Commission on Jamaican Lithostratigraphy

by Simon Mitchell

The Commision on Jamaican Lithostratigraphy is chaired by Dr. Simon Mitchell and is run under the auspices of the Geological Society of Jamaica. The aim of the commission is to develop a usable lithostratigraphic scheme for Jamaica with unambiguous, well-defined units that meet international guidelines. Wherever possible previously used, well-established names will be retained.

Although numerous 'lithostratigraphic units' have been erected in Jamaica, many of these were either erected prior to the establishment of international guidelines, or have been subsequently erected without regard to such international guidelines. Some of the more significant problems associated with Jamaican lithostratigraphic units are as follows.

1. Individual formations has not been adequately defined, particularly their relationship with other formations.

2. Formations are based on biostratigraphic criteria. This is particularly the case with the Tertiary limestones where formational names are used for biostratigraphic divisions.

3. Type localities are not formally defined.

4. Graphic logs of sections at the type localities (or other sections) are not available or are too generalised for subsequent use.

5. Names are invariably introduced informally, and are never given formal definitions.

The aim of the commission is to address these points. It is anticipated that the role of the commission should be:

1. To formalise, where possible, names that are poorly defined, but which can be modified to have a sound lithostratigraphic base.

2. To investigate particular areas of Jamaica where there are serious problems with the lithostratigraphy. This will be attempted by setting up working groups and field mapping by individuals or groups (e.g., university undergraduate students).

3. To publish regular updates on the progress of refining Jamaican lithostratigraphy.

4. To produce an extensive bibliographic index to lithostratigraphic names used in Jamaica and their validity.

5. To define type localities (were necessary) and produce graphic logs for sections at type localities for all formal lithostratigraphic units.

It is anticipated that the final results of the commission should be published as a 'working nomenclature for Jamaican lithostratigraphy'. As with any scheme, such a publication is expected to be tested and not remain as a bible to Jamaican lithostratigraphy that is beyond reproach.

The following working groups are provisionally suggested.

1. Quaternary Sediments
2. Coastal Group
3. White Limestone
4. Yellow Limestone
5. Wagwater Belt
6. Blue Mountains
7. John Crow Belt
8. Central Inlier
9. St James Inliers
10. Minor Inliers

Membership of working groups is open to anyone with an interest in Jamaican lithostratigraphy. Working groups will work on a semiformal basis and publish progress reports and recommendations.

For more information contact: Dr. Simon Mitchell, Department of Geography and Geology, University of the West Indies, Mona, Kingston 7, JAMAICA. [email smitchell@cwjamaica.com]