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In this text, two of the world's leading experts in palynology and paleobotany provide a comprehensive account of the fate of land plants during the 'great extinction' about 65 million years ago. They describe how the time boundary between the Cretaceous and Paleogene Periods (the K–T boundary) is recognised in the geological record, and how fossil plants can be used to understand global events of that time. There are case studies from over 100 localities around the world, including North America, China, Russia and New Zealand. The book concludes with an evaluation of possible causes of the K–T boundary event and its effects on floras of the past and present. This book is written for researchers and students in paleontology, botany, geology and Earth history, and everyone who has been following the course of the extinction debate and the K–T boundary paradigm shift.

The Paleocene‐Eocene Thermal Maximum (PETM) was a climate/carbon cycle perturbation recognized in stable carbon isotope (δ13C) records with a negative carbon isotope excursion (CIE). The PETM CIE termination has been associated with a δ13C inflection with pre‐PETM‐like values referred to as the G point. However, the G point approach has produced variable PETM CIE duration estimates (∼120–230 kyr), which reflects a need to test its reliability. Here, we apply statistical analyses to existing δ13C records and reveal that the G point is sensitive to underlying δ13C uncertainties. We generate a probabilistic‐based CIE detection limit, which constrains the time range over which the PETM is detected in δ13C records. This protocol reveals a protracted CIE recovery (>145 kyr) that accounts for a 268.8+21.2/−20.5 kyr PETM CIE duration. Our new duration estimate exceeds previous values, which confirms the potential of extreme carbon cycle perturbations to cause long‐lasting carbon cycle disruptions.

The Paleocene‐Eocene Thermal Maximum (PETM) was an extreme fluctuation of Earth's climate and a potential analog for future unmitigated anthropogenic climate change, but whose cause is debated. We show that fluctuations in Cenozoic benthic foraminiferal δ13 ${\\delta }^{13}$C and δ18 ${\\delta }^{18}$O follow a Laplace distribution. We present a simple model to explain this behavior: isotopic fluctuations respond to big and small “kicks” in the same way. We then use this to develop an expectation for the largest Cenozoic δ13 ${\\delta }^{13}$C and δ18 ${\\delta }^{18}$O fluctuations. While the other hyperthermals of the early Cenozoic are encompassed the expected range, we quantify that the PETM isotopic signatures were larger than these expectations, by 1.15 ± $\\pm $ 0.25‰ for δ18 ${\\delta }^{18}$O and 1.75 ± $\\pm $ 0.24‰ for δ13 ${\\delta }^{13}$C. This supports the view that the PETM is an extreme outlier amongst Cenozoic perturbations to the climate system and thereby was likely triggered by a large and unusual external perturbation.

The Paleocene—Eocene Thermal Maximum (PETM; 56 Ma) is one of our best geological analogs for understanding climate dynamics in a “greenhouse” world. However, proxy data representing the event are only available from select marine and terrestrial sedimentary sequences that are unevenly distributed across Earth’s surface, limiting our view of the spatial patterns of climate change. Here, we use paleoclimate data assimilation (DA) to combine climate model and proxy information and create a spatially complete reconstruction of the PETM and the climate state that precedes it (“PETM-DA”). Our data-constrained results support strong polar amplification, which in the absence of an extensive cryosphere, is related to temperature feedbacks and loss of seasonal snow on land. The response of the hydrological cycle to PETM warming consists of a narrowing of the Intertropical Convergence Zone, off-equatorial drying, and an intensification of seasonal monsoons and winter storm tracks. Many of these features are also seen in simulations of future climate change under increasing anthropogenic emissions. Since the PETM-DA yields a spatially complete estimate of surface air temperature, it yields a rigorous estimate of global mean temperature change (5.6 ◦C; 5.4 ◦C to 5.9 ◦C, 95% CI) that can be used to calculate equilibrium climate sensitivity (ECS). We find that PETM ECS was 6.5 ◦C (5.7 ◦C to 7.4 ◦C, 95% CI), which is much higher than the present-day range. This supports the view that climate sensitivity increases substantially when greenhouse gas concentrations are high.

A fundamental challenge in resolving evolutionary relationships across the tree of life is to account for heterogeneity in the evolutionary signal across loci. Studies of marsupial mammals have demonstrated that this heterogeneity can be substantial, leaving considerable uncertainty in the evolutionary timescale and relationships within the group. Using simulations and a new phylogenomic data set comprising nucleotide sequences of 1550 loci from 18 of the 22 extant marsupial families, we demonstrate the power of a method for identifying clusters of loci that support different phylogenetic trees. We find two distinct clusters of loci, each providing an estimate of the species tree that matches previously proposed resolutions of the marsupial phylogeny. We also identify a well-supported placement for the enigmatic marsupial moles (Notoryctes) that contradicts previous molecular estimates but is consistent with morphological evidence. The pattern of gene-tree variation across tree-space is characterized by changes in information content, GC content, substitution-model adequacy, and signatures of purifying selection in the data. In a simulation study, we show that incomplete lineage sorting can explain the division of loci into the two tree-topology clusters, as found in our phylogenomic analysis of marsupials. We also demonstrate the potential benefits of minimizing uncertainty from phylogenetic conflict for molecular dating. Our analyses reveal that Australasian marsupials appeared in the early Paleocene, whereas the diversification of present-day families occurred primarily during the late Eocene and early Oligocene. Our methods provide an intuitive framework for improving the accuracy and precision of phylogenetic inference and molecular dating using genome-scale data.

The Paleocene–Eocene Thermal Maximum (PETM) (55.6 Mya) was a geologically rapid carbon-release event that is considered the closest natural analog to anthropogenic CO₂ emissions. Recent work has used boron-based proxies in planktic foraminifera to characterize the extent of surface-ocean acidification that occurred during the event. However, seawater acidity alone provides an incomplete constraint on the nature and source of carbon release. Here, we apply previously undescribed culture calibrations for the B/Ca proxy in planktic foraminifera and use them to calculate relative changes in seawater-dissolved inorganic carbon (DIC) concentration, surmising that Pacific surface-ocean DIC increased by + 1 , 010 − 646 + 1 , 415 μmol/kg during the peak-PETM. Making reasonable assumptions for the pre- PETM oceanic DIC inventory, we provide a fully data-driven estimate of the PETM carbon source. Our reconstruction yields a mean source carbon δ13C of −10‰and a mean increase in the oceanic C inventory of +14,900 petagrams of carbon (PgC), pointing to volcanic CO₂ emissions as the main carbon source responsible for PETM warming.

The main phases of plant dispersal into, and out of the South-East Asian region are discussed in relation to plate tectonics and changing climates. The South-East Asian area was a backwater of angiosperm evolution until the collision of the Indian Plate with Asia during the early Cenozoic. The Late Cretaceous remains poorly understood, but the Paleocene topography was mountainous, and the climate was probably seasonally dry, with the result that frost-tolerant conifers were common in upland areas and a low-diversity East Asian aspect flora occurred at low altitudes. India's drift into the perhumid low latitudes during the Eocene brought opportunities for the dispersal into South-East Asia of diverse groups of megathermal angiosperms which originated in West Gondwana. They successfully dispersed and became established across the South-East Asian region, initially carried by wind or birds, beginning at about 49 Ma, and with a terrestrial connection after about 41 Ma. Many Paleocene lineages probably went extinct, but a few dispersed in the opposite direction into India. The Oligocene was a time of seasonally dry climates except along the eastern and southern seaboard of Sundaland, but with the collision of the Australian Plate with Sunda at the end of the Oligocene widespread perhumid conditions became established across the region. The uplift of the Himalaya, coinciding with the middle Miocene thermal maximum, created opportunities for South-East Asian evergreen taxa to disperse into north India, and then with the late Miocene strengthening of the Indian monsoon, seasonally dry conditions expanded across India and Indochina, resulting eventually in the disappearance of closed forest over much of the Indian peninsula. This drying affected Sunda, but it is thought unlikely that a ‘savanna’ corridor was present across Sunda during the Pleistocene. Some dispersals from Australasia occurred following its collision with Sunda and following the uplift of New Guinea and the islands of Wallacea, Gondwanan montane taxa also found their way into the region. Phases of uplift across the Sunda region created opportunities for allopatric speciation and further dispersal opportunities. There is abundant evidence to suggest that the Pleistocene refuge theory applies to the South-East Asian region.

Establishing the frontal extent of ancient flat subduction events from the geologic record can be challenging. This difficulty arises because magmatic activity in the arc typically ceases during complete slab flattening, and other meaningful proxies are usually absent. To address this issue, we examine early Paleocene intraplate magmatic units in central Patagonia, specifically, the La Angostura and Pagasartundua basalts. These basalts erupted and were emplaced during the final phase of a significant flat subduction event, referred to as the Nalé flat slab. The small outcrops of these units are composed of metaluminous alkaline basalts, whose origin would be related to the decompression melting of the sub‐slab asthenosphere. This melting likely occurred due to local slab gaps in the frontal section of a flattened slab, where the oceanic lithosphere resumed a steep angle. The resulting mantle primitive melts would have caused partial melting of minor portions of the upper slab (including eclogitized components). The interaction of these two end‐member melts results in slight hybridization, as evidenced by positive anomalies in Cs, Pb, and Li, subtle Ta depletion, and local Th enrichment in the basalts. By recognizing these basalts and their geochemical characteristics in relation to the geodynamic context, we can establish the maximum frontal extent of a large‐scale Late Cretaceous‐Paleocene flat subduction event. Thus, this case represents the first ancient flat slab that is frontally constrained by slab gap‐related intraplate magmatism, a pattern that could be replicated in other similar settings worldwide.

• Premise of the study: The fossil record provides information about the long-term response of plants to CO2-induced climate change. The Paleocene-Eocene Thermal Maximum (PETM), a 200000-yr-long period of rapid carbon release and warming that occurred ∼56 million years ago, is analogous to future anthropogenic global warming.• Methods: We collected plant macrofossils in the Bighorn Basin, Wyoming, United States, from a period spanning the PETM and studied changes in floristic composition. We also compiled and summarized published records of floristic change during the PETM.• Key results: There was radical floristic change in the Bighorn Basin during the PETM reflecting local or regional extirpation of mesophytic plants, notably conifers, and colonization of the area by thermophilic and dry-tolerant species, especially Fabaceae. This floristic change largely reversed itself as the PETM ended, though some immigrant species persisted and some Paleocene species never returned. Less detailed records from other parts of the world show regional variation in floristic response, but are mostly consistent with the Bighorn Basin trends.• Conclusions: Despite geologically rapid extirpation, colonization, and recolonization, we detected little extinction during the PETM, suggesting the rate of climate change did not exceed the dispersal capacity of terrestrial plants. Extrapolating the response of plants from the PETM to future anthropogenic climate change likely underestimates risk because rates of climate change during the PETM may have been an order of magnitude slower than current rates of change and because the abundant, widespread species common as fossils are likely resistant to extinction.

Deep-water agglutinated Foraminifera (DWAF) are investigated from Paleocene sediments recovered from IODP Hole U1511B in the northeastern Tasman Sea. The recovered foraminifera display exceptional three-dimensional preservation: they are relatively unaltered by sediment diagenesis and compaction. We examined 27 samples from Cores U1511B-45R to -47R, and recovered over 70 species of DWAF. The assemblage consists entirely of “cosmopolitan” forms originally described from the Carpathians, Caucasus, Trinidad, and the western Tethys, implying that there is no provinciality among DWAF faunas in the world ocean.