Bali Workshop Announcement

Paul Blanchon blanchon at
Mon Sep 25 14:31:28 EDT 2000

Invitation to attend and participate in:

A Virtual Reef-Core Workshop
9th International Coral Reef Symposium, Bali, Indonesia 23-27 Oct 2000
Evening of Tues 24th. Room TBA
Convenor: Paul Blanchon, UNAM.

Over the last decade the use of coral-reef sequences to study climate 
variability during the Quaternary has increased significantly. In 
some classic areas, like Barbados and the Huon Peninsula, rapid 
neotectonic uplift has elevated reef sequences and allowed important 
discoveries to be made about the link between the Earth's orbital 
parameters and the timing of climate oscillations. But the very 
process that makes these records accessible--uplift--also creates 
uncertainty in determining the rate and magnitude of such changes, 
especially in the case of sea level. As a consequence, many 
investigators interested in climate change have now started to 
examine reef sequences in more stable areas that are below sea-level.

The recovery of these submerged records commonly requires a major 
drilling operation because alternations of coral, rubble and sand can 
make downhole conditions difficult for portable rigs which can only 
handle short, small-diameter cores. The problem with large rigs, 
however, is that they restrict operations to accessible areas on the 
reef crest, which makes it difficult to recover of a complete record 
when a reef has undergone retro- or progradation during its 
development. Once a complete record is recovered, however, the next 
problem is obtaining an accurate description and interpretation of 
the complex textures and fabrics found in reef facies. This 
complexity can be severe. Even in outcrop, coral reef sequences are 
an intricate mosaic of corals and sediment that have been encrusted 
and bioeroded: they commonly bear little resemblance to the surface 
zonations we find covering modern reefs. In core, such complexities 
are magnified ten-fold and even distinguishing in-place coral from 
biodetritus can be impossible in some cases.

Workshop Objectives
This Virtual Reef-Core Workshop is a forum in which to discuss not 
only new and improved drilling methods but also how to improve the 
scientific description and analysis of reef deposits from core data. 
Participants will be asked to bring high-resolution, full size images 
of reef cores that have been assembled so as to represent a 'virtual' 
core. (A good way to do this is to scan sliced pieces of core into an 
illustration program and print on a photo-quality printer. Each core 
section can then be taped together and fan-folded). By collectively 
examining these virtual reef cores, we hope to:

1) familiarize ourselves with the often complex fabrics and textures 
of reef facies and see how they compare/contrast with the modern 
surface assemblages:

2) incite some constructive discussion on how to schematically 
represent the biosedimentology of the cores in an efficient and 
objective way:

3) establish some possible ways of identifying (and even quantifying) 
in-place framework from biodetrital deposits.

At regular intervals during the workshop, we will try to arrange 
brief presentations on specific drilling methodologies, hopefully 
including advances in technology and techniques.

Contributions to date

 Dennis Hubbard (Oberlin College). Virtual Core from St. Croix 
and/or Puerto Rico

 Dennis Hubbard. Video/slide show on the SCARID underwater drilling system

 Paul Blanchon (National Autonomous U. Mexico). Short cores from the 
crest of an early Holocene relict reef discovered recently off the 
east coast of Grand Cayman.

 Paul Blanchon. Informal poster on classification of reef deposits.

 Zelinda Leão (U. Federal da Bahia). Core from a reef flat in the 
Abrolhos Region, Eastern Brazil (southernmost coral reefs in Western 
Atlantic). Core is ~13 meters long and reaches Pleistocene basement. 
This reef is surrounded by siliciclastic sediments and its major 
reef-building corals are endemic forms from Brazil.

 Keiichi Sasaki (Kanazawa U.). Cores from Kikai Island Reefs, Ryukyus.

 Ian Macintyre (Smithsonian). Cores that show development of 
pavement limestone. It forms when there is a hiatus in reef accretion 
and is due to multicyclic boring and inflilling which tend to destroy 
all evidence of the original skeletal framework.

 David Blakeway (U. Western Australia). Core from Ningaloo Reef.

 David Kennedy (U. Wollongong). Virtual cores from Middleton Reef, 
Elizabeth Reef and fringing reefs in the Torres Strait.

Further contributions are welcome: for details email me at 
blanchon at

Dr. Paul Blanchon | Investigador

Coral-Reef Systems Lab.
Unidad Academica Pto. Morelos
Inst. de Ciencias del Mar y Limnologia (ICML)
Universidad Nacional Autonoma de Mexico (UNAM)
Ap. Postal 1152, CP 77500 Cancún,

Tel. (987) 10219,  Fax: (987) 10138
Work E-mail: blanchon at
Home E-mail: blanchon_s at
National Autonomous University of Mexico, 1553-2000
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