Editing Geography of Tuvalu (section)

===Structure of Funafuti atoll===
[[File:Funafuti bearbeitet.jpg|thumb|right|250px|Funafuti atoll]]

[[Funafuti]] [[atoll]] consists of a narrow sweep of land between {{convert|20|and|400|m|0|abbr=off}} wide, encircling a large lagoon (''Te Namo'') of about {{convert|18|km|0|abbr=in}} long and {{convert|14|km|0|abbr=in}} wide. The average depth in the Funafuti lagoon is about {{convert|20|fathom|m ft|abbr=off}}.<ref name="AC1">{{cite book |last=Coates|first=A. | title= Western Pacific Islands |year= 1970 |publisher= H.M.S.O.|pages=349}}</ref> With a surface of {{convert|275|km²|1|abbr=out}}, it is by far the largest lagoon in Tuvalu. The northern part of the lagoon has a deep basin (maximum depth recorded of 54.7 m) basin, and the southern part of the lagoon has very narrow shallow basin.<ref name="SOPAC"/> The land area of the 33 islets aggregates to {{convert|2.4|km²|1|abbr=out}}, less than one percent of the total area of the atoll.

The boreholes on [[Fongafale]] islet at the site now called ''Darwin's Drill'',<ref name="PDN">{{cite book |last1=Lal |first1=Andrick |title=South Pacific Sea Level & Climate Monitoring Project – Funafuti atoll |url=http://www.pacificdisaster.net/oip/FinalReport/Annex/3_Survey%20LDP/Survey_Diagrams_JPACE-TV.pdf |archive-url=https://web.archive.org/web/20140203011855/http://www.pacificdisaster.net/oip/FinalReport/Annex/3_Survey%20LDP/Survey_Diagrams_JPACE-TV.pdf |url-status=dead |archive-date=3 February 2014 |publisher=SPC Applied Geoscience and Technology Division (SOPAC Division of SPC) |pages=35 & 40}}</ref> are the result of drilling conducted by the [[Royal Society of London]] for the purpose of investigating the [[formation of coral reefs]] to determine whether traces of shallow water organisms could be found at depth in the [[coral]] of Pacific atolls. This investigation followed the work on [[The Structure and Distribution of Coral Reefs]] conducted by [[Charles Darwin]] in the Pacific. Drilling occurred in 1896, 1897 and 1898.<ref>{{cite news |url=http://nla.gov.au/nla.news-article17092086 |title=TO THE EDITOR OF THE HERALD |newspaper=[[The Sydney Morning Herald]] |date=11 September 1934 |access-date=20 June 2012 |page=6 |publisher=National Library of Australia}}</ref> Professor [[Edgeworth David]] of the [[University of Sydney]] was a member of the 1896 "Funafuti Coral Reef Boring Expedition of the Royal Society", under [[William Johnson Sollas|Professor William Sollas]] and lead the expedition in 1897.<ref>David, Mrs Edgeworth, ''Funafuti or Three Months on a Coral Atoll: an unscientific account of a scientific expedition'', London: John Murray, 1899</ref> However, the geologic history of atolls is more complex than Darwin (1842) and Davis (1928)<ref name="WMD1">{{cite journal| last = Davis, W.M. |title= The coral reef problem | journal = American Geographical Society Special Publication | volume = 9| issue = | pages = 1–596|date = 1928}}</ref> envisioned.<ref name="DRS">{{cite journal| last = Stoddart, D. R.|title= Theory and Reality: The Success and Failure of the Deductive Method in Coral Reef Studies–Darwin to Davis| journal = Earth Sciences History | volume = 13| issue =1 | pages = 21–34|date = 1994|doi= 10.17704/eshi.13.1.wp354u3281532021}}</ref><ref name="WRD">{{cite journal|last1= Dickinson |first1=William R. |title= Pacific Atoll Living: How Long Already and Until When?|url= https://www.geosociety.org/gsatoday/archive/19/3/pdf/i1052-5173-19-3-4.pdf|year= 2009 |journal= GSA Today |volume=19|issue=3|pages=4–10 |doi= 10.1130/GSATG35A.1 }}</ref> The survey of the atoll published in 1970 described its structure as being:

{{cquote| “[[Funafuti]] is an almost circular and conical submarine mountain 12,000 feet high, originally volcanic, and of immense geological age, much older than the relatively young and active mountains of the [[Vanuatu|New Hebrides]] and [[Solomon Islands|Solomons]]. At its base on the ocean bed it is 30 miles wide in one of the directions tested, and 28 miles wide on the other. It rises in a gentle slope which gradually steepens to a point 2,400 feet below water level, after which it rises at an angle of 80 degrees to 840 feet below water level. From this point it rises vertically, like an enormous pillar, till reaches the surface in the form of a reef enclosing a lagoon of irregular size, but of which the extremities give a measurement of 13.5 by 10.0 miles".<ref name="AC1"/>}}