Pennsylvanian tropical floras from the United States as a record of changing climate

Pfefferkorn, Hermann W.; Gastaldo, Robert A.; DiMichele, William A.; Phillips, Tom

doi:10.1130/2008.2441(21)

Cited by 26 publications

(23 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Correlations of sections follow Willman et al (1975) and Nelson et al (2011). generally consistent with climate models, which suggest that low-latitude aridification was caused by weaker Hadley cell convection and southward drift of the ITCZ during periods of minimum glacial ice (Poulsen et al 2007). Regardless of the precise mechanism(s) for low-latitude climate change there is a growing consensus that tropical paleoclimate underwent a transition to drier, warmer, and more seasonal conditions Pfefferkorn et al 2008) across the middle-late Pennsylvanian boundary perhaps on the timescale of one cyclothem (, 10 4 to 10 5 years; Heckel 2008).…”

Section: Middle-late Pennsylvanian (Desmoinesian-missourian) Climaticmentioning

confidence: 99%

Polygenetic History of Paleosols In Middle-Upper Pennsylvanian Cyclothems of the Illinois Basin, U.S.A.: Part II. Integrating Geomorphology, Climate, and Glacioeustasy

Rosenau¹,

Tabor²,

Elrick³

et al. 2013

Journal of Sedimentary Research

View full text Add to dashboard Cite

Distinct lateral and stratigraphic trends in paleosol morphology and clay mineralogy, in conjunction with the stable-isotope composition of sub-millimeter-scale spherulitic siderite (sphaerosiderite) and flint-clay kaolinite in middle-upper Pennsylvanian cyclic coal-bearing strata of the Illinois basin (IB) presented herein provide proxy records of middle-late Pennsylvanian equatorial terrestrial environments. Collectively, these data provide a better understanding of the polygenetic history of ancient soils preserved in cyclic strata and indicate that low-latitude Pennsylvanian IB soil profiles were influenced by a combination of autogenic and allogenic controls.Lateral variations in paleosol morphology from the interior of the basin to the northern margin indicate that soil development was dominantly influenced by autogenic controls, such as differences in local paleohydrology (i.e., groundwater fluctuations) and subsidence rates across the basin. Conversely, allogenic controls (i.e., glacioeustasy and climate) are interpreted to be principally responsible for the preservation of features in gleyed Protosols, gleyed Vertisols, and gleyed calcic Vertisols that occur in the interior of the IB. These paleosols are characterized by a polygenetic development history that includes (1) an initial period of soil formation in well-drained environments with seasonal wetting and drying of the profile, followed by (2) a subsequent period of waterlogging and development of reducing conditions. Paleosols that lack evidence for extensive periods of waterlogging are restricted, with the exception of two examples, to the northern margin of the basin, and they become abundant in the stratigraphic record near the middle-upper Pennsylvanian boundary (uppermost Desmoinesian). The stratigraphic distribution of these paleosols, in conjunction with a decrease in the relative abundance of kaolinite in the , 2 mm size fraction of IB paleosols near the Desmoinesian-Missourian (D-M) boundary, is interpreted to reflect a shift in the overall low-latitude regional climate to drier conditions. The stable-isotope compositions of sphaerosiderite and flint-clay kaolinite in middle-upper Pennsylvanian strata of the IB provide an additional proxy record of past equatorial terrestrial environments and are used to constrain the magnitude of paleoclimate change across the D-M (, Moscovian-Kasimovian) boundary. Sphaerosiderite d 18 O V-PDB and d 13 C V-PDB values range from 23.6% to 20.5% and 212.8% to 23.2%, respectively. In particular, sphaerosiderite d 18 O values from the B horizons of paleosols display an approximate 21.5% shift across the D-M boundary. This stratigraphically short isotopic shift occurs across the D-M boundary, on the order of one cyclothem (, 400 kyr), and is followed by a subsequent shift on the order of one cyclothem, back to more positive siderite d 18 O values. The average d 18 O V-SMOW and dD V-SMOW values of kaolinite isolated from the , 0.2 mm size fraction of a latest Desmoinesian flint-clay breccia are +21.0% and 246.5...

show abstract

Section: Middle-late Pennsylvanian (Desmoinesian-missourian) Climaticmentioning

confidence: 99%

Polygenetic History of Paleosols In Middle-Upper Pennsylvanian Cyclothems of the Illinois Basin, U.S.A.: Part II. Integrating Geomorphology, Climate, and Glacioeustasy

Rosenau¹,

Tabor²,

Elrick³

et al. 2013

Journal of Sedimentary Research

View full text Add to dashboard Cite

show abstract

“…During this interval ecological stasis characterized the equatorial coal forests. We see similar communities comprising similar species and exhibiting similar ecological partitioning reoccurring from one coal bed to the next-an interval of several million years encompassing many glacialinterglacial cycles (DiMichele et al, 1996(DiMichele et al, , 2002Pfefferkorn et al, 2000Pfefferkorn et al, , 2008. If we assume that these Early-Middle Pennsylvanian coal forests were confined to refugia during glacial phases, then the ecological structure of tropical communities must have been conserved during this fragmentation.…”

Section: Explanatory Power Of Refugiamentioning

confidence: 99%

What Happened to the Coal Forests During Pennsylvanian Glacial Phases?

Falcon-Lang

DiMichele

2010

PALAIOS

101

View full text Add to dashboard Cite

Sequence stratigraphic analysis of Pennsylvanian coal-bearing strata suggests that glacial-interglacial fluctuations at high latitudes drove cyclic changes in tropical biomes. A literature review of plant assemblages in this paleoclimatic context suggests that coal forests dominated during humid interglacial phases, but were replaced by seasonally dry vegetation during glacial phases. After each glacial event, coal forests reassembled with largely the same species composition. This remarkable stasis implies that coal-forest refugia existed across the equatorial landscape during glacial phases, expanding to repopulate lowlands during and following deglaciation. One possibility is that refugia comprised small pockets of wetland forest strung out along valleys at some sites, but data are currently insufficient to test this hypothesis. The model presented here, if accepted, dramatically alters our understanding of the coal forests and helps explain aspects of their dynamics.

show abstract

“…Analysis of the wetland biome, particularly that of peat-forming landscapes, indicates a considerable amount of conservatism in species composition and dominance-diversity structure through millions of years and multiple glacial-interglacial cycles. This assessment has been based on both macrofossils and microfossils recovered from successive coal beds Willard and Phillips 1993;DiMichele and Phillips 1996b;Peppers 1996;Pfefferkorn et al 2000Pfefferkorn et al , 2008DiMichele et al 2002;Willard et al 2007), representing the wettest parts of glacial-interglacial cycles. It appears, furthermore, to be undergirded by considerable phylogenetic conservatism in the resource centroids of the major clades, resulting in phylogenetically conservative patterns of species replacement through time (DiMichele and Phillips 1996a), so-called niche conservatism (this is currently an active field of study; see Ackerly 2003;Wiens 2004;Wiens and Graham 2005;Wiens et al 2010).…”

Section: Ecological and Evolutionary Implicationsmentioning

confidence: 99%

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

DiMichele¹

2014

International Journal of Plant Sciences

Self Cite

158

View full text Add to dashboard Cite

Premise of research. The Late Paleozoic Ice Age was the last extensive pre-Pleistocene ice age. It includes many climate changes of different intensities, permitting examination of many and varied biotic responses. The tropical Pennsylvanian Subperiod, usually visualized as one vast wetland coal forest, in fact also was dominated, periodically, by seasonally dry vegetation that, in turn, covered most of the central and western Pangean supercontinent. Equatorial wetland and dryland biomes oscillated during single glacial-interglacial cycles. This recognition changes understanding of the Coal Age tropics; examination of their spatiotemporal patterns indicates that these vegetation types responded differently to global environmental disturbances and long-term trends and points to potentially different underlying controls on evolutionary histories of their component lineages.Methodology. This study is based on the published literature and on examination of geological exposures and fossil floras, mainly from North America but also from other parts of the world.Pivotal results. Wetlands and seasonally dry habitats were equally part of the Coal Age Pangean tropics. They dominated these landscapes at different times, under different climatic regimes. Wetland vegetation was likely forced into refugia during seasonally dry (subhumid to semiarid) parts of glacial-interglacial cycles; it reemerged/reassembled during wet (humid to perhumid) periods. Seasonally dry vegetation resided permanently in areas of western and central Pangea and in microhabitats within the Central Pangean Mountains. Both floras had lower biodiversity than modern floras in similar habitats. The wetland flora species pool was more phylogenetically disparate than any modern vegetation. In contrast, seasonally dry floras were dominated by seed plants. These biomes responded differently to acute environmental changes and chronic long-term aridification.Conclusions. From ecological or evolutionary perspectives, the present-day world is but one possibility. Lower-diversity worlds such as the late Paleozoic, with a rich spectrum of environmental variations, offer insights into relationships between organisms and environments that expand understanding of these phenomena and enlarge our sense of what is possible or probable as we look to the future.

show abstract

Pennsylvanian tropical floras from the United States as a record of changing climate

Cited by 26 publications

References 53 publications

Polygenetic History of Paleosols In Middle-Upper Pennsylvanian Cyclothems of the Illinois Basin, U.S.A.: Part II. Integrating Geomorphology, Climate, and Glacioeustasy

Polygenetic History of Paleosols In Middle-Upper Pennsylvanian Cyclothems of the Illinois Basin, U.S.A.: Part II. Integrating Geomorphology, Climate, and Glacioeustasy

What Happened to the Coal Forests During Pennsylvanian Glacial Phases?

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

Contact Info

Product

Resources

About