Part 12

The Vatna Jökull is a vast accumulation of volcanoes, ice, and snow, comprising an area of over 3000 square miles. It is for the most part surrounded by a wilderness, formed by the destructive outbursts of its volcanoes, and the constant drifting of the glacial torrents which flow from its melting snows. The Vatna Jökull and its immediate surroundings constitute the most lofty portions of Iceland, and I believe the oldest, for we find lava streams which have flowed from its volcanoes in a state of ruin and decay unequalled in any other part of the country; and, again, we find it bounded upon the south by sea cliffs that were washed by pre-historic oceans when many other parts of the island must necessarily have been under water, unless very serious depressions have taken place since the waters which washed the south outlying hills of the Vatna receded to their present limit. The Vatna Jökull comprises by far the most important mountain section in Iceland, and a far greater area is covered by its snows than could be occupied by the sum of all the remaining snow-clad mountains in Iceland. As may be supposed, perhaps half the river water of Iceland flows either directly or indirectly from the Vatna Jökull, either issuing in torrents from the extremity of its glaciers, or, after filtering for long distances through the loose and cavernous ground, appearing as land springs at a lower elevation. The rocks of the Vatna, as far as I have had an opportunity of judging, are purely and simply the product of this very remarkable cluster of volcanoes, which have piled up layer after layer of ash, sand, and agglomerate, until a mountain heap was formed of such a height that it allowed snow and ice to accumulate upon it to such an extent as to render the summer’s warmth quite inadequate to remove it. This vast snow pile then grew of its own accord, and glaciers commenced to creep down the sides of the barren mountains upon which it rested. Volcanoes continued to erupt, but the effect of their fires upon the accumulating snow must have been purely local and limited in the extreme; for volcanic productions are the worst possible conductors of heat, and I should imagine that a lava stream, unless it be of gigantic proportions, conducts itself beneath the profound snows of the Vatna much as a lava stream would beneath the sea, without producing any very violent commotion. Thus this vast mountain mass was accumulated, growing with each succeeding winter and each eruption. The Vatna Jökull rises by a very gradual slope upon the south, and it is not until more than thirty miles of snow fields have been traversed that the highest part of the Vatna, viz., 6,150 feet, can be reached from that direction. I have at present omitted any mention of the snow line in Iceland; this is on account of its variable nature, incidental to local causes. Thus upon the Vatna we have the snow line much lower upon its southern than northern slopes, the cause of which we will consider presently. Of late years the volcanic forces of Iceland appear to have retreated to the Vatna Jökull and its immediate neighbourhood, and volcanic eruptions have been witnessed in force in several directions. The Kverkfjall we found to be smoking and Öskjugjá can only be regarded as a lateral crater of the Vatna, and, I doubt not, had we been favoured with better weather, we should have found many other eruptive vents; but so rapid is the accumulation of snow upon the Vatna, and so bad a conductor of heat are all volcanic eruptions, that the traces of them are very soon obliterated. As may be supposed, such a prodigious accumulation of ice and snow as the Vatna Jökull produces a very sensible and marked effect upon the climate of certain parts of Iceland. It has this effect--it deluges the country to the south of it with rain, and gives to those districts which lie to the north of it a happier climate than they would otherwise possess. The snowy heights of the Vatna attract to themselves the aqueous vapours which travel northwards from more southern latitudes, depositing them upon their broad shoulders in the form of snow and hail, and refrigerating and drying the vapours which travel across their snows, thus rendering the south wind a wet one in the country to the south of the Vatna and the north wind a dry one, whilst in those districts which lie to the north of it the reverse is the case. And since by far the greater part of the aqueous vapours which reach Iceland are borne thither from the more readily evaporating waters of southern oceans by that bugbear to travellers in the south of Iceland, the southerly wind, we see at once why the snow line is lower upon the south than the north of the Vatna Jökull. When we inspect the glaciers which fringe the south of the Vatna Jökull, we find they have decidedly advanced; indeed, at one point so much so as to almost destroy communication along that part of the south shore. Upon the north we find that a huge tongue of glacier has flowed down full ten or twelve miles beyond the utmost limit assigned to it by Gunnlaugsson some forty years ago, while the route traversed by that enterprising man is completely overrun by the ice, and the traditionary road of the Vatna Jökull’s verge is now amongst the high snows of the Vatna. Icelanders, as a rule, are loth to admit the advance of their glaciers, and vainly appeal to striated rocks at much lower altitudes than most of the Icelandic glaciers of the present day, and to moraines stranded upon the plains beneath some of the principal mountain sections; but since it is impossible to say when these rocks were scratched, or even whether the very rocks to whose striæ they so confidently point were not erupted long before Northern Europe and America disappeared beneath the ice and snow of the earlier glacial period, what is the use of such evidence? The very moraines may have been produced by the glaciers which have strewn even our own country with erratic boulders and glacial _débris_. Again, it is no uncommon thing in Iceland for huge masses of glaciers to slide down the mountain side during periods of eruption, scratching the harder and furrowing the softer rocks in their progress, and leaving heaps of _débris_ in no way distinguishable from terminal moraines. These facts are rather startling. True, the glaciers of Iceland may, and, no doubt, do ebb and flow, but they gain upon the whole, and never would increase to this extent was not the annual accumulation vastly in excess of the waste. It may be said this is due to a cycle of unpropitious seasons. Possibly; but we find this advance of northern glaciers is not peculiar to Iceland. Dr. Nordenskjöld has proved a considerable advance in the glaciers of Spitzbergen; Greenland gives us the same intelligence. This seems to point to something more than a local advance, compensated for by a retreat in other places. It is too rapid an advance to be accounted for by astronomical causes; but cannot we suggest some comparatively slight physical changes which may account for it? Granted that above a certain latitude the earth only receives as much heat during the summer as it does during the winter, and that in one winter it will accumulate just as much snow and ice as the summer’s heat will suffice to melt, if it were all employed for that purpose. Now we are perfectly aware that snow and ice having once accumulated, a greater part of the succeeding summer’s heat would be reflected back into space and not employed in melting them, while the aqueous vapours condensing above it would screen the snow from solar influence. Thus a new glacial period would creep upon us, heralding its approach by an advance band of low temperature of its own production were it not for the warm oceanic and atmospheric currents, for the beneficial influence of which we have only to look at the varying temperature of many localities in similar latitudes to appreciate. A great alteration in temperature and climate would certainly take place supposing any variation should occur in the direction of these currents--in the Gulf Stream, for instance. Supposing that its waters, instead of reaching so far north, were deflected southwards, then not only would Arctic climates and Arctic ice be less affected by it, but the deflected stream would heighten the temperature of the waters of lower latitudes, and cause an increased evaporation; consequently there would be an increased condensation upon northern mountains and Polar shores, and an increased reflection of the succeeding summer’s sun. It is rather a curious fact that less American driftwood has been brought to the northern shores of Iceland during late years, and an increased amount has been cast upon its southern coast. This little fact of course proves nothing in itself; but when we see northern glaciers advancing to the extent they have done one naturally asks the reason. Astronomical causes we must put on one side, for the glacial advance is too rapid to admit of that solution. But if northern glaciers continue to advance, it will be a matter of some interest if we could ascertain whether those mysterious forces which give birth to the earthquake and the volcano have wrought any alteration in the flow of that guardian angel of the north--the Gulf Stream.

We will now pass on to the volcanic rocks of which Iceland is constituted. The foundation of Iceland is palagonitic tuff of sub-aqueous origin, disturbed and at times metamorphosed by enormous masses of amygdaloidal basaltic lava whose cavities abound with zeolites, being traversed by dykes and layers of interjected basaltic and trachytic lava at all times dislocated and confused by the various earthquakes which from time to time have shaken Iceland to its nethermost stone. These rocks are overlaid by lava streams of sub-ærial origin, pumiceous tuffs and agglomerates that have been formed by debacles and atmospheric influences. Concerning the strike and dip of the various layers of trap and basalt there is no general inclination, no uniformity--all is confusion. The loose soil of Iceland is entirely composed of disintegrated and decomposed volcanic rocks and decayed vegetable matter, and would be very fruitful if it were in a lower latitude. The vast period of time which it must have taken to decompose the huge lava streams that we find almost entirely converted into humus may be appreciated when we look upon pre-historic lava fields, grey with lichens, like that of Thingvellir, while the actual decomposition of its surface scarcely amounts to half-an-inch. We may divide the lavas of Iceland, like those of most other volcanic districts, into two classes; first, the basalts passing into dolerites, and secondly, the trachytic lavas. The more ancient basalts occur most frequently as intruded masses of amygdaloidal character; the doleritic lavas of Iceland are the more recent products of its volcanoes, varying only in this respect, that the earlier erupted lavas contain crystals of olivine, in addition to the felspar and augite which occur in most of the lavas of our own time.

Trachytic lava occurs but sparingly in the parts of Iceland that I have visited. It has for a long time been assumed that a trachytic band was disposed upon a fissure which bisected Iceland from N.E. to S.W., namely from Cape Langanes to Reykjanes upon which the principal centres of eruption were supposed to be situated. This, however, is a presumption unwarranted by investigation. A glance at the map will show us that there are many other centres of volcanic activity which do not occur in this imaginary trachytic band. True most of the more recently active volcanoes occur upon this rectilinear, but there are Myrdals Jökull, Eyjafjalla and Örœfa Jökull, all volcanoes that have erupted comparatively recently, and a host of more ancient volcanoes distributed over other portions of the island, which might lead us to surmise that there were a dozen instead of one great fissure in the superficial rocks of Iceland.

Trachytes, principally I believe in an altered condition, have been found around and between Hekla and the Geysers, and notably at the volcano of Rauðarkamb. I was informed, however, that we must look for the greater part of the trachyte of Iceland other than in a pumiceous form upon the peninsulars of Snæfells Jökull. Certainly I found that trachytic lava almost died out upon the north side of the Vatna Jökull, or else it is so covered up with recent volcanic productions as to be undiscernible. The obsidians of Iceland, which are found so universally distributed in fragmentary forms upon the sides of the volcanoes are seldom to be met with _in situ_, indeed the only instance that I have met with of obsidian _in situ_ was at Mount Paul, in the heart of the Vatna Jökull. That mountain, as we have already seen, is entirely composed of obsidian, varying from the vitreous to the grey stony variety.

The obsidians of Iceland seldom contain the beautiful felspar crystals, so characteristic of the Arran pitch-stones, but some of them are of a porphyritic nature, showing under the microscope crystals of quartz much fissured and split about, no doubt during the process of cooling. We must also regard the greater part of the pumice which was ejected last year from the Öskjugjá as an obsidian, in spite of its remarkably vesicular character. The fine dust which was carried to Norway during the eruption of last Easter-day resembled powdered glass, and led geologists there to come to the conclusion that the mountain which was erupting must have been pouring out great quantities of obsidian. As compared with the lavas of Vesuvius, I cannot help suggesting that many of the more ancient lavas in both instances are of a more trachytic and porphyritic character. In the Vesuvian lavas especially, the crystals contained by the older rocks have crystallized out of the uncrystalline or semi-crystalline mass. A prevalent mineral in the older Vesuvian lavas is leucite, which corresponds to the olivine that occurs so frequently in the older erupted lavas of Iceland, while those minerals are seldom to be met with in the more recent lavas of either Iceland or Italy.

I must now bring these few pages to a close. I dare say they contain a great deal of what is not worth reading; but as they give the only account of the Vatna Jökull and the part of the Ódáðahraun which I traversed, I trust those that may take the trouble to read them, will accept them as the best and the most accurate account of those districts that I am able to give.

INDEX.

PAGE.

Agglomerates 183

Akreyri 143

Alderjufoss 159

Arnarfell-hið-Mikla 166

Ásberg 136

Askja, plain of 86

Birch-tree 20

Borðeyri 138

Breiðamerkr Glacier 17, 24 ” ” Sandr 23

Climate 180

Crater Lakes 122

Dettifoss 119

Dyngjufjöll 83 ” ascent of 101

Equipment 28

Eyrarbakki 8

Glaciers 190

Grafalandá River 76

Grímstaðir 70

Heiði 11

Hekla 181

Hengill, volcano of 6

Herðubreið 65, 103

Hot Springs 185

Hraun 7

Hrossaberg 75

Húsavík 133

Iron Pyrites, sublimation of 174

Jökulls 186

Jökulsá-á-fjöllum 61

Kaldbakkr 14

Kálfafellsfjall 30

Kálfafellstaðr 25

Kiðagil 160

Kistufell 54

Kötlugiá 181

Krafla 123

Lœkjarbotn 5

Lake Grœnavatn 126 ” Mývatn 111

Lavas of Iceland 183, 193 ” ” Mývatns Orœfí 108, 155

Laxá River 131

Lindá River 77

Lómagnúpar 19

Mount Paul 36

Mud-pools 115

Mývatns Orœfí, eruption of 146

Námufjall 113

Núpstað 15

Núpstaða-skógr 21

Núpsvatn River 18

Obsidian 36, 124

Ódáðahraun 95

Ölfusá, river of 8

Öskjugjá, crater of 88 ” volcano of 84

Pemmican, preparation of 26

Perlite 38

Provisions 29

Pumice 63, 78

Querkfjall 63

Reykjahlíð 112

Rivers, diversion of 57

Seljalandsfoss 13

Shark-liver oil 144

Skeiðarár Sandr 18

Skjaldbreið, ascent of 83, 96

Skjálfandifljót 145

Skógarfoss 11

Snow, camping in 32

Solfataras 174

Spherulite 38

Sprengisandr 165

Storms on the Vatna 46

Sulphur mines 112, 129

Svartfugl 23, 25

Swans 13

Thjórsá 10, 167

The “Great Kettle” 129

Trachytic lava 170

Vaðalda Hills 61

Vatna Jökull 32, 186 ” ” Housie 41

Volcanic mud 84, 88, 92

Water, eruption of 89

FOOTNOTES:

[1] So called from a particular kind of bird, called Lómi, which frequents this mountain.

[2] Not marked on the map.

TRANSCRIBER’S NOTE

For consistency all occurrences of a.m. and p.m. have been changed to A.M. and P.M.

Icelandic names often have accents and hyphens, but they are applied inconsistently in the original text. Names in the etext have been adjusted to be consistent and follow the most common variant in the text. For example Reykjahlid, Reykjahlið, Reykjahlíð, have all been rendered as Reykjahlíð.

Five occurrences of Öskjagjá have been changed to Öskjugjá. Eight occurrences of Dyngjufjall have been changed to Dyngjufjöll. Seven occurrences of Reykjahlaíð have been changed to Reykjahlíð.

Obvious typographical errors and punctuation errors have been corrected after careful comparison with other occurrences within the text and consultation of external sources.

Except for those changes noted below, all misspellings in the text, and inconsistent or archaic usage, have been retained: for example, sandbank, sand-bank; mid-day, midday; grass land, grass-land; under weigh; negociated; felspar; enwrapped; indurated; coign.

Pg 3: ‘Oddr Gíslason upon’ replaced by ‘Oddr Gíslasson upon’. Pg 14: ‘named Eyólfr; he’ replaced by ‘named Eyólfur; he’. Pg 27: ‘and Eyólfr, from’ replaced by ‘and Eyólfur, from’. Pg 28: ‘accomodate six’ replaced by ‘accommodate six’. Pg 37: ‘known as spherolites’ replaced by ‘known as spherulites’. Pg 38: ‘pearlite and obsidian’ replaced by ‘perlite and obsidian’. Pg 38: ‘spherolites cemented’ replaced by ‘spherulites cemented’. Pg 52: ‘reached the the height’ replaced by ‘reached the height’. Pg 66: ‘to develope into’ replaced by ‘to develop into’. Pg 70: ‘baleing and rowing’ replaced by ‘bailing and rowing’. Pg 70: ‘Ha had passed’ replaced by ‘He had passed’. Pg 74: ‘and Eyolpur, while’ replaced by ‘and Eyólfur, while’. Pg 82: ‘The circumtances’ replaced by ‘The circumstances’. Pg 92: ‘again begining to’ replaced by ‘again beginning to’. Pg 111: ‘wady near the’ replaced by ‘wadi near the’. Pg 114: ‘which upon eastern’ replaced by ‘which upon the eastern’. Pg 127: ‘at the the time of’ replaced by ‘at the time of’. Pg 128: ‘the commencment of’ replaced by ‘the commencement of’. Pg 136: ‘north, insoculating’ replaced by ‘north, inosculating’. Pg 139: ‘into a karal’ replaced by ‘into a corral’. Pg 139: ‘the obstreporous cargo’ replaced by ‘the obstreperous cargo’. Pg 141: ‘cross the Sprengrtandr’ replaced by ‘cross the Sprengisandr’. Pg 168: ‘view of Hecla’ replaced by ‘view of Hekla’. Pg 185: ‘almost insoculate’ replaced by ‘almost inosculate’. Pg 190: ‘by Gunlaugson some’ replaced by ‘by Gunnlaugsson some’. Pg 190: ‘vergr is now’ replaced by ‘verge is now’.

Index. ‘Dyngjafjöll’ replaced by ‘Dyngjufjöll’. Index. ‘Lake Grænavatn’ replaced by ‘Lake Grœnavatn’. Index. ‘Myvatus’ replaced by ‘Mývatns’. Index. ‘Námurfjall’ replaced by ‘Námufjall’. Index. ‘Núpsvatu’ replaced by ‘Núpsvatn’. Index. ‘Querkfjöll’ replaced by ‘Querkfjall’.