Correlation of a Valanginian Stable Isotopic Excursion in Northeastern Mexico with the European Tethys

2001 ◽  
Author(s):  
Thierry Adatte ◽  
Wolfgang Stinnesbeck ◽  
Hans Hubberten ◽  
Jürgen Remane ◽  
José Guadalupe López-Oliva
Keyword(s):  
Stable Isotopic ◽  
Northeastern Mexico

Seasonal trends in the stable isotopic composition of snow and meltwater runoff in a subarctic catchment at Okstindan, Norway

2004 ◽  
Vol 35 (2) ◽  
pp. 119-137 ◽  
Author(s):  
S.D. Gurney ◽  
D.S.L. Lawrence
Keyword(s):  
Isotopic Composition ◽  
Mean Value ◽  
Mean Values ◽  
Stable Isotopic Composition ◽  
Meltwater Runoff ◽  
Stable Isotopic ◽  
The Mean ◽  
The Difference ◽  
Δ18o And Δd

Seasonal variations in the stable isotopic composition of snow and meltwater were investigated in a sub-arctic, mountainous, but non-glacial, catchment at Okstindan in northern Norway based on analyses of δ18O and δD. Samples were collected during four field periods (August 1998; April 1999; June 1999 and August 1999) at three sites lying on an altitudinal transect (740–970 m a.s.l.). Snowpack data display an increase in the mean values of δ18O (increasing from a mean value of −13.51 to −11.49‰ between April and August), as well as a decrease in variability through the melt period. Comparison with a regional meteoric water line indicates that the slope of the δ18O–δD line for the snowpacks decreases over the same period, dropping from 7.49 to approximately 6.2.This change points to the role of evaporation in snowpack ablation and is confirmed by the vertical profile of deuterium excess. Snowpack seepage data, although limited, also suggest reduced values of δD, as might be associated with local evaporation during meltwater generation. In general, meltwaters were depleted in δ18O relative to the source snowpack at the peak of the melt (June), but later in the year (August) the difference between the two was not statistically significant. The diurnal pattern of isotopic composition indicates that the most depleted meltwaters coincide with the peak in temperature and, hence, meltwater production.

Continuities in Architectural Traditions: The Subterráneos of Prehistoric and Modern Northern Mexico

1997 ◽  
Vol 18 (2) ◽  
pp. 105-120
Author(s):  
Solveig A. Turpin ◽  
Herbert H. Eling ◽  
Moisés Valadez Moreno
Keyword(s):  
New World ◽  
Site Occupancy ◽  
Northern Mexico ◽  
Conventional View ◽  
Northeastern Mexico ◽  
Small Valley

The recent discovery of a pit house village, 40 km northwest of Monterrey, challenges the conventional view of inland northeastern Mexico as the domain of purely nomadic hunters and gatherers throughout prehistory. Las Casitas consists of fifty-three subterranean rooms and forty-eight smaller depressions aligned in three slightly arcuate tiers in a small valley adjacent to Boca de Potrerillos, an extremely large open campsite and petroglyph complex that is now an archeological park. Other features of the site are some 325 hearths that surround the depressions and a very limited artifact assemblage numbering only thirty-seven items. Two hearths produced radiocarbon samples that date site occupancy to approximately a.d. 1450, just prior to the arrival of the Spanish in the New World. Las Casitas provides the first evidence of semi-sedentary, surplus producing populations in central northeastern Mexico.

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