Tropical islands - phosphate rock/TITLE></HEAD>
<H1>Geology - phosphate rock</H1>
A very special type of rock occurring on oceanic islands in the tropical belt are phosphate rocks. I became acquainted with phosphate rocks when working on my thesis concerning the geology and mining history of the phosphate rocks of the
southern Netherlands West Indies. An introduction to my thesis
(and information on how to obtain it) is available
<A HREF="c111.html">here</A>.
<P>
<IMG ALIGN="left" WIDTH=120 SRC="hpgif/beach2.gif">
It is interesting to realise that originally untreated guano and simply
ground phosphate rock were used as fertilizers. This guano was found
on small, tropical, oceanic islands such as Nauru and Curacao.
The first type of phosphate to be 'mined' (or rather: harvested) on tropical islands was
guano, or leached bird droppings.
<A HREF="http://geowww.gcn.uoknor.edu/www/ascension/BOATBIRD.HTM" TARGET="_new">Boatswain Bird
Island</A>, near Ascension Island in the south Atlantic, is a nice example of a site where bird
guano may accumulate: isolated, in waters teaming with fish and therefore a good place for bird colonies
to settle.
<P>
<A HREF="http://gurukul.ucc.american.edu/ted/GUANO.HTM" TARGET="_new">This site</A> summarizes
the guano trade as it started in the 19th century.
<P>
Guano is still 'mined' and used as a
<A HREF="http://www.homeharvest.com/guano.html" TARGET="_new">natural fertilizer</A>.
<P>
The history of Ocean Island or
<A HREF="http://www.ion.com.au/~banaban/histovie.htm" TARGET="_new">Banaba </A>,
situated in the Pacific Ocean,
is closely related to the insular phosphate rocks
which were exploited there. Before phosphate mining began, the island
was a
<A HREF="http://www.ion.com.au/~banaban/pmining.htm" TARGET="_new">tropical heaven </A>, which changed
when the
<A HREF="http://www.ion.com.au/~banaban/phosph.htm" TARGET="_new">Ocean Island phosphorites </A>
were mined and shipped, leaving a barren coral surface.
<P>
<P>
<IMG ALIGN="right" WIDTH="60%" SRC="hpgif/ckar1.jpg">A similar environmental devastation occurred on Curacao. Over there, part of one
of the islands coastal terraces consisted of limestone pinnacles, with
rubble phosphate in between. This 'rubble phosphate' was mined out during the first decades of this
century. This was done by simply shoveling it out
by hand, as is beatifully seen on this picture on the left.
<P>
This picture was taken in about 1930 by Dr Wagenaar Hummelinck, who courteously put much of his
original observations and unique pictures on the Netherlands Antilles
phosphate rocks at my disposal.
<P>
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c010/updated 2004-12-24
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