Geoconservation in the Overseas Territories of the UK

UK Overseas Territories and Crown Dependencies Training and Research Programme

JNCC Research Contribution Project Report

Geoconservation in the Overseas Territories of the UK

2009

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Geoconservation in the

Overseas Territories of

the UK

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Acknowledgements

This report was commisioned by the Joint Nature Conservation Committee to helpimprove our understanding of the geological importance and diversity of the UKOverseas Territories. A further aim was to broadly review the geoconservationactivity being carried out there, and identify any particularly significant threats toimportant geological features. The project was managed by Neil Ellis for JNCC.

Grateful thanks is afforded to all those who provided information that helped createthe present document, in particular:

British Indian Ocean Territory: Joanne Yeadon; Anguilla: Karim Hodge; Bermuda:Jack Ward; British Virgin Islands: Bertrand Lettsome; Cayman Islands: GinaEbanks-Petrie; Gibraltar: Albert Bruzon; Montserrat: Gerard Gray; Turks and CaicosIslands: Wesley Clerveaux; Pitcairn Islands: Jay Warren; St. Helena: Isabel Peters;Tristan da Cunha: James Glass; Ascension Island: Susanna Musick; FalklandsHelen Otley; South Georgia and South Sandwich Islands: Darren Christie; BritishAntarctic Territory, Kevin Hughes.

JNCC is also grateful tor all those who supplied photographs – each of which is individually acknowledged – which clearly demonstrate the diverse natural heritageof the Overseas Territories.

M. Stanley

Geodiversity Consulting, Park House, 8 King Street, Ripon,North Yorkshire, HG4 1PJ, UK

2009

Overseas Territories

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Introduction

The Joint Nature Conservation Committee (JNCC)is the statutory adviser to Government on UK andinternational nature conservation.

JNCC has an Overseas Territories and CrownDependencies programme which aims to giveadvice and support to UK, Overseas Territory andCrown Dependency governments on nature conservation.

The present desk-based study was commissionedin 2009 to provide information specifically on thegeo logical and geomorphological features of theOverseas Territories (OTs).

The OTs were introduced by an Act of BritishParliament in 2002. They were previously knownas ‘British-Dependent Territories’, and before that,‘Crown Colonies’. The OTs range across theglobe from Anguilla in the Caribbean to BritishAntarctic Territory to the Pitcairn Islands in thePacific Ocean. The territories of Jersey,Guernsey, and the Isle of Man, though under thesovereignty of the British Crown, have a slightlydifferent constitutional relationship, they areclassed as Crown Dependencies, and are not thesubject of this study.

The study provides a simple summary of the geo-

diversity features that are of special conservationvalue. ‘Geodiversity’ is the abiotic parallel of bio-diversity. It is the variety of rocks, minerals, fos-sils, landforms, sediments and soils on Earth andit encompasses the natural processes which formand alter them. Geoconservation is the activityconcerned with protecting, and where possible,enhancing and promoting geodiversity.

For the study, contacts were made in each territoryto find out what specific geoconservation activityexists; and whether there were other conservationprogrammes that could embrace geodiversity.

For each territory, a list of geoconservation sites(where they exist) including national and interna-tional designations, geoparks, World Heritagesites, and other protected sites that encompassgeology and landscape is provided. There is alsoa summary of the major threats and ‘environmen-tal pressures’ potentially affecting the sites andareas, and existing, or opportunities for, geo -tourism and relevant web links to relevant sourcesof inform ation.

World Heritage SitesIn the 14 OTs there are three World Heritage sites:

at the historic town of St George and its fortifications in Bermuda, Henderson Island(Pitcairn Islands), and Gough and InaccessibleIslands (Tristan de Cunha). The historic and natural environment of St. Helena may be addedto the World Heritage Tentative List for inclusion infuture years.

Henderson Island, part of the Pitcairn group, is afossilized raised coral atoll sitting on a volcanicisland with the nearest land mass, New Zealand,some 4 800 km away. The Pitcairn Islands areyoung at 0.8 to 0.9 million years old, but the weightof its volcanic material depressed the crust andlithospheric flexure uplifted Henderson Island, 200km from Pitcairn Island itself. The 380 000 year lifthas produced a dry, fossil lagoon with corals in situsome 33 m above sea level.

Gough and Inaccessible Islands are part of theTristan da Cunha group in the South Atlantic.Gough Island is the summit of a Tertiary-aged volcano with dramatic, steep sea cliffs, andInaccessible Island, a 2–3 million year old erodedremnant of an extinct shield volcano, not surpris-ingly (from its name) has quite inaccessible cliffs.

GeodiversityThe geodiversity seen across the OTs is spec -tacular with a range of superbly exposed featuresincluding the stages in the evolution of an activeplate margin and marine basin with remnants of anancient volcanic arc in South Georgia and theSouth Sandwich Islands.

On Montserrat the Soufrière Hills volcano killed 19people on 25 June 1997 in a pyroclastic eruptionwhich went on to destroy the capital Plymouth inAugust of that year. The eruption caused half ofthe island to be evacuated and much will remainuninhabitable for decades.

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Sandy Bay, St. Helena, which may be added to theWorld Heritage List in the future. (Photo: Ashley Leo.)

Anegada, geologically distinct from the rest of theBritish Virgin Islands, is flat and composed of lime-stone and coral with white sand beaches and thelong Horseshoe Reef, the largest in the Caribbeanand the second largest in the world.

Darwin’s geologyIn this Darwin anniversary year (2009), his Beaglevoyage is remembered in the OTs of the SouthAtlantic Ocean. He recognized that deposits fillingthe central depression in the Devil’s Riding Schoolon Ascension were formed in a lake suggestingthat the climate was substantially wetter in thepast. St. Helena boasts snail fossils of evolution-ary significance; they were found at the base ofFlagstaff Hill and were studied by Darwin. Darwinalso collected brachiopods, crinoids and trilobitesfrom the Fox Bay Formation sandstones in themiddle of the West Falkland Group. On Falklandhe also recorded the periglacial landforms wheresolifluction has smoothed slopes and formedstone-runs, but left rock outcrops unaffected.These stone-runs are unique, spectacular and dis-tinctive with delicate environments occurring invalley bottoms and on slopes as alternate strips ofboulders and sparse vegetation. Darwin calledthem ‘streams of stones’.

Geodiversity controlling biodiversity and land-useOn Anguilla, in the Caribbean, there are 25 saltponds scattered throughout the island, in the pastthese have supported a thriving salt industry, andnow prevent the flooding of roads, farms, busi-nesses, and homes by providing a place forexcess rainfall to be absorbed and held. Theyalso protect fragile and sensitive coral reefs andseagrass beds by catching, holding, and filteringfresh water before it can reach them.

There are no streams on the Cayman Islandsbecause of the limestone bedrock, the absence ofsediment run-off gives clear waters making theCaymans one of the most popular snorkelling and

diving areas in the world.

All of the islands in the Turks and Caicos Islandshave caves and those on Middle Caicos form thelargest cave network in the archipelago, especial-ly Conch Bar Caves with the largest sub-aerialcave system in the Caribbean. It is a national parkwith significant human history from the pre-Columbian past. Grand Turk has an extensive,pristine barrier reef system 200 m from shore,shallow depressions called ‘Salinas’ in the lime-stone contain heavily-alkaline salt water that sea-sonally evaporates, depositing gypsum, calciumcarbonate, and sea salts. These Salinas attractedseasonal salt rakers from Bermuda in the 17thcentury who settled and formed the basis of thesalt industry which lasted into the mid-20th century.

Environmental pressureParticular environmental pressures include coastaldevelopment. Geological features and ‘type sec-tions’, benchmark reference points for geologists,which are described in technical papers datingback over 100 years are under threat from coastalprotection measures, from excavations, and fromshotcrete used to re-enforce rock faces.

In Bermuda, limestone quarrying, water pollution,waste dumping, littering, and vandalism ofspeleothems and other cave deposits continue tothreaten the unique cave resources.

In Gibraltar the greatest pressure is on Quaternarysediments as urban development has been dra-matic since the early 20th century and continuesapace. All major reclamation projects includingthe extension of the dockyards between1895–1900 and the extension of the airfield in1942 used scree breccias, but sea-dredged sandwas used to infill part of the northern harbour areaand to build high-rise housing and office develop-ments.

Indian Ocean

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Clear waters surround the Cayman Islands making ita popular snorkelling and diving destination. (Photo:Nickki Chapman.)

Soufrière Hills on Montserrat. (Photo: Tara Pelembe.)


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Grand Cayman has more than 900 000 visitors ayear who come for water sports and leisure, put-ting pressure on the cave systems, but touriststhere visit Hell to see the dark-grey to black phytokarst, a landform of the limestone formationsproduced by boring plant filaments, with sharp,jagged surfaces and razor edges. Geotourism isnot always inconsistent with geoconservation,depending on the resilience of the resource, andwhether rates of erosion are accelerated byhuman activity.

In Antarctica the Mount Flora SSSI, designated forits rich fossil flora, was one of the first discoveredin Antarctica and could be vulnerable to souvenirfossil collectors and merits protection.

Geoconservation activitiesGeoconservation activities are few in number inthe OTs, but worthy of mention is the multi -disciplinary Bermuda Cave and Karst InformationSystem (BeCKIS) project, established in 2002 withprofessionals and volunteers working to produce acommon GIS database. This includes cave maps,water quality information, potential threats, livingand fossil species distributions, palaeontologicalexcavations of the talus cone in Admiral’s Caveand dating and analysis of stalagmites.

The Ascension Environmental InformationOperations Utility (AEIOU) project will synthesizeexisting information from land jurisdiction, environ-mental mapping and monitoring, and geologicaland cultural data with new land-cover data into asingle manageable framework. Resulting mapswill provide the means to implement the plan forGreen Mountain. This has the opportunity to pro-mote and include geoconservation into the GreenMountain National Park.

Also in the Atlantic Ocean, St. Helena’sEnvironment Charter’s Guiding Principles andCommitments broadly supports geoconservationand within the Strategy for Action there are actionsand programmes specifically related to conservation of geodiversity features and theissues surrounding that activity.

The whole of Antarctica is designated as a naturalreserve devoted to peace and science by theAntarctic Treaty’s Protocol on EnvironmentalProtection. There are certain areas given evengreater protection through the protocol’s system ofprotected and managed areas with 70 AntarcticSpecially Protected Areas (ASPAs, formerlySSSIs), five Antarctic Specially Managed Areas(ASMAs) and over 80 Historic Sites andMonuments (HSMs).

The OTs are geodiversity rich, perhaps surprisingly so, as they cover such a small area ofthe Earth’s crust. They certianly do however showthe link between the natural, cultural heritage andlandscape of these former Crown colonies.

Indian Ocean

British Indian OceanTerritory (BIOT)

IntroductionThe islands and reefs of the Chagos Archipelagoform the part of the Laccadives–Chagos Ridgethat runs north to south in the middle of the IndianOcean. There are five atolls at Chagos: Bank,Peros Banhos, Salomon, Egmont and the largestatoll in the world at Diego Garcia. There are tenreefs and submerged shoals including BlenheimReef, Speakers Bank, Pitt Bank and CenturianBank. The islands, 1000 in total, cover an area ofaround 60 km2, but the area of near-surface coralreefs is 4000 km2 representing 1.5% of the globalarea of reefs. The terrain is flat and low, with mostareas not more than 2 m above sea level. The climate is tropical marine, hot and humid andswept by trade winds. The only inhabitants are onDiego Garcia and the BIOT is a protected area.

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Diego Garcia, British Indian Ocean Territory, thelargest atoll in the world. (Photo: Serendigity, CreativeCommons)

Geoconservation programmes

Existing NoneActivities None

Geoconservation sitesThere is one Ramsar site and seven strict naturereserves.

Environmental pressuresThe main pressure is rising sea level.

Web linkshttp://www.chagos-trust.org/http://www.islandvulnerability.org/otuk.htmlhttp://www.ukotcf.org/territories/biot.htm

North Atlantic Ocean

Anguilla

IntroductionAnguilla is the most northerly of the LeewardIslands in the Lesser Antilles and lies 235 km eastof Puerto Rico and 10 km north of St. Martin. Theterritory consists of the main island, approximately26 km long by 5 km wide, together with 22 small-er islands and cays which have no permanentpopulation. The land area of the territory is 102km² with a population of about 13 500, most livingin Anguilla’s capital The Valley. The name‘Anguilla’ means ‘eel’ and it fits the island’s sinu-ous flat shape with the highest point of 65 m onCrocus Hill. Rainfall is low and the vegetation ismainly small trees and bush. It has a dry and hotclimate with an average temperature of 28°C andthe mean annual rainfall is 1 017 mm. The coast-line has sandy bays in the south and cliffs in thenorth. There are extensive reefs off the northcoast and fringing reefs along most of the southcoast. The 17 km-long reef along the south-eastcoast is considered to be one of the most impor-tant largely unbroken reefs in the easternCaribbean. Anguilla arguably has the best beaches in the Caribbean.

Anguilla and the islands of St. Bartholomew andSt. Martin consist of andesitic tuffs and tuff-brec-cias of Middle and Late Eocene age with intrudedbasalt, andesite, and quartz diorite of a slightlylater date. The tuffs were tilted and faulted by volcanic activity in the Late Eocene and during theOligocene–Miocene periods limestone and marlswere deposited unconformably on the tuffs. Theselimestones cover the island except for two smalloutcrops of tilted tuffs and basalt. Later the

limestones were gently folded and duringPliocene and Pleistocene times the islands wereprobably connected to form one large island. Thearea is now submerged to form the Anguilla–St.Bartholomew Platform. Beyond the island ofSombrero is a very deep channel, the only one ofits kind, dissecting the Antillean chain and cuttingoff the sunken plateau of the Virgin Islands to thewest.

Anguilla has few natural resources, but there are25 salt ponds scattered throughout the island,which in the past supported a thriving salt industry,pictured on postage stamps of the island, but nowabandoned. Salt ponds are able to prevent theflooding of roads, farms, businesses, and homesby providing a place for excess rainfall to beabsorbed and held. They also protect fragile andsensitive coral reefs and seagrass beds by catch-ing, holding, and filtering fresh water before it canreach them. The value of the flood control servic-es (“ecosystem services”) provided by Anguilla’ssalt ponds is estimated at almost EC$3 millionannually.

The topography is characterized by limestonesinkholes or ‘bottoms’ scattered throughout theisland and development has occurred in a few ofthe larger sinkholes including The Valley.


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Northern Anguilla cliffs. (Photo: Anguilla NationalTrust.)


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Fountains Cavern, a large limestone cavern located on a ridge at about 20 m above sea level,is one of 19 Amerindian sites identified and is considered to be the most important archaeo -logical (Pre-Columbian) site on the island. Its historic significance has led the government ofAnguilla to develop a national park with the cavernas the focus, and it has been nominated as aWorld Heritage Site. The cavern has been closedto ensure its protection and is not accessible to thepublic. The cave has various geological formations and a cave lake which the Amerindiansused as a source of fresh water.



Geoconservation sitesThe only site is Fountains Cavern, nominated as aWorld Heritage site, but there are ten nationallyprotected sites. None are specific for geo -conservation.

Environmental pressuresTourism is very important to the economy, andalong with house building, puts pressure on natu-ral resources, but the major pressure comes fromhurricanes, tropical storms and flooding. The low-lying topography and drainage pattern of the sink-holes and salt ponds increases the risk of high-winds, flood damage, coastal erosion and land-slides, all of which affect the geodiversity.

Web linkshttp://gov.ai/doenvironment/http://www.axanationaltrust.org/http://www.wdpa.org/MultiSelect.aspxhttp://www.islandvulnerability.org/otuk.htmlhttp://www.ukotcf.org/territories/anguilla.htm

Bermuda

IntroductionBermuda lies at approximately 32° N, 64° W and900 km (570 miles) from North Carolina, USA. Itis 25 km long, 2.5 km wide with a total land area of53 km2 and has 65 000 inhabitants. It comprises offour main islands and more than 130 smaller reef-protected islands at the southern rim of theBermuda Platform. Land is generally low lyingwith heights over 50 m at a number of locationsand the highest of 76 m on Town Hill, Smiths’Parish.

The characteristic geology of sandy, limestoneaeolianites interlayered with palaeosols (‘fossil’soils) is a result of the cyclical submerging andemerging of the Bermuda Platform during thePleistocene period. The 50 m of limestone rest ona truncated volcanic seamount of basaltic rocksbuilt up in two eruptions between 45 and 33 millionyears ago. The topography consists ofPleistocene wind-blown sand dunes or aeolianitescemented into limestone, locally called ‘Dunerock’with large-scale cross bedding indicative of dunemigration. There are no rivers, but significantreserves of fresh ground water in ‘lenses’ in theyounger limestones that have high inter-granularporosity and relatively low permeability. There areinland marshes and salt water lakes and 179known caves, most located in the narrow strip ofland separating Harrington Sound from CastleHarbour where the Walsingham limestone, theisland’s oldest, is exposed.

Bermuda has one of the highest concentrations ofcaves in the world which are significant with deepanchialine pools, extensive underwater networks,numerous and delicate speleothems, and uniquefauna and flora with 21 currently listed as critically

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New developments being built at Barnes Bay,Anguilla contributing to environmental pressures onthe island. (Photo: Anguilla National Trust.)

Crystal Caves, Bermuda. (Photo: Andy Dobson.)

endangered under the Bermuda ProtectedSpecies Act.

The caves show a large amount of roof collapse,irregular chambers and fissure entrances probablycaused by collapse that occurred when sea levelsfell. Today’s caves are only a fraction of the sizeof the original solutional voids dissolved by fresh-water early in Bermuda’s geological history. Thereare a number of sinkholes, and it is not unusual todiscover caves on the edges of the large collapsedareas. Many caves in Bermuda are beautiful,large and historically important and have beenopened to visitors including Crystal, Island,Cathedral, Admiral’s, Castle Grotto, Leamington,Wonderland, Walsingham, and Tuckers’ IslandCaves. The Devil’s Hole, a collapse cave that wasfirst opened for public exhibition in 1843, is utilizedas a natural fishpond. Blue Grotto, another water-filled collapse cave, was recently the site of traineddolphin shows. Prospero’s Cave previouslyknown as ‘Island Cave’ contains an undergroundbar and discotheque. The caves and speleothemsare thought to be at least 200 000 years old.


Existing NoneActivities The multidisciplinary BermudaCave and Karst Information System (BeCKIS)project was established in 2002 with professionalsand volunteers working to produce a common GISdatabase. This includes cave maps, water qualityinformation, potential threats, living and fossilspecies distributions, paleontological excavationsof the talus cone in Admiral’s Cave and dating andanalysis of stalagmites.

Geoconservation sitesThere is one World Heritage site, the historic townof St. George and its related fortifications, sevenRamsar sites and 135 nationally protected siteslisted by UNESCO and WDPA respectively. TheWorld Heritage site has great potential for geo-conservation and along with some of the thenational sites, but the caves are not listed as such.Bermuda has a well-developed system of parksthat serve to protect natural features both biologi-cal and geological. For example a large section ofthe south shore of Bermuda including many of thesignature beaches and coastal dunes are in theparks system and are protected.

Environmental pressuresEscalating development, filling for constructionprojects, limestone quarrying, water pollution,waste dumping, littering, and vandalism ofspeleothems and other cave deposits continue to

threaten the unique cave resources. Geologicalfeatures and ‘type sections’ which are described intechnical papers dating back over 100 years areunder threat from coastal protection measures,from excavations, and from methods (such asshotcrete) used to re-inforce rock faces. Similarly,modern geological features such as beaches anddunes are being modified by private landowners.

Web linkshttp://www.bnt.bm/http://www.tamug.edu/cavebiology/BeCKIS/Intro.htmlhttp://www.wdpa.org/MultiSelect.aspxhttp://www.islandvulnerability.org/otuk.htmlhttp://whc.unesco.org/en/list/983www.bamz.orgwww.biodiversityactionplan.bmwww.bnt.bmhttp://www.ukotcf.org/territories/bermuda.htm

British Virgin Islands(BVI)

IntroductionThe British Virgin Islands comprise of 60 semi-tropical islands with four large islands, Tortola,Virgin Gorda, Anegada and Jost Van Dyke. Theislands are part of the Virgin Islands archipelago inthe Leeward Islands in the Caribbean Sea at theeastern extremity of the Greater Antilles and aretopographic highs on the Puerto Rico Bank, a sub-merged platform on the Puerto Rico–Virgin Islandsmicroplate located between the Caribbean andNorth American plates.

The islands are composed of Mesozoic and LowerTertiary deformed island-arc rocks and underlainby the Virgin Gorda granite batholith intruded in


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Paget Marsh, Bermuda, is a peat marsh covered witha cedar and palmetto forest. (Photo: Andy Dobson.)


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Mid to Late Eocene times. Weathered exposuresin tonalitic rocks at the south end of Virgin Gordagives huge boulders on beaches created as ‘tors’due to the classic deep weathering of graniticrocks along joints. The removal of the weatheredmaterial has produced spectacular boulder-strewnbeaches on the south-west coast of Virgin Gordaand at Fallen and Broken Jerusalem. Spring BayNational Park and The Baths National Park, two of17 managed by the BVI National Parks Trust, aretourist sites with salt water pools at the base of thetor boulders that are up to 4 m high and 15 m indiameter. Anegada is geologically distinct fromthe rest of the group and is a flat island composedof limestone and coral with white sand beachesand the long Horseshoe Reef, the largest in theCaribbean and the second largest in the world.Anchoring on Horseshoe Reef is illegal.



Geoconservation sitesThere are 46 protected areas and the BVI NationalParks Trust currently manages 17 national parksincluding 16 terrestrial parks and one marine park,the wreck of the Rhone. None are specificallygeological but geodiversity features in two:

• The Baths National Park, declared in 1990, fea-tures giant boulders forming a cave with a sandbottom pool in one area, which is one of themost photographed spots and more than 50%of the visitors to the BVI visit The Baths.

• Spring Bay National Park, declared in 1974, isto the east of The Baths and has giant boulders,but more-open beach.

Environmental pressuresThe UK Overseas Territories Conservation Forum(UKOTCF) notes that development of marinasalong the coastal areas has been an on-goingissue in the territory. Mangroves and sea grassbeds are destroyed and reefs are smothered tomake way for the tourism-related infrastructure asdevelopment continues to compete with the envi-ronment on which it is based. The BVI govern-ment has made anchoring on Horseshoe Reef illegal in an attempt to protect the reef.

Web linkswww.bvinationalparkstrust.orgwww.bvidef.orghttp://www.ukotcf.org/territories/bvi.htmhttp://www.islandvulnerability.org/otuk.html

Cayman Islands

IntroductionThe Cayman Islands, in the western Caribbean tothe north-west of Jamaica, comprise of threeislands, Grand Cayman, Cayman Brac, and LittleCayman representing uplifted fault blocks formedat the margin of the North American andCaribbean plates. The islands are part of theCayman Ridge, stretching from south-east Cuba,through the Gulf of Honduras to the MisteriosaBank near Belize, which forms the northern mar-gin of the 5 000 m deep and 250 km wide CaymanTrough.

The island’s bedrock is granodiorite with basaltcovered by the Mid-Tertiary Bluff Group limestoneand dolostones, and fringed unconformably bypoorly lithified Pleistocene Ironshore formations,and recent carbonate sediments. CaymanFormation limestones from the Miocene age canbe found on Grand Cayman and Cayman Brac

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Horseshoe Reef off Anegada in the British VirginIslands, the second largest reef in the world. (Photo:BVI National Trust.)

‘Tor’ boulders on the beach. (Photo: BVI NationalTrust.)


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and there are extensive cave systems at BoddenTown and Pollard Bay respectively. Many of thecaves have a range of speleothems deposits, e.g.stalactites, stalagmites, pisoliths and calcite rafts,some are filled or partly filled with a banded, multi-coloured, hard, crystalline dolostone calledCaymanite, which is used to make jewellery.Caves are rare in the Pliocene Pedro CastleFormation and absent from the IronshoreFormation on both main islands.

Phytokarst, dark grey to black with sharp, jaggedsurfaces and razor edges, produced by boringplant filaments is a landform of all of the limestoneformations and is best known at Hell on GrandCayman. Fossil mould cavities caused throughthe dissolution of aragonitic skeletons of corals,gastropods and bivalves, are common in the lime-stones which have also been dolomitized to vary-ing degrees. The islands have narrow insularshelves supporting prolific coral reef. There areno streams due to the limestones and the absenceof sediment runoff gives clear waters making theCaymans one of the most popular snorkeling anddiving areas in the world.



Geoconservation sitesThere is one Ramsar site, 48 protected areasranging from marine parks through to grouperspawning sites to reserves, replenishment and nodiving zones, and a botanic park, but no geo -diversity sites as such.

Environmental pressuresShallow lagoon bedrock facies of the shore zoneof the North Sound in the 1990s was dredged tosupply marl for the reclamation of swampland.There are more than 900 000 visitors a year whocome to Grand Cayman for water sports andleisure putting pressure on the cave systems.Geotourists visit Hell to see the black phytokarst.

Web linkshttp://www.islandvulnerability.org/otuk.htmlhttp://www.ukotcf.org/territories/cayman.htm

Gibraltar

IntroductionThe Rock of Gibraltar is a 398 m monolithic lime-stone klippe. This eroded remnant of a nappe islate Cenozoic in age and is part of the Gibraltar arcformed when the Betic Mountains of southernSpain and the Rif mountains of northern Moroccowere created from the collision of the African andEuropean plates. Eroded wave-cut platforms arewidespread at different levels (at least eightmarine abrasions), scree breccias, raised beachesand caves are apparent. Marine abrasions areprominent at the Plateau of Europa Flats at 30–40m above sea level, and Windmill Hill at 90–130 mabove sea level. This evidence and the sheernorth face of the Rock and boreholes showingconsiderable thicknesses of marine sands andclays beneath the surface of the isthmus provethat Gibraltar once was an island separated fromthe Spanish mainland.

The main ridge is massive Gibraltar Limestonedipping west at high angles, and underlain byyounger Catalan Bay Shale to the north-east andeast and overlain with older shale to the west. TheGreat Main Fault zone trends north-west to south-east from the Dockyard South Gate to Hole-In-the-Wall and separates the east dipping limestone ofthe Southern Plateaux from the main ridge. Thenorth face of the Rock overlooks the Isthmus andwas formed during the Quaternary period along a

Phytokarst specimens at Hell on Grand Cayman.(Photo: James Nicholls, Creative Commons.)

Diving in the clear waters at Little Cayman. (Photo:Nikki Chapman, JNCC.)


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zone of weakness. Shoreline features notch theRock and there are 165 caves. Both the Isthmusand lower slopes of the Rock are covered by thickQuaternary sands and scree breccias, a mixture oflimestone blocks, some several metres across,and beach sands.

Raised beach sands and gravels are widespreadand are metres thick on the eastern side of theSouthern Plateau 80 m above present sea level.The Alameda Sands are wind-blown sands, up to16 m thick, originally spread from the Glacis andsouth towards North Pavilion are the remnants ofa capping scree on the western side of the Rock.Recent Catalan Sands, truncated cross-beddedunits occur at the foot of the east coast and lieabove a raised beach at about 8 m above sealevel. Isthmus aeolian sands are exposed onWestern Beach the only strip of land that remainsof the Isthmus as Gibraltar airport covers most ofthe narrow stretch of low lying land standing 3 mabove sea-level, and extending from the northface northwards for 800 m beyond the British linesinto Spain.



Geoconservation sitesThe entire area of the Upper Rock is a naturereserve, but there are no specific geoconservationsites protected.

Environmental pressuresThe most pressure is on Quaternary sedimentsbeing used for building as urban development hasbeen dramatic since the early 20th century andcontinues apace. All major ‘land reclamation’ projects including the extension of the dockyardsbetween 1895–1900 and the extension of the air-field in 1942 used scree breccias, but sea-dredgedsand was used to infill part of the northern harbourarea and to build high-rise housing and officedevelopments. Limited reclamation has takenplace since 1995.

Web linkshttp://www.parks.it/world/UK/Eindex.html#Gibraltar#Gibraltarhttp://www.islandvulnerability.org/otuk.htmlhttp://www.ukotcf.org/territories/gibraltar.htm

Montserrat

IntroductionMontserrat, is 17 km long and 11 km wide, moun-tainous, with streams and waterfalls in dense trop-ical vegetation and situated in the northern part ofthe Lesser Antilles. It is one of the LeewardIslands and lies 43 km south-west of Antigua and64 km north-west of Guadeloupe. The Antilles is avolcanic island arc formed where the Atlantic

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The Rock of Gibraltar, a 398 m monolithic limestone klippe. (Photo: Allie Caulfield, Creative Commons.)

St. Michael’s Cave, Upper Rock, Gibraltar. (Photo:Allie Caulfield, Creative Commons.)

tectonic plate is subducted beneath the Caribbeanplate. Montserrat, a strato-volcano, is composedof andesitic lavas and volcaniclastic rocks pro-duced by dome-forming eruptions; although theSouth Soufrière Hills are of basalt-andesite com-position.

The main features are the remnants of andesitelava domes; andesitic breccias representing thetalus of previous lava domes; pyroclastic flowdeposits formed by the collapse of lava domes;lahar and debris avalanche deposits; and subordi-nate tephra fall deposits. There are three volcaniccentres of differing age, from oldest (Pleistocene)to youngest (Recent) and north to south are theSilver Hills complex composed of two-pyroxeneandesite lavas and agglomerates; Centre HillsComplex characterized by steep-sided peaks(remnants of Pelean domes) surrounded byaprons of block and ash flow and surge deposits,a distinctive pumice lapilli fall deposit, reworkedequivalents of the pyroclastic deposits as well asmudflow/lahar deposits.

Petrographically it is composed of two-pyroxeneand hornblende-hypersthene andesites; and theactive andesitic volcano of the Soufrière Hills con-sisting of a series of lava domes emplaced alongan ESE-trending zone. Block-and-ash flow andsurge deposits predominate in flank deposits withhydrothermally altered rocks and active fumarolefields, known locally as soufrières. Garibaldi Hilland St. George’s Hill form two smaller, isolatedtopographic highs. Rock exposures are limited tocoastal cliffs, road cuttings, and inland cliffs.

The Soufrière Hills volcano became active for thefirst time in 350 years on 18 July 1995 following athree year period of seismic activity, two yearslater pyroclastic activity killed 19 people and twomonths after that the capital Plymouth was

destroyed. Half of the island was been evacuatedand much will remain uninhabitable for the nextdecade or more. The eruption has been charac-terized by the growth of an andesite lava domewith associated pyroclastic flows, vulcanian explo-sion and debris flows, and there have been fivedistinct phases to the eruption so far. Volcanicactivity has declined since March 1998, but is con-tinuously monitored. Since volcanic activity beganpopulation of the island has declined from about11 000 to 4500.



Geoconservation sitesThere is one national park and 17 other protectedareas, but none specifically for geodiversity,although the Soufrière Hills volcano is a wonderfulopen-air laboratory.

Environmental pressuresNone recognized, but the weather is degrading thenewly erupted rocks and deposits on the Soufrièrevolcano.

Web linkshttp://www.volcano.si.edu/world/region.cfm?rnum=1805http://www.mvo.ms/http://www.islandvulnerability.org/otuk.htmlhttp://www.uwiseismic.com/General.aspx?id=1http://www.ukotcf.org/territories/montserrat.htm


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The Soufrière Hills volcano and in the foreground thecapital city Plymouth, which was devestated by theeruption in 1995. (Photo: Mike Schinkel, CreativeCommons.)

Dense tropical vegetation on mountainous scenery onMontserrat. (Photo: C. McCauley.)


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Turks and CaicosIslands

IntroductionThe Turks and Caicos Islands, part of theBahamian archipelago which is a large carbonateplatform along the subsiding continental margin ofNorth America, are south of the Bahamas andcomprise eight islands and 32 uninhabited cayscovering 430 km2 with a population of 8100.Grand Turk, Providenciales, North, South, West,East and Middle Caicos and Salt Cay are in -habited and lie on the Caicos Bank, a plateau thatrises 2400 m from the ocean floor.

The oldest rock is a Cretaceous fossil reefexposed on West Caicos. The topography is lowand most of the islands are nearly flat with a max-imum height of 63 m. The islands are dominatedby complex ridges of aeolian calcarenite on a platform of Pleistocene marine limestones. Theridges have asymmetric cross-sections, largecross-bedded units and occasional fossil land molluscs and are interpreted as dunerocks. Theolder ridges are highly indurated with extensivepot holes and well-developed lapies.

All of the islands have caves and those on MiddleCaicos form the largest cave network in the archi-pelago, especially Conch Bar Caves with thelargest sub-aerial cave system. It is a nationalpark with significant human history from the pre-Columbian past. The island of Grand Turk has anextensive, pristine barrier reef system 200 m fromshore and there are also shallow depressionscalled ‘Salinas’, in the limestone which containheavily-alkaline salt water that seasonally evapo-rates, depositing gypsum, calcium carbonate, andsea salts. These Salinas attracted seasonal saltrakers from Bermuda in the 17th century who set-tled and formed the basis of the salt industry whichlasted into the mid-20th century.



Geoconservation sitesThere are four national parks, three marine nation-al parks, four land and sea national parks, and tennature reserves, only Conch Bar Caves NationalPark is geological.

Environmental pressuresThe area is susceptible to the usual tourism anddevelopment pressures exerted especially onbeaches which are one of the most dynamic andfast changing parts of the islands’ landscape.

Web linkshttp://www.tcmuseum.org http://www.ukotcf.org/territories/turksCaicos.htmhttp://www.islandvulnerability.org/otuk.htmlhttp://www.environment.tc/

Pacific Ocean

Pitcairn Islands

IntroductionThe Pitcairn Islands are very remote with the near-est land mass, New Zealand, some 4 800 kmaway. The Pitcairn Islands consisting of PitcairnIsland, the only inhabited island; HendersonIsland, the largest; and the two atolls Ducie andOeno, lie at the east end of the Tuamotu chain onthe Pacific tectonic plate. Henderson Island, aWorld Heritage Site, is 37 km2 of raised coral atollsitting on a volcanic island which formed about 13million years ago; Pitcairn is younger at 0.8 to 0.9million years old. The weight of this volcanic

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The low lying topography of the Turks and CaicosIslands. (Photo: Tara Pelembe..)

Exploring the caves on Turks and Caicos. (Photo: EricSalamanca.)

material depressed the crust and lithospheric flex-ure with uplift 200 km from the load started raisingHenderson Island above sea level. The 380 000year lift has formed a fossil raised reef and a dry,fossil lagoon with corals in situ. The rise continuesat a rate of 0.1mm/yr and has lifted the coral atollto 33 m. Henderson Island has vertical cliffs risingto 30 m. Marine erosion at the southern end hasformed arches in the sea cliffs and a ‘blow-hole’100 m inland. Several reef terraces with caves atdifferent heights are preserved in the bays as theprocess of uplift is not continuous; these caveswere used for shelter and habitation by the earlyPolynesian settlers.

Henderson Island provides a unique opportunityfor documenting climate change in the second halfof the Pleistocene. Fringing reefs 50–100 m off-shore occur around half of the island and protectthe principal beaches. There is no fringing reefbetween South Point and the north-west beach oraround the extreme north-east point where thecliffs are severely undercut. The central plateau ofthe island is formed by the fossil lagoon floor andthe island has eroded karst with limestone pinnacles and rugged areas of steep-sided 2–3 mdeep pits.



Geoconservation sitesHenderson Island is a World Heritage site and it is‘a unique example of a raised coral atoll charac-terized by a fossil lagoon surrounded by intricate-ly eroded karst surfaces. Corals dating back overhalf a million years remain in situ and provide anexceptional opportunity for exploring the relation-ships between tectonic uplift (caused by the

loading of the Earth’s crust by neighbouringPitcairn), sea-level fluctuation, and climate changeover hundreds of thousands of years.’

Environmental pressuresNone of the geological materials may be removedfrom Henderson without a licence granted by thePitcairn Islands. The administration of which mustbe sanctioned by the Management Committee.

Web linkshttp://www.ukotcf.org/territories/pitcairn.htmhttp://www.ukotcf.org/pdf/Henderson.pdfhttp://www.islandvulnerability.org/otuk.html

South Atlantic Ocean

St. Helena

IntroductionSt. Helena is 122 km2 and 700 miles south eastfrom Ascension Island and 1200 from Tristan daCunha, which are dependencies. It has a popula-tion of 5644 and no airport. It was discovered bythe Portuguese in 1502 and settled by the EastIndia Company in 1659. It was also home to theexiled Emperor Napoléon Bonaparte from 1815until his death in 1821. Ascension Island andTristan da Cunha are dependencies of St Helenawhere the Governor is based.

The island is the deeply eroded summit of a massive composite volcano 130 km in diameterrising from the sea floor at a depth of 4224 m;Diana’s Peak is 823 m above sea level. Theisland is 16 km long by 10 km wide bearing north-east to south-west with a high central ridge andradiating from it are 300 m deep dry valleys.There are cliffs over 300 m high along the island’scoastline, and a height of 494 m is reached atGreat Stone Top. The valley sides and cliffs reveala succession of alkali olivine basalt-trachyte-


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The location of Adamstown on Pitcairn Island. (Photo:Wesley Fryer, Creative Commons.)

Great Stone Top, the highest sea cliff in the SouthernHemisphere. (Photo: Ashley Leo.)


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phonolite lava flows with interbedded ash andpyroclastic deposits. The basalts exposed on St.Helena have undergone much alteration, and aredeep-weathered and friable; the clay mineral halloysite is a common alteration product.Spheroidal weathering forms, typical in basalts,are a common sight, particularly in the valleysfringing Deadwood Plain (Netley Gut, BilberryField Gut). These valleys are currently affected byaccelerated erosion. Fresh exposures, best seenin cliff faces, reveal the basalts to be typicallyblock-jointed. Both vesicular and amygdaloidalforms abound, the latter being infilled with zeolitesand calcites.

The island was formed by two coalescing shieldvolcanoes with centres in the north east atFlagstaff Hill/Knotty Ridge area, and in the southwest at Sandy Bay. Another more recent centre isin the east. The Sandy Bay centre is later than thenorth east and provides most of the volume of therocks with eruptions along fissures, and bothmajor centres have transgressive dyke swarms.Marine volcanic lava forms are rare and pillowlavas are not recorded. Trachytes and phonolitesform plugs, domes and, more rarely, dykes, andthe Asses Ears and Castle Rock are particularlyfine examples of columnar phonolitic intrusions;Lot’s Wife is a volcanic neck. The oldest rocks aregreatly altered breccias exposed between dykeswarms, some intense with the ridge connectingFlagstaff Hill with the Barn composed of 200 dykeswith no intervening tuffs or other material. Thebasalts and trachybasalts are 10–13 million yearsold and 8–8.5 million years for the later intrusions.

Geoconservation programmesAt present St. Helena’s Environment Charter’sGuiding Principles and Commitments broadly supports geoconservation and within the Strategyfor Action there are actions and programmesspecifically related to geoconservation featuresand issues. There is broad protection for areas ofgeoconservation significance under the LandDevelopment Control Plan (LDCP), (December

2006 http://www.shda.co.sh/data/files/downloads/ldcp_vol_1.pdf) which sets out the land use plan-ning policies. ‘It’s purpose is to act as a guide toresidents and prospective developers as to whattype of development will be encouraged or accept-able and where such development can be locat-ed.’

Key landscape and geological features are pro-tected through a number of policies and strategi-cally the LDCP recognises three very different andidentifiable land zones, the Greenheartlandnotable for its great scenic beauty; Coastal Zonewith spectacular coastal scenery, rugged, remoteand unique and visible geology, and theIntermediate Zone where most development willbe accommodated. Specific policy areas relevantto geoconservation include: encouraging whereappropriate landscaping around new built devel-opments; sympathetic build design including siting, materials, screening and landscaping; andpolicies and guidelines relating to alterations, further development and signage in conservationareas and on listed buildings.

The importance of various specific landscapesand geological features have been afforded spe-cial protection through the proposed NationalProtected Areas Plan which lists 14 areas thathave been proposed (not yet legally designated)for special protection for among other featurestheir ‘outstanding geological, physiographical or

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Coastal Zone, St. Helena. (Photo: Tara Pelembe.)

Flagstaff Hill, where Darwin studied fossilized snails.(Photo: Steve Plato.)

historic features’. The LDCP and new LandPlanning and Development Control Ordinance(2008) does make provision for EnvironmentalImpact Assessments for major developments,which will allow a full assessment (expertize andresources permitting) of geoconservation featureswhere applicable. Provision is also made in theOrdinance for building preservation orders andconservation areas.

Geoconservation sitesThe historic and natural environment of St. Helenais comparable with, and exceeds in conservationvalue, many of the sites presently inscribed underthe World Heritage Convention, and the UK mayadd teh area to its Tentative List.

There are 21 protected areas on St. Helena including nine protected landscape and naturalmonuments. Specific geoconservation sites are:

North Easterly Protected AreaAn area of outstanding natural beauty and one ofthe most prominent features of the island’s land-scape. Snail fossils of evolutionary significancehave been found at the base of Flagstaff Hill andstudied by (among others) Charles Darwin. Thearea should be managed to protect the outstand-ing natural features of Flagstaff and the Barn andto preserve an important fossil deposit site.

South East Protected AreaGreat Stone Top boasts the highest sea cliff in theSouthern Hemisphere at 494 m. There are alsoimpressive views down the cliffs and seaward toGeorge and Shore Islands.

South West Protected AreaThis area contains some of the most dramatic andbeautiful land and seascapes on St. Helena.Physical features are not only visually impressive

but represent scientifically important geologicalfeatures. Lot is a plug of a volcano and Lot’s Wife,the Gates of Chaos, Asses Ears and Speery formpart of a volcanic dyke.

Heartshaped WaterfallHeartshaped Waterfall is a natural monument in ascenically beautiful area.

Plantation ForestThis forest should be protected to enable man-agement of this area of national forest as a publicpark.

Casons (including George Benjamin’s Arboretumand Nature Trail Area)George Benjamin’s Arboretum provides easyaccess to the endemic species of flora on St.Helena, and the Casons Nature Trail guides visi-tors through stands of Cape Yew trees andendemic ferns.

Environmental pressuresThere are no known mineral deposits on St.Helena, but it is quarried for building stone andthree sites are earmarked in the LandDevelopment Control Plan for quarrying. Thereare also deposits of blown white sand which wasused in building, but today sand pumped from thesea is used instead. A proposal has been put for-ward to mine the white sands in an area that holdsbird bone deposits. The issue has not yet beenfully addressed due to a variety of factors, it is gen-erally considered that this area should be pre-served for its environmental value and future sci-entific study.

Web linkswww.bweaver.nom.shhttp://www.volcano.si.edu/world/region.cfm?rnum=1805http://www.islandvulnerability.org/otuk.htmlhttp://www.ukotcf.org/territories/stHelena.htm


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Heart Shaped Waterfall, St. Helena. (Photo: StevePlato.)

Lot’s Wife, St. Helena. (Photo: Ashley Leo.)


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Tristan da Cunha

IntroductionTristan da Cunha, a dependency of St. Helena, isa 2060 m shield volcano in the South AtlanticOcean, is 1900 km from St. Helena and 2400 kmwest of Cape Town. It has nearby islands ofNightingale, Inaccessible and Gough, the last twoare known as ‘Gough and Inaccessible IslandsWorld Heritage Site’. Inaccessible Island is 35 kmsouth-west of Tristan da Cunha and 340 km north-northwest of Gough Island. Only Tristan da Cunhais inhabited with 284 people in 2000.

Tristan da Cunha, 13 km wide, lies about 500 kmeast of the Mid-Atlantic Ridge and has high cliffson most sides. Lava flows dominate the low-anglebase and the steep upper flanks and pyroclasticcones ringing the central cone are scatteredaround the lower flanks. Eruptions have occurredfrom Queen Mary’s Peak, a 300 m wide summitcrater, which has a small lake, and from numerousflank vents and radial fissures. Radial dykeswarms are prominently exposed on all sides ofthe island. Strombolian cinder cones occur on theflanks along concentric ring structures and NNW-and ENE-trending radial fissures. The only erup-tion since the island was settled occurred during1961. Inaccessible Island is a 2–3 million year olderoded remnant of an extinct shield volcano,which has built up a wide submarine plateau, andhas thin basaltic flows interleaved with ash andscoria overlain in places by later volcanic domes,plugs and dykes. The island is an undulatingplateau rising to 500 m above steep sea cliffs cutby waterfalls.

Gough Island is the summit of a Tertiary volcanowith dramatic steep sea cliffs forming, and anundulating plateau rising up 910 m. The east hasdeep, steep-sided valleys, known as glens, sepa-rated by narrow, serrated ridges. The west hasrounded slopes running down from the centralplateau to sea cliffs.



Geoconservation sitesOf the four islands 40% is protected naturereserve and Gough and Inaccessible islands are aWorld Heritage site.

Environmental pressuresThere are no apparent environmental pressues.

Web linkshttp://www.volcano.si.edu/world/region.cfm?rnum=1805http://www.islandvulnerability.org/otuk.htmlhttp://www.tristandc.com/

Ascension Island

IntroductionAscension Island, like Tristan da Cunha is adependency of St. Helena where the Governor isbased. Ascension Island, population 1250, wasdiscovered on Ascension Day in 1501 by thePortuguese navigator Joao da Nova, and lies inthe South Atlantic about 750 miles north west ofSt. Helena and covers an area of 98 km2 with thehighest point of 859 metres on Green Mountain.

Ascension Island is located just west of the Mid-Atlantic ridge and just south of the AscensionFracture Zone (50 km to the north). Unusually forthe mid Atlantic, the island is a not a mantle‘hotspot’; in fact the hotspot lies to the east of theMid-Atlantic Ridge about 175 miles away. The

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West coast of Tristan da Cunha. (Photo: MichaelClarke, Creative Commons.)

Ascension Island. (Photo: Anselmo Pelembe.)

island is a broad emergent summit of a massivestrato-volcano that rises 3200 m above the 5–6million-year-old oceanic crust of the SouthAmerican Plate. The base of the volcano is 60 kmdiameter, and the island represents only the top-most and youngest few per cent of the volcano’smass.

Ascension Island is unusual among oceanicislands in having a high proportion of pyroclasticdeposits relative to lava flows, approximately40:60 based on exposure. The mafic and silicicpyroclastic deposits, and trachyte lava flows anddomes, predominate in the centre and east of theisland. The remainder of the island comprisesscoria cones and mafic lava flows, some with athin veneer of pyroclastic deposits. There are over50 scoria cones all with an oxidized surface layer,and most composed of cinders with minor blocksand bombs. K–Ar whole rock age dates (mostlyfor trachyte) suggest that the oldest exposed rocksare about 1 million years old. There have been noeruptions since the discovery of the island and thelast major volcanic eruption took place about 700to 1 000 years ago on Sisters Peak, although theisland was uninhabited until 1815.

Nearly all of the mafic (basalt to benmoreite) lavaflows, typically a few metres thick and scoria-ceous, are flows of variable and small volume,erupted from breached scoria cones with steepflow fronts. Dykes are rare. Trachyte and rarerrhyolite flows on and around Green Mountain are0.8 to 1 million years old and those at WeatherPost and Devil’s Cauldron flow domes were erupt-ed within the last 60 000 years. Green Mountainis composed of pyroclastic deposits, both scoriaand pumice, and many show evidence of rework-ing by water, suggesting that the climate was sub-stantially wetter in the past. Darwin recognizedthat deposits filling the central depression in

Devil’s Riding School were formed in a lake.

Ascension is famous for xenolith suites. Granitexenoliths are the intrusive equivalents of the rhyo-lite flows; gabbroic xenoliths have isotopic compo-sitions different to those of the exposed volcanicrocks and syenite xenoliths are partially meltedand contain veins and small pods of glass.


Existing NoneActivities The Ascension EnvironmentalInformation Operations Utility (AEIOU) project willsynthesize existing information from land jurisdic-tion, environmental mapping and monitoring, geo-logical and cultural data with new land cover datainto a single manageable framework. Resultingmaps will provide the means to implement the planfor Green Mountain. This has the opportunity topromote and include geoconservation into theGreen Mountain National Park.

Geoconservation sites

Green Mountain National Park Letterbox National Park The name of the latter park comes from the habitof sailors leaving letters for collection.

Nature reserves

Sisters Nature Reserve (geology)This reserve is the site of the youngest volcanic(Icelandic type) eruption on the island estimated at700 to 1000 years old, with a young Hawaiite floworiginating from a breach high on the flank of thecone. This flow extends 3 km to the coast andflows around Broken Tooth. There is no centralcrater, but the fissure is marked by a line of ovaldepressions caused by eruptions.


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Mexican Thornbush has been reported to threatenthe green turtle population on Ascension Island.(Photo: Anselmo Pelembe.)

Ascension Island is the summit of a massive strato-volcano that rises 3 200 m above the oceanic crust ofthe South American Plate. (Photo: AnselmoPelembe.)


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Devil’s Riding School Nature Reserve (geology)An example of one vent producing trachyte lavaand basalt forming what was the island’s largestfreshwater lake, but it dried up and was found tocontain unique sedimentary deposits, the ‘Devil’seyeballs’. The reserve also has the most recentgaseous fumarole activity.

Environmental pressuresThe UKOTCF reports that the recently introducedMexican Thorn bush threatens the green turtlepopulation, the surviving unique desert flora andfauna and some geological features, but these arenot specified.

Web linkswww.ascensionconservation.org.achttp://www.the-islander.org.ac/art_3838_59_0.htmlhttp://www.volcano.si.edu/world/region.cfm?rnum=1805http://www.islandvulnerability.org/otuk.htmlhttp://www.ukotcf.org/territories/ascension.htm

Falkland Islands

IntroductionThe Falkland Islands archipelago consists of twolarge islands, East and West Falkland and 780smaller islands extending 250 km from east towest and 155 km north to south. The highest pointis Mt. Usborne (705 m) on East Falkland, and thecoastline is deeply incised forming sheltered inletswith some high cliffs of 50–100 m high. Theislands lie at the western end of the FalklandPlateau, a relatively shallow water area of conti-nental crust that extends towards South Georgia, and are surrounded by four majorMesozoic–Cenozoic sedimentary basins with con-siderable potential for oil and gas.

There are Precambrian gneisses and granite atCape Meredith in the southern part of WestFalkland, but rocks are mainly Silurian–Devoniansediments with the southern part of East FalklandCarboniferous–Permian. The rocks split into theWest Falkland Group, underlying West Falkland,and the northern uplands of East Falkland andconsist of Silurian–Devonian quartzose and sub-arkosic sandstones with siltstone and mudstoneforming a rugged landscape, and the LafoniaGroup underlying the low lying areas of southernEast Falkland (Lafonia). The surrounding islandsare also mainly Carboniferous–Permian tillites,mudstones, sandstones and siltstones. There areno Jurassic, Cretaceous or Tertiary sediments butthere are three sets of dolerite dykes ranging inage from Early-Jurassic to Mid-Cretaceous periodcutting across the islands and representing thebreak up of Gondwana. The Falklands were notcovered by ice sheets or subject to extensiveglaciations, but there are glacial deposits andlandforms above 500 m on north-east and south-east facing slopes on East and West Falkland;corries and hollows and tarns on Mt. Usborne andMt. Adam.

There are many periglacial landforms especiallywhere solifluction has smoothed slopes andformed stone-runs, but has left rock outcrops unaf-fected. Stone runs are unique, spectacular, dis-tinctive and delicate environments occurring in val-ley bottoms and on slopes as alternate strips ofboulders and sparse vegetation. Darwin calledthem ‘streams of stones’.

Brachiopods, crinoids and trilobites are found inthe Fox Bay Formation sandstones in the middleof the West Falkland Group; the same assem-blage of fossils is found throughout southernBrazil, South Africa and Antarctica; Darwin collect-ed fossils from here on the Beagle voyage. TheFitzroy Tillite from the Permo-Carboniferousglaciation is widespread and has a distinctive darkmatrix.

There are striking geological similarities betweenthe Falklands and South Africa’s Cape Fold Beltand Karoo Basin which suggests that theFalklands might contain similar mineral wealth andrecent exploration has found possible diamond-indicator minerals and fresh, angular gold grainshave been discovered in streams.



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King Penguin on South Georgia. (Photo: Wili_Hybrid,Creative Commons.)

Geoconservation sitesNo sites are protected under legislation, but thereare 33 protected nature reserves and sanctuaries.The Falkland Islands State of the Environment2008 report notes ‘A number of sites are tentative-ly recognized for their geodiversity assets, due tobeing:

● exposed type sections of a stratigraphic unitgeologically unique to the Falkland Islands;

● geologically unique to/characteristic of theFalkland Islands;

● contain important fossil beds;● historical importance, such as sites visited by

Charles Darwin.

The list is tentative only and a more-comprehen-sive assessment is needed. The suggested sitesinclude: Cape Meredith complex, West Point for-est beds, Pebble Island, Jenesta Point and PurvisPoint, South Harbour neptunian dykes, Devoniansequence along the Port North coast, Port Louissites visited by Charles Darwin, Princes Streetstone run, tillite cliffs to the east of Hill Cove (E.Edwards and P. Stone, personal communications).

Environmental pressuresThe important geological sites are known andnone appear to be under threat from any incom-patible activities.

Web linkshttp://www.ukotcf.org/territories/falkland.htmhttp://www.volcano.si.edu/world/region.cfm?rnum=1805http://www.islandvulnerability.org/otuk.htmlhttp://www.epd.gov.fkh t t p : / / w w w . e p d . g o v . f k / w p - c o n -tent/uploads/Falkland%20Islands%20State%20of%20the%20Environment%20Report%202008_final_sm.pdfh t t p : / / w w w . b g s . a c . u k / f a l k l a n d s -oil/onshore/onshore_intro.htm

South Georgia and theSouth SandwichIslands

IntroductionSouth Georgia, an emergent part of a small blockof continental crust, is connected southwards by aline of sea mounts to the volcanically and tecton -ically active South Sandwich Islands where thereare seven strato-volcanoes, a shield volcano anda submarine volcano.

The geology of South Georgia shows the stages in

the evolution of an active plate margin and marinebasin with remnants of the ancient volcanic arc.The rocks are in five distinct sequences, dominat-ed by sediment. The Cumberland Bay Formation,a thick sequence of volcaniclastic sandstones andshales, intruded by quartz and feldspar rich veins,forms half of the island and all of the high ground.A fault zone separates it from the SandbugtenFormation’s Gondwana derived sandstones andshales containing fragments of continental margingranites and sediments. The Annekov IslandFormation is 3 km thick and has andesite and gab-bro plutons intruded into finely banded mudstonesand conglomerates. The Drygalski FjordComplex, forming part of the central SalvesenRange of peaks rising to 2000 m, is composed ofgneisses and is intruded by granites and gabbros.This is separated from the Larsen Harbour com-plex (ocean floor lavas and rocks) by another faultzone and together was part of the original marginof Gondwana. Ammonites, bivalves and fossilwood are found on Annekov Island.

There are heavily dissected mountains of theSalvesen and Allardyce Ranges with Mt. Paget at2 960 m. Over 50% of the island is permanent icecover with steep sided valleys filled with glacialdeposits and glaciers extend to sea level. Thecoastline has extensive wave-cut platforms andthe north east is indented with fjords.

The Thule Islands, at the southern end of theSouth Sandwich island arc bordering the ScotiaSea, consist of three strato-volcanoes constructedalong an E–W trending line.

Bristol Island on the South Sandwich arc liesacross Forster’s Passage from the Southern ThuleIslands and forms one of the largest islands of thechain. It is glacier covered, and a steep-sidedflank cone or lava dome, Havfruen Peak, is locat-ed on the east side, and a young crater and fissureare on the west flank. Montagu Island, largest inthe group, is a massive shield volcano cut by a 6km wide ice-filled summit caldera rising 3 000 mfrom the sea floor between Bristol and SaundersIslands. Around 90% of the island is ice-covered;glaciers extending to the sea typically form verticalice cliffs.

The young 990 m Mt. Michael strato-volcano dom-inates glacier covered Saunders Island, and has a700 m wide summit crater and a remnant of asomma rim to the south east. Tephra layers arevisible in ice cliffs. The southern end ofCandlemas Island consists of an eroded, glacier-covered basaltic strato-volcano cut by steep cliffson the east.


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Protector Shoal seamount, located 56 km northwest of Zavodovski Island, forms the northernmostvolcano of the arcuate South Sandwich Islands.



Geoconservation sitesThe only site for geoconservation specifically pro-tected is Annekov Island SSSI.

Environmental pressuresThere are none apparent.

Web linkshttp://www.sgisland.gs/index.php/Main_Pagehttp://www.volcano.si.edu/world/region.cfm?rnum=1805http://www.islandvulnerability.org/otuk.html

British AntarcticTerritory (BAT)

IntroductionAntarctica is the fifth largest continent and is divid-ed into West Antarctica and East Antarctica sepa-rated by the mountains of the Trans-AntarcticRange. East Antarctica is a stable sedimentaryplatform with metamorphosed rocks overlain byyounger sediments. West Antarctica, including theBritish Antarctic Territory, is a complex of foldedand metamorphosed, mainly volcanic sediments.There is one active volcano in the AntarcticPeninsula on Deception Island. There are twomicroplates, the Ellsworth Mountains block,formed in the early Mesozoic, and the AntarcticPeninsula block, the most recent addition to thecontinent, formed by the Andean Orogeny of latemesozoic–early Cenozoic that coincided with thebreakup of Gondwana; the peninsula is an exten-sion of the Andes and is composed of igneousintrusive rocks, volcanic and metamorphosed sed-iments.

Cumberland Bay: Thatcher Peninsula with King Edward Cove, the Allardyce Range and the summit Mt. Paget,South Georgia. (Photo: NASA.)


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Geoconservation sitesThe whole of Antarctica is designated as a naturalreserve devoted to peace and science by theAntarctic Treaty’s Protocol on EnvironmentalProtection. There are certain areas given evengreater protection through the protocol’s system ofprotected and managed areas with 70 AntarcticSpecially Protected Areas (ASPAs, formerlySSSI), five Antarctic Specially Managed Areas(ASMAs) and over 80 Historic Sites andMonuments (HSMs).

ASPA 170 Marion Nunataks, Charcot IslandThis site was designated for the nunataks whichare composed of turbiditic sandstones and mud-stones, which are different to those on AlexanderIsland, and possibly the whole of the AntarcticPeninsula. The sediments were originally deposit-ed within a deep marine trench that formed as aresult of the destruction of the Pacific platebeneath the edge of the ancient continent ofGondwana. The sedimentary rocks were scrapedoff the Pacific plate as it was destroyed andaccreted to the Gondwana continent, causingthem to be folded and metamorphosed under highpressure. Charcot Island sedimentary rocks arethought to be Cretaceous.

ASPA 126 Byers Peninsula, Livingston Island,South Shetland IslandsDesignated for the well-preserved sub-fossil whalebones present in raised beaches, and the lakesand their sediments are important for the study ofthe Holocene palaeoenvironment, and for estab-lishing a regional Holocene tephrachronology.The peninsula is of exceptional historical interestwith the greatest concentration of 19th century his-torical sites in Antarctica.

ASPA 140 Parts of Deception Island, SouthShetland IslandsThis ASPA site is designated for its volcanic activ-ity, having had major eruptions in 1967, 1969 and1970. It has a unique landscape of barren vol-canic slopes, steaming beaches and ash-layered

glaciers forming a horse-shoe shaped opening tothe sea at Neptune’s Bellows. Neptune’s Bellowsis one of the few places where vessels can saildirectly into the centre of a restless volcano.

ASPA 147 Ablation Point–Ganymede Heights,Alexander IslandDesignated as one of the largest ablation areas inWest Antarctica with a complex lithology and widerange of features including raised beaches,moraine systems, and patterned ground.

ASPA 148 Mount Flora, Hope Bay, AntarcticPeninsula (previously SSSI 31)This site is designated for its rich fossil flora, andwas one of the first discovered in Antarctica.

Environmental pressuresMount Flora ASPA is vulnerable to souvenir fossilcollectors and merits protection.

Web linkshttp://www.volcano.si.edu/world/region.cfm?rnum=1805http://www.islandvulnerability.org/otuk.htmlhttp://www.ukotcf.org/territories/bat.htmhttp://www.antarctica.ac.uk/about_antarctica/geopolitical/environmental_issues/mining.php

British Antarctic Territory. (Picture: Lokal _Profil,Creative Commons.)

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Geoconservation in the Overseas Territories of the UK

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