Structural setting and timing of hydrothermal veins and breccias on Hurd Peninsula, South Shetland Islands: a possible volcanic-related epithermal system in deformed turbidites

1994 ◽  
Vol 131 (4) ◽  
pp. 465-483 ◽  
Author(s):  
Robert C. R. Willan
Keyword(s):  
Open Space ◽  
Hydrothermal Activity ◽  
South Shetland Islands ◽  
Shetland Islands ◽  
Quartz Veins ◽  
Intrusive Rocks ◽  
Extensional Faulting ◽  
High Level ◽  
The Antarctic ◽  
Main Vein

AbstractQuartz veins and vein-breccias in a greywacke-shale sequence of ?Carboniferous-Triassic age were previously regarded as mesothermal silicified fault breccias, and related to an adjacent Eocene granodiorite pluton. New mapping of vein assemblages and textures, and their structural and cross-cutting relationships, demonstrates that the steeply dipping, sheeted, epithermal-textured vein array was hydraulic in origin and possibly Cretaceous in age. The main vein and breccia swarm trends for 14 km NNE along-strike and 2 km across-strike, cutting large irregular areas of silicified and brecciated sandstone, and patchy areas of pyritic, propylitic and K-feldspar alteration. Angular vein fabrics and hydraulic disruption textures indicate wedging by hydrothermal solutions, hydraulic rupture, brecciation and fragment transport, followed by open-space precipitation, in veins generally < 15 cm thick and breccias up to a few metres thick. Hydrothermal quartz, chlorite, calcite and chalcedony predominate, with variable amounts of chalcopyrite, galena, sphalerite and pyrite. Epidote, arsenopyrite, K-feldspar and andradite garnet are conspicuous in places. Breccias were pre-and syn-mineralization, whereas mineral precipitation was pre-, syn- and post-breccia formation. Hydrothermal activity was simultaneous with extensional faulting, striking NNE, and accompanied by intrusion of dacitic dykes. There followed conjugate shearing on east- and ESE-striking faults, intrusion of high-level tonalite stocks, and several phases of basaltic andesite dyke intrusion. These hypabyssal rocks were probably coeval with the Antarctic Peninsula Volcanic Group dominating Livingston Island, dated between 130 and 75 Ma. Minor copper and iron sulphide-bearing veins occur in adjacent volcanic and hypabyssal intrusive rocks. The Hurd Peninsula veins may, therefore, form part of a volcanic-epithermal hydrothermal system (adularia-sericite-quartz type), of Cretaceous age, rather than a porphyry-related system of Eocene age.

The summer diet of demersal fish at the South Shetland Islands

1997 ◽  
Vol 9 (4) ◽  
pp. 407-413 ◽  
Author(s):  
Masanori Takahashi ◽  
Tetsuo Iwami
Keyword(s):  
Marine Ecosystem ◽  
Stomach Contents ◽  
Demersal Fish ◽  
South Shetland Islands ◽  
Fish Prey ◽  
Shetland Islands ◽  
Antarctic Marine ◽  
Dietary Component ◽  
Gobionotothen Gibberifrons ◽  
The Antarctic

The stomach contents of demersal fish in late January 1982 were analysed. Samples were taken at 100, 300 and 500 m depth south of Elephant Island, Bransfield Strait and north of Livingston Island, and at 800 m to the east of Smith Island. Fifty four taxa of fish belonging to 11 families were collected. The diets of 2101 fish representing 38 taxa were examined. These were classified into three categories, fish feeders, krill feeders and benthos feeders. Fish prey species fed on krill and/or benthos. Krill was a major dietary component for 32 (84.2%) out of 38 taxa. Gobionotothen gibberifrons was distributed at all 10 stations (100–800 m in depth) and its diet comprised krill and benthos. The present findings verify the importance of krill in the Antarctic marine ecosystem and indicate that krill is consumed by benthic fish at greater depths than previously reported.

Fur seals, whales and tourists: a commercial history of Deception Island, Antarctica

Polar Record ◽  
2009 ◽  
Vol 46 (3) ◽  
pp. 210-221 ◽  
Author(s):  
J. Stephen Dibbern
Keyword(s):  
South Shetland Islands ◽  
Deception Island ◽  
Commercial Activity ◽  
Early 19Th Century ◽  
Cruise Industry ◽  
Shetland Islands ◽  
Fur Seals ◽  
History Of ◽  
The Antarctic ◽  
Antarctic Fur Seals

ABSTRACTDeception Island in the South Shetland Islands was the site of some of the earliest commercial activity to be carried out in the Antarctic with the early 19th century hunting of Antarctic fur seals. Nearly a century later it was the site of the most extensive anchorage for the reconstructed ships and ocean liners used as non-pelagic whale processing factories. Deception was also the site of what is the only successful land based commercial activity in Antarctic history. The Hektor whaling station operated in Whalers Bay from 1912 until 1931. Most of the remains of the station have now been obliterated by the volcanic activity that occurred in the late 1960s and 1970. By the later part of the twentieth century Deception Island had become a regular stop for the growing Antarctic tourist cruise industry. No other place in Antarctica has been so thoroughly identified with commercial activity.

New trigonioid bivalves from the Early Jurassic to earliest Cretaceous of the Antarctic Peninsula region: systematics and austral paleobiogeography

1995 ◽  
Vol 69 (1) ◽  
pp. 66-84 ◽  
Author(s):  
Simon R. A. Kelly
Keyword(s):  
New Zealand ◽  
Antarctic Peninsula ◽  
Southern Africa ◽  
Late Jurassic ◽  
Early Jurassic ◽  
South Shetland Islands ◽  
Shetland Islands ◽  
Livingston Island ◽  
History Of ◽  
The Antarctic

New discoveries of trigonioid bivalves are documented from three areas in the Antartic Peninsula: the Fossil Bluff Group of Alexander Island, the Latady Formation of the Orville Coast, and the Byers Group of Livingston Island, South Shetland Islands. Eleven taxa are described, representing six genera or subgenera. The faunas are characterized by genera including Vaugonia (Vaugonia), the first Early Jurassic trigonioid recognized on the continent; Vaugonia (V.) and V. (Orthotrigonia?) in the Late Jurassic; and Iotrigonia (Iotrigonia), Myophorella (Scaphogonia), and Pterotrigonia (Pterotrigonia), which span the Jurassic–Cretaceous boundary, reaching the Berriasian stage. The following species are new: Pterotrigonia (P.) cramei n. sp., Pterotrigonia (P.) thomsoni n. sp., Vaugonia (V.) orvillensis n. sp., and V. (Orthotrigonia?) quiltyi n. sp. The faunas show affinities with those of New Zealand and southern Africa. Trigonioids characterize the shallower marine biofacies in the Jurassic of the Antarctic and reflect the principal shallowing events in the history of the region.

scholarly journals New records of isopod species of the Antarctic Specially Managed Area No. 1, Admiralty Bay, South Shetland Islands

2017 ◽  
Vol 38 (3) ◽  
pp. 409-419
Author(s):  
Karol Zemko ◽  
Krzysztof Pabis ◽  
Jacek Siciński ◽  
Magdalena Błażewicz
Keyword(s):  
Southern Ocean ◽  
New Records ◽  
South Shetland Islands ◽  
Small Scale ◽  
King George Island ◽  
Admiralty Bay ◽  
Shetland Islands ◽  
The Antarctic ◽  
First Time ◽  
Marine Basins

AbstractAdmiralty Bay (King George Island) is an Antarctic Specially Managed Area and one the most thoroughly studied small-scale marine basins in the Southern Ocean. Our study provides new data on the isopod fauna in this glacially affected fjord. Twelve species of isopods were recorded in this basin for the first time. Six of them were found for the first time in the region of the South Shetland Islands. The highest number of species new for Admiralty Bay were found in the families Munnopsidae (4 species) and Munnidae (3 species).

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.

Cretaceous angiosperms from an allegedly Triassic flora at Williams Point, Livingston Island, South Shetland Islands

1989 ◽  
Vol 1 (3) ◽  
pp. 239-248 ◽  
Author(s):  
P.M. Rees ◽  
J.L. Smellie
Keyword(s):  
Antarctic Peninsula ◽  
Direct Evidence ◽  
South Shetland Islands ◽  
Fossil Flora ◽  
Volcanic Arc ◽  
Shetland Islands ◽  
Active Volcanism ◽  
Livingston Island ◽  
Radiometric Ages ◽  
The Antarctic

A terrestrial sequence on Livingston Island, South Shetland Islands, known as the Williams Point Beds contains a well-preserved, diverse fossil flora previously assigned a Triassic age. Because of their supposed age, volcanic provenance and evidence for active volcanism, the Williams Point Beds have occupied a unique position in Gondwana (pre-Jurassic) stratigraphy in the Antarctic Peninsula region. However, a large new collection of plant specimens obtained at Williams Point has yielded several species of angiosperm leaves, which are abundant and occur at all levels within the Williams Point Beds sequence. Thus, a Triassic age is no longer tenable. On the basis of the plants present and published radiometric ages for associated strata, the Williams Point Beds fossil flora is reassigned to the Cretaceous, and there is some evidence for a more restricted Albian–Cenomanian age. This revision of the age of the Williams Point Beds removes all direct evidence for an active Triassic volcanic arc in the Antarctic Peninsula region.

Sign in / Sign up

Export Citation Format

Share Document