Slideshow Transcript

1. Slide 1: A point in space, a moment in time: towards an integrated view of the Santorini eruption Stuart Dunn Centre for e-Research, King’s College London Santorini Chronology Workshop, Aarhus, 10th November 2007
2. Slide 2: Objectives: • Overview of tephra fallout • Consistent representation of data • Estimation of bulk volume of ejecta • Towards ‘encoding archaeology’ - associating archaeological and natural sciences data spatially and temporally
3. Slide 3: Constructing a geodatabase of Theran tephra Place name: Santorini archipelago (northern caldera basin) (26) Place name: Hagia Varvara Deposit type: sea-floor sediment ( 400m) Grid reference: 25.46 E; 35.29 N Grid reference: not given Deposit type: pumice layer Area: - Area: unknown Thickness: 40m Thickness: 5 10 cm Deposition method: waterborne or human agency Deposition method: composite Archaeological context: LM IA or possibly IB c up included in pumice layer and Archaeological context: - filled with p umice, immediately below a s urface layer Comments: - containing LM III pottery. Literature: Woods Hole Oceanographic Institute Research Vessel Chain Cruise # Comments: Very badly eroded by modern tourist pathways. Illegal 61, ref. no. 67 34. development in the area has further damaged the stratigraphy. As far as the author is a ware, however, this is the only inst ance where a vesse l is included in situ with the volcanic material. Literature: Blackman 2001: 138; Mﾟller Celka 1996: 928 8; also Mﾟl ler Celka personal communication, 6/8/2001.
4. Slide 4: Constructing a geodatabase of Theran tephra
5. Slide 5: Constructing a geodatabase of Theran tephra
6. Slide 6: Constructing a geodatabase of Theran tephra: problems • Accuracy and (versus) precision • Georeferencing from heterogeneous formats
7. Slide 7: Constructing a geodatabase of Theran tephra: problems • Accuracy and (versus) precision • Georeferencing from heterogeneous formats and sources • Georeferencing places -formal, based on lat/long or other mathematical expressions -Informal, based on placenames, and/or where 34.87 no formal mathematical identifier is present • Assessing deposition process • Harmonizing points, sections and stratigraphies 24.87
8. Slide 8: Estimation of bulk volume of ejecta • Geographical Information Systems (GIS) • Triangulated Irregular Network (TIN) ‘Conceptually like bending a sheet of rubber to pass through the point, while minimizing the curvature of the surface’ - total raster cell value of 132,508,783.441, or… - 134.343 +/- 4 km3 • This is a maximum estimate - c. 90-100 km3 is nearer the mark
9. Slide 9: Towards ‘encoding archaeology’ • Parallel between referencing points on the earth’s surface and referencing points in time • Relative and absolute • Development of reasoning models to manage space and time The CIDOC-CRM www.ahessc.ac.uk/ briefing_paper M. Doerr et al 2004, fig 1.
10. Slide 10: Towards ‘encoding archaeology: ‘meetings’ “The concept of “meetings is extraordinarily powerful: Chronology concerns and involves events … “Dating” an object actually means approximating the coherence volume of some event(s) in which the object was present.” -Supporting Chronological Reasoning in Archaeology, Doerr et al 2004 M. Doerr et al 2004, fig 2.
11. Slide 11: Towards ‘encoding archaeology: ‘meetings’ “The concept of “meetings is extraordinarily powerful: Chronology concerns and involves events … “Dating” an object actually means approximating the coherence volume of some event(s) in which the object was present.” - Doerr et al 2004 • A. Deposition of a tephra deposit • B. Production of a LMIA cup in Crete - predates A, but with smaller ‘coherence volume’. • C. Deposition of cup • D. C14-datable fire destruction M. Doerr et al 2004, fig 2.
12. Slide 12: A future project: Agent-based modelling
13. Slide 13: A future project: Agent-based modelling After Giuseppe Trautteur and Raniero Virgilio
14. Slide 14: To Conclude… stuart.dunn@kcl.ac.uk