2. Bathymetrical survey of the South Atlantic Ocean and Weddell SEA

Proceedings of the Geologists' Association

2015

The geological character of the South Atlantic islands was only slowly established during the first half of the 20 th century. That same period was marked by a generally dismissive view of continental drift but, as the continental nature of the islands became apparent, their 'oceanic' setting was utilised by both sides of the 'drift' debate to support their respective positions. So islands such as the Falklands archipelago and South Georgia were cited either as fragments detached from larger continental bodies during drift, or as the last surviving vestiges of a huge continental landmass that had subsided beneath the water of the South Atlantic. The appreciation of the Scotia Arc as a dynamic geological construct arising from lateral tectonics, and the Falkland Islands as representative of an itinerant continental fragment, were features of some early accounts of the region, but such ideas were generally discounted by the geological establishment of the day. This paper reviews the early, pioneering contributions to the geological understanding of the Falkland Islands, South Georgia and the Scotia Arc region, assessing their contemporary reception and tracing their influence on the developing continental drift controversy. Though commonly dismissed or ignored at the time, many of the 'pro-drift' ideas expressed were subsequently rediscovered by proponents of plate tectonics as that revolution swept through geology in the late 1960s.

Section: Early Regional Assessments Of the Scotia Arcmentioning

confidence: 99%

Section: Geological Pioneers In South Georgiamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Geological exploration of South Atlantic islands and its contributions to the continental drift debate of the early 20th century

Proceedings of the Geologists' Association

2015

“…In this he followed Arçtowski (1895) Suess (1909, 488-497). One possibility that he considered was that a submerged geological link followed the Scotia Arc, a submarine feature defined by soundings taken during the SNAE and named after the Scotia, the expedition's ship (Bruce 1905). The Scotia Arc extends through South Georgia, around the South Sandwich Islands and on into the South Orkney Islands (Figure 1) but Suess, whilst supporting the broad idea, felt it more likely that the eastward bend Gregory supported the view that the ocean basins were created by the fault-controlled subsidence of continental areas, but though he was certainly influential in delaying acceptance of Wegener's (1912Wegener's ( , 1915 formulation of continental drift, Leake (2011, 187-191) suggests that Gregory's position on the subject was in fact rather ambivalent.…”

Section: Epilogue: the Regional Perspectivementioning

confidence: 99%

The mineral prospecting expeditions to the South Atlantic islands and Antarctic Peninsula region made by the Scottish geologist David Ferguson, 1912–1914

Faithfull

2013

SJG

Synopsis David Ferguson’s mineral prospecting expeditions to South Georgia (1912), the Falkland Islands and the South Shetland Islands (1913–1914), on behalf of the Christian Salvesen whaling company of Leith and now largely forgotten, were early examples of commercially motivated terrestrial exploration in the South Atlantic region. Prior geological knowledge was very limited and Ferguson complemented his unsuccessful prospecting work with attempts to understand the regional geology of the areas that he visited. These interpretations were based on relatively cursory fieldwork undertaken in an arduous environment, and did not prove robust; but the well-documented specimen collections that Ferguson accumulated provided the basis for excellent and much-cited petrographical accounts by G. W. Tyrrell of Glasgow University. Ferguson had studied geology at the university and the influence of his mentor there, Professor J. W. Gregory, is apparent. In turn, Gregory utilized Ferguson’s observations in support of a subsided ‘South Atlantic continent’, opposing the ‘displacement hypothesis’ for that region formalized by Alfred Wegener from 1912 onwards. Ferguson’s field notebooks and most of his rock specimens are now held by Glasgow University (Archive Services and Hunterian Museum, respectively) but he distributed representative specimen collections widely, and these are extant in several other British museums. Specimens were also supplied to, and discussed with, William Speirs Bruce who, following the 1902–1904 Scottish National Antarctic Expedition, took a keen interest in Ferguson’s discoveries.

“…Led by William Speirs Bruce (1867Bruce ( -1921 it set sail aboard Scotia on 2 nd November 1902 from the what is now known as the Scotia Sea, by means of an arduous programme of ocean sounding (Bruce 1905), is probably the expedition's best-known achievement.…”

Section: Introductionmentioning

confidence: 99%

The geological work of the Scottish National Antarctic Expedition, 1902 – 04

2017

SJG

The Scottish National Antarctic Expedition (1902 – 04) made the first topographical survey and geological assessment of Laurie Island, one of the South Orkney Islands. The expedition's surgeon and geologist, J. H. H. Pirie, provided competent geological descriptions but these were largely overshadowed by his misidentification of an obscure plant fossil as a graptolite. Erroneous confirmation by eminent British palaeontologists led to Triassic rocks being regarded as Lower Palaeozoic for fifty years. The mistake arose from the familiarity of all concerned with the geology of the Scottish Southern Uplands: they were led astray by the preconception that, as in Scotland, deformed ‘greywacke–shale’ successions would contain Lower Palaeozoic fossils. Other, more successful aspects of the expedition's geological investigations are less well known. Fossils acquired in the Falkland Islands expanded that archipelago's poorly known Devonian brachiopod fauna, but arguably the most important palaeontological discovery lay unrecognized for ten years. A limestone block dredged from the bed of the Weddell Sea contained Early Cambrian archaeocyath fossils which, had they been promptly identified, would have been the first record of this important Antarctic palaeofauna. Instead, the Weddell Sea material complemented fossils recovered on the opposite, Ross Sea side of the Antarctic continent during Shackleton's British Antarctic Expedition (1907 – 09).