Tuesday 3 May 2022

Evolution News - How the Distribution of Alaska's Dinosaurs was Determined by Their Environment.

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Sedimentary deposits of the Prince Creek Formation are exposed in bluffs adjacent to the Colville River, on Alaska’s North Slope, in this July 2007 photograph. The sedimentary rocks represent prehistoric river channels, floodplains, lakes and ponds, and thin peat swamps.

Photo: Professor Paul J. McCarthy
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Sedimentary rocks of the Cantwell Formation, representing a prehistoric floodplain environment, are shown in this June 2017 photograph. Dinosaur tracks are visible at the base of the thick, upper sandstone bed.

Photo: Professor Paul J. Paul McCarthy
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Thick fossil soil in the Chignik Formation at Aniakchak Bay, southwest Alaska, is preserved beneath sandstone of a meandering river channel in this July 2021 photograph. Tree trunks that have turned to coal are visible at the top of the fossil soil in a few places.

Photo: Professor Paul J. Paul McCarthy
Precipitation helped drive distribution of Alaska dinosaurs | Geophysical Institute

It's been another terrible week for Creationists, especially those who have been deluded into the absurd notion that the Theory of Evolution is about to be replaced by their favourite childish superstition.

Following quickly on the heels of a paper by a team from Leipzig, Germany, showing that the evolution of plants was strongly influenced by major environmental changes caused by the extermination of large, herbivorous dinosaurs and the rise of large herbivorous mammals 25 million years later, exactly as the theory of Evolution predicts, we have news of another study, by scientists from the Geophysical Institute of the University of Alaska Fairbanks, USA, Southern Methodist University, Texas, USA, Hokkaido University, Japan and the University of Kansas, USA, showing how the distribution of dinosaurs was affected by the environment in which they lived, just as the TOE predicts.

Specifically, the team have show that it was

The reason we've been looking at Cretaceous environments up here is because Earth was in a greenhouse state at that point in time, and it offers the potential to provide analogs to what we might see, eventually, if global warming continues. We can't simulate the rates of change, which are likely to have been totally different in the Cretaceous, but we can simulate what an ice-free coast would look like and also see how rivers and floodplains would respond to spring snowmelt from the mountains if everything's not frozen. And we can look at the distribution of plants and animals.

We can look at microscopic features preserved in the fossil soil samples and relate that to modern soil types to get an idea of where they formed. Are we looking at deserts? Are we looking at tropical rainforest or temperate forest? Or grasslands?

Fossil soil also preserves pollen grains that can tell us something about the composition of the local vegetation, and it contains clay minerals, organic matter and the iron-carbonate mineral siderite, all of which can be used to determine precipitation and temperature using stable isotopic methods.

Professor Paul J. McCarthy
Department of Geosciences, and Geophysical Institute
University of Alaska, Fairbanks, Alaska, USA.
precipitation rather than temperature, that was the main factor in these distribution patterns across the range of large herbivorous dinosaurs in what is now Alaska.

The work could provide useful data for predicting how climate change could affect the arctic if the climate turns warm and wet, as it was during the Late Cretaceous Period, 100.5 million to 66 million years ago.

From the Geophysical Institute’s news release:
McCarthy, a sedimentologist and a fossil soils specialist, led the analysis of the depositional environments and ancient soils of three rock formations: the fossil-rich Prince Creek Formation along the Colville River in northern Alaska, the Lower Cantwell Formation in the Central Alaska Range and the Chignik Formation on the Alaska Peninsula.

The three formations are close enough to one another on the geologic time scale to allow for a climate comparison, according to the research paper. They all contain Late Cretaceous rocks that were deposited approximately 83 million to 66 million years ago.

Maps showing general locations of study areas. (A) Modern Alaska. (B) Polar projection of tectonic plates during the Late Cretaceous (Base map from PLATES Project, University of Texas Institute of Geophysics). The inner latitudinal ring on map represents 45° N. (C) Examples of vertebrate fossil data used in this study. (1) PCF, North Slope, C1, bonebed. (2) LCF DENA, C2, ceratopsian footprint, DENA. (3) CF, ANIA, C3 hadrosaur footprint.

Fossilized plants and animals and ancient footprints get most of the public attention, but fossil soil has equally important information to offer through its preserved features, mineral composition and chemical makeup.

From that, paleontologists can learn about the distribution of Alaska’s dinosaurs.

Through analysis at UAF and elsewhere, scientists studying the three Alaska formations found a correlation between the amount of precipitation and the distribution of hadrosaurids and ceratopsids. They also found a lesser correlation between temperature and the distribution of those two groups of dinosaurs.

Hadrosaurids, the duck-billed family of dinosaurs, preferred climates that were wetter and had a narrower annual temperature range. Adults weighed about 3 tons and reached about 30 feet in length. Their percentage dominance over the ceratopsids in the three studied formations increased in the more-favorable climate.

Ceratopsids, a family with beaks and horns, preferred a milder and drier climate but never became dominant in percentage over the hadrosaurids in the three formations. Triceratops is perhaps the best known ceratopsid, at a length of about 25 to 30 feet and weighing 4.5 to 5.5 tons.

The finding for greater influence of precipitation than temperature was based in part on prior research that looked at dinosaur teeth from the Prince Creek Formation, including teeth of hadrosaurids and ceratopsids. That study was led by Celina A. Suarez of the University of Arkansas and included work by McCarthy.

Results from that dental study, authors of the new paper write, suggest that ceratopsids preferred the drier, better-drained regions of the Late Cretaceous Arctic landscape and that hadrosaurids preferred wetter regions of the landscape.
Copyright: © 2022 The authors. Published by MDPI
Open access
The team's findings were published open access recently in the journal Geosciences:

The partially correlative Alaskan dinosaur-bearing Prince Creek Formation (PCF), North Slope, lower Cantwell Formation (LCF), Denali National Park, and Chignik Formation (CF), Aniakchak National Monument, form an N–S transect that, together, provides an unparalleled opportunity to examine an ancient high-latitude terrestrial ecosystem. The PCF, 75–85° N paleolatitude, had a Mean Annual Temperature (MAT) of ~5–7 °C and a Mean Annual Precipitation (MAP) of ~1250 mm/year. The LCF, ~71° N paleolatitude, had a MAT of ~7.4 °C and MAP of ~661 mm/year. The CF, ~57° N paleolatitude, had a MAT of ~13 °C and MAP of ~1090 mm/year. The relative abundances of the large-bodied herbivorous dinosaurs, hadrosaurids and ceratopsids, vary along this transect, suggesting that these climatic differences (temperature and precipitation) played a role in the ecology of these large-bodied herbivores of the ancient north. MAP played a more direct role in their distribution than MAT, and the seasonal temperature range may have played a secondary role.

And yet still, in the face of so much evidence refuting it, creationist dupes continue to believe that the Theory of Evolution is being increasingly rejected by serious biologists in favour of their childish fairy-tale based, as it is, on the best guesses of superstitious Bronze Age hill farmers who also believed earth runs on magic and is small, flat and has a dome over it to keep the water above the sky from leaking in.

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