Identification

Title

Plant proxy evidence for high rainfall and productivity in the Eocene of Australia

Abstract

During the early to middle Eocene, a mid-to-high latitudinal position and enhanced hydrological cycle in Australia would have contributed to a wetter and "greener" Australian continent where today arid to semi-arid climates dominate. Here, we revisit 12 southern Australian plant megafossil sites from the early to middle Eocene to generate temperature, precipitation, and seasonality paleoclimate estimates, net primary productivity (NPP), and vegetation type, based on paleobotanical proxies and compare them to early Eocene global climate models. Temperature reconstructions are uniformly subtropical (mean annual, summer, and winter mean temperatures 19-21 degrees C, 25-27 degrees C, and 14-16 degrees C, respectively), indicating that southern Australia was similar to 5 degrees C warmer than today, despite a >20 degrees poleward shift from its modern geographic location. Precipitation was less homogeneous than temperature, with mean annual precipitation of similar to 60 cm over inland sites and >100 cm over coastal sites. Precipitation may have been seasonal with the driest month receiving 2-7x less than the mean monthly precipitation. Proxy-model comparison is favorable with a 1,680 ppm CO2 concentration. However, individual proxy reconstructions can disagree with models as well as with each other. In particular, seasonality reconstructions have systemic offsets. NPP estimates were higher than modern, implying a more homogenously "green" southern Australia in the early to middle Eocene when this part of Australia was at 48-64 degrees S and larger carbon fluxes to and from the Australian biosphere. The most similar modern vegetation type is modern-day eastern Australian subtropical forest, although the distance from coast and latitude may have led to vegetation heterogeneity.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7hx1hcm

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2022-06-26T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact