BrVQ: Difference between revisions
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'''Historical:''' 1197-1490 | '''Historical:''' 1197-1490 | ||
Block 2b is very problematic. It is dated by Bråthen to 1490, and the youngest part is obviously correct dated, but the older part does not correlate at all on that position! Instead it correlates very well at the position corresponding to 1197 for the whole block. I.e the samples in the oldest part are erroneously dated | Block 2b is very problematic. It is dated by Bråthen to 1490, and the youngest part is obviously correct dated, but the older part does not correlate at all on that position! Instead it correlates very well at the position corresponding to 1197 for the whole block. I.e the samples in the oldest part are erroneously dated 293 years too late! Samples of two very different ages are mixed together. | ||
Reading carefully the documentation, and constructing the samples positions and lengths the mistakes was revealed: Six samples from Götene and Kungslena churches which are from early 12'th century are mixed into the chronology at a position 293 years too late. As there is only an average series available only the "clean ends" may be used as reference, i.e 1419-1490 and 904-974 (missdated as 1267-1197). And of those only 939-974 (35 yrs) and 1419-1482 (63 years) has at least 4 samples depth. | Reading carefully the documentation, and constructing the samples positions and lengths the mistakes was revealed: Six samples from Götene and Kungslena churches which are from early 12'th century are mixed into the chronology at a position 293 years too late. As there is only an average series available only the "clean ends" may be used as reference, i.e 1419-1490 and 904-974 (missdated as 1267-1197). And of those only 939-974 (35 yrs) and 1419-1482 (63 years) has at least 4 samples depth. | ||
Revision as of 22:48, 9 June 2009
BraVSQ Oak Chronology for the region Västra Götaland by Alf Bråthen. It was originally published in the book: Alf Bråthen: Dendrokronologisk serie från västra Sverige 831-1975. Rapport RAÄ 1982:1. ISBN 91-7192-511-2.
In the book four different Chronologies are given, with annual average values and number of measurements behind each value. There are also detailed documentation about the origins of each sample. The four chronologies are originally named: "Block 1", "Block 2", "Block 2b" and "Block 3". Unfortunately there are some severe errors in the material, which have to be corrected before the chronologies can be used. The wrong date for the Lödöse Chronology was discovered soon after the publication, and a corrected (and enlarged) chronology was published by Bråthen later [ref needed].
Still the material from the book are very valuable and useful, when missdatings are corrected and bad sequences are removed. The measurements was originally done in 0.1 mm resolution, but the average series are given in 0.01 mm resolution.
Analyze of the BraVSQ-material
For the following analyze, I have used four independent oak-chronologies: OlandQUSP, WestDK, BohusRec and HllndQUB (see List of references). The documentation and result of this analysis is available at http://www2.hemsida.net/taxelson/dendro/BrathenEk.zip (WebCite). A weighted chronology of correct and corrected blocks when at least four samples are present is available at http://www2.hemsida.net/taxelson/dendro/BraVSQ.dec .
Block 1
Recent: 1615-1975. At least 4 samples depth: 1634-1974, 9 contemporary stems as best. No problems found.
Block 2
Historical: 1337-1804. At least 4 samples depth: 1380-1779, 16 contemporary stems as best. Problems:
- The period 1554-1613 has almost zero-correlation towards other references, and has to be removed. It is obviously erroneous. The reason for this problem is not yet known.
- Value for 1650 is missing.
Block 2b
Historical: 1197-1490
Block 2b is very problematic. It is dated by Bråthen to 1490, and the youngest part is obviously correct dated, but the older part does not correlate at all on that position! Instead it correlates very well at the position corresponding to 1197 for the whole block. I.e the samples in the oldest part are erroneously dated 293 years too late! Samples of two very different ages are mixed together.
Reading carefully the documentation, and constructing the samples positions and lengths the mistakes was revealed: Six samples from Götene and Kungslena churches which are from early 12'th century are mixed into the chronology at a position 293 years too late. As there is only an average series available only the "clean ends" may be used as reference, i.e 1419-1490 and 904-974 (missdated as 1267-1197). And of those only 939-974 (35 yrs) and 1419-1482 (63 years) has at least 4 samples depth.
On page 32-33 is a list of 12 samples which are said to be the samples in the average serie "Block2b", but that list is not correct. That is obvious when compared to the number of samples said to be behind each value in the average chronology. The correct list could almost be reconstructed from the complementary list at pp. 90-94 and the years when the number of years are altered. It is than revealed that one sample from Hedared is forgotten in the first list and that one sample from Götene church is confused i the table.
| Id | Bråthen's id | Description | use | Correct dating (used part) |
|---|---|---|---|---|
| Ba1 | Bälinge 1 | 1436-1314 | yes | yes |
| Ba2 | Bälinge S. remstycke | 1482-1313 | yes | yes |
| Ba3 | Bälinge N. remstycke | 1506-1280 | 1490-1280 | yes |
| Go1 | Götene 1 | 1418-1213 | yes | 1125-920[1] |
| Go3 | Götene 3 | 1396-1239 | yes | 1103-946 |
| Go4 | Götene 4 | 1301-1157 | 1301-1197 | 1008-864 (-904) |
| Go5 | Götene 5 | 1383-1198[2] | yes | 1090-905 |
| He1 | Hedared 1 | 1487-1338 | yes | yes |
| He3 | Hedared 3[3] | 1426-1268 | 1426-1302[4] | yes |
| He4 | Hedared 4 | 1455-1327 | yes | yes |
| He5 | Hedared 5 | 1488-1346 | yes | yes |
| Ku1 | Kungslena 1 | 1401-1268 | yes | 1108-975[5] |
| Ku2 | Kungslena 2 | 1393-1227 | yes | 1100-934 |
Block 3
Lödöse, archeological: 780-1298 (Missdated: 831-1349). At least 4 samples depth: 867-1185. As best: 19. No other problems found.
Notes
- ↑ At p.102 Bråthen remarks that there are Earlywood only for the year 1418. According to the missdating this is to be interpreted as summer (june) 1125! He also remarks that Prof. Erik Lundberg, in a paper 1968, dated the church to 12' century. Lundberg was right! (The correct dating (1125) is noted in Bebyggelseregistret)
- ↑ See p.91 (erroneously 1488-1346 in main table)
- ↑ Not in list, but according to p.91, and as the youngest year corresponds with an altering of the annual number of samples.
- ↑ It may also possibly continue backwards in all its length. There are indeed several possibilities which which sample is the truncated one: It may be He3 or Go4 (young end) or Ku1 (old end).
- ↑ The logs from Kungslena church are cut after 1108 and not after 1401.