recovered fall from the Desert Fireball Network<\/strong><\/p>\n\n\n\n

S. Anderson G. K. Benedix L. V. Forman L. Daly R. C. Greenwood I. A. Franchi J. M. Friedrich R. Macke S. Wiggins D. Britt J. M. Cadogan M. M. M. Meier C. Maden H. Busemann K. C. Welten M. W. Caffee F. Jourdan C. Mayers T. Kennedy B. Godel L. Esteban K. Merigot A. W. R. Bevan P. A. Bland J. Paxman M. C. Towner M. Cupak E. K. Sansom R. Howie H. Devillepoix T. Jansen\u2010Sturgeon D. Stuart D. Strangway<\/p>\n\n\n\n

MAPS, 12 February 2021<\/p>\n\n\n\n

LINK<\/strong><\/a><\/p>\n\n\n

Murrili meteorite’s fall and recovery from Kati Thanda<\/strong><\/p>\n

E. K. Sansom, P. A. Bland, M. C. Towner, H. A. R. D. Devillepoix, M. Cupak, R. M. Howie, T. Jansen-Sturgeon, M. A. Cox, B. A. D. Hartig, J. P. Paxman, G. Benedix, L. V. Forman (15 June 2020)<\/p>\n

PDF<\/strong><\/a><\/p>\n

Fall and Recovery of the Murrili Meteorite, and an Update on the Desert Fireball Network<\/strong>
\nBland P. A. * Towner M. C. Sansom E. K. Devillepoix H. Howie R. M. Paxman J. P. Cupak M. Benedix G. K. Cox M. A. Jansen-Sturgeon T. Stuart D. Strangway D.
\n79th Annual Meeting of the Meteoritical Society (2016) [#6265<\/strong><\/a>]\n

Mineralogy and Petrology of the Murrili Meteorite<\/strong>
\nBenedix G. K. * Forman L. V. Daly L. Greenwood R. C. Franchi I. A. Friedrich J. M. Meier M. M. M. Maden C. Busemann H. Welten K. C. Caffee M. W. Bland P. A. Paxman J. Towner M. C. Cupak M. Sansom E. K. Howie R. Devillepoix H. Cox M. A. Jansen-Stugeon T. Merigot K. Stuart D. Strangway. D.
\n79th Annual Meeting of the Meteoritical Society (2016) [#6237<\/strong><\/a>]\n

Density, Porosity and Magnetic Susceptibility of the Murrili Meteorite Recovered by the Desert Fireball Network<\/strong>
\nMacke R. J. SJ Wiggins S. Britt D. T. Benedix G. K. Bland P. A. Desert Fireball Network Team
\n79th Annual Meeting of the Meteoritical Society (2016) [#6147<\/strong><\/a>]\n

Fe-57 M\u00f6ssbauer Study of the Murrili Ordinary Chondrite <\/strong>
\nCadogan J. M. Bland P. A. Benedix G. K. Towner M. C. Sansom E. K. Devillepoix H. Howie R. M. Paxman J. P. Cupak M. Cox M. A. Jansen-Sturgeon T. Stuart D. Strangway D.
\n79th Annual Meeting of the Meteoritical Society (2016) [#6311<\/strong><\/a>]\n\n\n

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