Carboniferous macrofloral biostratigraphy – an overview

2020 ◽  
pp. SP512-2020-97
Author(s):  
Stanislav Opluštil ◽  
Christopher J. Cleal ◽  
Jun Wang ◽  
Mingli Wan
Keyword(s):  
High Latitude ◽  
Fossil Record ◽  
Seed Plants ◽  
Terrestrial Vegetation ◽  
Low Resolution ◽  
Middle Latitudes ◽  
Global Cooling ◽  
The Tropics ◽  
Northern And Southern Hemispheres

AbstractIn the Carboniferous, terrestrial vegetation became widespread, diverse and abundant. The resulting fossil record has proved to be an effective biostratigraphic tool for intra- and interbasinal correlations. Besides palaeogeographic configurations, Carboniferous plant biostratigraphy is affected by a transition from greenhouse conditions during most of the Mississippian to an icehouse climate in the Pennsylvanian. The greenhouse Mississippian climate resulted in weak provincialism, with a cosmopolitan flora ranging from the tropics to middle latitudes. The global cooling around the Mississippian - Pennsylvanian boundary enhanced development of a latitudinal climatic zonation and related floral provincialism. These changes are expressed in the recognition of distinct realms or kingdoms, where the tropical Amerosinian Realm (or Euramerican and Cathaysian realms) is surrounded by the Angaran and Gondwanan realms occupying middle to high latitude of the northern and southern hemispheres, respectively. Floristic endemism in the Pennsylvanian precludes development of a global macrofloral biostratigraphy. Instead, each realm or area has its own biostratigraphic scheme. Poorer and less diverse floras of the Gondwanan and Angaran realms resulted in the establishment of relatively low-resolution macrofloral biostratigraphic schemes. Higher resolution macrofloral zonations exist only in the tropical Amerosinian Realm due to diverse and abundant floras dominated by free-sporing and early seed plants occupying extensive wetlands.

Wood evolution: Baileyan trends and Functional traits in the fossil record

IAWA Journal ◽  
2019 ◽  
Vol 40 (3) ◽  
pp. 488-529 ◽  
Author(s):  
Elisabeth A. Wheeler ◽  
Pieter Baas
Keyword(s):  
High Latitude ◽  
Fossil Record ◽  
Tropical Conditions ◽  
Low Levels ◽  
Low Incidence ◽  
Wood Evolution ◽  
Tropical Woods ◽  
Almost All ◽  
The Tropics ◽  
Transformation Series

ABSTRACTWe revisited questions about changes in the incidences of functional wood anatomical traits through geologic time and compared the incidences of these traits in the fossil record with modern wood anatomical diversity patterns in order to test classical (“Baileyan”) and more recent ecophyletic hypotheses of xylem evolution. We contrast patterns through time for tropical and higher (paleo)latitudes. Data are from the InsideWood database. There are striking differences between woods from high and mid latitudes versus tropical (paleo)-latitudes. At temperate and subtropical latitudes (Laurasia and high latitude Gondwana), the epoch by epoch time series supports the Baileyan transformation series of vessel-bearing woody angiosperms (basal woody angiosperms and eudicots): “primitive” features such as scalariform perforations, exclusively solitary vessels, apotracheal diffuse parenchyma and heterocellular rays abound in the Cretaceous and become much less frequent in the Cenozoic, especially post-Eocene. In contrast, in the paleotropics hardly any changes occur in the incidences – each epoch has an equally “modern” spectrum of wood anatomical attributes. Although climatic gradients from the poles to the equator were less steep in the Cretaceous than in the late Cenozoic, the wood anatomical differences between mid-high latitude woods and tropical woods were much more pronounced in the Cretaceous than in later epochs. This seeming paradox is discussed but we cannot resolve it.We suggest that tropical conditions have accelerated xylem evolution towards greater hydraulic efficiency (simple perforations), biological defense and hydraulic repair (elaborate paratracheal parenchyma patterns) as evidenced by late Cretaceous tropical latitude woods having near modern incidences of almost all traits. At higher paleolatitudes of both the Northern and Southern Hemisphere “ancestral” features such as scalariform perforations were retained in cooler and frost-prone regions where they were not selected against in mesic habitats because of lower demands on conductive efficiency, and could even be advantageous in trapping freeze-thaw embolisms. The fossil wood record remains too incomplete for testing hypotheses on the wood anatomy of the earliest angiosperms. The low incidence of so-called “xerophobic” woods sensu Feild with scalariform perforations with numerous (over 40) closely spaced bars in the Cretaceous tropical fossil record is puzzling. At higher paleolatitudes such woods are common in the Cretaceous.Ring porosity, an indicator of seasonal climates and deciduousness, occurs at low levels in the Cretaceous and Paleogene at higher paleolatitudes only, and reaches modern levels in the Miocene. In Neogene and Recent temperate Northern Hemisphere, wide vessels are virtually restricted to ring-porous woods. In the tropics, there is a low incidence of ring porosity throughout all epochs.The fossil record indicates that ecophysiological adaptation to tropical or temperate conditions was already evident in the Cretaceous with considerable latitudinal differences.

scholarly journals Obliquity forcing of low-latitude climate

2015 ◽  
Vol 11 (1) ◽  
pp. 221-241 ◽  
Author(s):  
J. H. C. Bosmans ◽  
F. J. Hilgen ◽  
E. Tuenter ◽  
L. J. Lourens
Keyword(s):  
High Latitude ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Rotational Axis ◽  
Low Latitude ◽  
Low Latitudes ◽  
Paleoclimate Records ◽  
Induced Changes ◽  
The Tropics

Abstract. The influence of obliquity, the tilt of the Earth's rotational axis, on incoming solar radiation at low latitudes is small, yet many tropical and subtropical paleoclimate records reveal a clear obliquity signal. Several mechanisms have been proposed to explain this signal, such as the remote influence of high-latitude glacials, the remote effect of insolation changes at mid- to high latitudes independent of glacial cyclicity, shifts in the latitudinal extent of the tropics, and changes in latitudinal insolation gradients. Using a sophisticated coupled ocean–atmosphere global climate model, EC-Earth, without dynamical ice sheets, we performed two experiments of obliquity extremes. Our results show that obliquity-induced changes in tropical climate can occur without high-latitude ice sheet fluctuations. Furthermore, the tropical circulation changes are consistent with obliquity-induced changes in the cross-equatorial insolation gradient, implying that this gradient may be used to explain obliquity signals in low-latitude paleoclimate records instead of the classic 65° N summer insolation curve.

scholarly journals Estimating the Ice Crystal Enhancement Factor in the Tropics

2011 ◽  
Vol 68 (7) ◽  
pp. 1424-1434 ◽  
Author(s):  
Xiping Zeng ◽  
Wei-Kuo Tao ◽  
Toshihisa Matsui ◽  
Shaocheng Xie ◽  
Stephen Lang ◽  
...  
Keyword(s):  
Ice Crystal ◽  
Middle Latitudes ◽  
Ice Nuclei ◽  
Significant Difference ◽  
Physically Based ◽  
Cloud Resolving Model ◽  
The Difference ◽  
The Tropics ◽  
Cloud Condition

Abstract The ice crystal enhancement (IE) factor, defined as the ratio of the ice crystal to ice nuclei (IN) number concentrations for any particular cloud condition, is needed to quantify the contribution of changes in IN to global warming. However, the ensemble characteristics of IE are still unclear. In this paper, a representation of the IE factor is incorporated into a three-ice-category microphysical scheme for use in long-term cloud-resolving model (CRM) simulations. Model results are compared with remote sensing observations, which suggest that, absent a physically based consideration of how IE comes about, the IE factor in tropical clouds is about 103 times larger than that in midlatitudinal ones. This significant difference in IE between the tropics and middle latitudes is consistent with the observation of stronger entrainment and detrainment in the tropics. In addition, the difference also suggests that cloud microphysical parameterizations depend on spatial resolution (or subgrid turbulence parameterizations within CRMs).

scholarly journals Obliquity forcing of low-latitude climate

2015 ◽  
Vol 11 (10) ◽  
pp. 1335-1346 ◽  
Author(s):  
J. H. C. Bosmans ◽  
F. J. Hilgen ◽  
E. Tuenter ◽  
L. J. Lourens
Keyword(s):  
High Latitude ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Rotational Axis ◽  
Tropical Circulation ◽  
Low Latitude ◽  
Low Latitudes ◽  
Induced Changes ◽  
The Tropics

Abstract. The influence of obliquity, the tilt of the Earth's rotational axis, on incoming solar radiation at low latitudes is small, yet many tropical and subtropical palaeoclimate records reveal a clear obliquity signal. Several mechanisms have been proposed to explain this signal, such as the remote influence of high-latitude glacials, the remote effect of insolation changes at mid- to high latitudes independent of glacial cyclicity, shifts in the latitudinal extent of the tropics, and changes in latitudinal insolation gradients. Using a sophisticated coupled ocean–atmosphere global climate model, EC-Earth, without dynamical ice sheets, we performed two idealized experiments of obliquity extremes. Our results show that obliquity-induced changes in tropical climate can occur without high-latitude ice sheet fluctuations. Furthermore, the tropical circulation changes are consistent with obliquity-induced changes in the cross-equatorial insolation gradient, suggesting that this gradient may be used to explain obliquity signals in low-latitude palaeoclimate records instead of the classical 65° N summer insolation curve.

Interannual Variability in the Southern Hemisphere Circulation Organized by Stratospheric Final Warming Events

2007 ◽  
Vol 64 (8) ◽  
pp. 2968-2974 ◽  
Author(s):  
Robert X. Black ◽  
Brent A. McDaniel
Keyword(s):  
Southern Hemisphere ◽  
High Latitude ◽  
Large Scale ◽  
Lower Troposphere ◽  
Southern Annular Mode ◽  
Atmospheric Variability ◽  
Middle Latitudes ◽  
Stratospheric Final Warming ◽  
Circulation Change ◽  
Large Scale Atmospheric Circulation

A composite observational analysis is presented demonstrating that austral stratospheric final warming (SFW) events provide a substantial organizing influence upon the large-scale atmospheric circulation in the Southern Hemisphere. In particular, the annual weakening of high-latitude westerlies in the upper troposphere and stratosphere is accelerated during SFW onset. This behavior is associated with a coherent annular circulation change with zonal wind decelerations (accelerations) at high (low) latitudes. The high-latitude stratospheric decelerations are induced by the anomalous wave driving of upward-propagating tropospheric waves. Longitudinally asymmetric circulation changes occur in the lower troposphere during SFW onset with regionally localized height increases (decreases) at subpolar (middle) latitudes. Importantly, the tropospheric and stratospheric circulation change patterns identified here are structurally distinct from the Southern Annular Mode. It is concluded that SFW events are linked to interannual atmospheric variability with potential bearing upon weather and climate prediction.

Retrieval of Latent Heating from TRMM Measurements

2006 ◽  
Vol 87 (11) ◽  
pp. 1555-1572 ◽  
Author(s):  
W.-K. Tao ◽  
E. A. Smith ◽  
R. F. Adler ◽  
Z. S. Haddad ◽  
A. Y. Hou ◽  
...  
Keyword(s):  
Latent Heat ◽  
Large Scale ◽  
Climate Models ◽  
Hydrological Cycle ◽  
Tropical Rainfall Measuring Mission ◽  
Phase Changes ◽  
Latent Heating ◽  
Middle Latitudes ◽  
Rate Profile ◽  
The Tropics

Rainfall is a fundamental process within the Earth's hydrological cycle because it represents a principal forcing term in surface water budgets, while its energetics corollary, latent heating, is the principal source of atmospheric diabatic heating well into the middle latitudes. Latent heat production itself is a consequence of phase changes between the vapor, liquid, and frozen states of water. The properties of the vertical distribution of latent heat release modulate large-scale meridional and zonal circulations within the Tropics, as well as modify the energetic efficiencies of midlatitude weather systems. This paper highlights the retrieval of latent heating from satellite measurements generated by the Tropical Rainfall Measuring Mission (TRMM) satellite observatory, which was launched in November 1997 as a joint American–Japanese space endeavor. Since then, TRMM measurements have been providing credible four-dimensional accounts of rainfall over the global Tropics and subtropics, information that can be used to estimate the space–time structure of latent heating across the Earth's low latitudes. A set of algorithm methodologies for estimating latent heating based on precipitation-rate profile retrievals obtained from TRMM measurements has been under continuous development since the advent of the mission s research program. These algorithms are briefly described, followed by a discussion of the latent heating products that they generate. The paper then provides an overview of how TRMM-derived latent heating information is currently being used in conjunction with global weather and climate models, concluding with remarks intended to stimulate further research on latent heating retrieval from satellites.

Ten years in the library: new data confirm paleontological patterns

Paleobiology ◽  
1993 ◽  
Vol 19 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J. John Sepkoski
Keyword(s):  
Fossil Record ◽  
Goodness Of Fit ◽  
Marine Animal ◽  
Low Resolution ◽  
Data Bases ◽  
Marine Fauna ◽  
Paleontological Data ◽  
Principal Difference ◽  
Library Research

A comparison is made between compilations of times of origination and extinction of fossil marine animal families published in 1982 and 1992. As a result of ten years of library research, half of the information in the compendia has changed: families have been added and deleted, low-resolution stratigraphic data have been improved, and intervals of origination and extinction have been altered. Despite these changes, apparent macroevolutionary patterns for the entire marine fauna have remained constant. Diversity curves compiled from the two data bases are very similar, with a goodness-of-fit of 99%; the principal difference is that the 1992 curve averages 13% higher than the older curve. Both numbers and percentages of origination and extinction also match well, with fits ranging from 83% to 95%. All major events of radiation and extinction are identical. Therefore, errors in large paleontological data bases and arbitrariness of included taxa are not necessarily impediments to the analysis of pattern in the fossil record, so long as the data are sufficiently numerous.

Impact of SSM/I Observations Related to Moisture, Clouds, and Precipitation on Global NWP Forecast Skill

2008 ◽  
Vol 136 (7) ◽  
pp. 2713-2726 ◽  
Author(s):  
G. A. Kelly ◽  
P. Bauer ◽  
A. J. Geer ◽  
P. Lopez ◽  
J-N. Thépaut
Keyword(s):  
Initial Conditions ◽  
Forecast Skill ◽  
Clear Sky ◽  
Microwave Imager ◽  
Set Up ◽  
The Tropics ◽  
The Impact ◽  
Northern And Southern Hemispheres ◽  
Experiment Duration

Abstract This paper presents the results from the Observing System Experiments (OSEs) with the current ECMWF data assimilation and modeling system for quantifying the impact on both analysis and forecast quality of Special Sensor Microwave Imager (SSM/I) observations sensitive to moisture and clouds as well as precipitation. SSM/I radiances have been assimilated operationally in clear-sky areas for 8 yr and in cloud- and rain-affected areas since June 2005. This paper examines experiments set up such that clear-sky and rain-affected observations were either added to a baseline with a restricted observing system configuration or withdrawn from the full system. The experiment duration was 10 weeks of which the first 14 days were excluded from the evaluation to allow the system to lose the memory of the initial conditions at day −1. It is shown that both clear-sky and rain-affected observations account for the bulk correction of moisture in the ECMWF analysis. SSM/I data adds 1 day of forecast skill over the first 48 h when evaluated in addition to a baseline-observing system. In the tropics, the rain-affected data contributes more skill to the moisture forecast than the clear-sky data at 700 hPa and above. In the Northern and Southern Hemispheres, the effect is generally weaker and slightly in favor of clear-sky observations. A similar performance can be seen with respect to the wind vector forecast skill, which reflects the connection between the analysis of moisture and dynamics.

Sign in / Sign up

Export Citation Format

Share Document