Changing sea-level along the north coast of Kuwait bay

Abstract

Field investigations have been carried out to study the changes of sea level-along the north coast of Kuwait Bay. Four zones have been studied in detail viz: Kathma, Ghidhai, Mudairah and Al-Bahra. The area is characterized by the existence of several terraces which lie between the Jal-Az-Zor escarpment and the coastline which may represent stages of changes in sea-level. Three techniques have been adopted to study the terraces: 1.Levelling, 2.Radiocarbon dating of shells, and 3. Sediment analysis by particle size analysis and scanning electron microscope. The results show that there are six terraces in the area. The highest levelled point for the First terrace was obtained from Ghidhai at 92.62 m. above Kuwait Datum, while the least elevation for a fragment of the lowest terrace was 5.99 metres above Kuwait Datum, at Al-Bahra the terraces, besides having a general tendency to decrease in height from west to east, also indicate local instability and warping. Although the upper terraces can be identified as conspicuous physiographic features, it has been difficult to correlate them according to their height. Radiocarbon dating of a small number of shell samples from the Third, Fourth and Fifth terraces gave a range of ages between >42,950 years BP. and 23,300+600 years BP.; no simple correlation between height and age is observable and the possibility of shell contamination cannot be excluded. The evidence as a whole suggests that these upper terraces are not younger than Pleistocene in age. Radiocarbon dating for the extreme lowest terraces gave an age range of between 4,570+70 years BP. and 3,560160 years BP. which suggests a time of formation in the Holocene. The sediment investigations confirm the existence of three depositional environments; fluvial, Aeolian and marine. The sediment analysis results together with their gemorphological character indicate that it is possible that the upper two or three terraces originated as a result of fluviatile as well as marine action and were affected by tectonic movements. The lowest terraces are likely to be of marine origin deformed by tectonic movements.