BUILDING ROMA AETERNA MORTAR DATING AND ROMAN POZZOLANA,

RESULTS AND INTERPRETATIONS

Diagram of Mortar samples from the Åland Islands, 140 samples

Correct resultsPlausible results Results wrong, but reason known Wrong results

0

10

20

30

40

50

60

70

1 2 3 4

1

2

3

4

Correct or plausible results 81,4%

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%

0

5

10

15

20

25

30

35

40

45

1 2 3

1

2

3

Sampling at the Romanvilla of Torre de PalmaPortugal was done in 1997-2000. It resulted in a chronology of the site

Beginning with The East Bath in the first century AD

Ending with the largefont of the Baptistery

Samples from Trajan’s Samples from Trajan’s market, frommarket, from 19991999

and Hadrianic Samples and Hadrianic Samples from Ostiafrom Ostia

Rome

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

Santo Urbano, excavated underVia dei Fori Imperiali

Trajan’s Forum,Basilica Ulpia, calibrated result

60AD-140 AD

Rome, Torre delle Milizie, analyzed in Aarhus in two CO2 fractions, and in Oxford in five.Calibrated ageAD 1260-1285.

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 0,2 0,4 0,6 0,8 1

C-14 age (BP)

F

Rome007

Expected age

007 Aarhus

008

009

To begin with, in 1998, three samples fromTorre delle Milizie were analyzed in twoCO2 fractions in Aarhus

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 0,2 0,4 0,6 0,8 1

C-14 age (BP)

F

Rome007

Expected age

007 Oxford

007 Aarhus

008

009

Sample Rome 007 was lateranalyzed in five fractions byThe Oxford Radiocarbon Accelerator Unit. It confirmedthe results yielded by the firstfractions. Calibrated age:Ca 1205 AD-1260 AD

Coloss 1, 2.1, 2.2, 2-2, 3-2

1800

2000

2200

2400

2600

2800

3000

0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00

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

The temple of Jupiter Anxur, Terracina

2000

2100

2200

2300

2400

2500

2600

2700

2800

2900

3000

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

Terracina 001 (AAR-9780.1-4)

C-14 age BP

46-75µm

F

210-90 BC

Sampling at Terracina, a candidate for early pozzolana,from a spot which had beenexposed to maximal erosion. Theconcrete 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.

T, C-14 age BP

1500

2000

2500

3000

3500

4000

4500

5000

10 100 1000 10000 100000

t (s) dissolution time

Portus 2002 01, subaqueous sample , 46-75µm. (OxA-x2173, 2172. AAR-10603, 1-3)

ÅrhusOxford

AD 130-250

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.

Pompeii, Casa di MarcusLucretius, sampling in Collaboration with theEPUH (Excavationes Pompeii UniversitatisHelsinkiensis).All samples from Pompeiiand Herculaneum went wrong

The Suburban Baths at Herculaneum, with optimistic group in May2006...

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 Costanzais 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.

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

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.

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

0 0,2 0,4 0,6 0,8 1

Santa CostanzaC-14 age BP

F

46-75µm fractionsSamples

Rome 017Rome 046

Rome 017, from Oxford and Aarhus

Rome 046 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.

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

0 0,2 0,4 0,6 0,8 1

St CostanzaC-14 age BP

F

46-75µm fractionsSamplesRome 017Rome 046

046

017

42

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

0 0,2 0,4 0,6 0,8 1

Santa CostanzaC-14 age BP

F

46-75µm fractionsSamplesRome 017Rome 042Rome 046

046

017

42

1689±14 ; AD 340-395

The results of two samples of three from Sant’Agnese look even moreproblematic

1200

1400

1600

1800

2000

2200

2400

0 0,2 0,4 0,6 0,8

St AgneseC-14 age BP

46-75µm fractionsSamplesRome 043Rome 044Rome 045

F

045

04443

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

0 0,2 0,4 0,6 0,8 1

Sant'AgneseC-14 age BP

46-75µm fractionsSamplesRome 043Rome 044Rome 045

F

045

044

43

1799±19; AD 140-200 (23.5%) 210-260 (44.7%)

1631±17; AD395-435

-16

-14

-12

-10

-8

-6

-4

-2

0

0 0,2 0,4 0,6 0,8 1

Sant’Agnese: the interpretation of the results suggests two possible dates, one too ancient and the other one too recent

Possible explanations: bad sampling!a) Re-crystallization with rejuvinating effect on 044b) 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.

Delta 13C values of samples from Santa Costanza and Sant’Agnese

Diagram of all mortar samples, Classical and Medieval

1. Correct results2. Plausible results 3. Results wrong, but reasons known3. Results wrong Correct + plausible 72%

0

10

20

30

40

50

60

1 2 3 4

1

2

3

4

Statistical diagram from Torre de Palma, non-hydraulicClassical mortar, 65 samples analyzed in two fractions

CorrectPlausibleWrong, but reason knownWrong

Correct or plausible 83%

Pozzolana mortarsDiagram of Pozzolana mortars, 63 samples

Correct: 19 samples

Plausible: 14 samples

Wrong but reasons known: 19 samples

Totally wrong: 11 samples

Correct or plausible 52 %

0

2

4

6

8

10

12

14

16

18

20

1 2 3 4

1

2

3

4

Pozzolana mortars, results wrong, reasons known

1. Buried under volcanic ashes2. Too few fractions dated3. Crushed bricks in the aggregate4. Bad sampling (secondary repairs) 5. Delayed hardening

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5

1

2

3

4

5

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

1) The profile created no horizontal plateau 2) 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!

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