scholarly journals Quantitative assessment of the oxygen isotope composition of fish otoliths from Lake Mungo, Australia

2021 ◽  
pp. 1-13
Author(s):  
Kelsie Long ◽  
David Heslop ◽  
Eelco J. Rohling
Keyword(s):  
Oxygen Isotope ◽  
Arid Zone ◽  
Isotope Composition ◽  
Archaeological Site ◽  
World Heritage Site ◽  
Balance Model ◽  
Southeastern Australia ◽  
Annual Growth Rings ◽  
Dry Conditions ◽  
Fish Otoliths

Abstract The Willandra Lakes region is a series of once interconnected and now-dry lake basins in the arid zone of southeastern Australia. It is a UNESCO World Heritage Site of cultural, archaeological, and geological significance, preserving records of Aboriginal occupation and environmental change stretching back to at least 50 ka. Linking the archaeology with the commensurate palaeoenvironmental information is complicated by the millennial time spans represented by the past hydrological record preserved in the sediment vs. the subdecadal evidence of each archaeological site. Oxygen isotope records across annual growth rings of fish otoliths (ear stones) can elucidate flooding and drying regimes on subannual scales. Otoliths from hearth sites (fireplaces) link lake hydrology with people eating fish on the lakeshore. Oxygen isotopic trends in hearth otoliths from the last glacial maximum (LGM) were previously interpreted in terms of high evaporation under dry conditions. However, this ignored hydrology-driven changes in water δ18O. Here, a mass balance model is constructed to test the effect lake desiccation has on water δ18O and how this compares with the LGM otolith records. Based on this modelling, we suggest that Lake Mungo otolith signatures are better explained by evaporation acting on full lakes rather than by lake drying.

Oxygen isotope composition of Holocene dolomite formed in a humid hypersaline setting: Comment and Reply

Geology ◽  
1993 ◽  
Vol 21 (3) ◽  
pp. 281 ◽  
Author(s):  
Gerald M. Friedman ◽  
R. P. Major ◽  
R. Michael Lloyd ◽  
F. Jerry Lucia
Keyword(s):  
Oxygen Isotope ◽  
Isotope Composition ◽  
Oxygen Isotope Composition

Stable Hydrogen and Oxygen Isotope Composition of Waters from Mine Tailings in Different Climatic Environments

2007 ◽  
Vol 41 (6) ◽  
pp. 1870-1876 ◽  
Author(s):  
Jorge E. Spangenberg ◽  
Bernhard Dold ◽  
Marie-Louise Vogt ◽  
Hans-Rudolf Pfeifer
Keyword(s):  
Oxygen Isotope ◽  
Mine Tailings ◽  
Isotope Composition ◽  
Oxygen Isotope Composition ◽  
Hydrogen And Oxygen Isotope

Oxygen isotope composition of kaolinite rocks as an indicator of different stages of their lithogenesis

2011 ◽  
Vol 438 (1) ◽  
pp. 697-700
Author(s):  
N. S. Bortnikov ◽  
V. M. Novikov ◽  
E. O. Dubinina ◽  
A. D. Savko ◽  
A. G. Berketa ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Isotope Composition ◽  
Oxygen Isotope Composition

scholarly journals A Semiempirical Microscale Model of the Surface Energy Balance and Its Application to Two Urban Rooftops

2008 ◽  
Vol 47 (3) ◽  
pp. 819-834 ◽  
Author(s):  
Timothy M. Barzyk ◽  
John E. Frederick
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Balance Model ◽  
Site Specific ◽  
City Hall ◽  
Microscale Model ◽  
Dry Conditions ◽  
Stone Concrete ◽  
The City

Abstract Individual structures within the same local-scale (102–104 m) environment may experience different microscale (<103 m) climates. Urban microclimate variations are often a result of site-specific features, including spatial and material characteristics of surfaces and surrounding structures. A semiempirical surface energy balance model is presented that incorporates radiative and meteorological measurements to statistically parameterize energy fluxes that are not measured directly, including sensible heat transport, storage heat flux through conduction, and evaporation (assumed to be negligible under dry conditions). Two Chicago rooftops were chosen for detailed study. The City Hall site was located in an intensely developed urban area characterized by close-set high-rise buildings. The University rooftop was in a highly developed area characterized by three- to seven-story buildings of stone, concrete, and brick construction. Two identical sets of instruments recorded measurements contemporaneously from these rooftops during summer 2005, and results from the week of 29 July to 5 August are presented here. The model explains 83.7% and 96% of the variance for the City Hall and University sites, respectively. Results apply to a surface area of approximately 1260 m2, at length scales similar to the dimensions of built structures and other urban elements. A site intercomparison revealed variations in surface energy balance components caused by site-specific features and demonstrated the relevance of the model to urban applications.

Pleistocene–Holocene environmental change in the Canary Archipelago as inferred from the stable isotope composition of land snail shells

2011 ◽  
Vol 75 (3) ◽  
pp. 658-669 ◽  
Author(s):  
Yurena Yanes ◽  
Crayton J. Yapp ◽  
Miguel Ibáñez ◽  
María R. Alonso ◽  
Julio De-la-Nuez ◽  
...  
Keyword(s):  
Environmental Change ◽  
Canary Islands ◽  
Environmental Changes ◽  
Isotope Composition ◽  
Moving Average ◽  
Land Snail ◽  
Balance Model ◽  
Low Latitude ◽  
The Times

AbstractThe isotopic composition of land snail shells was analyzed to investigate environmental changes in the eastern Canary Islands (28–29°N) over the last ~ 50 ka. Shell δ13C values range from −8.9‰ to 3.8‰. At various times during the glacial interval (~ 15 to ~ 50 ka), moving average shell δ13C values were 3‰ higher than today, suggesting a larger proportion of C4 plants at those periods. Shell δ18O values range from −1.9‰ to 4.5‰, with moving average δ18O values exhibiting a noisy but long-term increase from 0.1‰ at ~ 50 ka to 1.6–1.8‰ during the LGM (~ 15–22 ka). Subsequently, the moving average δ18O values range from 0.0‰ at ~ 12 ka to 0.9‰ at present. Calculations using a published snail flux balance model for δ18O, constrained by regional temperatures and ocean δ18O values, suggest that relative humidity at the times of snail activity fluctuated but exhibited a long-term decline over the last ~ 50 ka, eventually resulting in the current semiarid conditions of the eastern Canary Islands (consistent with the aridification process in the nearby Sahara). Thus, low-latitude oceanic island land snail shells may be isotopic archives of glacial to interglacial and tropical/subtropical environmental change.

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