Seismicity and tectonics around the northern Antarctic Peninsula from King Sejong station data

2000 ◽  
Vol 12 (2) ◽  
pp. 196-204 ◽  
Author(s):  
D.K. Lee ◽  
Y.K. Jin ◽  
Y. Kim ◽  
S.H. Nam
Keyword(s):  
Antarctic Peninsula ◽  
Fracture Zone ◽  
Normal Fault ◽  
The South ◽  
Seismicity And Tectonics ◽  
South Shetland Trench ◽  
Bransfield Basin ◽  
Shackleton Fracture Zone ◽  
The Antarctic ◽  
South Scotia Ridge

Local earthquakes recorded at the King Sejong station (62° 13′31″S, 58° 47′07″W) from 1995–96 have been analysed to study the seismicity and tectonics around the northern Antarctic Peninsula. The nature of shallow-focused normal fault earthquakes along the South Shetland Platform is still unclear. Dominant normal fault earthquakes and minor strike-slip earthquakes in the Eastern Bransfield Basin suggest 1) ongoing extension, and 2) transtensional stress transmitted from the Antarctic–Scotia transform boundaries, the South Scotia Ridge and the Shackleton Fracture Zone. A lack of seismicity in the Central Bransfield Basin supports that active seismicity in the Eastern Bransfield Basin is not a result of subduction along the South Shetland Trench. Shallow focused earthquakes have been observed along the NW–SE trending gravity low line between the Central and the Eastern Bransfield Basins that approximately coincides with the landward projection of a fracture zone in the former Phoenix Plate.

Chapter 3.2b Bransfield Strait and James Ross Island: petrology

2021 ◽  
pp. M55-2018-37 ◽  
Author(s):  
Karsten M. Haase ◽  
Christoph Beier
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Island ◽  
The South ◽  
Bransfield Strait ◽  
Geodynamic Processes ◽  
James Ross Island ◽  
South Shetland Trench ◽  
Low Degrees ◽  
Back Arc ◽  
The Antarctic

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.

Gravity models for the South Shetland Trench and the Shackleton Fracture Zone, Antarctica

1997 ◽  
Vol 1 (2) ◽  
pp. 89-98 ◽  
Author(s):  
Young Keun Jin ◽  
Yeadong Kim ◽  
Sang Heon Nam ◽  
Duk Kee Lee ◽  
Kiehwa Lee
Keyword(s):  
Fracture Zone ◽  
Gravity Models ◽  
The South ◽  
South Shetland Trench ◽  
Shackleton Fracture Zone

scholarly journals Surface Circulation at the Tip of the Antarctic Peninsula from Drifters

2009 ◽  
Vol 39 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Andrew F. Thompson ◽  
Karen J. Heywood ◽  
Sally E. Thorpe ◽  
Angelika H. H. Renner ◽  
Armando Trasviña
Keyword(s):  
Antarctic Peninsula ◽  
Weddell Sea ◽  
Ecosystem Dynamics ◽  
Mean Flow ◽  
The South ◽  
Scotia Ridge ◽  
Surface Circulation ◽  
Dominant Feature ◽  
The Antarctic ◽  
South Scotia Ridge

Abstract An array of 40 surface drifters, drogued at 15-m depth, was deployed in February 2007 to the east of the tip of the Antarctic Peninsula as part of the Antarctic Drifter Experiment: Links to Isobaths and Ecosystems (ADELIE) project. Data obtained from these drifters and from a select number of local historical drifters provide the most detailed observations to date of the surface circulation in the northwestern Weddell Sea. The Antarctic Slope Front (ASF), characterized by a ∼20 cm s−1 current following the 1000-m isobath, is the dominant feature east of the peninsula. The slope front bifurcates when it encounters the South Scotia Ridge with the drifters following one of three paths. Drifters (i) are carried westward into Bransfield Strait; (ii) follow the 1000-m isobath to the east along the southern edge of the South Scotia Ridge; or (iii) become entrained in a large-standing eddy over the South Scotia Ridge. Drifters are strongly steered by contours of f /h (Coriolis frequency/depth) as shown by calculations of the first two moments of displacement in both geographic coordinates and coordinates locally aligned with contours of f /h. An eddy-mean decomposition of the drifter velocities indicates that shear in the mean flow makes the dominant contribution to dispersion in the along-f /h direction, but eddy processes are more important in dispersing particles across contours of f /h. The results of the ADELIE study suggest that the circulation near the tip of the Antarctic Peninsula may influence ecosystem dynamics in the Southern Ocean through Antarctic krill transport and the export of nutrients.

Tectonic development of the Bransfield Basin and its prolongation to the South Scotia Ridge, northern Antarctic Peninsula

2004 ◽  
Vol 206 (1-4) ◽  
pp. 267-282 ◽  
Author(s):  
Jesús Galindo-Zaldı́var ◽  
Luiz Gamboa ◽  
Andrés Maldonado ◽  
Seizo Nakao ◽  
Yao Bochu
Keyword(s):  
Antarctic Peninsula ◽  
The South ◽  
Scotia Ridge ◽  
Tectonic Development ◽  
Bransfield Basin ◽  
South Scotia Ridge

Geotectonic evolution of the Bransfield Basin, Antarctic Peninsula: insights from analogue models

2008 ◽  
Vol 20 (2) ◽  
pp. 185-196 ◽  
Author(s):  
M.A. Solari ◽  
F. Hervé ◽  
J. Martinod ◽  
J.P. Le Roux ◽  
L.E. Ramírez ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
The West ◽  
Shetland Islands ◽  
Scotia Ridge ◽  
The North ◽  
Analogue Models ◽  
Bransfield Basin ◽  
The Phoenix

AbstractThe Bransfield Strait, located between the South Shetland Islands and the north-western end of the Antarctic Peninsula, is a back-arc basin transitional between rifting and spreading. We compiled a geomorphological structural map of the Bransfield Basin combining published data and the interpretation of bathymetric images. Several analogue experiments reproducing the interaction between the Scotia, Antarctic, and Phoenix plates were carried out. The fault configuration observed in the geomorphological structural map was well reproduced by one of these analogue models. The results suggest the establishment of a transpressional regime to the west of the southern segment of the Shackleton Fracture Zone and a transtensional regime to the south-west of the South Scotia Ridge by at least c. 7 Ma. A probable mechanism for the opening of the Bransfield Basin requires two processes: 1) Significant transtensional effects in the Bransfield Basin caused by the configuration and drift vector of the Scotia Plate after the activity of the West Scotia Ridge ceased at c. 7 Ma. 2) Roll-back of the Phoenix Plate under the South Shetland Islands after cessation of spreading activity of the Phoenix Ridge at 3.3 ± 0.2 Ma, causing the north-westward migration of the South Shetland Trench.

scholarly journals Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy

2004 ◽  
Vol 16 (3) ◽  
pp. 339-344 ◽  
Author(s):  
BRENDA L. HALL ◽  
ETHAN R. PERRY
Keyword(s):  
Antarctic Peninsula ◽  
Ocean Circulation ◽  
Late Holocene ◽  
Warming Trend ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Livingston Island ◽  
The Antarctic ◽  
Glacial Advance

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.

A fission track thermochronological study of King George and Livingston islands, South Shetland Islands (West Antarctica)

2004 ◽  
Vol 16 (2) ◽  
pp. 191-197 ◽  
Author(s):  
I. SELL ◽  
G. POUPEAU ◽  
J.M. GONZÁLEZ-CASADO ◽  
J. LÓPEZ-MARTÍNEZ
Keyword(s):  
South Shetland Islands ◽  
West Antarctica ◽  
The South ◽  
North West ◽  
The North ◽  
Early Oligocene ◽  
Barton Peninsula ◽  
Bransfield Basin ◽  
Back Arc ◽  
The Antarctic

This paper reports the dating of apatite fission tracks in eleven rock samples from the South Shetland Archipelago, an island arc located to the north-west of the Antarctic Peninsula. Apatites from Livingston Island were dated as belonging to the Oligocene (25.8 Ma: metasediments, Miers Bluff Formation, Hurd Peninsula) through to the Miocene (18.8 Ma: tonalites, Barnard Point). Those from King George Island were slightly older, belonging to the Early Oligocene (32.5 Ma: granodiorites, Barton Peninsula). Towards the back-arc basin (Bransfield Basin), the apatite appears to be younger. This allows an opening rate of approximately 1.1 km Ma−1 (during the Miocene–Oligocene interval) to be calculated for Bransfield Basin. Optimization of the apatite data suggests cooling to 100 ± 10°C was coeval with the end of the main magmatic event in the South Shetland Arc (Oligocene), and indicates slightly different tectonic-exhumation histories for the different tectonic blocks.

scholarly journals Kinematics and segmentation of the South Shetland Islands-Bransfield basin system, northern Antarctic Peninsula

2008 ◽  
Vol 9 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Frederick W. Taylor ◽  
Michael G. Bevis ◽  
Ian W. D. Dalziel ◽  
Robert Smalley ◽  
Cliff Frohlich ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Bransfield Basin ◽  
Basin System

The Bellingshausen-Palmer meeting

Polar Record ◽  
2015 ◽  
Vol 51 (6) ◽  
pp. 644-654 ◽  
Author(s):  
Rip Bulkeley
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Contentious Issue ◽  
Balanced Assessment ◽  
Absolute Certainty ◽  
South Shetlands ◽  
The Antarctic

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.

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