The project collected samples of coral blocks used in the Bidiyah Mosque and the watchtowers in Rul Dibba and Rul Dhadnah. These were then sent to the University of Minnesota in the United States, where they were dated, using a technique known as uranium-thorium radiometric dating. This provided new information about the dates of construction. Besides providing insights into the architecture and any architectural parallels, the results can also be interpreted in conjunction with archaeological finds, like fragments of pottery, discovered on the surface or during excavations.
For the Bidiyah mosque, the research has made a clearer understanding of its probable date of construction possible. During archaeological excavations in 1997 and 1998, led by Dr Ziolkowski, several dates obtained through radiocarbon dating of charcoal fragments suggested that it was built between 1450-1655. Fragments of pottery and porcelain excavated at the site have also been dated to the 16th Century.
Uranium-thorium radiometric dating of two of the coral blocks from the mosque also fall within the 16th Century, 1530, plus or minus 71 years, and 1599, plus or minus 9 years. Retrum and Ziolkowski suggest that the mosque was probably built by 1599, the more clearly defined date. At this time, the Portuguese controlled trade in the Arabian Sea. Historical archives in Portugal refer to the presence of a fort in Bidiya at this time, the site of which was excavated by Ziolkowski in 1999.
At Rul Dibba, the dating of coral blocks has suggested that the now dilapidated large earth-filled defensive tower was initially constructed during the second half of the 19th Century. Pottery and porcelain recovered from the surface of the site has been dated to the 17th to 20th centuries.
The coastal tower at Rul Dhadnah, also now ruined, has architectural similarities to the tower at Rul Dibba, while artefacts like pottery and porcelain suggest a similar date of construction, in the second half of the 19th Century.
However, the coral blocks from the Rul Dhadnah tower have been dated to the 10th Century AD. This suggests, according to Retrum and Ziolkowski, that the tower was built using recycled material from earlier buildings, dating to the early to mid-Islamic period. Traces of these earlier buildings have not yet been identified.
"This research has helped to throw new light on the ages of some of Fujairah's historic buildings, like the Bidiyah Mosque," Ziolkowski said. "It also provides evidence of the longevity of this form of construction, stretching back for a thousand years."
Thanking the Fujairah Crown Prince for his support for their research, they are now planning further studies into the emirate's architectural heritage.
