Palaeoenvironment and ecology of the middle Cretaceous Grebenka flora of northeastern Asia

Spicer, Robert A.; Ahlberg, Anders; Herman, Alexei B.; Kelley, Simon P.; Raikevich, Mikhail I.; Rees, P. J.

doi:10.1016/s0031-0182(02)00247-x

Cited by 91 publications

(39 citation statements)

References 21 publications

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“…The weaker warming here is also linked to the decrease in poleward oceanic heat transport resulting from the weakening of MOC, which is not resolved in the earlier studies. The simulated mean annual temperatures over the Eurasian interior and Arctic Ocean only increase ∼2 • C by vegetation and are up to 10 • C lower than those estimated by proxies such as leaf physiognomy (Spicer et al, 2002(Spicer et al, , 2008 and TEX 86 method (Jenkyns et al, 2004). Moreover, as the vegetationinduced warming is most pronounced during the warm late spring-early summer (Fig.…”

Section: The Role Of Vegetation Feedbacks Under High Comentioning

confidence: 82%

“…Paleoclimate proxies indicate that mean annual temperature were as high as 20 • C and 13 • C over polar ocean and land (Bice et al, 2003;Jenkyns et al, 2004;Spicer et al, 2002Spicer et al, , 2008. The cause of global warmth is widely accepted to be caused by high atmospheric CO 2 levels (Barron and Washington, 1985) resulting from volcanic outgassing.…”

Section: Introductionmentioning

confidence: 99%

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Vegetation-climate interactions in the warm mid-Cretaceous

et al. 2012

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Abstract. Vegetation-climate interactions are thought to have amplified polar warmth during past warm periods. Here, we explore the vegetation-climate interactions in the mid-Cretaceous using a fully coupled ocean-atmosphere general circulation model with a dynamic vegetation component. We run simulations with 1x, 10x and 16x pre-industrial atmospheric CO 2 . Results show that forests expand from mid-latitudes to high latitudes as CO 2 increases from 1x to 10x and 16x, mainly due to the CO 2 -induced warming. This expansion of mid-to-high latitude forests are largely supported by the distribution of mid-Cretaceous fossil woods and coal deposits. Globally, the presence of vegetation increases mean annual temperature and precipitation by 0.9 • C and 0.11 mm day −1 relative to bare ground. High-latitude warming induced by the presence of vegetation (∼1.9 • C) is less than half of that reported in previous studies. The weaker warming here is mainly due to less pronounced albedo feedbacks, and to a less extent, reduced poleward heat transport via weakening of the meridional overturning circulation. Our results suggest that other mechanisms in addition to high atmospheric CO 2 and high-latitude vegetation are required to maintain the polar warmth.

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Section: The Role Of Vegetation Feedbacks Under High Comentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Vegetation-climate interactions in the warm mid-Cretaceous

et al. 2012

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“…Global vegetation distributions for each of the four time slices were created in MATLAB by hand and are based on published paleobotanical data (Aptian: Vakhrameev, 1991;Saward, 1992;Archangelsky, 2001;Mohr and Rydin, 2002;van Waveren et al, 2002;Archangelsky, 2003) (Albian;Vakhrameev, 1991;Saward, 1992;Spicer and Herman, 2001;Mohr and Rydin, 2002;Spicer et al, 2002) (Cenomanian/Turonian: Saward, 1992;Spicer et al, 2002;Wing, 2006personal communication) (Maastrichtian: Vakhrameev, 1991Saward, 1992;Mohr and Lazarus, 1994;Otto-Bliesner and Upchurch, 1997;van der Ham et al, 2003) and reconstructions (Spicer and Chapman, 1990;Vakhrameev, 1991;Saward, 1992;Spicer and Corfield, 1992;Otto-Bliesner and Upchurch, 1997). The vegetation types used have been generalized from those of the NCAR Land Surface Model (Bonan, 1998) in an effort to make them broadly applicable to both our degree of understanding of Cretaceous vegetation distributions and the varying vegetation schemes employed in different land surface models.…”

Section: Methodsmentioning

confidence: 99%

Climate model boundary conditions for four Cretaceous time slices

et al. 2007

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Abstract. General circulation models (GCMs) are useful tools for investigating the characteristics and dynamics of past climates. Understanding of past climates contributes significantly to our overall understanding of Earth's climate system. One of the most time consuming, and often daunting, tasks facing the paleoclimate modeler, particularly those without a geological background, is the production of surface boundary conditions for past time periods. These boundary conditions consist of, at a minimum, continental configurations derived from plate tectonic modeling, topography, bathymetry, and a vegetation distribution. Typically, each researcher develops a unique set of boundary conditions for use in their simulations. Thus, unlike simulations of modern climate, basic assumptions in paleo surface boundary conditions can vary from researcher to researcher. This makes comparisons between results from multiple researchers difficult and, thus, hinders the integration of studies across the broader community. Unless special changes to surface conditions are warranted, researcher dependent boundary conditions are not the most efficient way to proceed in paleoclimate investigations. Here we present surface boundary conditions (land-sea distribution, paleotopography, paleobathymetry, and paleovegetation distribution) for four Cretaceous time slices (120 Ma, 110 Ma, 90 Ma, and 70 Ma). These boundary conditions are modified from base datasets to be appropriate for incorporation into numerical studies of Earth's climate and are available in NetCDF format upon request from the lead author. The land-sea distribution, bathymetry, and topography are based on the 1 • ×1 • (latitude × longitude) paleo Digital Elevation Models (paleoDEMs) of Christopher Scotese. Those paleoDEMs were adjusted using the paleogeographical reconstructions of Ronald BlakeyCorrespondence to: J. O. Sewall (jsewall@vt.edu) (Northern Arizona University) and published literature and were then modified for use in GCMs. The paleovegetation distribution is based on published data and reconstructions and consultation with members of the paleobotanical community and is represented as generalized biomes that should be easily translatable to many vegetation-modeling schemes.

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“…The relationship between angiosperm foliar physiognomy and climate appears to have evolved early in flowering plant history, and CLAMP has been used successfully to explore paleoclimates as old as the early Late Cretaceous (Herman and Spicer 1996;Herman et al 2002;Kennedy et al 2002;Spicer et al 2002). For paleotemperatures, CLAMP complements the marine oxygen isotope record in that it provides air temperature estimates over land; moreover, CLAMP temperature estimates are consistent with those for nearby sea surface waters Manuscript received January 13, 2004;accepted July 19, 2004. 1 Geological Institute of the Russian Academy of Sciences, 7 Pyzhevskii Pereulok, 119017 Moscow, Russia.…”

Section: Introductionmentioning

confidence: 99%

Foliar Physiognomic Record of Climatic Conditions during Dormancy: Climate Leaf Analysis Multivariate Program (CLAMP) and the Cold Month Mean Temperature

Spicer¹,

Herman²,

Kennedy³

2004

The Journal of Geology

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A B S T R A C TThe extent to which the leaves of woody dicots encode in their physiognomy the climatic conditions that exist during dormancy was tested by sampling 20 sites along an approximately west-east transect across European Russia, the Crimean Peninsula, Western Siberia, and central Eastern Siberia. This transect encompassed the most extreme mean annual temperature range recorded in the modern world where vegetation exists. Climate Leaf Analysis Multivariate Program (CLAMP) revealed little change in calibration of the warm month mean temperature compared with the PHYSG3AR data set derived from less extreme sites primarily in North America and Japan, but significant change with respect to the cold month mean temperature (CMMT) calibration. Although CLAMP underestimated the CMMT by up to 9ЊC in the coldest sites, the addition of the transect sites improved CLAMP's performance at low temperatures. This suggests that winter cold is encoded in foliar physiognomy even though the leaves are functional only during the late spring and summer months. This increase in performance was, however, at the cost of decreasing precision. Precipitation predictive capabilities were only slightly affected, but calibration of key climatic variables such as enthalpy, used in determining palaeoaltitude, remained more or less unchanged after the inclusion of the cold transect samples.

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Palaeoenvironment and ecology of the middle Cretaceous Grebenka flora of northeastern Asia

Cited by 91 publications

References 21 publications

Vegetation-climate interactions in the warm mid-Cretaceous

Vegetation-climate interactions in the warm mid-Cretaceous

Climate model boundary conditions for four Cretaceous time slices

Foliar Physiognomic Record of Climatic Conditions during Dormancy: Climate Leaf Analysis Multivariate Program (CLAMP) and the Cold Month Mean Temperature

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