[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Antarctic dinosaur environment on Seymour Island (free pdf)



From: Ben Creisler
bcreisler@gmail.com

A recent paper that may be of interest, with artist's impressions of
scenes of dinosaurs and plants.  The pdf is free in open access.

Vanessa C. Bowman,  Jane E. Francis, Rosemary A. Askin, James B.
Riding & Graeme T. Swindles (2014)
Latest Cretaceous–earliest Paleogene vegetation and climate change at
the high southern latitudes: palynological evidence from Seymour
Island, Antarctic Peninsula.
Palaeogeography, Palaeoclimatology, Palaeoecology 408: 26–47
doi: http://dx.doi.org/10.1016/j.palaeo.2014.04.018
http://www.sciencedirect.com/science/article/pii/S0031018214002156



Fluctuations in Late Cretaceous climate were already influencing
biotic change prior to the environmental upheaval at the
Cretaceous–Paleogene (K–Pg) boundary, but their general nature,
magnitude and timing remain controversial. A high-resolution dataset
on terrestrially-derived palynomorphs is presented from the high
southern palaeolatitudes that unlocks details of small-scale climate
variability throughout this period of significant global change.
Specifically, this is a quantitative spore and pollen analysis of an
expanded uppermost Cretaceous to lowermost Paleogene
(Maastrichtian–earliest Danian) shallow marine sedimentary succession
from Seymour Island, off the northeastern tip of the Antarctic
Peninsula, then (as now) located at ~ 65°S. Using nearest living
relatives the first detailed vegetation, habitat and climate
reconstruction is presented for the emergent volcanic arc at this
time. On the coastal lowlands, a cool to warm temperate rainforest is
envisaged growing in a riverine landscape, with both wet (river
margin, pond) and relatively dry (interfluve, canopy gap) habitats.
Diverse podocarps and southern beech trees grew alongside angiosperm
herbs and shrubs in mean annual temperatures of ~ 10–15 °C. Higher
altitude araucarian forests gave way to open ericaceous heathland,
beyond the tree line, in subalpine to alpine conditions with mean
annual temperatures of a cold ~ 5–8 °C. There is no exact modern
botanical equivalent, but the closest modern flora is that of the
Andes of southern Chile and Argentina. Maastrichtian climate is shown
to have fluctuated from cool, humid conditions, through a rapid
warming ~ 2 million years prior to the K–Pg transition, followed by
cooling during the earliest Danian, a trend supported by previous work
on this interval.


Highlights

First quantitative vegetation analysis for the Antarctic during the
Maastrichtian

Terrestrial palynology suggests a temperate rainforest on the
Antarctic Peninsula.

Floral trends were influenced by concurrent changes in temperature and humidity.

Cool, humid conditions gave way to a warmer climate ~ 2 myr before the
K–Pg event.