Coats Land Research Articles

Upper mantle seismic anisotropy beneath Antarctica and the Scotia Sea region

Recent investigations on shear wave splitting from recordings of permanent and temporary Antarctic seismological stations have lead to a greater understanding of the upper mantle dynamics of the Scotia Sea region and the continental margin in the eastern Weddell Sea in terms of their tectonic evolution. The analysis of shear wave splitting from teleseismic core (SKS, SKKS, PKS) and direct S waves reveals the seismic anisotropy and the strain field of the upper mantle. Similar to the Caribbean, anisotropy structures in the Antarctic Peninsula and Scotia Sea regions are assumed to be influenced by mantle flows in easterly directions around the subducting Nazca plate. In general, anisotropy polarization directions in the Scotia Sea do not contradict this hypothesis, with polarizations oriented nearly E-W and therefore aligning with the suggested mantle flow patterns. Anisotropy strengths decrease from delay times of δt=1.8s (PMSA, Palmer Station) in the west towards the east with delay times of δt=0.3s beneath HOPE (South Georgia) and CAND (Candlemas, South Sandwich Islands). Nevertheless, a lithospheric and therefore fossil origin cannot be ruled out. Only the exceptionally high delay times at PMSA probably originate in part from recent asthenospheric flow around the subduction slab of the former Phoenix Plate beneath the northwestern margin of the Antarctic Peninsula. The continental margin of western Dronning Maud and Coats Land plays a crucial role in understanding the early processes during the break-up of Gondwana. Upper mantle seismic anisotropy with delay times well over δt=1s in this region gives new constraints on ancient deformation processes during break-up and former episodes. Two-layer modelling reveals Archaean anisotropy in the upper layer corresponding well to polarization directions of the South African Kaapvaal Craton. Lower layer anisotropy is assumed to have been created during early Gondwana rifting stages.

Rodinia: the evidence from integrated palaeomagnetism and U–Pb geochronology

Of many hundreds of well-defined palaeomagnetic poles that have been reported from cratons around the world in the 1700–500 Ma period, only a few are precisely dated. However, such ‘key’ palaeopoles are a prerequisite for establishing rigorous palaeomagnetic reconstructions in order to chart the assembly, drift and breakup of the postulated late Precambrian supercontinent of Rodinia. Most key palaeopoles are derived from mafic dykes and sills that have been dated by U–Pb techniques. Most are from Laurentia, the largest and best studied of the continental fragments that are thought to have comprised Rodinia. Thirteen key Laurentia palaeopoles form an incomplete reference set that can be used for comparison with key palaeopoles from other cratons as they become available. Currently, there are four key palaeopoles for Baltica between 1700 and 500 Ma, although only one allows a direct comparison with a similar aged pole from Laurentia. The 1265 Ma match between Baltica and Laurentia is consistent with reconstructions in which Baltica is adjacent to present-day east Greenland, with the ca. 1700–1500 Ma Gothian and Labradorian belts aligned. Few key palaeopoles are yet available from other cratons. However, recent U–Pb dating of dykes, sills, or volcanic rocks in the Siberian, Australian and Kalahari cratons and in Coats Land of Antarctica constrains the ages of individual palaeopoles from each of these areas. Most of these are not key palaeopoles because they have not been conclusively demonstrated to be primary, or local tectonic rotations have not been ruled out. Nevertheless, they are useful in testing Rodinia reconstructions. In this paper, a U–Pb baddeleyite age is reported from the late Gardar magmatic rocks of southwest Greenland. Along with the previously published palaeopole for this unit, this age helps constrain the Mesoproterozoic location of southwest Greenland relative to North America.

Crustal structure of the Filchner‐Ronne Shelf and Coats Land, Antarctica, from gravity and magnetic data: Implications for the breakup of Gondwana

Understanding the tectonic evolution of the Weddell Sea embayment provides valuable insights on the breakup of Gondwana. Existing geodynamic models for this region differ mainly in the nature of the crust beneath the Filchner‐Ronne shelf and the movement of the Ellsworth‐Whitmore Mountains (EWM) crustal block. New gravity data presented here constrain the area and timing of this EWM movement from its prebreakup position to its present‐day position. The crustal thickness estimates of 29±5 km and 27±4 km derived from power spectral analysis as well as forward gravity modeling make the existence of oceanic crust beneath the Filchner‐Ronne shelf unlikely. A new crustal unit consisting of Precambrian crust has been identified with gravity and magnetic data and extends ∼175 km off the coast of Coats Land. This crustal unit conflicts with the late Mesozoic movement of the EWM in this area. The effective elastic thickness of Te = 35±5 km has been estimated from coherence spectra for the Ronne shelf. Together with the crustal thickness of 27 km from refraction seismic studies and comparison with theoretical models, the thermal age is estimated to be between 165 and 230 Ma for the Ronne shelf. This age marks the last significant tectonic event in this area and is in good agreement with the breakup of Gondwana. It further makes later movements of microplates like the EWM in this region unlikely. Thus a Filchner block consisting of continental crust should be considered in any geodynamic model of the early Weddell Sea evolution.

Mesozoic dolerite dykes of the Falkland Islands: petrology, petrogenesis and implications for geochemical provinciality in Gondwanaland low-Ti basaltic rocks

The dolerite dykes of central West Falkland provided the first palaeomagnetic evidence of the near-180° rotation of the islands during the break-up of Gondwanaland. Here we present the results of a petrological and geochemical study of those dolerites. Most of the dykes sampled can be assigned to one of two suites named north-south and east-west respectively in recognition of their dominant strike. E–W dykes have compositional affinities with magmas such as the Rooi Rand dolerites of SE Africa whose geochemical characteristics (e.g. 87 Sr/ 86 Sr<0.704) are suggestive of predominantly asthenospheric mantle derivation. N–S dykes, which are the most numerous, resemble the Ferrar magma type of Antarctica and the rare Hangnest and Kraai River magma types of the Karoo. The N–S dykes evolved by assimilation and fractional crystallization (AFC), most likely at crustal levels, leading to initial 87 Sr/ 86 Sr=0.708–0.712, but there is no compelling evidence for initial 87 Sr/ 86 Sr<0.708, perhaps suggesting an enriched lithospheric mantle source. Dykes from Lively Island and Mount Alice appear to be correlatives of other Karoo magma types. All the Falklands dykes are low-Ti in character. However, within this one small area a variety of Karoo low-Ti magma types coexist with the Ferrar magma type of Antarctica. This overlap in space of different low-Ti magma types resembles the situation in Coats Land, Antarctica and enables us to propose an extension of the boundary of the Ferrar province parallel to the subducting margin of Gondwanaland.

Antarctic snow record of cadmium, copper, and zinc content during the twentieth century

A snowpit in Coats Land, Antarctica, has been sampled in order to obtain a record of Cd, Cu and Zn covering the period 1923–1986. The snowpit record gives an indication of southern hemisphere (SH) pollution reaching Antarctica. For Zn, concentrations (averaging 1.5 ng kg -1) can be explained as arising from natural crustal dust (based on Zn/Al ratios). No increase is observed over the period of the record here, despite a large increase in emissions from smelting operations. The main emitters are near the equator, and this may explain the lack of response in the Antarctic record. For Cd, concentrations (averaging 0.1 ng kg -1) cannot easily be explained in terms of natural emissions, unless the volcanic input is dominant. No significant increase is seen in the snow for this metal also. For Cu, the natural input can explain only a small part of the concentration (averaging 3.5 ng kg -1) measured, and increased concentrations (factor 2) are seen in the 1970s and 1980s compared to earlier decades. This is consistent with increased emissions from Cu smelting activities, particularly in Chile, where emissions are relatively far south compared to the main part of SH landmasses. Cu thus joins Pb as a metal whose natural cycle has been significantly perturbed even in the Antarctic atmosphere.

Evidence for Cambrian deformation in the Ellsworth-Whitmore Mountains terrane, Antarctica: Stratigraphic and tectonic implications

Research Article| January 01, 1998 Evidence for Cambrian deformation in the Ellsworth-Whitmore Mountains terrane, Antarctica: Stratigraphic and tectonic implications Ernest M. Duebendorfer; Ernest M. Duebendorfer 1Department of Geology, Northern Arizona University, Flagstaff, Arizona 86011 Search for other works by this author on: GSW Google Scholar Margaret N. Rees Margaret N. Rees 2Department of Geoscience, University of Nevada, Las Vegas, Nevada 89154 Search for other works by this author on: GSW Google Scholar Geology (1998) 26 (1): 55–58. https://doi.org/10.1130/0091-7613(1998)026<0055:EFCDIT>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Ernest M. Duebendorfer, Margaret N. Rees; Evidence for Cambrian deformation in the Ellsworth-Whitmore Mountains terrane, Antarctica: Stratigraphic and tectonic implications. Geology 1998;; 26 (1): 55–58. doi: https://doi.org/10.1130/0091-7613(1998)026<0055:EFCDIT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The Ellsworth-Whitmore Mountains terrane is a large geologically and geophysically defined crustal block that lies between the Transantarctic Mountains and West Antarctica. The Cambrian position of the terrane is controversial, with many workers placing it between East Antarctica and southern Africa and distant from Cambrian orogenic belts. We present structural and stratigraphic evidence for Cambrian deformation in the Heritage Range, Ellsworth Mountains. From our revised stratigraphy and structural history of the Heritage Range, we propose that the Ellsworth-Whitmore Mountains block was located within the belt of Pan-African deformation, within the Late Cambrian continental arc, and was part of a collage of allochthonous terranes that included the Queen Maud terrane and probably the Bowers terrane of Antarctica. These terranes were situated outboard of Coats Land in the Cambrian and were subsequently translated and accreted to East Antarctica, probably during early Paleozoic time. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Evidence for Cambrian deformation in the Ellsworth-Whitmore Mountains terrane, Antarctica: Stratigraphic and tectonic implications: Comment and Reply

The Ellsworth-Whitmore Mountains terrane is a large geologically and geophysically defined crustal block that lies between the Transantarctic Mountains and West Antarctica. The Cambrian position of the terrane is controversial, with many workers placing it between East Antarctica and southern Africa and distant from Cambrian orogenic belts. We present structural and stratigraphic evidence for Cambrian deformation in the Heritage Range, Ellsworth Mountains. From our revised stratigraphy and structural history of the Heritage Range, we propose that the Ellsworth-Whitmore Mountains block was located within the belt of Pan-African deformation, within the Late Cambrian continental arc, and was part of a collage of allochthonous terranes that included the Queen Maud terrane and probably the Bowers terrane of Antarctica. These terranes were situated outboard of Coats Land in the Cambrian and were subsequently translated and accreted to East Antarctica, probably during early Paleozoic time.

Correction to “Paleomagnetic data and U‐Pb isotopic age determinations from Coats Land, Antarctica: Implications for Late Proterozoic plate reconstructions” by Wulf A. Gose, Mark A. Helper, James N. Connelly, Fred E. Hutson, and Ian W. D. Dalziel

Correction to “Paleomagnetic data and U‐Pb isotopic age determinations from Coats Land, Antarctica: Implications for Late Proterozoic plate reconstructions” by Wulf A. Gose, Mark A. Helper, James N. Connelly, Fred E. Hutson, and Ian W. D. Dalziel

Paleomagnetic data and U‐Pb isotopic age determinations from Coats Land, Antarctica: Implications for late Proterozoic plate reconstructions

Paleomagnetic results and isotopic age determinations for granophyre and rhyolite from small, isolated nunataks in southern Coats Land, Antarctica, are used to evaluate late Proterozoic plate reconstructions. U‐Pb zircon dates for the two rock types indicate coeval crystallization at 1112±4 Ma. A concordant 1106±3 Ma titanite date from the granophyre overlaps the crystallization age, implying rapid cooling, and is consistent with field and petrographic evidence of no subsequent penetrative deformation, metamorphism, or hydrothermal disturbance. The mean direction of magnetization of the rhyolite at Littlewood Nunataks is statistically indistinguishable from the mean directions of five sites in the granophyre and crosscutting rhyolite dikes at Bertrab Nunataks. The group mean virtual geomagnetic pole of 22.9°N, 80.3°E (N=6, A95=6.8°) compares favorably with the only other extant Precambrian paleomagnetic poles for the East Antarctic craton, two poles from western Dronning Maud Land. The East Antarctic and Laurentian poles of 1.1 Ga do not coincide after restoration of the continents to a position suggested by the SWEAT hypothesis juxtaposing the Pacific margins of East Antarctica‐Australia and Laurentia, indicating either that the hypothesis is incorrect or that Coats Land and parts of western Dronning Maud Land (herein the CMG province) were not part of the East Antarctic craton at 1.1 Ga. In support of the latter, there is reasonable agreement of the 1.1 Ga CMG poles and approximately coeval poles from the Kalahari craton of West Gondwana when the CMG is restored to a position adjacent the Kalahari craton. Such a reconstruction places the CMG in West Gondwana rather than East Gondwana, as originally implied in Rodinia reconstructions, and is consistent with previously recognized links between the geology of the Kalahari craton and western Dronning Maud Land. It further implies that the CMG did not become part of East Antarctica until latest Precambrian to Cambrian time. A new reconstruction places a partially assembled West Gondwana off the present southeastern margin of Laurentia at 1.1 Ga such that poles of the CMG and Kalahari fall on the Laurentian polar wander path for this time period.

Pelagic distribution and numbers of the Antarctic petrel Thalassoica antarctica in the Weddell Sea during spring

Estimates of the population size of the Antarctic petrelThalassoica antarctica are hampered by its breeding locations in remote nunatak areas of the Antarctic continent. Studies at sea can provide additional information on numbers. Seabird censuses during spring 1992 showed few Antarctic petrels in the western part of the Weddell Sea, but high numbers east of the South Sandwich Islands. The vast majority of the birds occurred in a band of 300 km north to 150 km south of the outer ice edge. Numbers at sea fluctuated in agreement with synchronized colony attendance patterns in the pre-breeding phase and peaked shortly before egglaying when colonies are completely deserted. In this period, densities of Antarctic petrels in the marginal ice zone suggest that at least 2.7±0.5 million individuals occur in the Weddell Sea. It is likely that similar numbers occur immediately east of the study area. The distribution of the petrels matches the location, but not the size, of known breeding colonies in Dronning Maud Land and Coats Land, which suggests that important colonies in this area remain to be discovered. The observations imply that Antarctic petrels in the Weddell Sea commute over ice a surprisingly large distance of at least 2,000 km for a single pre-breeding visit to the colonies.

Weddell Sea tectonics and Gondwana break-up: an introduction

The Weddell Sea, part of the circumpolar Southern Ocean, is probably the most remote, least known and least accessible sea in the world. Difficult ice conditions have limited the acquisition of ship data, although this has been partly offset in recent years by access to satellite radar altimetry data. The Weddell Sea was originally defined by the Admiralty Hydrographic Department in 1932 and redefined by the Antarctic Place Names Committee in 1976 (Hattersley-Smith 1991). It is bounded on the western side by the east coast of the Antarctic Peninsula, on the southern side by the Ronne and Filchner ice fronts, and on the southeastern side by the Dronning Maud Land and Coats Land coasts of East Antarctica (Fig. 1). The South Scotia Ridge separates the Weddell Sea from the Scotia Sea to the north and a line joining Southern Thule in the South Sandwich Islands and Kapp Norvegia in Dronning Maud Land, separates it from the South Atlantic Ocean to the NE. Within this volume, papers relate to the Weddell Sea as defined above, together with part of the adjoining South Atlantic Ocean up to 50°E, and to the geology of the once neighbouring continents of Gondwana. The term Weddell Sea embayment is also used informally throughout this volume to include the embayment area to the south of the Weddell Sea now covered by the Ronne and Filchner ice shelves, including Berkner Island, and the continental shelf north of the Ronne and Filchner ice fronts (Figs 1 & 2).

The Grenville Province within Antarctica: a test of the SWEAT hypothesis

Geochronological, isotopic and aeromagnetic data, including a new Rb-Sr isochron of 1076 ± 7 Ma for volcanic rocks at Bertrab Nunatak, Coats Land, confirm the existence of rocks of Grenvillian age within both East and West Antarctica and support the juxtaposition of Antarctica and western North America in Neoproterozoic reconstructions.

Character of Clasts in Glaciomarine Sediments as an Indicator of Transport and Depositional Processes, Weddell and Lazarev Seas, Antarctica

ABSTRACT The gravel component in marine sediments on the continental margin of Antarctica is almost entirely from transport by grounded ice, ice shelves, ice tongues, and icebergs. About 2000 gravel clasts from about 40 sites were examined for roundness, Zingg shape, and Krumbein sphericity. Surface characteristics, like faceting, striations, and other specific glacigenic shapes, were recorded as well as lithology. The samples were from both shallow and deep waters along > 1500 km of the Antarctic margin bordering the eastern Weddell Sea and Lazarev Sea. In addition, onshore observations were made in ice-marginal areas at Schirmacher Oasis. Few systematic differences in clasts shape in modern sediments could be detected among the various glaciological environments; variation in shape within a given environment is greater than that between different environments. Abrasion of clasts at the interface between glacier and bedrock, before transport into the ocean, is less important than in temperate regions. This reflects the cold thermal regime of Antarctic glaciers, a view confirmed by the similarity in shape of debris from basal ice and from sandy basal tills at Schirmacher Oasis. More angular debris was recovered off grounded-ice margins in Coats Land, but given the absence of supraglacial sources this debris seems to be the product of rock fracturing at a relatively dry, frozen ice bed. More than half, and sometimes nearl all, the clasts are faceted. Faceting, roundness, and sphericity are independent of lithology. In contrast, striae on clasts are strongly dependent on lithology: few gneissic clasts have striae, but nearly half the clasts of fine-grained basic igneous or metavolcanic rocks are striated. Each area studied has a distinct population of rock types of limited variety, suggesting that deposition is predominantly from the nearest land-ice source, and that mixing of sediment with that from far-traveled icebergs is unimportant.

Coats Land dolerites and the generation of Antarctic continental flood basalts

Abstract On the basis of geochemical signatures, Mesozoic magmatism in Antarctica is divided into the Ferrar Magmatic Province and the Dronning Maud Land Province. The tholeiitic magmatism of the Ferrar Magmatic Province is distinguished by such features as low Ti/Y (&lt; 200) and Zr/Y (&lt; 5.0) ratios, negative εNd values (&lt; −3) and relatively enriched initial 87 Sr/ 86 Sr ratios (&gt; 0.709). All of these geochemical features indicate a major contribution from the continental mantle lithosphere in the generation of these magmas. In contrast, the Dronning Maud Land magmatism has elevated trace element ratios and εNd values (Ti/Y 250–600; Zr/Y 3.0–9.0; εNd −2 to +3) and lower initial 87 Sr/ 86 Sr ratios (&lt; 0.707) relative to the Ferrar Magmatic Province. The trace element and isotopic correlations suggest that these magmas were derived by the mixing of an OIB like asthenospheric component with a continental lithosphere component. The transition between these two geochemical provinces is located in Coats Land. In Coats Land, the Mesozoic tholeiitic magmatism is represented by doleritic sills and minor dykes which intrude Permo-Triassic sedimentary rocks. The dolerites can be subdivided into two series based on their TiO 2 contents. Series 1 dolerites (TiO 2 &lt; 1.5%) can be further subdivided into three groups, which give Ar/Ar ages of 171±6 Ma (Group 1) and 193±7 Ma (Groups 2 and 3). It is only Group 2 magmas which have trace element and isotopic signatures akin to the Ferrar Magmatic Province. Group 1 dolerites have geochemical signatures which are transitional between the Ferrar Magmatic Province and Dronning Maud Land magma types. The Ferrar Magmatic Province signature in Coats Land is confined to the early magmatic episode (193±7 Ma) and this appears to mark the initiation of rift related magmatism in this region. It is argued that extension was limited and that most of the melt was derived from the continental mantle lithosphere. In contrast, the younger rocks (176±5 Ma) have relatively lower initial 87 Sr/ 86 Sr and higher trace element ratios relative to the Ferrar Magmatic Province, and this appears to be associated with the later stages of rifting and relatively enhanced crustal extension which allowed for the encorporation of a small asthenosphere component.

26-Year High Resolution Profile Of Major Anions In Snow From Coats Land, Antarctica

In January 1987, an 7.8 m core, with an age at the bottom of 26 years, was collected from a site approximately 150 km inland from Halley Station (77°02.2′S, 22°32′W; altitude 1862 m a.s.l.); 10 m temperature ≈ −30°C; accumulation rate ≈ 14 g cm−2 a−1). The site lies some 140 km from the coast of the Weddell Sea and within the area bounded in winter by the polar vortex. The core has been analysed at a frequency of ≈28 samples per accumulation year for sulphate, nitrate and chloride, and has been dated stratigraphically from the clear seasonal cycles in non sea salt sulphate (Mulvaney and Peel, 1988). With this resolution it is possible to examine the seasonal pattern of deposition of chemical species and their phase relationships. Of particular interest is the possibility that ice cores may preserve evidence for disturbances in tropospheric chemistry, associated with the recent spring-time depletion of stratospheric ozone. It has been proposed that this is accompanied by a denitrification of the stratosphere during the winter months, implying enhanced levels of NOX in the late winter/spring troposphere and in precipitation. Our data reveal a strong seasonal signal in nitrate deposition, apparently peaking in spring. Similar behaviour has been reported by Wagenbach and others (1988) for nitrate in the atmospheric aerosol, in a 3-year sequence (1983–86) from Georg von Neumayer Station (70°S, 8°W). There does not appear to be any evidence in our data of an increase in spring-time nitrate deposition since the appearance of the Antarctic ozone hole in 1978.

26-Year High Resolution Profile Of Major Anions In Snow From Coats Land, Antarctica

In January 1987, an 7.8 m core, with an age at the bottom of 26 years, was collected from a site approximately 150 km inland from Halley Station (77°02.2′S, 22°32′W; altitude 1862 m a.s.l.); 10 m temperature ≈ −30°C; accumulation rate ≈ 14 g cm−2 a−1). The site lies some 140 km from the coast of the Weddell Sea and within the area bounded in winter by the polar vortex.The core has been analysed at a frequency of ≈28 samples per accumulation year for sulphate, nitrate and chloride, and has been dated stratigraphically from the clear seasonal cycles in non sea salt sulphate (Mulvaney and Peel, 1988). With this resolution it is possible to examine the seasonal pattern of deposition of chemical species and their phase relationships.Of particular interest is the possibility that ice cores may preserve evidence for disturbances in tropospheric chemistry, associated with the recent spring-time depletion of stratospheric ozone. It has been proposed that this is accompanied by a denitrification of the stratosphere during the winter months, implying enhanced levels of NOX in the late winter/spring troposphere and in precipitation. Our data reveal a strong seasonal signal in nitrate deposition, apparently peaking in spring. Similar behaviour has been reported by Wagenbach and others (1988) for nitrate in the atmospheric aerosol, in a 3-year sequence (1983–86) from Georg von Neumayer Station (70°S, 8°W). There does not appear to be any evidence in our data of an increase in spring-time nitrate deposition since the appearance of the Antarctic ozone hole in 1978.

Mesozoic dolerites from Whichaway Nunataks

The southernmost exposures of Mesozoic dolerites in Coats Land, the Omega dolerites, occur at Whichaway Nunataks. The dolerites are geochemically indistinguishable from the Theron Mountains' dolerites. In both regions high- and low-Ti compositions occur with trace element signatures more akin to island-arc magmas than within-plate tholeiites. From a preliminary Sr isotopic study the Omega dolerites can be classified as Ferrar type. The existence of Ferrar type material in these nunataks suggest that the boundary between the Ferrar and Weddell Sea sub-provinces occurs within the Theron Mountains.

The Scottish National Antarctic Expedition 1902–04

On 21 July 1904, just over 80 years ago, the barque-rigged, Norwegian-built auxiliary steamship Scotia sailed home up the Clyde with members of the Scottish National Antarctic Expedition (SNAE), concluding one of the most successful expeditions of the heroic period of Antarctic exploration. Contemporaneous with the more spectacular British Antarctic Expedition (1901–03) commanded by Robert Falcon Scott, the Scotia party under William Spiers Bruce had overwintered on Laurie Island (60° 44ʹ S, 44° 50ʹ W) in the South Orkney Islands, explored for the first time the oceanography of the Weddell Sea, assembled an important collection of scientific material, and discovered Coats Land, an icebound stretch of the East Antarctica coast.While Scott's Discovery expedition had emphasized geographical exploration inland from the Ross Sea sector of Antarctica, Bruce in the Scotia had concentrated more on scientific discovery in the Weddell Sea sector. On 12 November 1904 in Edinburgh, members of the Scotia and Discovery expeditions were guests at the 20th anniversary dinner of the Royal Scottish Geographical Society, Bruce and Scott together responding to a presidential toast that honoured the success of both.

Dr Harvey Pirie and the Scottish National Antarctic Expedition (1902-4). Scottish science and medicine in the Falklands and Antarctica.

Shortly after receiving a science and medical degree at Edinburgh, Dr Harvey Pirie joined the Scottish National Antarctic Expedition (1902-4) under Bruce. The naturalist team explored East Falkland, Laurie Island in the South Orkneys, and made the first oceanographic investigation of the Weddell Sea. After sighting Antarctica and naming the coast seen Coats Land, they returned to the Clyde via Gough Island and Cape Town. After a period in Scottish private practice, Pirie became a bacteriologist; he joined the Colonial Medical Service in 1913 and served in Kenya. In 1918 he organised the bacteriological services at the South African Institute for Medical Research in Johannesburg, and became deputy-director, 1926-41.

The Age of the Littlewood Volcanics of Coats Land, Antarctica

Acid volcanic or hypabyssal rocks from the Bertrab and the Littlewood Nunataks in Coats Land have been dated by the whole-rock Rb-Sr method. Five specimens from the Bertrab Nunatak define an isochron indicating an age of $$998 \pm 19 m.y.$$, based on a value of $$1.39 \times 10^{-11} year^{-1}$$ for the decay constant of $$Rb^{87}$$. Two specimens from the Littlewood Nunataks have possible ages ranging from 966 to 1,035 m.y. and fit the Bertrab isochron within experimental error. A pooled isochron of all the data leads to a best estimate of $$1,001 \pm 16 m.y.$$ for the age of these rocks. The initial $$Sr^{87}/Sr^{86}$$ ratio is $$0.7042 \pm 0.0011$$. A whole-rock K-Ar date of $$840 \pm 30 m.y.$$ reported in the literature shows no evidence of the expected argon loss caused by the Ross Orogeny.