[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Cretaceous forests mapped
Me too please!
On Tue, Feb 28, 2012 at 5:22 PM, Clair Ossian <firstname.lastname@example.org> wrote:
> If a copy is available, I'd appreciate it. Thanks
> Clair Russell Ossian, Ph.D.
> Professor Emeritus, Geology
> Tarrant County College
> 2805 Raintree Drive
> Carrollton, TX 75006
> On 2/28/12 2:00 AM, "Ben Creisler" <email@example.com> wrote:
>> From: Ben Creisler
>> An article in Geology that might interest some DML members:
>> Emiliano Peralta-Medina and Howard J. Falcon-Lang (2012)
>> Cretaceous forest composition and productivity inferred from a global
>> fossil wood database.
>> Geology 40 (3): 219-222
>> doi: 10.1130/G32733.1
>> Global patterns of Cretaceous forest composition and productivity are
>> analyzed using a comprehensive fossil wood database (n = 2238). To
>> ascertain forest composition, records were classified by botanical
>> affinity, plotted on georeferenced paleomaps, and analyzed with ArcGIS
>> tools. Results confirm previous conjecture that araucarioid and
>> podocarpoid conifers were globally codominant in Early Cretaceous
>> time, especially in humid tropical and paratropical biomes, but
>> drastically reduced in numbers and range during the Late Cretaceous.
>> Cupressoid conifers, which were most common in seasonally dry
>> mid-latitudes, and pinoid conifers, which were associated with
>> temperate conditions at higher northern latitudes, also declined at
>> the same time, though less markedly. Spatial analysis suggests that
>> the loss of conifer forests (especially araucarioids) was linked to
>> the rise of co-occurring angiosperms. Our data also show that while
>> angiosperms explosively diversified in mid-Cretaceous time, they did
>> not become forest dominants until the latest Cretaceous (25 m.y.
>> later), by which time the modern relictual pattern of conifer
>> distribution had been established. To ascertain forest productivity,
>> mean tree-ring width data were obtained from direct measurements and
>> literature reviews (n = 284) and plotted by paleolatitude. Comparison
>> with modern data shows that Cretaceous forest productivity was
>> significantly elevated (×2) in mid- and high paleolatitudes, implying
>> a poleward displacement of the temperate zone by >15°. Our data
>> provide quantitative verification of Cretaceous climate-vegetation
>> models and improve the understanding of the long-term effects of
>> future global warming.
>> For a news story: