scholarly journals Radiocarbon Reservoir Ages and Hardwater Effect for the Northeastern Coastal Waters of Argentina

Radiocarbon ◽  
2008 ◽  
Vol 50 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Eduardo A Gómez ◽  
C Marcela Borel ◽  
Marina L Aguirre ◽  
Daniel E Martínez
Keyword(s):  
Mass Spectrometry ◽  
Calibration Curve ◽  
Coastal Waters ◽  
Buenos Aires ◽  
Buenos Aires Province ◽  
Layer Model ◽  
Bahía Blanca Estuary ◽  
Radiocarbon Dates ◽  
The Difference ◽  
Blanca Estuary

Accelerator mass spectrometry (AMS) radiocarbon dates were obtained for 18 mollusk shells collected alive along the Buenos Aires province coast, Argentina, over the period AD 1914–1935. Reservoir ages were estimated for all samples on the basis of the tree-ring calibration curve for the Southern Hemisphere (SHCal04, McCormac et al. 2004) and the marine δR values calculated as the difference between the conventional 14C age and the age deduced from the marine, mixed-layer model calculation (Marine04, Hughen et al. 2004). For most coastal locations, a great δR scatter was observed, ranging from 191 to 2482 yr, which is explained by the input of varying content of dissolved carbonate by rivers and groundwater (“hardwater effect”) and indicates a serious limitation for shell-based 14C chronologies. Within the interior of Bahía Blanca estuary, δR values ranged from −40 to 50 ± 46 as a consequence of the local geological particularities of the environment. This suggests that, with some restrictions, the marine calibration curve with standard parameters (δR = 0) could be used at this location.

Description of Ptilohyale corinne sp. nov. (Amphipoda: Hyalidae) from the Bahía Blanca estuary, Argentina, including a key to all valid Ptilohyale species

Zootaxa ◽  
2020 ◽  
Vol 4763 (1) ◽  
pp. 125-137
Author(s):  
CATALINA DI ROSSI ◽  
MICHEL SCIBERRAS ◽  
VERONICA N. BULNES
Keyword(s):  
New Species ◽  
South America ◽  
Buenos Aires ◽  
First Record ◽  
Valid Species ◽  
Buenos Aires Province ◽  
Bahía Blanca Estuary ◽  
A New Species ◽  
Blanca Estuary

A new species of amphipod, Ptilohyale corinne sp. nov. (Hyalidae) is described from the Bahía Blanca estuary (38°53’S, 62°07’W) in Buenos Aires Province, Argentina. Ptilohyale corinne sp. nov. can be differentiated from its valid congeners by having two posterior marginal cusps on coxa 2 and 3, and asymmetrical telson lobes with a particular combination of setae: each lobe with three dorsal plumose setae and one seta on inner margin. This is the first record of Ptilohyale in South America. Additionally a key to the valid species of the genus is provided 

scholarly journals Recent Reservoir Ages for Danish Fjords and Marine Waters

Radiocarbon ◽  
1995 ◽  
Vol 37 (3) ◽  
pp. 875-882 ◽  
Author(s):  
Susanne Heier-Nielsen ◽  
Jan Heinemeier ◽  
H. L. Nielsen ◽  
Niels Rud
Keyword(s):  
Calibration Curve ◽  
Weighted Average ◽  
Hard Water ◽  
Experimental Uncertainty ◽  
Water Effect ◽  
Layer Model ◽  
Marine Waters ◽  
Marine Samples ◽  
The Difference ◽  
Reservoir Age

AMS 14C dates were measured for 28 mollusk shells collected live in Danish waters over the period ad 1885 to 1945. Fourteen samples were from fjords and 14 were marine samples from the Danish Skagerrak-Kattegat coastal area and from the Belts. Reservoir ages were calculated for all samples on the basis of the tree-ring calibration curve. For the marine samples, which cover the period ad 1885–1916, we found a weighted-average reservoir age of 377 ± 16 yr. The marine ∆R values (the difference between the measured 14C age and the age deduced from marine, mixed-layer model calculation of Stuiver, Pearson and Braziunas (1986)) were found to be uniform within the experimental uncertainty with a weighted average of ∆R = 13 ± 16 yr. Based on the observed scatter, the standard deviation is 21 yr. This result shows that it is justified to use the marine calibration curve with standard parameters (∆R = 0) when 14C-dating marine samples from the Danish area. Our value is consistent with the result ∆R = −33 ± 27 yr previously found for the Norwegian and Swedish Skagerrak-Kattegat coasts. In contrast, reservoir ages for Danish fjords were found to vary from 400 to >900 yr, far beyond experimental uncertainty. We ascribe this to varying content of dissolved, old soil carbonate (hard-water effect). Therefore, dating of samples from such fjord environments is expected to be uncertain by several hundred years.

scholarly journals Individual biovolume of some dominant copepod species in coastal waters off Buenos Aires Province, Argentine Sea

2010 ◽  
Vol 58 (2) ◽  
pp. 177-181 ◽  
Author(s):  
María Delia Viñas ◽  
Nadia Rosalía Diovisalvi ◽  
Georgina Daniela Cepeda
Keyword(s):  
Coastal Waters ◽  
Buenos Aires ◽  
Copepod Species ◽  
Buenos Aires Province ◽  
Argentine Sea

scholarly journals Did the Megafauna Range to 4300 BP in South America?

Radiocarbon ◽  
2001 ◽  
Vol 43 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Alberto L Cione ◽  
Aníbal J Figini ◽  
Eduardo P Tonni
Keyword(s):  
South America ◽  
Buenos Aires ◽  
Bone Sample ◽  
Collagen Content ◽  
Buenos Aires Province ◽  
Radiocarbon Dates ◽  
Fossil Remains ◽  
The Poor ◽  
Bone Preservation ◽  
The City

A date of 4300 ± 90 BP for extinct megafauna in Argentina is discussed. The fossil remains come from the Guerrero Member (area) of the Luján Formation near the city of Luján, Buenos Aires Province. The age of the top of the Guerrero Member is constrained by more than 60 radiocarbon dates obtained from the overlying Río Salado Member of Luján Formation, Las Escobas Formation, and Puesto Callejón Viejo Soil, most of them older than 4300 BP. In view of its low collagen content, the 14C measurement of bone sample from Luján should not be accepted uncritically. Because of the poor bone preservation and the possible introduction of “young” contaminants that were not completely eliminated, the 14C date of 4300 ± 90 BP is not reliable. Both biostratigraphic and 14C dating evidence indicates that the date of 4300 BP for the last representative of extinct megafauna in South America is unsupported.

scholarly journals Radiocarbon Calibration for Japanese Wood Samples

Radiocarbon ◽  
2003 ◽  
Vol 45 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Minoru Sakamoto ◽  
Mineo Imamura ◽  
Johannes Van der Plicht ◽  
Takumi Mitsutani ◽  
Makoto Sahara
Keyword(s):  
Mass Spectrometry ◽  
North America ◽  
Tree Ring ◽  
Calibration Curve ◽  
Accelerator Mass Spectrometry ◽  
The Difference ◽  
Radiocarbon Calibration

The radiocarbon content of Japanese cedars was measured by accelerator mass spectrometry for decadal tree-ring samples from the period of 240 BC to AD 900. Conventional gas counting was also used for part of the samples. The data were compared with the INTCAL98 calibration curve (Stuiver et al. 1998). The results indicate that the difference in atmospheric 14C between Japan and North America or Europe is negligible at this period, less than 18 14C yr using an average of 50 yr. However, in the period of about AD 100 to about AD 200, we cannot exclude the possibility of a deviation of the order of 30 to 40 14C yr to the older ages.

Dense Bathymetry in Turbid Coastal Zones Using Airborne Hyperspectral Images

2021 ◽  
Vol 87 (12) ◽  
pp. 923-927
Author(s):  
Steven Martinez Vargas ◽  
Claudio Delrieux ◽  
Katy L. Blanco ◽  
Alejandro Vitale
Keyword(s):  
Hyperspectral Images ◽  
Average Error ◽  
Support Vector ◽  
Buenos Aires Province ◽  
Coastal Zones ◽  
Bahía Blanca Estuary ◽  
Data Set ◽  
Spectral Bands ◽  
Unseen Data ◽  
Blanca Estuary

We used airborne hyperspectral images to generate a dense survey of bathymetric data in the Bahía Blanca estuary (Buenos Aires Province, Argentina). This estuarine area is characterized by intense sediment transport turning the water muddy, and thus optical bathymetric estimations are difficult. We used 24 spectral bands in a range of 500–900 nm acquired with a hyperspectral camera aboard an unmanned aerial vehicle, together with 100 bathymetry data points surveyed with a sonar sensor aboard an unmanned surface vehicle, covering an area of about 800 m2. Random-forest and support-vector-machine regressors were trained with this data set. The resulting model yielded a determination coefficient of 0.815 with unseen data, a root-mean-square error of 0.166 m, and an absolute average error less than 2%. These results allow dense and accurate reconstructions of the underwater profile in wide, muddy, shallow regions of the Bahía Blanca estuary, showing the feasibility of hyperspectral imagery combined with sonar data in turbid shallow waters.

Hydrography of the Inner Continental Shelf along the Southwest Buenos Aires Province, Argentina: Influence of an Estuarine Plume on Coastal Waters

2017 ◽  
Vol 33 (4) ◽  
pp. 907-916 ◽  
Author(s):  
Ana Laura Delgado ◽  
María Clara Menéndez ◽  
María Cintia Piccolo ◽  
Gerardo Miguel Eduardo Perillo
Keyword(s):  
Continental Shelf ◽  
Coastal Waters ◽  
Buenos Aires ◽  
Buenos Aires Province ◽  
Inner Continental Shelf

scholarly journals Análisis tafonómico de moluscos holocenos en el área costera del Estuario de Bahía Blanca, Argentina

2001 ◽  
Vol 28 (1) ◽  
pp. 3 ◽  
Author(s):  
JORGE SPAGNUOLO ◽  
ESTER FARINATI ◽  
SALVADOR ALIOTTA
Keyword(s):  
Buenos Aires ◽  
Buenos Aires Province ◽  
Northern Coast ◽  
Medium Sand ◽  
Bahía Blanca Estuary ◽  
Storm Waves ◽  
Holocene Transgression ◽  
South West ◽  
Paleoenvironmental Evolution ◽  
Production Area

At the south west of the Buenos Aires province, Argentina, on the northern coast of the Bahía Blanca Estuary, sand-shell ridges sub-parallel to the coastline generated during the Holocene transgression-regression were deposited. These structures are composed mostly of coarse to medium sand and a high proportion of molluscs shells (19 species of bivalves and 16 species of gastropods). For this study three taxa from the fossil association located in the ridges (Brachidontes rodriguezi, Tegula patagonica and Crepidula aculeata) were selected and the mechanisms of taphonomic alteration that affected them were qualified. By means of ternary taphograms the variation of five taphonomic attributes (bioerosion, encrustation. fragmentation. wear and dissolution) was established. It has been determined that the bioestratinomic processes are subordinated to the fossildiagenetic mechanisms, where dissolution has left a series of taphonomic signatures. Based upon the taphonomic attributes of the fossil association a high stand sea level cycle with an important contribution of storm waves that affected the biogenic production area were established as a representation of the paleoenvironmental evolution.

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