Ben Gurion University of the Negev Department of

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Ben Gurion University of the Negev Department of Geological and Environemental Studies The Effect of Silicates Dissolution to the Isotopic Composition of Sr in Sea-Water Daniel Winkler Under the supervision of Prof. Jiwchar Ganor and Dr. Yehudit Harlavan [Geological Survey of Israel] Lookout eastwards from Mizpe Amram. Daniel Winkler 13. 1. 2009

The Goal of My M. Sc Study To contribute to the understanding of the effect of 87 Sr/86 Sr variations in the oceans, due to the interaction of Sillicates in ocean water 2

Sr Variation Model s=Sialic (Si+Al) Rocks [Aluminosillicates] v=Volcanics m=Carbonates Proposed by Gunter Faure [1965] s+v+m=1 3

Sr Budget of the Oceans 1 Sr is homogeneous in ocean water [Long Residence time compared to mixing rate of the oceans 2. There are significant differences in the concentrations and isotopic composition among the different contributors ? 4

The Goal of Research 1. Determining of Kinetic dissolution of sillicate sediments in interaction with seawater. 2. Examining the Sr concentration change with time due to the dissolution. 3. Tracking the variations of 87 Sr/86 Sr that is contributed along the dissolution stages. 5

Methodology: Laboratory Experiments: Interaction of sediment with seawater 1. Laboratory experiments allow controlling of the various parameters [temperature, p. H, chemical composition]. 2. Synthetic seawater solution is used, in order to avoid high Sr concnetration which will prevent us from noticing minute changes in Sr concentration over time. 6

Sampling Area Amram Rhyolite π Quartz Diorite Roded qδr Yehoshafat Granite γ ________ Tabe Gneiss γν Eilat Granite γ Eilat Schist μ Sachamon Amphibolite a 7

x 8 Methods: 1. Batch [closed] Experiment. Each tube is representing a single point on the graph. 2. Each one of the tubes is having the same conditions [temperaure, sediment/solution ratio, p. H] 3. After a specific time period, a separation of solution from the ‘solution+sediment’ is being done for various chemical analyses Solution 40 gr Sediment 0. 4 gr 8

0. 22μm filter [via Vacuum pump] t 0 + t Si, Al Analysis Spectrophotometer Perkin Elmer Lambda 2 S Precision ± 5% Sr, Ca, Mg, Fe, K Analysis [at the Geological Survey in Jerusalem] Perkin Elmer SCIEX ELAN Precision ± 10% 9

Sr-seperation in resin-columns in the clean-laboratory at the Geological Survey in Jerusalem 87 Sr/86 Sr Analysis Nu Plasma MC-ICP-MS Precision ± 0. 002% 10

Initial Results of the following minerals: x 8 Albite (63µm<f<75µm) Amram Rhyolite (0<f<63µm) Logarithmic-scale sampling [fator 2] [2. 5 d, 10 d… 320 d]. Roded Quartz Diorite (63<f<90µm) Yehoshafat Granite (63<f<90µm) Solution 40 gr Sediment 0. 4 gr 11

$Albite (size fraction 63µm<f<75µm) The mineral Albite was chosen, because: 1. Its dissolution kinetics$

Albite (size fraction 63µm<f<75µm) The mineral Albite was chosen, because: 1. Its dissolution kinetics is known from previous studies [Blum 1995, Brantley 1998] 2. Its interaction with seawater solution was never studied before Since the size fraction was not size-homogeneous and so that small particles were adhered to the larger ones, the sample was Ultrasonically-shaken. Results are indeed satisfactory, as the SEM photos below are showing Before After 12

Surface Area of the minerals Albite [before and after ultrasonic-cleansing] Before After 13

Results show that indeed Albite is dissolving in seawater solution 10/2/2012 30/4/2012 Via Spectrophotometer T=25 c p. H=8. 2 Surface Area=0. 277 m 2/gr Vol SW Solution=0. 04 L Alb=0. 4 gr

10/2/2012 21/3/2012 Via ICP-MS 15

Via Spectrophotometer 16

My experiments will contribute to the understanding of: 1. Which minerals are the major Sr contributors during sediment-seawater interaction process. 2. Which of the Eilat region rocks unit are the major Sr contributors. 3. The results of my ressearch will contribute to the understanding of the Sr budget of the oceans. 17

Next assignments: Finishing of experimental work and Thesis writing. October September August July June Chemical analysis of all the experiments up to this day. May April Mars New experiments for samples: Taba Gneiss, Eilat Granite, Eilat Schist, Sachmon Amphibolite February January December Mineral separation of the various minerals found within the alluvium sample. Bulk samples BET surface-area measurement November October 2013 September 2012 18 87 Sr/86 Sr analysis, as well as Ca, Mg, K, Fe, Sr analysis for the various experiments solution up to present date. August July

Thanks for listening… Lookout from top of Har Zfachot to the northern part of Eilat gulf. End of Israel Trail. 19 Daniel Winkler 13. 1. 2009

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