scholarly journals The submerged footprint of Perito Moreno glacier

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Emanuele Lodolo ◽  
Federica Donda ◽  
Jorge Lozano ◽  
Luca Baradello ◽  
Roberto Romeo ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Current Position ◽  
Seismic Profiles ◽  
Glacier System ◽  
Warming Climate ◽  
Glacier Front ◽  
Show Evidence ◽  
Glacier Advance ◽  
First Time ◽  
South Patagonia

Abstract Perito Moreno is the most famous calving glacier of the South Patagonia Icefield, the largest temperate glacier system of the Southern Hemisphere. Unlike most of the glaciers in the region that have strongly retreated in recent decades, the position of Perito Moreno glacier front remained relatively unchanged in the last century. However, earliest photographic documents show that, at the end of the nineteenth century, the front was ca. 800 m behind the current position. There is no reliable information about the positions of the Perito Moreno front in earlier times. Here we show evidence of two subaqueous moraine systems both in the Canal de Los Témpanos and in the Brazo Rico, the two arms of Lago Argentino along which Perito Moreno glacier has flowed over time. These moraines, identified for the first time in the Canal de Los Témpanos from bathymetric and high-resolution seismic profiles, mark the position of the largest glacier advance, tentatively correlated with the moraines of the “Herminita advance” identified and dated onland. We interpret these bedforms as the evidence of the most pronounced advance of Perito Moreno glacier during the mid-Holocene cooling event that characterized this sector of the Southern Hemisphere. This study highlights the importance of subaqueous glacial bedforms, representing decisive records of the glacial history and palaeoclimate, which could help unveiling the origin of the different behavior of glaciers like Perito Moreno that in a warming climate are relatively stable.

scholarly journals CPC2 Reduction with Hipparcos and Proper Motions in The Southern Hemisphere

1998 ◽  
Vol 11 (1) ◽  
pp. 551-551
Author(s):  
N. Zacharias ◽  
M.I. Zacharias ◽  
C. de Vegt ◽  
C.A. Murray
Keyword(s):  
Southern Hemisphere ◽  
Systematic Errors ◽  
Reference Star ◽  
Proper Motions ◽  
Positional Accuracy ◽  
Star Catalog ◽  
Naval Observatory ◽  
Celestial Reference System ◽  
First Time ◽  
Better Than

The Second Cape Photographic Catalog (CPC2) contains 276,131 stars covering the entire Southern Hemisphere in a 4-fold overlap pattern. Its mean epoch is 1968, which makes it a key catalog for proper motions. A new reduction of the 5687 plates using on average 40 Hipparcos stars per plate has resulted in a vastly improved catalog with a positional accuracy of about 40 mas (median value) per coordinate, which comes very close to the measuring precision. In particular, for the first time systematic errors depending on magnitude and color can be solved unambiguously and have been removed from the catalog. In combination with the Tycho Catalogue (mean epoch 1991.25) and the upcoming U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project proper motions better than 2 mas/yr can be obtained. This will lead to a vastly improved reference star catalog in the Southern Hemisphere for the final Astrographic Catalogue (AC) reductions, which will then provide propermotions for millions of stars when combined with new epoch data. These data then will allow an uncompromised reduction of the southern Schmidt surveys on the International Celestial Reference System (ICRS).

scholarly journals New velocity map and mass-balance estimate of Mertz Glacier, East Antarctica, derived from Landsat sequential imagery

2003 ◽  
Vol 49 (167) ◽  
pp. 503-511 ◽  
Author(s):  
Etienne Berthier ◽  
Bruce Raup ◽  
Ted Scambos
Keyword(s):  
Velocity Field ◽  
Drainage Basin ◽  
Flow Speed ◽  
East Antarctica ◽  
Landsat Images ◽  
Mean Velocity ◽  
Speed Increase ◽  
Glacier System ◽  
Show Evidence ◽  
Basal Melting

AbstractAutomatic feature tracking on two Landsat images (acquired inJanuary 2000 and December 2001) generates a complete and accurate velocity field of Mertz Glacier, East Antarctica. This velocity field shows two main tributaries to the ice stream. Between the tributaries, a likely obstruction feature in the bedrock results in a slow-down of the flow. A third Landsat image, acquired in 1989 and combined with the 2000 image, permits the determination of the glacier mean velocity during the 1990s. Although some parts of the Mertz Glacier system show evidence of slight speed increase, we conclude that the Mertz flow speed is constant within our uncertainty (35 m a−1). Using this complete velocity field, new estimates of the ice discharge flux, 17.8 km3 a−1 (16.4 Gt a−1), and of the basal melting of the tongue, 11 m a−1 of ice, are given. Our results lead to an apparent imbalance of the drainage basin (ice discharge 3.5 km3 a−1 lower than the accumulation). Considering previous studies in the Mertz Glacier area, we then discuss the uncertainty of this imbalance and the problems with accumulation mapping for this region.

scholarly journals Recent behaviour of Glaciar Upsala, a fast-flowing calving glacier in Lago Argentino, southern Patagonia

2003 ◽  
Vol 36 ◽  
pp. 184-188 ◽  
Author(s):  
Pedro Skvarca ◽  
Bruce Raup ◽  
Hernan de Angelis
Keyword(s):  
Cross Correlation ◽  
High Spatial Resolution ◽  
Winter Period ◽  
Optical Images ◽  
Southern Patagonia ◽  
Glacier Front ◽  
Calving Rate ◽  
Depth Relationship ◽  
Surface Ice ◽  
First Time

AbstractSequential optical images of high spatial resolution were used for the first time to derive surface ice velocities of Glaciar Upsala, a fast-moving fresh-water calving glacier in southern Patagonia. Cross-correlation methods applied to four Landsat ETM+ images acquired in 2000–01 yielded average velocities of around 1600 m a−1, similar to values measured in the field in November 1993. The derived velocities show almost no seasonal variation for the analyzed calving termini. During the period of satellite coverage, clear readvances were detected in the autumn–winter period, followed by recessions during summers. Between 24 April 1999 and 14 October 2001, the glacier front has been fluctuating seasonally within about 400 m, in contrast to the previous dramatic recession. During the last 2.5 years, Glaciar Upsala west terminus had a net advance of around 300 m. In addition, the available satellite images allowed us to determine recent calving speeds and confirm the improved calving-rate/water-depth relationship, recently proposed by incorporating new data from Patagonian glaciers.

ECTOMYCORRHIZAL FUNGI AND NON-AGARICOID BASIDIOMYCETOUS MACROMYCETES OF THE FALKLANDS

2012 ◽  
Vol 69 (2) ◽  
pp. 219-238 ◽  
Author(s):  
R. Watling
Keyword(s):  
Southern Hemisphere ◽  
Ectomycorrhizal Fungi ◽  
Falkland Islands ◽  
The World ◽  
First Time

Fifty-one species of basidiomycetes are recorded from the Southern Atlantic archipelago of the Falkland Islands. Several other fungi are discussed in the light of these findings. Some of these fungi are recorded for the first time from the Falklands and especially from some of the smaller islands of the group adjacent to West and East Falkland. The world distributions of the fungi dealt with in this compilation, particularly in the southern hemisphere, are given where they are known. Comments are made on the possible reasons for the occurrence of the species in the Falklands, especially the ectomycorrhizal taxa.

scholarly journals Upslope migration of snow avalanches in a warming climate

2021 ◽  
Vol 118 (44) ◽  
pp. e2107306118
Author(s):  
Florie Giacona ◽  
Nicolas Eckert ◽  
Christophe Corona ◽  
Robin Mainieri ◽  
Samuel Morin ◽  
...  
Keyword(s):  
Ice Age ◽  
Snow Avalanche ◽  
Bayesian Techniques ◽  
Vosges Mountains ◽  
Mountain Environments ◽  
Warming Climate ◽  
Avalanche Behavior ◽  
Show Evidence ◽  
Future Warming ◽  
Snow Conditions

Snow is highly sensitive to atmospheric warming. However, because of the lack of sufficiently long snow avalanche time series and statistical techniques capable of accounting for the numerous biases inherent to sparse and incomplete avalanche records, the evolution of process activity in a warming climate remains little known. Filling this gap requires innovative approaches that put avalanche activity into a long-term context. Here, we combine extensive historical records and Bayesian techniques to construct a 240-y chronicle of snow avalanching in the Vosges Mountains (France). We show evidence that the transition from the late Little Ice Age to the early twentieth century (i.e., 1850 to 1920 CE) was not only characterized by local winter warming in the order of +1.35 °C but that this warming also resulted in a more than sevenfold reduction in yearly avalanche numbers, a severe shrinkage of avalanche size, and shorter avalanche seasons as well as in a reduction of the extent of avalanche-prone terrain. Using a substantial corpus of snow and climate proxy sources, we explain this abrupt shift with increasingly scarcer snow conditions with the low-to-medium elevations of the Vosges Mountains (600 to 1,200 m above sea level [a.s.l.]). As a result, avalanches migrated upslope, with only a relict activity persisting at the highest elevations (release areas >1,200 m a.s.l.). This abrupt, unambiguous response of snow avalanche activity to warming provides valuable information to anticipate likely changes in avalanche behavior in higher mountain environments under ongoing and future warming.

LICHENS AND LICHENICOLOUS FUNGI NEW FOR ISRAEL AND OTHER COUNTRIES

1996 ◽  
Vol 44 (2-3) ◽  
pp. 181-193 ◽  
Author(s):  
I.L. Navrotskaya ◽  
S.Y. Kondratyuk ◽  
S.P. Wasser ◽  
E. Nevo ◽  
S.D. Zelenko
Keyword(s):  
New Zealand ◽  
North America ◽  
Southern Hemisphere ◽  
Lichen Species ◽  
European Countries ◽  
General Distribution ◽  
Lichenicolous Fungi ◽  
First Time

Thirteen lichen species (Arthopyrenia punctiformis, Bactrospora patellarioides, Caloplaca saxicola, C. ulcerosa, Lempholemma chalazanellum, Lichenothelia scopularia, Maronea constans, Micarea nitschkeana, Opegrapha rufescens, O. vulgata var. subsiderella, Physcia caesia, Schismatomma pericleum, and Thelenella modesta), one nonlichenized ascomycetes (Peridiothelia fuliguncta), and 5 species of lichenicolous fungi (Arthonia molendoi, Endococcus parietinarius, Guignardia Olivieri, Opegrapha physciaria, and Zwackhiomyces coepulonus) are recorded as new for Israel. Lichenochora wasseri S.Kondr. sp. nov. from Caloplaca species from Israel and Sweden is described. Lichenochora xanthoriae is reported for the first time from Austria for Europe as well as from Auckland Islands, New Zealand, for the Southern Hemisphere. Seven taxa mentioned (Caloplaca ulcerosa, Endococcus parietinarius, Guignardia olivieri, Micarea nitschkeana, Opegrapha physciaria, Peridiothelia fuliguncta, Zwackhiomyces coepulonus) are reported here for the first time for Asia as well. Guignardia Olivieri is first reported here from some European countries (Finland, Russia, Ireland, Germany, Portugal, Italy, Ukraine), and Zwackhiomyces coepulonus from North America and Africa as well. Synonyms, references to a modern description, ecological peculiarities, locations and dates of collection in Israel, general distribution, as well as taxonomical remarks regarding the foregoing lichens and lichenicolous fungi species are given.

Redescriptions and new species in the ‘Austrosignum–Munnogonium’ complex sensu Just & Wilson (2007), mainly from the Southern Hemisphere (Crustacea: Isopoda: Paramunnidae)

Zootaxa ◽  
2021 ◽  
Vol 4952 (3) ◽  
pp. 401-447
Author(s):  
JEAN JUST ◽  
GEORGE D.F. WILSON
Keyword(s):  
New Species ◽  
Southern Hemisphere ◽  
Type Material ◽  
First Time

Type material is used to illustrate and redescribe the following species in the paramunnid Austrosignum–Munnogonium complex (classification sensu Just and Wilson 2007): Cryosignum incisum (Richardson, 1908), Cryosignum latifrons (Menzies, 1962) comb. nov., Meridiosignum kerguelensis (Vanhöffen, 1914), Munnogonium falklandicum (Nordenstam, 1933), Munnogonium globifrons (Menzies, 1962), and Munnogonium tillerae (Menzies & Barnard, 1959,—topotypes). In addition, seven new species in the complex are described, Austrosignum pilosum, Austrosignum latum, Cryosignum nordenstami, Meridiosignum convexum, Meridiosignum macquariensis, Munnogonium longicaudatum, and Tethygonium monocuspis. Boreosignum Just and Wilson, 2007 is reported from Australia for the first time as Boreosignum specimens.                Keys to species in Austrosignum, Cryosignum, Meridiosignum, Munnogonium and Tethygonium are given. A summary of distribution with a list of all species in the complex including occurrence is presented. 

Artinskian conodonts from the Dingjiazhai Formation of the Baoshan Block, west Yunnan, southwest China

2002 ◽  
Vol 76 (4) ◽  
pp. 741-750 ◽  
Author(s):  
Katsumi Ueno ◽  
Yoshihiro Mizuno ◽  
Xiangdong Wang ◽  
Shilong Mei
Keyword(s):  
Southern Hemisphere ◽  
Southwest China ◽  
Warm Water ◽  
Early Permian ◽  
Northern Margin ◽  
Stratigraphic Unit ◽  
Current Definition ◽  
Conodont Fauna ◽  
Definition Of ◽  
First Time

Permian conodonts were recovered for the first time from the Dingjiazhai Formation, a well-known diamictite-bearing stratigraphic unit in the Gondwana-derived Baoshan Block in West Yunnan, Southwest China. The conodont fauna occurs in limestone units within the upper part of the formation and consists of Sweetognathus bucaramangus (Rabe), S. whitei (Rhodes), Mesogondolella bisselli (Clark and Behnken), and an unidentified ramiform element. Based on the known stratigraphic distribution of 5. bucaramangus (Rabe), the fauna is referable to the upper Sweetognathus whitei-Mesogondolella bisselli Zone, and thus is dated as middle Artinskian according to the current definition of the stage. The Dingjiazhai Formation is overlain paraconformably by the Woniusi Formation, which is represented mostly by basalts and basaltic volcaniclastics related to rifting volcanism during the separation of the Baoshan Block from Gondwanaland. The present discovery of conodonts from the upper part of the Dingjiazhai Formation reveals that the glaciogene diamictites in the Dingjiazhai Formation are older than middle Artinskian, and the inception of rifting volcanism of the Baoshan Block is later than middle Artinskian.Occurrence of an essentially warm water element, Sweetognathus bucaramangus (Rabe), in the Dingjiazhai conodont assemblage notwithstanding, the entire fossil faunas including brachiopods and fusulinoideans from the limestone units of the formation can be best interpreted as a middle latitudinal, non-tropical, and still substantially Gondwana-influenced assemblage developed at the northern margin of Gondwanaland just after deglaciation in the southern hemisphere during Early Permian time. This time could be regarded as the beginning of the Cimmerian Region, which had mixed or transitional paleobiogeographic characteristics between the Paleoequatorial Tethyan and cool/cold Gondwanan realms, and which became well developed during Middle Permian time.

scholarly journals Contribution to the knowledge of the lichen biota of Bolivia. 5

2013 ◽  
Vol 58 (2) ◽  
pp. 697-733 ◽  
Author(s):  
Adam Flakus ◽  
Harrie J. M. Sipman ◽  
Kerstin Bach ◽  
Pamela Rodriguez Flakus ◽  
Kerry Knudsen ◽  
...  
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
New Records ◽  
Lichen Species ◽  
Critical Groups ◽  
Lichen Biota ◽  
First Time

Abstract This paper presents new records of 180 lichen species from Bolivia; 103 are new national records. Three species, Bryonora curvescens (Mudd) Poelt (also from Ecuador), Lepraria elobata Tønsberg and Pyrenula laetior Müll. Arg., are reported for the first time from the Southern Hemisphere, and five, Bathelium aff. sphaericum (C. W. Dodge) R. C. Harris, Lepraria jackii Tønsberg, Psiloparmelia arhizinosa Hale, Szczawinskia tsugae A. Funk and Trinathotrema lumbricoides (Sipman) Sipman & Aptroot, are new to South America. To complement the rather poorly recognized distribution of some species, five of the taxa reported here are also new to Ecuador. Notes on distribution and chemistry are provided for most species, and some, especially those belonging to taxonomically critical groups, are discussed in greater detail.

Pingos in Antarctica

1983 ◽  
Vol 20 (1) ◽  
pp. 105-109 ◽  
Author(s):  
John Pickard
Keyword(s):  
Lake Sediments ◽  
Southern Hemisphere ◽  
Closed System ◽  
Climatic Conditions ◽  
Apparent Absence ◽  
Vestfold Hills ◽  
Water Saturated ◽  
First Time

AbstractPingos, or ice-cored mounds, are described for the first time from Antarctica and for the first time on ice-cored moraine. Seven pingos up to 4 m high and 12 m in diameter occur on former dering of lakes on the moraine exposes water-saturated sediments to freezing and consequent lake sediments on Flanders Moraine, Vestfold Hills, Antarctica (68°40'S 78°00'E). Lateral wandering formation of closed-system pingos. The pingos are probably only a few hundred years old. The apparent absence of pingo scars in the Southern Hemisphere may be due to lack of suitable substrates, rather than to unsuitable climatic conditions.

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