1 / 29

BUILDING ROMA AETERNA MORTAR DATING AND ROMAN POZZOLANA, RESULTS AND INTERPRETATIONS

BUILDING ROMA AETERNA MORTAR DATING AND ROMAN POZZOLANA, RESULTS AND INTERPRETATIONS. Diagram of Mortar samples from the Åland Islands, 140 samples. Correct or plausible results 81,4%. Correct results Plausible results Results wrong, but reason known Wrong results.

teige
Download Presentation

BUILDING ROMA AETERNA MORTAR DATING AND ROMAN POZZOLANA, RESULTS AND INTERPRETATIONS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. BUILDING ROMA AETERNA MORTAR DATING AND ROMAN POZZOLANA, RESULTS AND INTERPRETATIONS

  2. Diagram of Mortar samples from the Åland Islands, 140 samples Correct or plausible results 81,4% Correct results Plausible results Results wrong, but reason known Wrong results

  3. Åland mortars from securily dated structures, compared to dendrochronologi and 14C dated wood structures A total of 50 samples 42 correct 84% 5 wrong, but reason known 10% 3 results wrong 6%

  4. Sampling at the Roman villa of Torre de Palma Portugal was done in 1997-2000. It resulted in a chronology of the site Beginning with The East Bath in the first century AD

  5. Ending with the large font of the Baptistery

  6. Rome Samples from Trajan’s market, from1999 and Hadrianic Samples from Ostia

  7. Carolingian construction at Nerva’s Forum, analyzed in two fractions in 1998. Result of the first fraction plausible.

  8. Santo Urbano, excavated under Via dei Fori Imperiali

  9. Trajan’s Forum,Basilica Ulpia, calibrated result 60AD-140 AD

  10. Rome, Torre delle Milizie, analyzed in Aarhus in two CO2 fractions, and in Oxford in five. Calibrated age AD 1260-1285. To begin with, in 1998, three samples from Torre delle Milizie were analyzed in two CO2 fractions in Aarhus

  11. Sample Rome 007 was later analyzed in five fractions by The Oxford Radiocarbon Accelerator Unit. It confirmed the results yielded by the first fractions. Calibrated age: Ca 1205 AD-1260 AD

  12. The Colosseum, erected ca 80 AD, four different profiles agree on the first fractions with the estimated age

  13. The temple of Jupiter Anxur, Terracina

  14. Sampling at Terracina, a candidate for early pozzolana, from a spot which had been exposed to maximal erosion. The concrete still had imprints of the wooden moulding construction. Not hydraulic according to the hydraulic index. It reached a plausible age with the first CO2 fraction of the profile.

  15. The identical sample from the harbour construction at Portus, plausible result revealed at the joining point between the two profiles, one from Oxford and the other from Aarhus.

  16. Pompeii, Casa di Marcus Lucretius, sampling in Collaboration with the EPUH (Excavationes Pompeii Universitatis Helsinkiensis). All samples from Pompeii and Herculaneum went wrong

  17. The Suburban Baths at Herculaneum, with optimistic group in May 2006...

  18. The horse-shoe shape Basilica of Sant’Agnese, founded by Constantine the Great, during the pontificate of Silvester I (314-335 AD). The rotunda of Santa Costanza is not bonded with Sant’Agnese, and the pozzolana concrete is very different. Controversial date of Santa Costanza: a) Between 337-351 built by Constantina, daughter of Constantine the Great b) later half of the 4th C. C) around 400 AD.

  19. Rome 017, Santa Costanza, 14C AMS-analysis perfor-med in Aarhus, calibrated result, AD 330-390.

  20. However, an independent source seems to support our initial results. 14C AMS-analysis of the wood ashes embedded in the mortar of the foundation of Santa Costanza has been implement, with interesting results. According to David J. Stanley, who had wood ashes embedded in the concrete at the foundation level of Santa Costanza dated with 14C –analysis, the result yielded was AD 412 ± 43, or 369-455 AD (David J. Stanley, 2004). However, using mechanical calculation with ± 43 as margin errors, can be problematic. To reach the suggested date the uncalibrated BP age of 1632±43 comes close, without being identical. The original BP age, is at present unknown.

  21. Further samples from Santa Costanza were analyzed to confirm the earlier result. The first 14C fraction of Rome 046 does coincide with the earlier plateau, but the profile of Rome 042 is just strange. A narrow horizontal line along the agreeing fractions can, with good will, suggest the date of AD 340-395.

  22. The results of two samples of three from Sant’Agnese look even more problematic

  23. Sant’Agnese: the interpretation of the results suggests two possible dates, one too ancient and the other one too recent Delta 13C values of samples from Santa Costanza and Sant’Agnese • Possible explanations: bad sampling! • Re-crystallization with rejuvinating effect on 044 • The Delta 13C value of Rome 043 is different from the others, and • anomal 18O delta values of the same sample may indicate that • something could be wrong with the ancient horizontal level of the • profile.

  24. Diagram of all mortar samples, Classical and Medieval 1. Correct results 2. Plausible results 3. Results wrong, but reasons known 3. Results wrong Correct + plausible 72%

  25. Statistical diagram from Torre de Palma, non-hydraulic Classical mortar, 65 samples analyzed in two fractions Correct Plausible Wrong, but reason known Wrong Correct or plausible 83%

  26. Diagram of Pozzolana mortars, 63 samples Pozzolana mortars Correct: 19 samples Plausible: 14 samples Wrong but reasons known: 19 samples Totally wrong: 11 samples Correct or plausible 52 %

  27. Pozzolana mortars, results wrong, reasons known • Buried under volcanic ashes • Too few fractions dated • Crushed bricks in the aggregate • Bad sampling (secondary repairs) • Delayed hardening

  28. 11 samples went wrong without us as yet understanding why. • However – as a rule samples that go wrong are easily recognized, • even if the patterns may vary • The profile created no horizontal plateau • All the fractions yielded different results, all of them too recent • In three cases horizontal plateaux were created in the wrong • place of the profile, either far too recent or far too ancient, or • possibly correct, secondary repair!

  29. The team, in different constellations, trying to work out how to proceed with pozzolana mortars

More Related