Tamara FLETCHER

Dr. Tamara FLETCHER

Earth Science, University of Adelaide, Adelaide, South Australia, Australia
orcid

Research Focus & Metrics

Academic Career Length

2Years (2025-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 December 2010 in Journal of Vertebrate Paleontology
Verified
Journal Article
Closed access
TFTamara L. Fletcher
Tamara L. Fletcher
SSSteven W. Salisbury
Steven W. Salisbury
Pterosaur fossils from Australia are rare. All the specimens that have been described previously are Cretaceous in age, with the majority deriving from the Aptian–Albian shallow marine succession within the Eromanga Basin of western Queensland. The Queensland specimens have tentatively been referred to the pterodactyloid clades Pteranodontidae, Ornithocheiridae, and Archaeopterodactyloidea (cf. Ctenochasmatoidea), each in varying taxonomic guises. Due to their fragmentary nature, more specific referrals of these specimens have not been possible. As such, the overall composition and more precise relationships of Australia's Cretaceous pterosaur fauna have remained enigmatic. Since 1987, a number of new pterosaur specimens have been found in the shallow marine late Albian rocks of the Eromanga Basin of western Queensland. Four of these specimens are described herein: a partial mandible, a metacarpal IV, a wing phalanx, and a humerus. The mandible is assigned to Ornithocheiridae, gen. et sp. indet., whereas the metacarpal and wing phalanx are assigned Ornithocheiridae cf. Anhanguera. The morphology of the humerus suggests that it may belong to a ctenochasmatoid lophocratian. Based on these findings, we hypothesize that Australia's Early Cretaceous pterosaur fauna comprises a mix of taxa already known to occur in Europe and South America in addition to a slightly younger ctenochasmatoid. However, the older specimens may alternatively represent new taxa that combine cranial characteristics of an Ornithocheirus-like taxon or a closely related form, with an Anhanguera-like postcranium. A more precise characterization of Australia's Cretaceous pterosaur fauna cannot be resolved until more complete specimens are found.

1 May 2017 in Earth and Planetary Science Letters
Verified
Journal Article
Closed access
RFRan Feng
Ran Feng
BOBette L. Otto-Bliesner
Bette L. Otto-Bliesner
TFTamara L. Fletcher
Tamara L. Fletcher
CTClay R. Tabor
Clay R. Tabor
ABAshley P. Ballantyne
Ashley P. Ballantyne
EBEsther C. Brady
Esther C. Brady

23 June 2022 in Climate of the Past
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Journal Article
Open access
PDF file
JTJulia C. Tindall
Julia C. Tindall
AHAlan M. Haywood
Alan M. Haywood
USUlrich Salzmann
Ulrich Salzmann
ADAisling M. Dolan
Aisling M. Dolan
TFTamara Fletcher
Tamara Fletcher
Reconciling palaeodata with model simulations of the Pliocene climate is essential for understanding a world with atmospheric CO2 concentration near 400 ppmv (parts per million by volume). Both models and data indicate an amplified warming of the high latitudes during the Pliocene; however, terrestrial data suggest that Pliocene northern high-latitude temperatures were much higher than can be simulated by models. We focus on the mid-Pliocene warm period (mPWP) and show that understanding the northern high-latitude terrestrial temperatures is particularly difficult for the coldest months. Here the temperatures obtained from models and different proxies can vary by more than 20 ∘C. We refer to this mismatch as the “warm winter paradox”. Analysis suggests the warm winter paradox could be due to a number of factors including model structural uncertainty, proxy data not being strongly constrained by winter temperatures, uncertainties in data reconstruction methods, and the fact that the Pliocene northern high-latitude climate does not have a modern analogue. Refinements to model boundary conditions or proxy dating are unlikely to contribute significantly to the resolution of the warm winter paradox. For the Pliocene high-latitude terrestrial summer temperatures, models and different proxies are in good agreement. Those factors which cause uncertainty in winter temperatures are shown to be much less important for the summer. Until some of the uncertainties in winter high-latitude Pliocene temperatures can be reduced, we suggest a data–model comparison should focus on the summer. This is expected to give more meaningful and accurate results than a data–model comparison which focuses on the annual mean.

1 March 2014 in PALAIOS
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Journal Article
Closed access
TFTamara L. Fletcher
Tamara L. Fletcher
DGDavid R. Greenwood
David R. Greenwood
PMPatrick Moss
Patrick Moss
SSSteven W. Salisbury
Steven W. Salisbury
Although there is an emerging consensus about global climate patterns during the Cretaceous, details about the climate in Australia at this time are poorly resolved, and estimates for terrestrial climate are scarce. Using Climate Leaf Analysis Multivariate Program (CLAMP) and Bioclimatic Analysis (BA) on plant fossils from the mid- to Upper Cretaceous Winton Formation, central-western Queensland, and working within the context of global paleoclimatic reconstructions and the vertebrate fauna from this unit, we have improved the temporal and geographic resolution of Australia's Cretaceous climate. During the time that the Cenomanian–Turonian portion of the Winton Formation was deposited, the climate in central-western Queensland was warm, wet, and relatively equable. Frost would have been extremely uncommon, if it occurred at all, and much of the year would have been favorable for plant growth. These results are consistent with both previous isotope records for northern Australia, and the fauna of the Winton Formation, and are in keeping with current reconstructions of global Cretaceous climates.

26 August 2019 in Geophysical Research Letters
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Journal Article
Open access
PDF file
RFRan Feng
Ran Feng
BOBette L. Otto‐Bliesner
Bette L. Otto‐Bliesner
YXYangyang Xu
Yangyang Xu
EBEsther Brady
Esther Brady
TFTamara Fletcher
Tamara Fletcher
ABAshley Ballantyne
Ashley Ballantyne
Forcings and feedbacks controlling the seasonally sea ice‐free Arctic Ocean during the mid‐Piacenzian Warm period (3.264–3.025 Ma, MPWP), a period when CO2 level, geography, and topography were similar to present day, remain unclear given that many complex Earth System Models with comparatively higher skills at simulating twentieth century Arctic sea ice tend to produce perennial Arctic sea ice for this period. We demonstrate that explicitly simulating aerosol‐cloud interactions and the exclusion of industrial pollutants from model forcing conditions is key to simulating seasonally sea ice‐free Arctic Ocean of MPWP. The absence of industrial pollutants leads to fewer and larger cloud droplets over the high‐latitude Northern Europe and North Pacific, which allows greater absorption of solar radiation at the surface during the early summer. This enhanced absorption triggers the seasonally runaway sea ice surface albedo feedback that gives rise to September sea ice‐free Arctic Ocean and strongly amplified northern high‐latitude surface warmth.

1 June 2021 in Advances in Climate Change Research
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Journal Article
Open access
KJKe-Wei Jiao
Ke-Wei Jiao
JGJiang-Bo Gao
Jiang-Bo Gao
ZLZhi-Hua Liu
Zhi-Hua Liu
SWShao-Hong Wu
Shao-Hong Wu
TFTamara L. Fletcher
Tamara L. Fletcher