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17 recordsLinked to original sources
USGS1997

Palynology of the Lost Branch Formation of Kansas - New insights on the major floral transition at the Middle-Upper Pennsylvanian boundary

Palynological assemblages from two outcrops of the upper part of the Memorial Formation, the Lost Branch Formation, and the overlying Hepler unit in Kansas were examined to discover which stratigraphic interval marks the change from the lycopod-dominated coal swamp floras of Middle Pennsylvanian (Westphalian D) age to the fern-dominated coal swamp floras of Late Pennsylvanian (Stephanian) age. The Lost Branch Formation underlies the Pleasanton Group, whose base is recognized as the Middle-Upper Pennsylvanian boundary in the Midcontinent. The outcrops include the youngest Middle Pennsylvanian coal (Dawson), just below the Lost Branch Formation, and the oldest Upper Pennsylvanian coal ('Hepler') within the Pleasanton Group. Lycospora dominates the spore assemblage in the Middle Pennsylvanian (Desmoinesian) Dawson coal in the Memorial Shale and is abundant in shale between the coal and just below the Glenpool limestone bed at the top of the Lost Branch Formation. It is rare between the limestone and the Upper Pennsylvanian (Missourian) 'Hepler' coal. Granasporites medius and Thymospora pseudothiessenii disappear below the limestone. The 'Hepler' coal is dominated by fern and seed fern spores Cyclogranisporites and Apiculatasporites, and the sphenopsid spore Calamospora is third in abundance. Florinites, Potonieisporites and other gymnospermic monosaccate pollen are abundant between the two coals. Bisaccate conifer-like pollen, such as Protohaploxipinus, are most common between the Dawson coal and Glenpool limestone, but Wilsonites, which is thought to have been produced by seed ferns, is very abundant from the Glenpool limestone to the 'Hepler' coal. On the basis of macroinvertebrate evidence, the Glenpool limestone is Middle Pennsylvanian in age, but the palynological evidence indicates that the floral change took place slightly before deposition of the limestone. Thus, the major change in climate that occurred near the Middle-Upper Pennsylvanian boundary apparently affected the floras earlier than the faunas. The floral change cannot be explained as resulting from a major marine regression and hiatus because the change is recorded in a marine section within a single transgressive-regressive sequence.

Review of Palaeobotany and Palynology↗
USGS2011

An analysis of modern pollen rain from the Maya lowlands of northern Belize

In the lowland Maya area, pollen records provide important insights into the impact of past human populations and climate change on tropical ecosystems. Despite a long history of regional paleoecological research, few studies have characterized the palynological signatures of lowland ecosystems, a fact which lowers confidence in ecological inferences made from palynological data. We sought to verify whether we could use pollen spectra to reliably distinguish modern ecosystem types in the Maya lowlands of Central America. We collected 23 soil and sediment samples from eight ecosystem types, including upland, riparian, secondary, and swamp ( bajo ) forests; pine savanna; and three distinct wetland communities. We analyzed pollen spectra with non-metric multidimensional scaling (NMDS), and found significant compositional differences in ecosystem types' pollen spectra. Forested sites had spectra dominated by Moraceae/Urticaceae pollen, while non-forested sites had significant portions of Poaceae, Asteraceae, and Amaranthaceae pollen. Upland, bajo , and riparian forest differed in representation of Cyperaceae, Bactris -type, and Combretaceae/Melastomataceae pollen. High percentages of pine ( Pinus ), oak ( Quercus ), and the presence of Byrsonima characterized pine savanna. Despite its limited sample size, this study provides one of the first statistical analyses of modern pollen rain in the Maya lowlands. Our results show that pollen assemblages can accurately reflect differences between ecosystem types, which may help refine interpretations of pollen records from the Maya area.

Maya lowlands↗
USGS1994

Palynological record from the North Atlantic region at 3 Ma: Vegetational distribution during a period of global warmth

Pollen assemblages from five mid-Pliocene, deep-marine and shallow-marine sites in the North Atlantic Ocean region were analyzed quantitatively to estimate vegetational composition and terrestrial paleoclimates during a time interval centered at about 3 Ma. Three subarctic sites (58–67°N latitude) from the Norwegian Sea, northern Iceland, and the Labrador Sea yielded pollen assemblages characteristic of mixed conifer-hardwood vegetation; these assemblages have no close modern analogs, but the most similar modern vegetation is that of the Tsuga (hemlock)-northern hardwood forests of Newfoundland and Nova Scotia (45–50°N). The presence of such vegetation at these sites indicates mid-Pliocene January temperatures from 4 to 10°C warmer than today and a northward shift of the deciduous forest zone into areas presently occupied by boreal forests. Pollen assemblages from the mid-latitude (36°N) Yorktown Formation site in southeastern Virginia, USA represent Quercus-Carya-Pinus (oak-hickory-pine) forests, similar to those presently occupying much of the Atlantic coastal plain of the United States. Modern analogs for this site are located off the coasts of North Carolina and South Carolina, indicating mid-Pliocene January temperatures 3–5°C warmer than today. In southwestern Florida (27°N), pollen assemblages from the mid-Pliocene Pincrest Beds are representative of pine-dominated communities, similar to Pinus palustris/P. ellittii forests (longleaf/slash pine) growing in Florida today. Close modern analogs for the Pinecrest Beds are located at numerous sites around the Florida peninsula, indicating mid-Pliocene temperatures about the same as today for this region. These sites show a gradient from much higher than present temperatures at high latitudes to little change from present temperatures at low latitudes and low elevations; a similar pattern is shown by mid-Pliocene sea-surface and isotopic data. Such a gradient also is consistent with the northward migration of the boreal forest zone, covering sites as far north as Meighen and Banks Islands, a northward shift of the deciduous-boreal forest boundary in both North America and Europe, and little change in vegetational distribution in low elevation sites in subtropical latitudes during the mid-Pliocene warm interval. Atmospheric temperaturs estimated from vegetational distributions indicate a Pliocene to modern temperature anomaly of a similar pattern and magnitude to that indicated by sea-surface temperatures. These data are most consistent with current general circulation model simulations of climate changes in response to increased meridional heat transport.

Florida, Newfoundland and Labrador, Virginia↗
USGS1975

Sandrewia, n. gen., a problematical plant from the Lower Permian of Texas and Kansas

Sandrewia , n. gen., monotypified by S. texana , n. sp., is a plant from Lower Permian beds of north-central Texas and east-central Kansas. It is characterized by stout axes with spirally disposed, laxly inserted, petiolate leaves; the laminae are broadly flabelliform with coarse, open venation. The leaves are reminiscent of the vojnovskyalean Nephropsis , of the Permian Petchora Basin, U.S.S.R., but biologic relationships are only speculative because of limited material. However, leaf characteristics render Sandrewia easily identifiable. Its presently limited stratigraphic range, along with floristic associations, indicates it may be a useful guide fossil and supports the author's beliefs regarding important times and places in Paleozoic plant evolution.

Kansas, Texas↗
USGS1976

Morphologic interpretation of fertile structures in glossopterid gymnosperms

The problem of determining affinity among glossopterid gymnosperms is beset by deficiencies in preservation, natural dissociation of parts, and scarcity of features assuredly critical for morphologic comprarison. The glossopterids probably are not a very heterogeneous group of plants, but this is difficult to prove. The Gondwana glacial "hiatus" has resulted in the omission of a critical chapter glossopterid evolution. As a consequence, morphologic features and phyletic probabilities must be evaluated on a much more hypothetical basis than would otherwise be justified. Confusion has arisen from the lack of morphologic terms that permit clear discussion of a newly evolved type of reproductive structure in glossopterids. The structure, here designated a "fertiliger", consists of a leafy bract, a partially adnate stalk, and a fertile head or capitulum. Seven types of fertile structures are discussed, all of which are bilaterally symmetrical and have different features on dorsiventral surfaces. I regard all fertiligers as ovulate but this interpretation may bot be acceptable to some workers; others may not accept dorsiventral organization of the capitulum as being fundamental. Among glossopterids, however, in spite of differences in preservation that may seem to support a variant interpretation, these ovulate fertiligers are the distinctive features that show general consistency. A single fertile bract bearing several capitula, as exemplified by Lidgettonia, is called a compound fertiliger. Staminate structures (microsporophylls) of glossopterids are separately classified as Eretmonia, Glossotheca, and possibly as other taxa. Only the manner of sporangial attachment is not entirely clear. It seems likely the staminate parts have previously been confused with scale leaves and are actually coextensive in distribution with the glossopterids. A tentative phyletic model suggests the distant derivation of glossopterids from middle Carboniferous cordaiteans. Many details must be speculative due to the lack of a pertinent fossil record, but this interpretation accounts for some features that have no counterpart in pteridosperms. Permineralized ovules from Antarctica provide general support for this working hypothesis, but specific evidence is lacking. Furthermore, it seems unlikely angiosperms originated from glossopterids; it is more reasonable to consider the glossopterids as possible distant ancestors of the Gnetales. ?? 1976.

Review of Palaeobotany and Palynology↗
USGS1979

The genus Platychara from the Western Hemisphere

The systematics of four species belonging to the genus Platychara (Charophyta) from the Western Hemisphere is discussed. Three of the species, as defined herein, occur in Cretaceous and Paleocene rocks from Mexico through South America. The type species, P. compressa (Peck and Reker) Grambast, also of Cretaceous and Paleocene age, is herein restricted to deposits north of Mexico. These latter restrictions geographically separate P. compressa and P. perlata as presently defined but the relationship between these two species is still uncertain. A new species, P. grambastii, is proposed for specimens from Maestrichtian sediments in Jamaica. ?? 1979.

Review of Palaeobotany and Palynology↗
USGS1981

Geographic distribution and dispersal of normapolles genera in North America

Normapolles pollen have been found in North America in Cretaceous and Lower Tertiary rocks from the eastern Atlantic Seaboard, the Mississippi embayment region and from the states and provinces from western North America as far north as the District of Mackenzie, Northwest Territories. Previous postulates relating to the Normapolles floral province (western Europe-eastern North America) were re-examined in the light of new finds of Normapolles genera in rocks from west of the Cretaceous epeiric seaway which separated the Normapolles province from the western North American Aquilapollenites province. A study of published occurrences of Normapolles genera and U.S. Geological Survey Denver Laboratory Normapolles records revealed that of the approximately 60 Normapolles genera recognized from western Europe, only 26 of these have been recognized from eastern North America. These data suggest that Normapolles-producing plants originated in western Europe and migrated to eastern North America prior to the opening of the north Atlantic seaway. Ten of these 26 genera also have been found in rocks from west of the Cretaceous epeiric seaway, suggesting that these genera were the only ones able to cross this barrier. At least six genera having Normapolles characteristics occur in eastern North America but have not yet been recorded from Europe. Two additional genera with Normapolles characteristics have been reported only from the Aquilapollenites province of western North America. Several discrepancies in the record need resolution, such as the latitudinal restriction of Thomsonipollis and Nudopollis to areas south 40??N latitude, the absence of records of Thomsonipollis east and north of central Georgia, and the absence of records of Kyandopollenites and Choanopollenites west of eastern Texas. These data show that the known boundaries of the Normapolles province are somewhat hazy and that firm conclusions regarding the geographic distribution and history of dispersal of Normapolles genera are premature. ?? 1981.

Review of Palaeobotany and Palynology↗
USGS1986

Taeniopterid lamina on Phasmatocycas megasporophylls (Cycadales) from the Lower Permian of Kansas, U.S.A.

New specimens of Phasmatocycas and Taeniopteris from the original Lower Permian locality in Kansas demonstrate organic attachment of the two and corroborate Mamay's hypothesis that Phasmatocycas and Taeniopteris were parts of the same plant. These forms also suggest that cycads evolved from taxa with entire leaves; i.e. Taeniopteris, rather than from pteridosperms with compound leaves. ?? 1986.

Review of Palaeobotany and Palynology↗
USGS1992

Petrographic and anatomical characteristics of plant material from two peat deposits of Holocene and Miocene age, Kalimantan, Indonesia

Samples from two peat-forming environments of Holocene and Miocene age in Kalimantan (Borneo), Indonesia, were studied petrographically using nearly identical sample preparation and microscopic methodologies. Both deposits consist of two basic types of organic material: plant organs/tissues and fine-grained matrix. There are seven predominant types of plant organs and tissues: roots possessing only primary growth, stems possessing only primary growth, leaves, stems/roots with secondary growth, secondary xylem fragments, fragments of cork cells, and macerated tissue of undetermined origin. The fine-grained matrix consists of fragments of cell walls and cell fillings, fungal remains, spores and pollen grains, and resin. Some of the matrix material does not have distinct grain boundaries (at ??500) and this material is designated amorphous matrix. The major difference between the Holocene peat and Miocene lignite in reflected light, oil immersion is a loss of red coloration in the cell walls of tissue in the lignite, presumably due to loss of cellulosic compounds. In addition, cortex and phloem tissue (hence primary roots and stems) are difficult to recognize in the lignite, probably because these large, thin-walled tissues are more susceptible to microbial degradation and compaction. Particle size in both peat and lignite samples display a bimodal distribution when measurements are transformed to a - log2 or phi (??), scale. Most plant parts have modes of 2-3?? (0.25 - 0.125 mm), whereas the finer-grained particulate matrix has modes of 7-9?? (0.008-0.002 mm). This similarity suggest certain degradative processes. The 2-3?? range may be a "stable" size for plant parts (regardless of origin) because this is a characteristics of a substrate which is most suitable for plant growth in peat. The finer-grained matrix material (7-9??) probably results from fungal decay which causes plant material to weaken and with slight physical pressure to shatter into its component parts, i.e. fragments of cell walls and fillings. The absence of differences in particle size between the peat and lignite also indicate little compaction of organic components; rather an extreme loss in water content and pore space has occurred from between the particles of organic material. ?? 1992.

Review of Palaeobotany and Palynology↗
USGS1993

Revision of the biostratigraphy of the Chatham Group (Upper Triassic), Deep River basin, North Carolina, USA

Paleontological evidence from the Upper Triassic Chatham Group in the three subbasins of the Deep River basin (North Carolina, USA) supports a significant revision of the ages assigned to most of this non-marine continental sedimentary sequence. This study confirms an early(?) or mid-Carnian age in the Sanford subbasin for the base of the Pekin Formation, the lowest unit of the Chatham Group. However, diagnostic late Carnian palynomorphs have been recovered from coals in the lower part of the Cumnock Formation in the Sanford subbasin, and from a sample of the Cumnock Formation equivalent in the Wadesboro subbasin. Plant megafossils and fossil verebrates from rocks in the Sanford subbasin also support a late Carnian age for the Cumnock Formation and its equivalents. The overlying Sanford Formation, which has not yet been dated paleontologically, probably includes beds of Norian age, as over 1000 m of strata may be present between the Cumnock Formation coals (dated here as late Carnian) and the top of the Sanford Formation. This chronostratigraphic interval appears similar to, but slightly longer than, that preserved in the Dan River-Danville and Davie County basins 100 km to the northwest. Our evidence, therefore, indicates that the Chatham Group was deposited over a much longer time interval [early(?) to mid-Carnian through early Norian] than previously was believed. ?? 1993.

Review of Palaeobotany and Palynology↗
USGS1994

Paleocene floral diversities and turnover events in eastern North America and their relation to diversity models

This paper uses angiosperm pollen taxon turnover (first and last appearance) and diversity events as metrics to describe the Paleocene floral history of the eastern Gulf Coast; data are from 64 samples and 67 angiosperm pollen taxa. Angiosperm pollen diversity was very low at the beginning of the Paleocene, rose slowly and then somewhat more rapidly to a maximum for the epoch in the middle of the late Paleoceneas a result of the maximum in rate of first appearances during the late early Paleocene and earliest late Paleocene. Diversity then dropped very rapidly at or near the end of the epoch as the rate of last appearances reached its maximum, resulting in the Terminal Paleocene Extinction Event. The latest Paleocene diversity decline coincided with an increase in mean annual temperature and probably in rainfall, representing the beginning of the climatic maximum for the Tertiary which characterized the early Eocene. The increase in diversity of early Paleocene floras in the eastern Gulf Coast resulted from exploitation of unfilled ecospace originating from (1) low regional diversity following the Terminal Cretaceous Extinction Event, and (2) creation of many new niches during the Paleocene, resulting, according to megafloral evidence, from a change to a new vegetation type (multistratal tropical rainforest) brought about by an increase in rainfall. The slow rate of recovery of earliest Paleocene angiosperm diversity in the eastern Gulf Coast may be explained in part by the diversity-dependence model of Carr and Kitchell (1980). However, additional factors may have contributed to the slow recovery: (1) the adverse terminal Cretaceous climates may have extended into the early Paleocene, (2) the initial Paleocene environment of the eastern Gulf Coast may have contained relatively few niches, (3) some earliest Paleocene angiosperms, particularly trees, may have had inherently poor capabilities for rapid evolution, and (4) there was a lack of significant immigration of new taxa to the region. In contrast, the earliest Eocene angiosperm flora recovered very rapidly from the Terminal Paleocene Extinction Event, and this high recovery rate resulted to a significant degree from immigration of new taxa from Europe; thus, the shape of the earliest Eocene diversity curve supports the immigration-dependence recovery model of Barry et al. (1991). ?? 1994.

Review of Palaeobotany and Palynology↗
USGS2022

The effect of diagenesis and acetolysis on the preservation of morphology and ultrastructural features of pollen

Pollen morphology on its own and in conjunction with other characteristics has elucidated the origin and evolution of various plant groups. Previous studies of fossil pollen rarely discuss the effects of diagenesis and sample preparation on pollen characteristics, i.e., variability in staining, pollen morphology, and pollen wall ultrastructural characteristics. This paper examines the effect of acetolysis on reflectance and spectral epi-fluorescence measurements. Based on empirical studies, different species under similar experimental conditions display different reflectance values, indicating individual species respond differently to similar post-depositional thermal events. The quantitative pollen fluorescence spectra showed significant variability, but there is an overall increase in the mean wavelength of maximum emission with acetolysis. Increases in these spectral parameters are used to infer thermal maturation and diagenetic pathways in fossil pollen. The paper also discusses observations made on fossil pollen of a known thermal maturity using Pearson's Pollen/Spore Color Standard. Assessment of pollen thermal maturity using this color standard can be an indicator of the quality of morphological and ultrastructural information that can be extracted from fossil pollen. Increasing thermal maturity of pollen may have an effect on staining variability. Based on observations, staining for brightfield or electron microscopy in fossil pollen, although useful for improving contrast in the specimen, must be used with caution when interpreting pollen wall structure. Although single fossil pollen investigations are useful, replication of these studies on similar or the same specimens from the same locality or various localities will collectively provide more information for elucidation of the morphology and ultrastructure of the once living pollen, and is helpful in sorting out characteristics that may be artifacts from post-depositional diagenesis.

Review of Palaeobotany and Palynology↗
USGS2000

Charbeckia macrophylla gen. et sp. nov. from the Lower Mississippian Price (Pocono) Formation of southeastern West Virginia

A fossil plant discovery from the Price (Pocono) Formation of southeastern West Virginia provides new information on the poorly known compression floras of the Lower Mississippian of North America. The new plant described herein consists of long tapering bipinnate fronds with imbricate basal pinnae, planate apical pinnae, and unlobed, elliptical to obovate pinnules with open dichotomous venation. Veins concentrated in the medial region of the pinnule curve toward the lateral margin, suggestive of an early stage in the evolution of a midrib. Pinnules exhibit a distinctly revolute or otherwise reinforced margin. The exceptional length of some fronds (over 1 m) and pinnule size (some over 3 cm by 2 cm) strongly contrast with the generally diffusely branched fronds and small or highly dissected pinnule morphology that typify Early Mississippian leaf taxa. A new generic assignment, Charbeckia macrophylla , is thereby justified. The rigid appearance of the tapering rachis, the imbricate pinnae that appear to have resisted compression, and the reinforced pinnule margins imply thick evergreen leaves, perhaps adapted for drought tolerance. A possible Calamopityalean affinity is indicated by the size of the fronds and the stout petioles, which fall within the expected size range of the Kalymma -type petiole bases described from the nearby New Albany Shale of Tournaisian age.

Review of Palaeobotany and Palynology↗
USGS2001

Pollen assemblages as paleoenvironmental proxies in the Florida Everglades

Analysis of 170 pollen assemblages from surface samples in eight vegetation types in the Florida Everglades indicates that these wetland sub-environments are distinguishable from the pollen record and that they are useful proxies for hydrologic and edaphic parameters. Vegetation types sampled include sawgrass marshes, cattail marshes, sloughs with floating aquatics, wet prairies, brackish marshes, tree islands, cypress swamps, and mangrove forests. The distribution of these vegetation types is controlled by specific environmental parameters, such as hydrologic regime, nutrient availability, disturbance level, substrate type, and salinity; ecotones between vegetation types may be sharp. Using R-mode cluster analysis of pollen data, we identified diagnostic species groupings; Q-mode cluster analysis was used to differentiate pollen signatures of each vegetation type. Cluster analysis and the modern analog technique were applied to interpret vegetational and environmental trends over the last two millennia at a site in Water Conservation Area 3A. The results show that close modern analogs exist for assemblages in the core and indicate past hydrologic changes at the site, correlated with both climatic and land-use changes. The ability to differentiate marshes with different hydrologic and edaphic requirements using the pollen record facilitates assessment of relative impacts of climatic and anthropogenic changes on this wetland ecosystem on smaller spatial and temporal scales than previously were possible. ?? 2001 Elsevier Science B.V.

Review of Palaeobotany and Palynology↗
USGS1997

Two new species of Scolecopteris (Marattiales), sources of Torispora securis Balme and Thymospora thiessenii (Kosanke) Wilson et Venkatachala

Two biostratigraphically significant miospore species, Thymospora thiessenii and Torispora securis , were isolated from marattialean synangia preserved in coal-ball permineralizations from Pennsylvanian strata of the Illinois Basin and Western Interior coal region. Synangia containing Thymospora thiessenii were recovered from the Missourian Parker Coal Member (Patoka Formation) of Indiana and are described here as Scolecopteris parkerensis Lesnikowska et Willard, sp. nov. The uniformly thin outer sporangial walls and broadly enclosing, hirsute pinnule margins place the species in the Latifolia group sensu Millay (1979). It is distinguished from the other species of the group by the size of the synangia, by the size and shape of the pinnules, by features of the pedicel and by the spores. Coal balls from the Desmoinesian Cliffland Coal Member (Kalo Formation) of Iowa yielded synangia producing two different spore types: a peripheral layer of spores with a distinct apical crassitude ( Torispora securis ) and interior spores assignable to Laevigatosporites globosus . The crassitude of Torispora is shown to be a structure distinct from the main spore body but is enclosed with it by the exine. The fructifications are described as Scolecopteris dispora Lesnikowska et Willard, sp. nov. , which belongs to the Oliveri group sensu Millay (1979) on the basis of the uniformly thick outer sporangial wall and downturned, hairless pinnule margins. It is distinguished from the other members of the group by the large size of the synangia, the uniform histology of the outer sporangial walls, features of the pedicel, and by the spores. This is the first reported association of either of these spores with permineralized fructifications from coal.

Review of Palaeobotany and Palynology↗
USGS1998

Caradocian chitinozoans from the Central Basin, Tennessee

Chitinozoans occur in low numbers and diversity in all formations of the Caradocian Stones River and Nashville Groups of the Central Basin, Tennessee. Sixteen species have been found in the interval studied: Belonechitina micracantha, B. robusta, B. seriespinosa, B. wesenbergensis, Calpichitina lata, Conochitina elegans, C. minnesotensis, Cyathochitina kuckersiana, Desmochitina minor, Lagenochitina cf. L. baltica, Pistillachitina pistillifrons, Rhabdochitina magna, R. turgida, R. usitata, Sphaerochitina actonica and Spinachitina multiradiata . On the basis of the chitinozoans present, the lower part of the Stones River Group is correlated to the North American Black Riveran Stage interval (British lower Caradocian Series). The upper part of the Stones River Group and the Nashville Group are correlated to the Black Riveran-Edenian interval (lower to middle Caradocian).

Tennessee↗