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Sedimentary basins on the east flank of the Antarctic Peninsula: Proposed nomenclature

Authors:
Rodolfo del Valle at Instituto Antártico Argentino
Rodolfo del Valle
D. H. Elliot
D. H. Elliot
D. H. Elliot
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D. I. M. Macdonald
D. I. M. Macdonald
D. I. M. Macdonald
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Abstract and Figures

The first fossils from Antarctica were collected from Seymour Island in December 1892, during the voyage of the Jason under Captain C.A. Larsen. The Swedish South Polar Expedition of 1901–1903, led by Otto Nordenskjöld, proved that there were extensive deposits of fossiliferous Cretaceous and Tertiary sedimentary rock in the James Ross Island area. This was confirmed by later geological mapping (Bibby 1966). Subsequent investigations have led to the establishment of various lithostratigraphic schemes (e.g. Ineson et al. 1986), and interpretation of the sedimentary history in terms of basin evolution (Elliot 1988, Macdonald et al. 1988). Unfortunately, different names have been proposed for the depositional basin, with consequent confusion. The purpose of this note is to review previous usage and propose a new consistent nomenclature for the sedimentary basins east of the Antarctic Peninsula.
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Antarctíc Science 4 (4):
477-478
(1992)
Short note·
Sedimentary basins on the east flank of the Antarctic Peninsula:
proposed nomenclature.
R.A.
DEL
VALLE1,
D.H.
ELLlOP
and
D.I.M.
MACDONALD3
1Instituto Antártico Argentino,
Cerrito
1248, Buenos Aires
1010,
Argentina
2Byrd
Polar Research
Center,
The
Ohio
State
University,
Columbus,
Ohio
43210,
USA
3British
Antarctic
Survey,
Natural Environment Research
Council,
High
Cross,
Madingley
Road,
Cambridge
CB3
OET,
UK
Acceptcd 16 July 1992
Introduction
Thefirstfossils fromAntarctica were coIlected fromSeymour
Island in
December
1892, during the voyage
of
the Jason
under Captain C.A. Larsen.
The
Swedish South Polar
Expedition
of
1901-1903, led by Otto Nordenskjold, proved
that there were extensive deposits offossiliferous Cretaceous
and Tertiary sedimentary rock in the James Ross Island area.
This was confirmed by later geological mapping (Bibby
1966). Subsequentinvestigations have led
to
theestablishment
ofvarious lithostratigraphicschemes (e.g. Ineson
el
al. 1986),
and interpretation
of
the sedimentary history in terms
ofbasin
evolution (EIliot 1988, Macdonald
el
al. 1988). Unfortunatel
y,
different names have been proposed for the depositional
basin, with consequent confusion.
The
purpose
of
this note is
to
review previous usage and propose a new consistent
nomencIature for the sedimentary basins eas
t,
of
the
An
tarctic
Peninsula.
The term WeddeIl Basin was used by
Sto
John (1986) for the
whole
of
the WeddeIl
Sea
and i
ts
continentalshelves inc:luding
the eastern side
of
the Antarctic Peninsula. The name Larsen
Basin was proposed by Macdonald
el
al. (1988) for the
sedimentary basin
on
the continental shelf
to
the east
of
the
AntarcticPeninsula (Fig. 1). Thebasin limi
ts
weredefined as
theAntarctic Peninsula
to
the west, the
shelfbreak
to the east,
JoinvilIe IsIand to the north, and a poorIy defined southern
edge south
of
Kenyon Peninsula. Outside the James Ross
IsIand region, knowledge
of
the
basin's
deposits is limited
to
a few scattered outcrops adjacent
to
the Peninsula and
to
regional geophysical surveys (Thomson 1967, Renner
el
al.
1985, BeIl
el
al. 1990, KeIler
el
al. 1991). FoIlowing
Farquharson (1983), Macdonald
el
al. (1988) defined the
western basin margin on the basis
of
a change in the
aeromagnetic anomaly pattern; the interpretation was made
using new data, which have now been published (Maslanyj
el
al.
1991). EIliot (1988) proposed the name James Ross
Basin for the rcgion in the vicinity
of
James Ross Island where
extensive outcrops
of
Cretaceous (Barremian-Maastrichtian)
strata and relatively smaIl outcrops
of
lower Tertiary beds are
present; the latter are confined
to
Seymour (Marambio) and
Cockburn islands. Cuenca Marambio (Marambio Basin) has
been used for the
same
area by Argentine geologists (e.g.
KeIler & Diaz 1990)
but
has not been formaIly defined.
Field and laboratory studies
on
the rocks have been
supplemented
by
aeromagnetic, seismie and magnetoteIluric
studies (Diaz
el
al. 1988, Fournier
el
al. 1989 and KeIler &
Diaz 1990). Ice conditions have prevented access
to
offshore
areas for marine geophysical surveys, although widely spaced
line data were coIlected in the 1989-90 season
to
the south and
east of JoinvilIe Island (Traube & Rybnikov 1991), and a 20-
km grid covering about 100 x 100
km
was surveyed
to
the east
of
James Ross, Snow Hill and Seymour (Marambio) islands
(Anderson & Shipp in press) in the 1990-91 season. The
exposed sedimentary rocks in the James Ross Island area are
65'S
, \ I
Jolnvllle. Island
I
I
I
m Island
I
land
I
Island
I
,
I
I
I
I
J
I
,
,
I
I
I
I
,
I
I
I
I
I
,
I
I
I
I
I
I
I
I
J
!
70'S
I
I
I
I 55'W
200 km
Fig.
1.
Map
of northern Antarctic Peninsula, showing James
Ross
Island (dark stipple)
in
relation
to
the
probable limits of
the
James
Ross
and
Larsen basins (light stipple).
477
478
R.A.
DEL VALLE et al.
almost
the
only indicator of
the
nature of the sedimentary
sequences that undoubtedly underlie
the
Larsen Ice Shelf
and
extend
out
to
the
shelf break along the length of
the
Weddell
Sea margin of the Antarctic Peninsula.
As
the
names Larsen, Marambio
and
James Ross are
aJ1
in
current
use
for sedimentary depocentres
in
the area,
it
is
important
to
achieve a rational nomenclature acceptab1e
to
aJl
workers carrying out research
in
the area.
We
propose that
Larsen Basin be used
to
describe the regionally extensive
depositional area upper Mesozoic-Cenozoic sedimentary
rocks that occur
on
the continental shelf east of the Antarctic
Peninsula. Its boundaries
are
mostly
cJearly
defined:
the
shelf
break
to
the
east
and
a faulted margin against
the
Antarctic
Peninsula
to
the west; the definition ofthe southern boundary
should await further studies, but the
Jimit
proposed by
Macdonald et
al.
(1988)
is
retained here because
the
geological
history of
the
northem part of
the
Antarctic Peninsula differs
from thatsouth of69-70oS. Thewestem marginoftheLarsen
Basin curves around Jason Peninsula, which protrudes
near1y
100
km
from the generally smooth sweep of
the
east coast of
the
northem Antarctic Peninsula.
AlI
the exposed rocks
on
Jason Peninsula are Mesozoic
vo1canic
rocks belonging
to
the
Antarctic Peninsula VoJcanic Group. The
area
is
also marked
by
high-amplitude short-wavelength aeromagnetic anomalies
which contrast markedly with the low-amplitude long-
wavelength anomalies associated with
the
sedimentary
fill
of
the Larsen Basin. J
ason
Peninsula appears
to
be
a structurally
high
area
separating
the
Larsen
Ba~in
into northern
and
southern sub-basins.
We
propose that James Ross Basin be used for
the
northern
sub-basin, incJuding
the
James Ross Island area. The sub-
basin incJudes most of
the
exposed rocks
in
the
Larsen Basin
and
extends
to
the
edge of
the
continental shelf (Anderson &
Shipp
in
press), where, according
to
LaBrecque
and
Ghidella
. (in press)
it
merges with,
01'
overJies
an
older ?Jurassic basin.
We emphasize that
the
limits ofthe basín are poorly defíned.
James Ross Basin
is
proposed because
the
name Marambio
is
already part of
the
stratigraphical nomenclature asthe
Marambio
Group,
which encompasses Campanian-Palaeocene beds
forming part of
the
sedimentary
fi11
of the basin
in
the
James
RossIsland region (Rinaldietal. 1978, Inesonetal. 1986).
We
recommend that
the
term
WeddeJ1
Basin be restricted
to
the
ocean basin ofthe WeddeJl Sea.
In
particular,
it
should
not
be
used for
the
continentalshelfofthe AntarcticPeninsula, since
this region
has
ahistory very different from that ofthe rest of
the
WeddeJ1
Sea margins
in
that
it
has been influenced
by
active plate margin processes.
Acknowledgements
The authors
are
grateful
to
Drs M.R.A. Thomson
and
J.R. Ineson for comments
on
the manuscript.
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... Strata from the James Ross Basin crop out on the island. The James Ross Basin consists of a 6-7 km-thick sedimentary succession, which was deposited between the Late Cretaceous and the earliest Oligocene in marine and continental paleoenvironments (Macdonald et al., 1988;Del Valle et al., 1992;Hathway, 2000). Depositional settings change from continental-rift to back-arc (Hathway, 2000). ...
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... The Larsen Basin, along with other extensive back-arc basins located in the northern Antarctica Peninsula and Patagonia-region, was formed during the mid-Mesozoic and the early Cenozoic (Del Valle et al. 1992;Hathway 2000). The basin fill, composed of a thick sequence of marine sedimentary rocks, is most extensively exposed in the James Ross Archipelago (Figure 1), where a regressive megasequence is divided into three lithostratigraphic groups: Barremian-Coniacian Gustav Group, Santonian-Danian Marambio Group, and the Palaeogene Seymour Island Group (Riding and Crame 2002). ...
New records of hexanchiform sharks (Elasmobranchii: Neoselachii) from the Late Cretaceous of Antarctica with comments on previous reports and described taxa
Article
  • Nov 2022
Sharks are virtually absent from coastal Antarctica since the Late Eocene glaciations, but this group exhibited a notable austral diversity during the Cretaceous and Paleogene. Several species have already been described from the Aptian-Eocene successions of the Larsen Basin exposed in the James Ross Island area (northern Antarctic Peninsula) and the predominantly deep-water Hexanchiformes have a record that, although still rare, has been continually increased. Four species of this group are currently known from that basin: Notidanodon pectinatus, Xampylodon dentatus, Rolfodon thompsoni, and Rolfodon tatere. Such records are especially concentrated in the Gamma Member of the Snow Hill Island Formation (or Herbert Sound Member of Santa Marta Formation), on James Ross Island. Here we described four teeth assigned to X. dentatus and one identified as R. tatere from upper Campanian sections of James Ross Island, highlighting the nomenclatural changes that led to the definition of Xampylodon and Rolfodon. Some specimens of X. dentatus presented here are considerably more complete or represent teeth of different positions than most previous records. The material assigned to R. tatere represents the oldest record of this species in the world, extending its time range by more than 10 million years.
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New age constraints support a K/Pg boundary interval on Vega Island, Antarctica: Implications for latest Cretaceous vertebrates and paleoenvironments
Article
  • Jul 2022
A second K/Pg boundary interval in the northern sector of the Antarctic Peninsula on Vega Island has been proposed, yet current temporal resolution of these strata prohibits direct testing of this hypothesis. To not only test for the existence of a K/Pg boundary on Vega Island but also provide increased age resolution for the associated vertebrate fauna (e.g., marine reptiles, non-avian dinosaurs, and avian dinosaurs), the Vega Island succession was intensively re-sampled. Stratigraphic investigation of the Cape Lamb Member of the Snow Hill Island Formation, and in particular, the overlying Sandwich Bluff Member of the López de Bertodano Formation, was conducted using biostratigraphy, strontium isotope stratigraphy, magnetostratigraphy, and detrital zircon geochronology. These data indicate a Late Campanian−early Maastrichtian age for the Cape Lamb Member and present three possible correlations to the global polarity time scale (GPTS) for the overlying Sandwich Bluff Member. The most plausible correlation, which is consistent with biostratigraphy, detrital zircon geochronology, sequence stratigraphy, and all but one of the Sr-isotope ages, correlates the base of the section to C31N and the top of the section with C29N, which indicates that the K/Pg boundary passes through the top of the unit. A second, less plausible option conflicts with the biostratigraphy and depends on a series of poorly defined magnetic reversals in the upper part of the stratigraphy that also correlates the section between C31N and C29R and again indicates an inclusive K/Pg boundary interval. The least likely correlation, which depends on favoring only a single Sr-isotope age at the top of the section over biostratigraphy, correlates the section between C31N and C30N and is inconsistent with an included K/Pg boundary interval. Although our preferred correlation is well supported, we failed to identify an Ir-anomaly, spherules/impact ejecta, or other direct evidence typically used to define the precise position of a K/Pg boundary on Vega Island. This study does, however, confirm that Vegavis, from the base of the Sandwich Bluff Member, is the oldest (69.2−68.4 Ma) phylogenetically placed representative of the avian crown clade, and that marine vertebrates and non-avian dinosaurs persisted in Antarctica up to the terminal Cretaceous.
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Tectonic setting and evolution of the James Ross Basin, northern Antarctic Peninsula
Chapter
Full-text available
  • Jan 1988
The upper Mesozoic to lower Cenozoic sequence is the only exposed marine succession of that age in Antarctica. Sedimentary facies include proximal submarine fans, shelf settings, and deltaic environments. Sea-floor anomaly data from the Pacific Ocean suggest that development of Upper Mesozoic to Cenozoic fore-arc, magmatic arc, and back-arc terrains of the Peninsula resulted from the subduction of the Phoenix Plate until the early Tertiary, and, after reorganization of spreading centers in Late Cretaceous time, subduction of the Aluk Plate. Strata in the James Ross Island region constitute the sedimentary and volcanic fill of an ensialic back-arc basin developed on the Weddell Sea flank of the Antarctic Peninsula. -from Author
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Bathymetry, depth to magnetic basement, and sediment thickness estimates from aerogeophysical data over the western Weddell Basin
Article
Full-text available
  • Apr 1997
We estimated the bathymetry and sediment thickness of a remote and difficult to access portion of the Antarctic continental margin using aerogeophysical surveying techniques. The U.S. Argentina, Chile aerogeophysical survey collected magnetic and gravity data over the basins surrounding the Antarctic Peninsula. Thirty-seven of these flight lines were used to estimate bathymetry and depth to magnetic basement for the western Weddell Basin. A wavenumber technique was applied to individual magnetic anomaly profiles in an automated fashion to obtain estimates of the depth to magnetic basement. The bathymetric estimates were obtained by admittance inversions of the gravity field. The results were then gridded at a 40-km interval for the region 64°W, 44°W, 73°S, and 62°S. Bathymetric estimates and depth to magnetic basement estimates were differenced at each grid point to obtain a regional estimate of the thickness of nonmagnetic overburden (assumed to be sediment). Subsequent spot measurements of topography in the estimated region of the continental margin generally agree to about 52 m. The estimated magnetic basement deepens from the Antarctic Peninsula margin eastward to a maximum of 10-12 km near 54°W. We also postulate the existence of two moderately large basins flanking the eastward continuation of the Jason Peninsula. Farther east, the basement steps upward, with a correspondent thinning of the sedimentary layer. Along the east coast of the peninsula, results agree well with seismic studies on James Ross Island and magnetotelluric studies on Marambio Island and the Larsen nunatak, as well as the British Antarctic Survey basement estimates from aeromagnetic data. This study further demonstrates the utility of combined application of airborne and satellite geophysical techniques in the study of structure and tectonic evolution of continental margins and marine basins.
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Lithostratigraphy of the Cretaceous Strata of West James Ross Island, Antarctica
Article
  • Jun 1986
As a result of recent field work, a new lithostratigraphic group is defined on the west coast of James Ross Island, Antarctica. Characterised by comparatively coarse-grained sediments, the Gustav Group is 2300 m thick and has an approximate age range of Barremian-Santonian. Four formations are recognised within the group (the Lagrelius Point, Kotick Point, Whisky Bay and Hidden Lake Formations), and of these, the Whisky Bay Formation is further subdivided into six local members. Type sections are erected for each of these stratigraphic units and representative lithologies and faunas described.
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Interpretation of reconnaissance gravity and aeromagnetic surveys of the Antarctic Peninsula
Article
  • May 1990
Two-dimensional models are presented for the crustal structure of the Antarctic Peninsual, a Mesozoic-Cenozoic magmatic arc on the southeast Pacific margin. The models are constrained by measured rock properties. The West coast Magnetic Anomaly (WCMA) is caused by a zone of mafic plutons which is 70-150 km wide and over 1500 km long. In modelling of Bouguer anomalies, isostatic compensation is maintained by crustal thickness variations. The model Moho is deepest (35 km) beneath the mid-Cretaceous axis of the arc and shallowest (
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Mid cretaceous contact seen below seymour island and followed off shore by the magnetotelluric method along the ne coast of the Antarctic peninsula
Article
  • Sep 1989
  • COLD REG SCI TECHNOL
Magnetotelluric soundings were made on two off-shore islands and on the Larsen ice shelf. Below Seymour Island a thick sedimentary accumulation (6.7 km) is found. The mid Cretaceous contact is seen at a depth of 4.7 km. The first intermediate conductive layer appears at 65 km with a thickness of 20 km and a 10 ohm m resistivity. Two hundred km farther to the SW, from Robertson Island to Cape Fairweather, an anticline of the basement is possible; the depth ranges from 0.9 km at the top, to 2.3 and 3.6 km at the edges. The mid Cretaceous contact is followed off shore. The intermediate conductive layer begins at about 30 km depth on an average.
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Antarctica - Geology and Hydrocarbon Potential
Conference Paper
  • Sep 1984
The first impression of the hydrocarbon potential of Antarctica is generally negative. The environment is hostile and only 2% of the continent is seen through the ice. Careful study of the surprisingly ample volume of published data available on the geology and geophysics and Antarctica, coupled with the application of the principles and mechanics of plate tectonics relative to the oceans and adjacent land masses, gives a different and very positive attitude toward the hydrocarbon potential of this vast unexplored frontier area. On the basis of limited data, 21 sedimentary basins are identified for Antarctica and immediately adjacent areas. These include six onshore subglacial basins and 15 offshore basins. Excluding 11 basins considered to have little or no potential, the other 10 basins contain an estimated 16.9 million km/sup 3/ (4.05 million mi/sup 3/) of sediment having a potential hydrocarbon yield of 203 billion bbl oil equivalent. The problems associated with hydrocarbon exploration in Antarctica are formidable. Technology is adequate for seismic surveys and exploratory drilling of the Antarctic continental shelf, as concluded from current operations in the Arctic and from operating requirements of drilling rigs under construction. However, a working relationship among involved nations must first be evolved and production, storage, and transportation problems solved.
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