scholarly journals Carbon and Oxygen Isotope Records at DSDP Site 384 (North Atlantic) and Some Paleocene Paleotemperatures and Carbon Isotope Variations in the Atlantic Ocean

1979 ◽  
Author(s):  
A. Boersma ◽  
N. Shackleton ◽  
M. Hall ◽  
Q. Given
Keyword(s):  
Atlantic Ocean ◽  
Oxygen Isotope ◽  
Carbon Isotope ◽  
North Atlantic ◽  
Carbon And Oxygen Isotope ◽  
Dsdp Site

scholarly journals Stable isotope paleoecology of the Baynunah Formation

2021 ◽  
Author(s):  
Kevin Uno ◽  
Faysal Bibi
Keyword(s):  
Oxygen Isotope ◽  
Carbon Isotope ◽  
Tooth Enamel ◽  
Field Work ◽  
Wet Season ◽  
Isotope Data ◽  
Carbon And Oxygen Isotope ◽  
Herbivore Community ◽  
Vegetation Carbon ◽  
Seasonally Flooded

The Baynunah Formation contains the only known late Miocene terrestrial fossils from the Arabian Peninsula. Based on renewed field work since 2002, we present paleoenvironmental and dietary reconstructions from carbon isotope data from plant wax biomarkers and carbon and oxygen isotope data from fossil tooth enamel in combination with previously published fossil tooth enamel and pedogenic carbonate isotope data. The organic and isotopic data indicate that the highly seasonal ecosystem supported a herbivore community that relied heavily on C4 vegetation. Carbon isotope and molecular abundance data from n-alkanes indicate mostly mixed C3-C4 and C4-dominated ecosystems. Carbon isotope data from fossil teeth indicate a range of C3, mixed C3-C4, and C4 diets, with suids, deinotherids, and rhinocerotids browsing, and bovids, elephantids, and equids mixed feeding to grazing. Hippopotamids show the most positive carbon and most negative oxygen values, with narrow ranges indicating year-round grazing and semi- aquatic habits. The Baynunah sivatheres represent the earliest evidence for a C4-dominanted diet among giraffids. Equid intratooth oxygen isotope profiles indicate a highly seasonal hydroclimate regime, reflecting strong monsoonal conditions with a single rainy season. Corresponding carbon profiles record large seasonal changes in equid diets, with mainly grazing in the wet season and increased browsing in the dry season. Baynunah ecosystems comprised savanna habitats (woody grasslands) with the proboscidean trackway site of Mleisa 1 likely being a seasonally flooded C4 grassland.

The carbon- and oxygen-isotope record of the Precambrian–Cambrian boundary interval in China and Iran and their correlation

1990 ◽  
Vol 127 (4) ◽  
pp. 319-332 ◽  
Author(s):  
Martin D. Brasier ◽  
Mordeckai Magaritz ◽  
Richard Corfield ◽  
Luo Huilin ◽  
Wu Xiche ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Carbon Isotope ◽  
Oxygen Isotopes ◽  
Carbon And Oxygen Isotopes ◽  
Oxygen Isotope Record ◽  
Carbon And Oxygen Isotope ◽  
Isotope Record ◽  
Assemblage Zone ◽  
Stratotype Section ◽  
Zone Ii

AbstractThe fossiliferous section at Meishucun of Yunnan, China, is a candidate stratotype section for the Precambrian–Cambrian boundary. Early diagenetic dolomites and phosphorites have been sampled across the boundary interval here, and in the correlated section at Maidiping in Sichuanand Valiabad in Iran, for comparison of their carbon and oxygen isotopes. This is the first such study that is calibrated by biostratigraphy in the interval from the earliest (pre-Tommotian) skeletal fossils to trilobites. Although negative oxygen isotopes indicate a diagenetic signal in the Zhongyicun Member and basal Badaowan Member phosphorites, two carbon-isotope cycles are clearly present and can be correlated in dolomitic rocks between the two sections. The first appearance datum (FAD) of the earliest skeletal assemblage (zone I, Marker A), FAD of diverse micromolluscs (zone II, Marker B) and FAD of Chinese trilobites (zones IV, V) and Marker C appear at similar points on the carbon-isotope curve in the two Chinese sections. Integrated carbon-isotope and early skeletal fossil biostratigraphy is shown to have the potential to correlate further afield, with sections in Iran, as well as with India, Siberia, Morocco and Australia. We suggest that a distinctive positive excursion provides a global marker for the interval between Marker B and C in China and just below the Tommotian Stage of Siberia.

Canopy carbon and oxygen isotope composition of 9-year-old hoop pine families in relation to seedling carbon isotope composition, growth, field growth performance, and canopy nitrogen concentration

2001 ◽  
Vol 31 (4) ◽  
pp. 673-681 ◽  
Author(s):  
Nina V Prasolova ◽  
Zhihong Xu ◽  
Graham D Farquhar ◽  
Paul G Saffigna ◽  
Mark J Dieters
Keyword(s):  
Oxygen Isotope ◽  
Carbon Isotope ◽  
Isotope Composition ◽  
Nitrogen Concentration ◽  
Heritability Estimate ◽  
Carbon Isotope Composition ◽  
Oxygen Isotope Composition ◽  
Carbon And Oxygen Isotope ◽  
Canopy Position ◽  
Hoop Pine

Carbon isotope composition (δ13C), oxygen isotope composition (δ18O), and nitrogen concentration (Nmass) of branchlet tissue at two canopy positions were assessed for glasshouse seedlings and 9-year-old hoop pine (Araucaria cunninghamii Ait. ex D. Don) trees from 22 open-pollinated families grown in 5 blocks of a progeny test at a water-limited and nitrogen-deficient site in southeastern Queensland, Australia. Significant variations in canopy δ13C, δ18O, and Nmass existed among the 9-year-old hoop pine families, with a heritability estimate of 0.72 for branchlet δ13C from the upper inner canopy position. There was significant variation in canopy δ13C of glasshouse seedlings between canopy positions and among the families, with a heritability estimate of 0.66. The canopy δ13C was positively related to canopy Nmass only for the upper outer crown in the field (R = 0.62, p < 0.001). Phenotypic correlations existed between tree height and canopy δ13C (R = 0.37–0.41, p < 0.001). Strong correlations were found between family canopy δ13C at this site and those at a wetter site and between field canopy δ13C and glasshouse seedling δ13C. The mechanisms of the variation in canopy δ13C are discussed in relation to canopy photosynthetic capacity as reflected in the Nmass and stomatal conductance as indexed by canopy δ18O.

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