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(Friedman and Williams 1970). Although there has been a postvolcanic decline in thermal flux, vapour emissions still remain visible from numerous open fissures in the tuff. In 2002 a small hot spring with temperatures at 80°C was discovered at the western shore of Surtungur (Figs. 2.6 and 2.7). The drill hole on Surtsey provided important insights into the character of the hydrothermal system in the volcano. Figure 2.7 is a geological cross-section of Surtsey from northwest to southeast, based on the documented sequence of eruption events and on information from the drill hole. These data strongly suggest that the heat in the hydrothermal system was provided by intrusions which formed both below and above sea level from 1965 to 1966 at Vesturbunki, and from December 1966 to January 1967 at Austurbunki, in conjunction with lava extrusions in these areas (Sveinn P. Jakobsson 1978; Valgarður Stefánsson et al. 1985). Because of the high porosity of Surtsey formations, any water at sea level inside Surtsey is presumed to be boiling, which leads to vapour dominating the hydrothermal system above sea level and to temperatures of around 100° C 2 DESCRIPTION prevailing in the porous tephra pile (Friedman et al. 1976). Below sea level, on the other hand, temperatures of several hundred degrees C may occur, especially close to the inferred intrusions. Palagonite tuff The basalt tephra has been observed to alter rapidly within the hydrothermal portions of Surtsey, concluding with consolidation of the tephra into palagonite tuff. In 2004 the tuff area covered 0.24 km 2 , and some 85% of the volume of the tephra cones above sea level is estimated to have changed into hard palagonite tuff. During the alteration process, the original glass shards in the tephra are chemically modified, devitrified and hydrated to produce palagonite. This process is called palagonitisation and had not previously been monitored happening in nature (Sveinn P. Jakobsson 1972; 1978). During the process, a number of chemical elements are released from the original glass in the tephra to form an array of new secondary minerals which eventually fill the voids in the rock and at the same time cements its particles together (Sveinn P. Jakobsson and Moore 1986). Ten types of minor secondary minerals are found in the palagonite tuff (Table 2.1). Tuff sea cliff on the west coast. The red colour indicates oxidation of the tuff caused by the overlaying lava. (Photo: Daníel Bergmann 2003). 23
SURTSEY – NOMINATION FOR THE UNESCO WORLD HERITAGE LIST A further aspect to note is that signs of bacterial activity have been observed in many tuff samples from Surtsey (Thorseth et al. 1992; Sveinn P. Jakobsson 1996), and it appears possible that bacteria contribute to altering the tephra there. The transformation of tephra to tuff has an important implication for the future of Surtsey, since tuff has proved itself to be much more resistant to marine abrasion than tephra and even than lava. Through the formation of tuff, Surtsey has been ensured a longer life. The tuff sea cliffs on the northwestern coast are up to 130 m high and have changed little since 1980. (Photo Sveinn P. Jakobsson 1985). 24 Sediments The ferocity of wave action in the sea surrounding Surtsey has come as a surprise to geologists. Coastal erosion has been rapid, modifying the coastline markedly from year to year, above all during winter storms. Thus coastal sediments (Fig. 2.6), consisting mainly of boulders and cobbles derived from the break-up of lava (Norrman 1980; Calles et al. 1982), now covers an area of 0.15 km 2 . Most of the lava shore terrace has been eroded by longshore drift towards the north, and the boulders, among which the largest are about 1.5 m in diameter, have mainly been deposited in the northern spit. Partly covered with sand originating in the tephra and tuff of the two cones, the northern spit also has overflow channels where stranded driftwood indicates the floodline on the spit every winter. Coastal material is lost downhill, probably in intermittent slump motions, to form the 130-mdeep submarine slope of Surtsey. Surtsey presents conspicuous aeolian deposits, whose source material is mainly tephra. These wind-driven deposits can be divided into two groups: firstly, the sand dunes and ripples capping the slopes of the tephra and tuff cones and, secondly, sand blowing onto and covering the lava field (Calles et al. 1982). The aeolian deposits are characterised by considerably better The northern spit is made up of boulders, cobbles and sand. (Photo: Karl Gunnarsson 1998).
Page 1 and 2: Ministry of Education, Science and
Page 3 and 4: • O F ICELANDIC INSTITUTE N AT U
Page 5 and 6: This nomination has been commission
Page 8 and 9: Contents 1 Identification of the pr
Page 10 and 11: 22’’N 5’’W Surtsey Nature R
Page 12 and 13: 2 Description 2.a Description of pr
Page 14 and 15: Vestmannaeyjar archipelago Surtey i
Page 16 and 17: and of the islands of Bjarnarey and
Page 18 and 19: 150 m 100 m 50 m 0 m - 50 m - 100 m
Page 20 and 21: Typical ropy lava surface at the so
Page 22 and 23: Geological definitions Accretionary
Page 26 and 27: sorting than the original tephra, w
Page 28 and 29: Fig. 2.9. Wind direction frequency
Page 30 and 31: older and more eroded. It is likely
Page 32 and 33: The lichen Xanthoria parietina and
Page 34 and 35: study plots revealed four main vege
Page 36 and 37: carefully recording any observation
Page 38 and 39: carried out. In the early years of
Page 40 and 41: Amara quenseli Atheta graminicola B
Page 42 and 43: 1 2 3 4 6 - 8 northern sublittoral
Page 44 and 45: Marine mammals Marine mammals have
Page 46 and 47: 2.b History and development Geologi
Page 48 and 49: Lava effusion on Surtsey, April 21,
Page 50 and 51: 0 m -100 m -200 m -300 m 6/’65 (D
Page 52 and 53: 17 February 1964: hydromagmatic eru
Page 54 and 55: The hydrothermal area at the surfac
Page 56 and 57: Area [km 2 ] 3 2 1 0 1960 1970 1980
Page 58 and 59: History of life Influx of terrestri
Page 60 and 61: Number of vascular plant species 60
Page 62 and 63: upon later attempts after growing c
Page 64 and 65: colony, a community composed mainly
Page 66 and 67: Erling Ólafsson 1982; Gjelstrup 20
Page 68 and 69: Number of species 60 50 40 30 20 10
Page 70 and 71: 13 Justification for inscription 3.
Page 72 and 73: Surtsey's emergence has provided a
Page 74 and 75:
forms and biological communities. T
Page 76 and 77:
Italians landed and named it Ferdin
Page 78 and 79:
These include, to name but a few: s
Page 80 and 81:
The tephra cones have been converte
Page 82 and 83:
4 State of conservation and factors
Page 84 and 85:
Fig. 4.2. Mean yearly catches of fi
Page 86 and 87:
(iii) Natural disasters and prepari
Page 88 and 89:
15 5.a Ownership Protection and man
Page 90 and 91:
“A room with a view.” (Photo fr
Page 92 and 93:
The Surtsey Research Society has co
Page 94 and 95:
6 Monitoring 6.a Key indicators for
Page 96 and 97:
71Documentation 7.a Supplementary m
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except by permission of the Environ
Page 100 and 101:
Gjelstrup, P. 2000. Soil mites and
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8 8.a Preparer Contact information
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9 Signature on behalf of the State
Page 106 and 107:
List of figures Lists of figures, t
Page 108 and 109:
Appendices Appendix 1a. Declaration
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APPENDICES Species status in 2005 A
Page 112 and 113:
Appendix 4. Lichens species recorde
Page 114 and 115:
Appendix 6. Bird species seen on or
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Coccinellidae Coccinella undecimpun
Page 118 and 119:
Neomolgus littoralis (Linnaeus) Any
Page 120 and 121:
APPENDICES Appendix 9a. Marine zoob
Page 122 and 123:
Crustacea/Amphipoda amphipod Hippom
Page 124:
effects on natural features, landsc
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