9.Mathewes, RW; Greenwood, DR; Love, RL. (2020) The Kanaka Creek fossil flora (Huntingdon Formation), British Columbia, Canada - paleoenvironment and evidence for Paleocene age using palynology and macroflora.Can. J. Earth Sci. 57: 348-365 The Kanaka Creek fossil flora (Huntingdon Formation), British Columbia, Canada - paleoenvironment and evidence for Paleocene age using palynology and macroflora
Paleocene; paleobotany; palynology; paleoclimate; Huntingdon Formation; Kanaka Creek
Paleogene sediments of the Huntingdon Formation, a correlative to the Chuckanut Formation of neighbouring Washington State, USA, are exposed in the Greater Vancouver area, British Columbia, Canada. Palynology and plant macrofossils suggest the Kanaka Creek section is Paleocene rather than Eocene in age. Detrital zircon dating is less decisive, yet indicates the Kanaka rocks are no older than Maastrichtian. Analyses of plant macro- and micro-fossils suggest an early to middle Paleocene age for the Kanaka fossil flora. Paleocene indicators include macrofossils such as Platanus bella, Archeampelos, Hamamelites inequalis, and Ditaxocladus, and pollen taxa such as Paraalnipollenites, Triporopollenites mullensis, and Duplopollis. Paleogene taxa such as Woodwardia maxonii, Macclintockia, and Glyptostrobus dominate the flora. Fungal spores including the Late Cretaceous Pesavis parva and the Paleogene Pesavis tagluensis are notable age indicators. Physiognomy of 41 angiosperm leaf morphotypes from Kanaka Creek yields mean annual temperatures in the microthermal to lower mesothermal range (11.2 +/- 4.3 to 14.6 +/- 2.7 degrees C from leaf margin analysis; 14.8 +/- 2.1 degrees C from Climate Leaf Analysis Multivariate Program), with mild winters (cold month mean temperature 3.9 +/- 3.4 degrees C). Paleoclimate was cooler than the upper Paleocene and Eocene members of the Chuckanut Formation. Mean annual precipitation is estimated at similar to 140 cm with large uncertainties. The Kanaka paleoflora is reconstructed as a mixed conifer-broadleaf forest, sharing common taxa with other western North American Paleocene floras and growing in a temperate moist climate. Kanaka Creek is a rare coastal Paleocene plant locality that provides new insights into coastal vegetation and climate prior to the Paleocene-Eocene Thermal Maximum. DOI
8. Archibald, SB; Rasnitsyn, AP; Brothers, DJ; Mathewes, RW. (2018) Modernisation of the Hymenoptera: ants, bees, wasps, and sawflies of the early Eocene Okanagan Highlands of western North America.Can. Entomol. 150: 205-257 Modernisation of the Hymenoptera: ants, bees, wasps, and sawflies of the early Eocene Okanagan Highlands of western North America
Trigonalidae
Most major modern families of Hymenoptera were established in the Mesozoic, but the diversifications within ecologically key trophic guilds and lineages that significantly influence the character of modern terrestrial ecosystems - bees (Apiformes), ants (Formicidae), social Vespidae, parasitoids (Ichneumonidae), and phytophagous Tenthredinoidea - were previously known to occur mostly in the middle to late Eocene. We find these changes earlier, seen here in the early Eocene Okanagan Highlands fossil deposits of western North America. Some of these may have occurred even earlier, but have been obscured by taphonomic processes. We provide an overview of the Okanagan Highlands Hymenoptera to family level and in some cases below that, with a minimum of 25 named families and at least 30 when those tentatively assigned or distinct at family level, but not named are included. Some are poorly known as fossils (Trigonalidae, Siricidae, Peradeniidae, Monomachidae), and some represent the oldest confirmed occurrences (Trigonalidae, Pompilidae, Sphecidae sensu stricto, Peradeniidae, Monomachidae, and possibly Halictidae). Some taxa previously thought to be relictual or extinct by the end of the Cretaceous (Angarosphecidae, Archaeoscoliinae, some Diapriidae) are present and sometimes abundant in the early Eocene. Living relatives of some taxa are now present in different climate regimes or on different continents. DOI
7. Goring, S; Lacourse, T; Pellatt, MG; Mathewes, RW. (2013) Pollen assemblage richness does not reflect regional plant species richness: a cautionary tale.Journal of Ecology 101: 1137-1145 Pollen assemblage richness does not reflect regional plant species richness: a cautionary tale
WESTERN NORTH-AMERICA; TEMPERATE RAIN-FOREST; PALYNOLOGICAL RICHNESS; FLORISTIC DIVERSITY; TAXONOMIC RICHNESS; BRITISH-COLUMBIA; BIODIVERSITY; CLIMATE; RESOLUTION; DYNAMICS
1. Palaeoecological records of species richness spanning time intervals over which climate variables have shifted relative to one another can help reduce issues of colinearity that might affect our understanding of patterns of species richness. 2. Fossil pollen assemblages have the potential to serve as a proxy for past plant richness because they record the presence of plant taxa. However, pollen assemblages are typically limited by low taxonomic resolution and taphonomic processes (pollen production, transport, deposition and preservation), which may degrade the degree to which pollen accurately represents vegetation communities. 3. We combined pollen assemblages from modern lake sediments (n=546; n=167 in British Columbia, Canada) in the Pacific Northwest, with a detailed data base (n=16071) of plant presence across the province and a published record of gamma richness to test the accuracy of pollen assemblages as a proxy for regional patterns of plant richness. 4. A generalized linear model using plant richness resolved at multiple taxonomic levels suggests taxonomic differences between plant and pollen taxa may reduce the ability of pollen richness to predict plant richness at the site level, but that this relationship is still recoverable, albeit with broad confidence intervals. 5. Spatially explicit analysis using a generalized additive model shows that predicted plant richness has no relationship with raw pollen assemblage richness at all taxonomic levels. 6. The taxonomic composition of the region (i.e. the ratio of wind-pollinated to insect-pollinated species) and/or the morphological specificity of the dominant pollen types in the region may play a role in limiting the reconstruction of plant richness from pollen richness. Nonetheless, we believe this study is the first to empirically test the relationship between plant and pollen richness, and fails to find a significant relationship. 7. Synthesis. Palynological richness in itself cannot be considered a universally reliable proxy for inferring plant richness; however, broad spatial and temporal patterns of change in richness have been reported in the literature. Our findings suggest that more work is needed to understand previously reported patterns of pollen assemblage richness through time and in space. We suggest the use of functional diversity or phylogenetically based analysis may help link pollen richness to plant community richness. DOI
6. Archibald, SB; Johnson, KR; Mathewes, RW; Greenwood, DR. (2011) Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals.Proceedings of the Royal Society B-Biological Sciences 278: 3679-3686 Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals
Formicidae; Formiciinae; Titanomyrma; Holarctic dispersal; hyperthermals
Early Eocene land bridges allowed numerous plant and animal species to cross between Europe and North America via the Arctic. While many species suited to prevailing cool Arctic climates would have been able to cross throughout much of this period, others would have found dispersal opportunities only during limited intervals when their requirements for higher temperatures were met. Here, we present Titanomyrma lubei gen. et sp. nov. from Wyoming, USA, a new giant (greater than 5 cm long) formiciine ant from the early Eocene (approx. 49.5 Ma) Green River Formation. We show that the extinct ant subfamily Formiciinae is only known from localities with an estimated mean annual temperature of about 20 degrees C or greater, consistent with the tropical ranges of almost all of the largest living ant species. This is, to our knowledge, the first known formiciine of gigantic size in the Western Hemisphere and the first reported cross-Arctic dispersal by a thermophilic insect group. This implies intercontinental migration during one or more brief high-temperature episodes (hyperthermals) sometime between the latest Palaeocene establishment of intercontinental land connections and the presence of giant formiciines in Europe and North America by the early middle Eocene. DOI
5. Clague, JJ; Wohlfarth, B; Ayotte, J; Eriksson, M; Hutchinson, I; Mathewes, RW; Walker, IR; Walker, L. (2004) Late Holocene environmental change at treeline in the Northern Coast Mountains, British Columbia, Canada.Quat. Sci. Rev. 23: 2413-2431 Late Holocene environmental change at treeline in the Northern Coast Mountains, British Columbia, Canada
An integrated stratigraphic, paleoecological, and geochronological study of lake and fen sediments just beyond the terminus of Berendon Glacier provides insights into late Holocene climate, vegetation, and glacier change in the northern Coast Mountains of British Columbia. Cores collected from two small lakes in the foreland of Berendon Glacier and pits dug in a nearby fen record Little lee Age and older glacier advances. The first Little Ice Age advance in this area began more than 500 years ago and peaked in the early 17th century. An earlier Neoglacial advance began about 2800-3000 cal yr ago and may have lasted for hundreds of years. There is also evidence for an intervening advance of even smaller magnitude around 1200-1300 cal yr ago. The advances are broadly synchronous with those in other parts of western North America, indicating that they were caused by regional, possibly global, changes in climate. Plant communities within the study area did not change dramatically during the late Holocene. The ranges of some plants, however, likely retracted or extended near treeline in response to changes in mean temperatures of perhaps 1-2degreesC, as A well as changes in summer snow cover. The greatest changes in vegetation occurred within and just beyond the forefields of Berendon, Frank Mackie, and other nearby glaciers. The largest climate shifts of the last 3000 years took place during the late Little Ice Age and the last century. Climate warmed about 1-2degreesC during the 20th century, accompanied by a rise in treeline, an increase in coniferous tree cover in the subalpine zone, and an increase in the temperature and biological productivity of ponds. These trends are likely to continue if climate, as expected, continues to warm. (C) 2004 Elsevier Ltd. All rights reserved. DOI
4. Blais-Stevens, A; Clague, JJ; Mathewes, RW; Hebda, RJ; Bornhold, BD. (2003) Record of large, Late Pleistocene outburst floods preserved in Saanich Inlet sediments, Vancouver Island, Canada.Quat. Sci. Rev. 22: 2327-2334 Record of large, Late Pleistocene outburst floods preserved in Saanich Inlet sediments, Vancouver Island, Canada
Two anomalous, gray, silty clay beds are present in ODP cores collected from Saanich Inlet, Vancouver Island, British Columbia, Canada. The beds, which date to about 10,500 C-14 yr BP (11,000 calendar years BP), contain Tertiary pollen derived from sedimentary rocks found only in the Fraser Lowland, on the mainland of British Columbia and Washington just east of the Strait of Georgia. Abundant illite-muscovite in the sediments supports a Fraser Lowland provenance. The clay beds are probably distal deposits of huge floods that swept through the Fraser Lowland at the end of the Pleistocene. Muddy overflow plumes from these floods crossed the Strait of Georgia and entered Saanich Inlet, where the sediment settled from suspension and blanketed diatom-rich mud on the fiord floor. The likely source of the floods is Late Pleistocene, ice-dammed lakes in the Fraser and Thompson valleys, which are known to have drained at about the time the floods occurred. (C) 2003 Elsevier Ltd. All rights reserved. DOI
2. MATHEWES, RW; CLAGUE, JJ. (1994) DETECTION OF LARGE PREHISTORIC EARTHQUAKES IN THE PACIFIC-NORTHWEST BY MICROFOSSIL ANALYSIS.Science 264: 688-691 DETECTION OF LARGE PREHISTORIC EARTHQUAKES IN THE PACIFIC-NORTHWEST BY MICROFOSSIL ANALYSIS
Geologic and palynological evidence for rapid sea level change similar to 3400 and similar to 2000 carbon-14 years ago (3600 and 1900 calendar years ago) has been found at sites up to 110 kilometers apart in southwestern British Columbia. Submergence on southern Vancouver Island and slight emergence on the mainland during the older event are consistent with a great (magnitude M greater than or equal to 8) earthquake on the Cascadia subduction zone. The younger event is characterized by submergence throughout the region and may also record a plate-boundary earthquake or a very large crustal or intraplate earthquake. Microfossil analysis can detect small amounts of coseismic uplift and subsidence that leave little or no lithostratigraphic signature. DOI PubMed
