[Coral-List] Comment on Atoll formation

Ulf Erlingsson ceo at lindorm.com
Thu Sep 30 09:26:06 EDT 2010

I took a look at that paper and note that he has a VERY generic sea  
level curve, referenced to Clark et al (2004) which I don't have  
access to. However, the 2004 article deals with the sudden sea level  
rise at 19000 before present, not a Holocene maximum. Dickinson  
SHOULD have made reference to an article that explicitly investigated  
the Holocene sea level ATA THAT SITE. As it stands, the conclusion  
rests on loose sand. It could equally well be wrong as right.

On 2010-09-29, at 17:40, Lescinsky, Halard L wrote:

> I'd suggest that Ulf, and others who think that most inhabited  
> coral cays are simply the result of incremental build-up of storm  
> debris, should take a look at the recent paper by William Dickinson  
> (2009, GSA Today 4-10; http://www.geosociety.org/gsatoday/archive/ 
> 19/3/pdf/i1052-5173-19-3-4.pdf ).  A take home message of  
> Dickinson's work is that inhabited cays are generally stabilized or  
> "pinned" by reef deposits that formed during the Mid-Holocene  
> Highstand 4,000 years ago when sea level was a couple meters higher  
> than it is today.  The islands, therefore, owe their existence to  
> exposure and cementation of carbonate during sea-level fall, NOT  
> keep-up style carbonate accretion.  When rising sea-level floods  
> the islands in the near future they will again become  
> uninhabitable, as in fact they were until about 1500 years ago when  
> falling sea-level first exposed them and allowed for their  
> colonization.  ---  Hal Lescinsky
> -----Original Message-----
> From: coral-list-bounces at coral.aoml.noaa.gov [mailto:coral-list- 
> bounces at coral.aoml.noaa.gov] On Behalf Of Ulf Erlingsson
> Sent: Wednesday, September 29, 2010 10:13 AM
> To: coral-list at coral.aoml.noaa.gov
> Subject: Re: [Coral-List] Fw: Chagos MPA - Continuing international  
> dispute overboundaries
> Let me point out that the argument that atolls will sink due to sea
> level rise due to global warming fails to take into account the
> geomorphological mechanisms by which atolls are created and grow.
> They grow, slowly, through coral reef growth (as should be no news to
> anyone on this list), through littoral processes, and through
> chemical precipitation, i.e., when the water gets supersaturated with
> respect to CaCO2 the calcium is precipitated in layers on ooid sand
> grains, eventually building up large land masses such as the Bahamas.
> The problem is only when the sea level rises quicker than these
> processes can keep up with. However, the predicted rise in sea level
> is much smaller than the quickest and largest sea level rise in the
> recent past. See http://erlingsson.com/authorship/CIS2GOM.html
> Of course, that event did drown large areas that are now sea floor,
> but others managed to remain above water. A question of interest is,
> naturally, what lessons we can learn from that event.
> Ulf
> On 2010-09-28, at 22:41, Douglas Fenner wrote:
>> But those same atolls may not be
>>  inhabited much longer, due to sea level rise.
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
> http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
> http://coral.aoml.noaa.gov/mailman/listinfo/coral-list

More information about the Coral-List mailing list