Palynological Data Research Articles

Comparative pollen morphology of the genus Iberis L. (Brassicaceae) in Turkey and its taxonomic implications

In this study, we report the current palynological characteristics of Iberis taxa naturally distributed in Turkey. The pollen morphology of 10 native Iberis taxa was investigated across 35 populations. In the light of a reviewed taxonomical study on Turkish Iberis taxa, a detailed palynological description was provided for the genus. The palynological characteristics of Iberis taxa were examined by using scanning electron microscopy (SEM) and light microscopy (LM) to verify and confirm their diagnostic importance at a specific and/or generic level. We evaluated different characteristics including polar axis, equatorial axis, colpus length and width, Amb diameter, apocolpium, exine structure, and sculpture. Pollen characteristics were measured on 30 pollen grains from each specimen under light microscopy (LM). Detailed exine sculpture was also analyzed under scanning electron microscopy (SEM). Generally, the pollen grains of the genus Iberis are small to medium sized, radially symmetrical, isopolar, spheroidal, almost tricolpate, and rarely syncolpate or tetracolpate. The exine sculpture is reticulate, and the structure is semitectate. Two pollen types for the genus were identified based on the colpus surface feature: Iberis type-I (with non-ornamented colpus surface) and Iberis type-II (with ornamented colpus surface). Principal component analysis and cluster analysis were performed to reveal patterns and groupings within the related taxa concerning pollen morphology. It was found that pollen size may provide a limited but valuable metric to distinguishing Iberis species. However, due to the wide variation in some populations, it would be useful to have palynological data as well as chromosomal, molecular and macro-micromorphological data to resolve the complexity in the taxonomy of the genus.

Sole Survivors: Using Tree-Trunk Wells from Archaeological Excavations to Inform Reconstructions of Medieval Deforestation, and Future Reforestation

Abstract This paper represents an attempt at a detailed analysis of woodland presence and dynamics during the Middle Ages (AD 500-1500), as a contribution to the current debate on large-scale reforestation in the Netherlands. Palynological data for this particular period are scarce and allow only global reconstructions. To widen our search for historical woodland proxies, we investigated the potential of archaeologically excavated tree-trunk wells. We carried out a nation-wide inventory of this type of well, in which the shaft is formed by hollowed-out tree trunks, typically large oak trees. Our suspicion that such trees indicate the local presence of (old) woodland in the past was confirmed by a marked positive correlation with spatial reconstructions based on other sources of information: archaeological (charcoal kilns) and non-archaeological (place names and historical references). The observed correlations suggest that mapping the distribution of precisely dated tree-trunk wells can indeed contribute to achieving fairly detailed reconstructions of medieval woodland cover.

New findings of gymnosperms in the Middle Jurassic of the East European platform

The plant-bearing layers in the Stoilensky open mine (Belgorod Region, Russia) are dated to the middle Bathonian–early Callovian based on the dinoflagellate cysts and spore-pollen assemblages, and in the Mikhailovsky open mine (Kursk Region, Russia) – to the middle–late Bathonian based on palynological data. Representatives of Pseudotorellia are recorded in the Middle Jurassic of the Belgorod and Kursk regions for the first time. A new species, Pseudotorellia oskolica, is described from the Stoilensky open mine based on the unique morphological and epidermal features. Leaves of this species are very narrow, they are characterized by the presence of stomata on the adaxial leaf surface. The type material of Czekanowskia europea from the Middle Jurassic of the Pripyat depression in Belarus was restudied. The diagnosis for C. europea is provided, since only a description of this species was given in the original publication. Czekanowskia leaves are recorded from the Belgorod and Kursk regions for the first time. They are determined as C. europea based on the similar epidermal features as in the type leaves. A shoot of Pagiophyllum sp. and numerous leaf fragments of Podozamites sp. were found in association with C. europea in the Pripyat depression. These genera are recorded in Belarus for the first time. Findings of Pseudotorellia, Czekanowskia and Podozamites leaves in the Middle Jurassic floras of the East European platform are discussed.

The Pleistocene high-elevation environments between 2.02 and 0.6 Ma at Melka Kunture (Upper Awash Valley, Ethiopia) based upon stable isotope analysis

Pleistocene environments are among the most studied issues in paleoecology and human evolution research in eastern Africa. Many data have been recorded from archaeological sites located at low and medium elevations (≤ 1500 m), whereas few contexts are known at 2000 m and above. Here, we present a substantial isotopic study from Melka Kunture, a complex of prehistoric sites located at 2000—2200 m above sea level in the central Ethiopian highlands. We analyzed the stable carbon and oxygen isotopic composition of 308 faunal tooth enamel samples from sites dated between 2.02 and 0.6 Ma to investigate the animal diets and habitats. The carbon isotopic results indicate that the analyzed taxa had C4-dominated and mixed C3-C4 diets with no significant diachronic changes in feeding behavior with time. This is consistent with faunal and phytolith analyses, which suggested environments characterized by open grasslands (with both C3 and C4 grasses), patches of bushes and thickets, and aquatic vegetation. However, palynological data previously documented mountain forests, woodlands, and high-elevation grasslands. Additionally, the carbon isotopic comparison with other eastern African localities shows that differences in elevation did not influence animal feeding strategies and habitat partitioning, even though plant species vary according to altitudinal gradients. In contrast, the oxygen isotopic comparison suggests significant differences consistent with the altitude effect. Our approach allows us to detect diverse aspects of animal behavior, habitat, and vegetation that should be considered when reconstructing past environments.

Palynological data from the hauterivian Avilé Member, Pampa Tril section, Agrio Formation, Neuquén Basin, Argentina

The present contribution provides data to the palynological characterization of the non-marine deposits of the Avilé Member, Agrio Formation (Pampa Tril and San Eduardo sections), Neuquén Basin, Argentina. The Avilé Member, which represent a low-order regressive event, is one of the most important hydrocarbon reservoirs in the subsurface of the eastern part of the basin. A continental palynological association mainly represented by gymnosperms with Classopollis as a dominant taxon was recorded. The findings of Shambeipollenites proxireticulatus in the unit, extend the biostratigraphical range of the species to the Hauterivian and suggest the Neuquén Basin as an important dispersal place for the species within Gondwana landmass during the Early Cretaceous. A conifer-dominated forest was indicated by the pollen assemblage. The high percentages of Classopollis, the presence of pollen with Gnetidae affinity (Weltwischia/Ephedra) added to the evidence of fluvial-aeolian interaction given by the lithology, may be indicative of a deposition in a dryland setting. The recovered palynoflora was compared to published palynological data from different units underlying and overlying the Avilé Member, in order to evaluate the response of the vegetation in the central part of the basin, during the onset of non-marine accumulation relative to a sea level fall and the subsequent flooding again of the basin. An important variation in abundance between two groups of conifers (Cheirolepidiaceae versus Araucariaceae) is observed throughout the Agrio Formation members. Going up in the stratigraphic column there is an evident increase in abundance of Araucariaceae and a decrease in Classopollis and ferns spores.

Depositional system and plant ecosystem responses to long-term low tempo volcanism, the Interbasaltic Formation, Antrim Lava Group

Abstract The Antrim Lava Group of NE Ireland comprises a volcanic sequence dominated by basaltic lava flows. Including subsidiary sedimentary interlayers and some evolved lavas and intrusions, the overall sequence reaches a cumulative thickness of ∼800 m. The tempo of eruption of the Antrim Lava Group is poorly constrained but can be evaluated via weathering patterns and environmental reconstructions derived from lava-flow interbeds. In this contribution, we present palynology from a newly identified and well-developed 2.0–2.5 m thick sedimentary sequence (interbed) at Ross's Quarry, Ballycastle, Co. Antrim, that helps elucidate the contemporary development of environments in a setting subject to periodic basaltic volcanism. The interbed is subdivided into geologically distinct subunits of cross-bedded and parallel-bedded sandstones and sandy siltstones, all rich in visible organic remains such as rootlets and fragments of wood and bark. A total of 19 samples was collected from the sequence and subsequently analysed for palynological content. The palynomorph data point toward a diversity of inputs ranging from estuaries, chalky soils, dry soils, swamps, lakes, floodplains, sand bars, wet soils, established bogs and fenlands. In contrast to current understanding, the palynological data and their inferred environments collectively reveal the presence of flora that favour a temperate climate rather than the subtropical climate that has previously been inferred from the lateritic interbeds of the Antrim Lava Group. By combining the Ross's Quarry observations with palynological data from other quarry sites and boreholes in Antrim, we provide new insights into the climate, weathering systems and eruptive history of the Antrim Lava Group.

Holocene flood records and human impacts implied from the pollen evidence in the Daming area, North China Plain

Understanding the environmental significance of pollen and spores in alluvial plains is important for stratigraphic correlation and paleoenvironmental reconstruction. This paper presents palynological data from the North China Plain and explores their relationship with paleoflood records and human impacts since the Holocene. Our data reveal that pollen concentration and pollen assemblage vary in flood deposits (including overbank deposits and slackwater deposits) and inter-flood deposits (including sandy soils and lacustrine deposits). Flood deposits have higher fern percentages (28.6%) and lower herbaceous percentages (14.8%) compared to inter-flood deposits, though slackwater deposits share similar pollen concentrations and assemblages with sandy soils. Notably, overbank deposits are characterized by pollen-poor zones and aggregation of deteriorated pollen grains, especially in Unit III (755–385 cm, ca. 3.2–2.2 ka) and Unit V (190–0 cm, after ca. 0.6 ka). These findings suggest that overbank deposits correspond to strengthened hydrodynamic conditions at the flood-peak stage. Furthermore, the indicative pollen and spores provide compelling evidence for intensifying human impact in the North China Plain since the late Holocene. An aggregation of Selaginella sinensis at the depth of 640–610 cm indicates deforestation in the uplands since ca. 2.9 ka. Similarly, a sharp increase in Malvaceae percentage at the depth of 285–215 supports historical records of initial cotton planting in the Tang Dynasty (ca. 1.4–1.1 ka). The study underscores the value of palynological analysis for reconstructing paleoenvironment and human-environment interactions, providing a robust framework for understanding landscape evolution in the North China Plain.

Sedimentary facies and palynoflora of the Andirá and Arari formations in the Autazes region, Amazonas basin

This paper presents sedimentological, stratigraphic, and palynological data from borehole PBAT-15-43, in which a 230 m long continuous core was sampled in the central portion of the Amazonas Basin, where it was possible to define the contact relationship between Paleozoic deposits of the Andirá and Arari Formations (Tapajós Group). The drilling hole is located in the southern portion of the municipality of Autazes (Amazonas State) and was made available by the Potássio do Brasil Company. Six sedimentary facies were identified in the borehole and grouped into two associations, informally referred to as I and II, representing the Andirá (upper part) and Arari (lower part) formations, respectively. Association I was interpreted as a fluvial environment with channel deposits, flood barriers, and crevasses splay. Association II, on the other hand, represents an alluvial fan environment with predominantly gravitational flow deposits. The facies of association II proved to be sterile for palynomorphs, whereas facies I contain a rich palynoflora, including especially the species Lueckisporites virkkiae, Corisaccites alutas, Hamiapollenites andiraensis, H. karooensis, Vittatina costabilis, V. saccata, V. subsaccata, and Tornopollenites toreutos; secondarily by species of the genera Punctatisporites, Verrucosisporites, Limitisporites, Cycadopites and Stratopodocarpites, which are considered as belonging to the Permian age. The fact that no marine palynomorphs were detected supports the present interpretations regarding the age and the depositional environments previously predicted for these formations as predominantly fluvial deposits.

First palynological results from Spila nad Procjepom cave, Mljet island (Croatia)

This paper presents the first results of palynological research from the Spila nad Procjepom cave, situated in the Mljet National Park, Croatia. The palynological data obtained, enables a partial insight into the local vegetation cover, temporal changes in the vegetation during the accumulation of studied deposits (at ca. 3500 cal years BP), and post-depositional processes that influenced the palynomorph assemblage. Results of palynofacies analysis indicate changes from fluvial (channel deposits), through palustrine to terrestrial environments. Although the interpretation of changes in plant cover, due to the lack of statistical significance, should be taken with caution, preserved pollen types confirm the dominance of the Mediterranean evergreen forest vegetation on Mljet island. Moreover, a high proportion of non-arboreal pollen (NAP) indicates some level of forest degradation, ranging from Mediterranean open forest to degraded maquis. Abundant charcoal additionaly confirms that the cave was inhabited by humans.

Early onset of aridity in the past millennium: Insights from vegetation dynamics and climate change in the alpine, cold-desert region of Trans Himalaya, India.

Palynological analysis of surface soil and sub-surface sediments from the outwash plain of Hamtah Glacier, Lahaul-Spiti, India, has brought out the vegetation and climatic changes in the area during the last 1580 years. The arboreal and non-arboreal pollen ratio (AP/NAP) has been used to demarcate the different vegetation and climatic zones, complemented by the frequencies of the broad-leaved taxa. Lower values of thermophilous, broad-leaved arboreal taxa, indicate that the region experienced cold-arid conditions between 1580 and 1330 yr BP (AD 370-620); which can be related to the Dark Ages Cold Period (DACP). Thereafter, between 1330 and 950 yr BP (AD 620-1000), a rejuvenation of the broad-leaved elements reflects the initiation of a comparatively warm and moist phase, marking the Medieval Climatic Anomaly (MCA) in the region. The warm-moist phase was, however, short-lived, and from 950 yr BP to the Present (AD 1000 onwards), the region saw a return to cold-arid conditions, as evidenced by a sharp fall in the AP/NAP ratio. This cold-arid phase was, nevertheless, punctuated by a warm-moist period during 790 to 680 yr BP (AD 1160-1270), which marks the terminal phase of the MCA. After the termination of the MCA, the Little Ice Age (LIA) is well-marked in the area. The culmination of the long cold-arid regime is characterized by warmer conditions over the last 160 years, which is the manifestation of the Current Warm Period (CWP). Magnetic susceptibility (χlf) and sediment geochemistry (Weathering Index of Parker) were also attempted to have a multi-proxy approach, and show a general compatibility with the palynological data. The palaeoclimatic evidences suggest shorter warm periods and extended colder phases during the last 1580 years; in this high-altitude, cold-desert, Trans Himalayan region.

Quantitative biostratigraphy and paleoecology of Neogene tropical dinoflagellate cysts

Understanding the biostratigraphy of tropical areas during the Neogene period can be improved by studying dinoflagellate cyst events. These events have traditionally been identified through qualitative analysis. Nevertheless, to obtain consistent data on this subject, we used quantitative and probabilistic analysis of palynological data from the Southern Gulf of Mexico to identify dinoflagellate cyst events in the Neogene era. We analyzed a database of six wells, including 1,005 core and cuttings samples, a change from past qualitative analysis methods. With this quantitative approach with the RASC program, we obtained the Ranking Optimum Sequence (ROS) and compared it with ten published databases from Neogene tropical sites. The ROS identified eleven dinoflagellate species as age markers, we propose a most likely sequence of dinoflagellate cysts bioevents and define three assemblages: “Cantharellus” (Oligocene to early Miocene), “Hyalina” (Miocene), and “Patulum” (middle Miocene to Pleistocene), that can help recognize most Neogene stratigraphic stages in tropical areas. The comparison with the previous databases shows that the Gulf of Mexico and the tropical sites share 60% of the species, which enables age calibration of the optimal sequence and allows us to infer a possible provincial affinity. Additionally, we found a predominance of autotrophic dinocysts during the Neogene in tropical oceans. This trend mirrors the current abundance of gonyaulacoid cysts in tropical and subtropical areas, which has persisted since the Jurassic era.

First palynological data from the Amat and Plyavinsky Horizons of the Main Devonian field

Research subject. Spores of higher plants from the Early Frasnian deposits of the Main Devonian Field. Material and methods. The work is based on the biostratigraphic method with the following stages: determination of the taxonomic composition of palynospectra, substantiation of the host rocks age, and data correlation. Palynological analysis was conducted using an improved technique by I.Kh. Shumilov and O.P. Telnova, which produced positive results. Results. For the first time, spores of higher plants were found in the sections of the Amatsky and Plavinsky Horizons of the Main Devonian Field. The palynospectra of the Podsnetogorsk layers of the Amat and Snetogorsk layers of the Plyavinsky Horizons were described. The palynospectra of the Podsnetogorsk layers are correlated with the palynoassemblage from the upper part of the Timan, and the Snetogorsk layers are correlated with the palynoassembly of the Sargaev Horizons, established in the Timan-Pechora province. The identified palynospectra complement the associations of vertebrate and invertebrate fauna, as well as rare macroflora, previously studied in these sections. The palynospectra from the Snetogorsk beds are correlated with the palynoassemblage of the Cristatisporites deliquescens – Archaeoperisaccus mennerii regional zone of the Timan-Pechora province. The palynozone characterizes the stratigraphic interval corresponding to the rugosa–transitans conodont zones (middle–upper part of the Sargaev Horizon). Conclusions. The established palynoassemblage from the Snetogorsk layers corresponds to the middle part of the Sargaev Horizon – the stratigraphic interval of the rugosa conodont zone. For the first time, the conducted palynological studies established a binding between the regional stratigraphic unit of the Main Devonian Field and the standard conodont zone.

PRELIMINARY STUDY OF THE POLLEN MORPHOLOGY OF MALAYSIAN ZINGIBERACEAE (TRIBE ALPINIEAE) AND THE TAXONOMIC RELATIONSHIP

The family Zingiberaceae forms an important herbaceous layer in the tropical forests of Malaysia. From a phylogenetic point of view, certain genera of the problematic tribe Alpinieae are non-monophyletic and in need of more taxonomic evidence to support the classification. This study demonstrates how the palynological data could correlate with the proposed phylogenetic data, using representatives from the Malaysian species. The pollen morphology of 21 species from the tribe Alpinieae was investigated. Parameters including polarity, symmetry, shape, size, apertures, exine ornamentation, size of spine, type of spine apex, spine density, and distance between spine were analysed. The results demonstrated that the studied species were conveniently divided into two major groups based on the exine sculpturing of the spheroidal pollens, either psilate as in Etlingera and Hornstedtia, or echinate as in Alpinia, Conamomum, Meistera, Plagiostachys, Sundamomum, and Sulettaria. Hence, as far as the study is concerned, the main sculpturing is considered useful to generally distinguish the genera in the tribe.

Prehistoric farming in the south-eastern Baltic (Kaliningrad Region, Russia)

The article presents an overview of the currently available palaeoecological data on the prehistoric anthropogenic impact on the environment and emergence of farming in the south-eastern Baltic, an area poorly studied in palaeoenvironmental and archaeological terms. The recently obtained palynological data from the lake and bog sediments along with the existing archaeological finds allow us to consider several stages of prehistoric farming in the south-eastern Baltic. The first indications of forest management – the creation of open deforested areas, wood burning and probably cultivation (propagation) of hazel appear during the Mesolithic, 10 300–6500 cal BP. At about 6500–5200 cal BP, evidence of the first agricultural activity and local animal husbandry emerges. From 5200 cal BP onwards, farming probably occupies a permanent place in the subsistence strategy of the ancient population of the south-eastern Baltic.

Late and Final Neolithic Land Use Reconstructions Based on Floodplain Deposits from the ‘Nachtweide’ Site in Hesse, Central Germany – a Challenge for Palynology

ABSTRACTThis study reconstructs land use history with a focus on the Late and Final Neolithic using palynological data from floodplain deposits in the state of Hesse, central Germany. Our results demonstrate that humans were using the surrounding landscape continuously from the onset of the Michelsberg culture to the transition to the Bronze Age. However, a noticeable decline in human impact was shown during the transitional stage between the Michelsberg and Wartberg cultures. During this time, changes in the floodplain environment were noted that correlate with other floodplain pollen records from the region and supra-regional climate signals, thus providing other possible drivers for this socio-cultural change in addition to the factors coming from the archaeological side. Due to its location in the peripheral uplands of the Wetterau, the economy at the ‘Nachtweide’ site was based primarily on forest pasturing. However, cereal cultivation was also important. In contrast, no evidence was found for the use of open land for grazing during the Late Neolithic and only sporadic evidence for such use during the Final Neolithic. Our study also shows that, changes in land use were accompanied by hydrological changes within the floodplain and/or changes in the river dynamics.

Palynological Data on the Givetian and Frasnian Stage Boundary within the East European Platform

Palynological Data on the Givetian and Frasnian Stage Boundary within the East European Platform

The late Paleocene-Eocene interval of the Magallanes-Austral Basin (Chile-Argentina): Palynostratigraphy, paleoclimate and geochemical data

The Magallanes-Austral Foreland Basin preserves an important record of orogenesis and landscape evolution in the Patagonian Andes of Chile and Argentina. This paper evaluates the comparison between the thick Paleogene sequences in the Chilean Peninsula Brunswick (Chorrillo Chico and Agua Fresca formations) and the reduced Paleogene sequence (La Barca Formation) in the Punta Ainol locality, Argentina, by taking account of palynological and geochemical analyses. Warm and humid subtropical conditions (Subtropical Gondwanic Paleoflora) are inferred for the late Paleocene-Eocene interval studied. A new record of Lactoridaceae in the La Barca Formation expanded the known fossil range of this family in Patagonia. During the late Paleocene the Chorrillo Chico and La Barca formations would have been deposited mainly from hyperpycnal flows and this accumulation process continued until the Lutenian in the La Barca Formation. A relative rise in the sea level in the early Eocene would be recognized in both sections. In the middle Eocene a relative fall in the sea level would have occurred with increased terrigenous influx. The rate of sedimentation was similar in both sections during the Thanetian and Ypresian intervals according to the ages assigned by biostratigraphy, suggesting that the sedimentation rate would have been controlled mainly by relative changes in sea level during the Paleocene-Eocene transition. Paleoenvironmental changes during the Paleocene-Eocene transition were characterized at the La Barca Formation of the Punta Ainol section, considering the new geochemical and palynological data provided in this contribution.

Pollen morphology and its taxonomic potential in Stachytarpheta sect. Stachytarpheta (Verbenaceae) occurring in Brazil

Verbenaceae is an important element of Neotropical flora, and Stachytarpheta is the second largest genus in the family. Whereas pollen morphology has helped in the differentiation of several taxonomic groups, palynological data on Stachytarpheta are still scarce, especially for Brazil, where its greatest species richness is concentrated. The present work aimed to analyze the pollen morphology of selected species of Stachytarpheta sect. Stachytarpheta, to aid in the taxonomy of the group. Pollen grains from 11 species were analyzed before and after chemical treatment, measured and treated statistically; multivariate analyses were also performed. The pollen grains of S. sect. Stachytarpheta are large or very large monads, that are radially symmetric and isopolar, with amb varying among triangular, subtriangular, subcircular, and quadrangular, and shape among subspheroidal, oblate-spheroidal, prolate-spheroidal, and subprolate. The three or four apertures are of the colpus type and narrow. The ornamentation is verrucate, with perforations at the base of the verrucae and isolated granules. The pollen grains also possess a margin and an anapertural membrane, which are the main characteristics useful for differentiating the species of the section. The size, amb, shape, apertural type, and ornamentation are also important for morphological differentiation, but multivariate analyses did not support the groups formed based on pollen characterization. An identification key is provided to distinguish the 11 studied species based on pollen morphology.

The Age and Depositional Settings of the Upper Paleogene–Lower Neogene Kurshskaya Formation in its Stratotype Section (Kaliningrad Oblast) based on Palynological Data

The Age and Depositional Settings of the Upper Paleogene–Lower Neogene Kurshskaya Formation in its Stratotype Section (Kaliningrad Oblast) based on Palynological Data

Environmental evolution of western Tierra del Fuego (∼54°S) since ice-free conditions and its zonal/hemispheric implications

By virtue of its position adjacent to the Drake Passage, Tierra del Fuego in South America allows examining the vegetation and environmental history of the southernmost continental landmass outside Antarctica, and the evolution of the Southern Westerly Winds-Southern Ocean (SWW–SO) coupled system since the Last Glacial Maximum (LGM). For that purpose, we studied sediment cores from Lago Charquito, a small closed-basin lake in central-west Tierra del Fuego with a continuous lacustrine record since ∼17.3 ka. Ice-free conditions at the site imply a ∼70 km retreat of the Bahía Inútil glacier lobe from its LGM position during a ∼800-year interval, a trend that continued until its disappearance ∼100 km upstream from L. Charquito, ∼800 years later. Our palynological data show an open landscape dominated by cold-tolerant shrubs and herbs between ∼17.3–12.9 ka, with increases in precipitation of SWW origin at ∼16.3 ka, ∼14.7 ka, between ∼8.7–7.6 ka, and after ∼6.8 ka. Warming at ∼12.9 ka initiated an abrupt afforestation trend that stalled during the early Holocene (∼12–8.7 ka) owing to a precipitation decline and wildfires, and later resumed in response to invigorated SWW. We hypothesize that sparse Nothofagus tree populations inhabited the periphery of the Patagonian Ice Sheet (PIS) during the LGM and migrated toward the Andes contemporaneous with glacier recession as temperature rose during the Last Glacial Termination (T1). We posit that besides establishing topographic and climatic barriers for land biota, the PIS enabled the connectivity of cold-tolerant hygrophilous plant populations along a humid fringe adjacent to its land-based perimeter, despite the presumably dry conditions downwind from the eastern PIS margin. Our results suggest that southward shifts or expansion of the SWW toward or beyond Tierra del Fuego enhanced upwelling and ventilation of deep waters in the SO, northward shifts or weakening had the opposite effect. We observe that the time evolution of atmospheric CO2 concentrations, high-latitude air and sea-surface temperatures, and sea level during T1 fall short in explaining the timing and abruptness of the Bahía Inútil glacier lobe collapse, and quite possibly multiple other glacier lobes from the PIS.