Arrival, 16:30 - 19:30
Short introduction; goals of the workshop; introduction to lab and analytical facilities; agreement on workplan; first sample preparation steps.
Wednesday: 09:00 - 21.00
Presentation of the different preparation methods; problems of the Blagnac experiment; Holocene sample set; preparation of Holocene samples;
Preparation of Holocene sample set; list of Neogene samples; plans for the next sample preparation workshop.
Decisions and recommendations:
1. It would be desirable to add to the currently available global set of Holocene samples (Fig. 1) additional samples from a number of critical areas. Information of cores containing such desirable samples and their "owners" will be supplied to Hans Thierstein as soon as possible by the following persons:
Patrizia Ziveri: California Borderland, Mediterranean Sea, Arabian Sea Joerg Bollmann: Eastern equatorial Pacific, northern North Atlantic, Namibia.
2. The preparation methods for quantitative coccolith determinations in sediment samples were discussed: 1. Random settling, 2. filtration, 3. microbead-spraying. It was decided to test all three also with the Blagnac sample. Since the microbead-spraying technique seemed the most efficient and widely applicable (LM, SEM, filters, glass) it was decided to use that method for the CODENET sample preparations.
3. The differing oppinions of sample choices for the Neogene sediment samples were apparently based on different selection criteria, the occasionally poor data documentation in many Site descriptions, and changing age models. The ETH-group would like to get samples from maximum and minimum oxygen isotope levels as close as possible to the 1, 2, 3, 4 Ma levels at each site, with the emphasis on sampling endmember climate states near each level. The underlaying assumption for this strategy is that generally evolutionary changes seem to have been rather gradual, but that morphology is dependent on environmental gradients, and that the latter should be included in the initial sample set. The NHM-group emphasised chronology, i.e. same isotope stages at every site. The issue needs to be decided as soon as possible between the two groups. A reasonable compormise may be to work with the initally ordered sample set and order more samples later.
4. By Thursday, when Patrizia Ziveri and Markus Geisen had to return to their home institutions, the Blagnac sample test had been initiated and about half of the 30 Holocene samples had been prepared.
5. At least two more sediment sample preparation
will be necessary for the initial Holocene and late Neogene sample set.
The second workshop is planned for 15-19 June with Joerg Bollmann, Markus
Geisen, Sabrina Renaud. A third workshop will be planned for July with
Mario Cachão, Markus Geisen, Sabrina Renaud (in charge of planning
Jörg Bollmann (ETHZ)
Markus Geisen (NHM)
Sabrina Renaud (ETHZ)
Hans R. Thierstein (ETHZ)
ODP sample request
The remaining questions concerning the sample request have been clarified. The participants agreed in using the samples which have already been requested by the ETHZ. Additional samples from problematic sections will be requested together with the 500ka samples by the NHM. Jeremy Young will get into contact with ODP and inform them to send the remaining samples to the ETHZ.
Where the sample selection is based on age models the age model will be corrected to the latest age model of Shakleton et al. to calculate error margins for the different time slices.
16 preparations of the samples prepared in the first workshop proved to be good enough for examination. Further on 9 samples have been prepared using spraying techniques with tracer beads. The preparations (4 LM slides and 2 SEM stubs) will be mailed to the participants. The sample ID as well as the properties of the slides are given in the attached Excel document. If possible all participants working on these preparations should check the quality of the slides.
To prove the reproducibility of the settling method several experiments have been carried out. The best results were obtained with a solution of tab water with NH3 added (pH 8.5 - 9). 13 samples from ODP 607- 7 have been settled and 900 pictures of each sample at a magnification of 3000 have been captured under the SEM. The frames will be counted at the NHM and partly at the ETHZ.
The next workshop will take place from the 17-24.6 in Zurich. Core participants will be Mario Cachão (MNHN-UL, 17-22.6), Markus Geisen (NHM, 16-24.6), Sabrina Renaud (16-24.6) and Hans R. Thierstein (ETHZ). The aim of this workshop will be to provide the participants with preparations of the initial Neogene sampleset as requested from ODP. Sabrina Renaud will be in charge of planning and organisation.
Sabrina Renaud (ETH, Zurich)
Markus Geisen (NHM, London)
Mario Cachão (MNHN, Lisbon)
Jens Herrle (Universität Tübingen, guest scientist)
Aim of the workshop
The aim of the workshop was the to prepare the samples from 6 DSDP / ODP cores from the Atlantic, Pacific and Indian Ocean. The corresponding samples had to be prepared according to the method used during the second workshop for the Holocene samples. Techniques used in the previous workshops (spraying, sieving, filtering and settling) were demonstrated to the new participants of this workshop (Mario Cachão, Jens Herrle).
The spraying techique used during the first and second workshops has been adapted to the preparation of ODP samples, by finding a satisfying estimate of the concentration of sediments and tracer beads to be used.
30 samples, corresponding to the cores 552A, 659A,and 704A had been sieved previously. The preparation consisted with the spraying of slides for optical microscope and SEM stubs.
27 samples, corresponding to the cores 709C, 806B and 849, arrived shortly before the worshop and the whole preparation process had to be conducted during the workshop: sieving of the fine fraction and preparation by the spraying technic. During the sieving procedure, the intermediate and large fraction were collected, allowing eventual studies of other microfossil groups. Four slides for light microscopy (ETHZ, NHM, MNHN, FUA) have been prepared as well as two electron microscopy suds (ETHZ, FUA).
Standard smear slides have been prepared for all Holocene and ODP samples, according to the wish of Mario Cachão (MNHN), in order to compare the results derived from both approaches.
The samples ID as well as the properties of the samples are given in attached Excel document.
The next possible meeting for the participants will be at the occasion of the courses about SEM and study of the nannofossils through light microscopy, organized in the ETH from 5.10 to 9.10.1998.