Thermogenic hydrocarbons in surface sediments of the Bransfield Strait, Antarctic Peninsula

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.

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Depositional environment of near-surface sediments, King George Basin, Bransfield Strait, Antarctica

Geo-Marine Letters ◽

10.1007/bf01204465 ◽

1994 ◽

Vol 14 (1) ◽

pp. 1-9 ◽

Cited By ~ 19

Author(s):

H. I. Yoon ◽

B. K. Park ◽

S. K. Chang ◽

M. W. Han ◽

J. K. Oh

Keyword(s):

Depositional Environment ◽

Surface Sediments ◽

Near Surface ◽

Bransfield Strait

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Lithospheric structure of an incipient rift basin: Results from receiver function analysis of Bransfield Strait, NW Antarctic Peninsula

Polar Science ◽

10.1016/j.polar.2018.02.003 ◽

2018 ◽

Vol 16 ◽

pp. 47-58 ◽

Cited By ~ 2

Author(s):

C. Berk Biryol ◽

Stephen J. Lee ◽

Jonathan M. Lees ◽

Michael J. Shore

Keyword(s):

Antarctic Peninsula ◽

Receiver Function ◽

Function Analysis ◽

Lithospheric Structure ◽

Rift Basin ◽

Bransfield Strait ◽

Receiver Function Analysis

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Effect of the abundance of three predominating copepod species on adequate sample volume and sample size in Bransfield Strait (Antarctic Peninsula) and waters north of the Weddell Sea

Polar Biology ◽

10.1007/bf00236992 ◽

1992 ◽

Vol 12 (6-7) ◽

Author(s):

Ilppo Vuorinen ◽

Erik Bonsdorff

Keyword(s):

Sample Size ◽

Antarctic Peninsula ◽

Sample Volume ◽

Weddell Sea ◽

Copepod Species ◽

Bransfield Strait

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Encounter rates and abundance of humpback whales (Megaptera novaeangliae) in Gerlache and Bransfield Straits, Antarctic Peninsula

J. Cetacean Res. Manage. ◽

10.47536/jcrm.vi.312 ◽

2020 ◽

pp. 107-111

Author(s):

Eduardo R. Secchi ◽

Luciano Dalla Rosa ◽

Paul G. Kinas ◽

Raquel F. Nicolette ◽

Anne N. M. Rufino ◽

...

Keyword(s):

Antarctic Peninsula ◽

Distance Sampling ◽

Austral Summer ◽

Humpback Whales ◽

Encounter Rate ◽

Encounter Rates ◽

Abundance Estimate ◽

Bransfield Strait ◽

Distance Data ◽

The Difference

During the austral summer of 2006, the Projeto Baleias/Brazilian Antarctic Program (PROANTAR) conducted ship surveys for estimating whale encounter rates and abundance in Gerlache and Bransfield Straits, westward of the Antarctic Peninsula (edge between IWC Areas I and II). The encounter rate was higher in the Bransfield Strait (0.32 groups n. mile–1; 95% CI: 0.26–0.39) than in the Gerlache Strait (0.24 groups n. mile–1; 95% CI: 0.13–0.44), though the difference was not statistically evident. An abundance estimate using conventional distance sampling methods was computed only for the Bransfield Strait. The perpendicular distance data was best fitted by the half-normal model without adjustments. Derived abundance for the surveyed area was 865 humpback whales (95% CI = 656–1,141; CV = 14.13). This area represents only a small fraction of the Stock G feeding ground.

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