Shell plea

PUBLISHED : Thursday, 15 May, 1997, 12:00am
UPDATED : Thursday, 15 May, 1997, 12:00am

I am writing to seek the help of readers in the provision of sea shells collected from Hong Kong and/or the coastal waters of southern China, in order to assist my geological research.

In my study to reconstruct past sea-levels and environmental change in Hong Kong, fossil sea shells found in geological deposits are dated by the radiocarbon method. However, nuclear testing in the 1950s and early 1960s increased the global radioactivity level, significantly changing the ocean carbon reservoir which influences living sea shells. This can lead to misleading results. In order to refine the results obtained by radiocarbon dating, it is necessary to correct using a pre-determined factor obtained for the region.

I am appealing for sea shells collected alive between 1920 and 1960. The location and year (or month if possible) should be known and the sea shells should preferably weigh no less than 20 grams. Further information on the requirements is available by contacting me - phone, 2859-2829; fax, 2517-6912.

WYSS YIM Department of Earth Sciences The University of Hong Kong