222Rn in the Antarctic Peninsula During 1986

1988 ◽  
Vol 24 (1-4) ◽  
pp. 85-88 ◽  
Author(s):  
E.B. Pereira ◽  
A.W. Setzer ◽  
I.F.A. Cavalcanti

Abstract 222Rn was continuously measured at the Brazilian Antarctic Station (62 oS, 58 oW) during the year of 1986. Baseline radon concentration averaged 0.02 Bq.m-3 with surges peaking at 0.4 Bq.m-3. The data exhibited a characteristic periodicity of about 25 days and a strong positive association with short term fluctuations of atmospheric temperature. No seasonal variation of radon were observed. Interpretation of the radon surges with reference to synoptic charts and weather satellite pictures showed that the continental influence of radon at the Antarctic Peninsula is very small and comes only from the tip of the South American cone.

2021 ◽  
pp. M55-2018-37 ◽  
Author(s):  
Karsten M. Haase ◽  
Christoph Beier

AbstractYoung volcanic centres of the Bransfield Strait and James Ross Island occur along back-arc extensional structures parallel to the South Shetland island arc. Back-arc extension was caused by slab rollback at the South Shetland Trench during the past 4 myr. The variability of lava compositions along the Bransfield Strait results from varying degrees of mantle depletion and input of a slab component. The mantle underneath the Bransfield Strait is heterogeneous on a scale of approximately tens of kilometres with portions in the mantle wedge not affected by slab fluids. Lavas from James Ross Island east of the Antarctic Peninsula differ in composition from those of the Bransfield Strait in that they are alkaline without evidence for a component from a subducted slab. Alkaline lavas from the volcanic centres east of the Antarctic Peninsula imply variably low degrees of partial melting in the presence of residual garnet, suggesting variable thinning of the lithosphere by extension. Magmas in the Bransfield Strait form by relatively high degrees of melting in the shallow mantle, whereas the magmas some 150 km further east form by low degrees of melting deeper in the mantle, reflecting the diversity of mantle geodynamic processes related to subduction along the South Shetland Trench.


1997 ◽  
Vol 71 (2) ◽  
pp. 348-350 ◽  
Author(s):  
S. F. Vizcaino ◽  
M. Bond ◽  
M. A. Reguero ◽  
R. Pascual

The record of fossil land mammals from Antarctica has been restricted previously to the middle levels of the Eocene-?early Oligocene La Meseta Formation in Seymour Island, Antarctic Peninsula. This mostly shallow-marine sequence was divided informally into seven subunits (Tertiary Eocene La Meseta or TELM 1 to 7) by Sadler (1988). Land mammals, representing South American lineages of marsupials, edentates, and ungulates were recovered from TELM 3, 4, and 5 (Marenssi et al., 1994; Vizcaíno et al., 1994). The purpose of the present note is to report the discovery of a well-preserved ungulate tooth from the uppermost level of the La Meseta Formation (TELM 7) and to discuss its paleoenvironmental implications.


2004 ◽  
Vol 16 (3) ◽  
pp. 339-344 ◽  
Author(s):  
BRENDA L. HALL ◽  
ETHAN R. PERRY

Raised beach ridges on Livingston Island of the South Shetland Islands display variations in both quantity and source of ice rafted detritus (IRD) received over time. Whereas the modern beach exhibits little IRD, all of which is of local origin, the next highest beach (∼250 14C yr BP) has large amounts, some of which comes from as far away as the Antarctic Peninsula. Significant quantities of IRD also were deposited ∼1750 14C yr BP. Both time periods coincide with generally cooler regional conditions and, at least in the case of the ∼250 yr old beach, local glacial advance. We suggest that the increases in ice rafting may reflect periods of greater glacial activity, altered ocean circulation, and/or greater iceberg preservation during the late Holocene. Limited IRD and lack of far-travelled erratics on the modern beach are both consistent with the ongoing warming trend in the Antarctic Peninsula region.


2012 ◽  
Vol 77 (4) ◽  
pp. 288-292 ◽  
Author(s):  
Maritza Sepúlveda ◽  
Renato A. Quiñones ◽  
Pablo Carrasco ◽  
M. José Pérez-Álvarez

Polar Record ◽  
2015 ◽  
Vol 51 (6) ◽  
pp. 644-654 ◽  
Author(s):  
Rip Bulkeley

ABSTRACTThe celebrated meeting between Captain Bellingshausen of the Imperial Russian Navy and the American sealing skipper Nathaniel Brown Palmer, off the South Shetland Islands in February 1821, has often been described by following just one or other of the two men's divergent and in some respects irreconcilable accounts. The most contentious issue is whether or not Palmer told Bellingshausen about the existence of a body of land to the south of the South Shetlands, known today as the Antarctic Peninsula. This note attempts to reach a balanced assessment of the matter by examining evidence from both sides, including several previously unconsidered items. It concludes that, although the truth will never be known with absolute certainty, the basic American account is more plausible, by the narrowest of narrow margins, than the Russian.


Polar Biology ◽  
2016 ◽  
Vol 40 (3) ◽  
pp. 649-658 ◽  
Author(s):  
Evelin Troncoso ◽  
Salvador Barahona ◽  
Mario Carrasco ◽  
Pablo Villarreal ◽  
Jennifer Alcaíno ◽  
...  

Nukleonika ◽  
2020 ◽  
Vol 65 (2) ◽  
pp. 153-157
Author(s):  
Iveta Smetanová ◽  
Karol Holý ◽  
Ľubica Luhová ◽  
Kristian Csicsay ◽  
Dagmar Haviarová ◽  
...  

AbstractThe continuous monitoring of 222Rn activity concentration, CO2 concentration, and microclimatologic parameters (internal air temperature and relative humidity) in the Važecká Cave (Northern Slovakia) is being carried out at three monitoring stations, namely, Gallery, Lake Hall, and Entrance Hall. Radon activity concentration and CO2 concentration exhibited a clear annual variation. The daily average of radon concentration ranged 1300–27 700 Bq/m3 at the Lake Hall station and 3600–42 200 Bq/m3 at the Gallery station. Radon reached its maximum in the summer months, from June to September. The annual maximum of CO2 concentration is registered approximately one month later than radon maximum. The annual variation of radon and CO2 is controlled by the seasonal change of ventilation regime associated with the seasonal variation of the difference between the temperature measured inside the cave and the atmospheric temperature.


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