ORIGINAL ARTICLE
The Miocene Red Lake macroflora of the Deadman River Formation (Chilcotin Group), Interior Plateau, British Columbia, Canada
1 1 | Department of Biology, Brandon University, 270-18th Street, Brandon, Manitoba, R7A 6A9, Canada |
2 | Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon,
Saskatchewan, S7N 5E2, Canada |
Online publication date: 2020-11-27
Publication date: 2020-12-30
Acta Palaeobotanica 2020; 60(2): 213–250
KEYWORDS
ABSTRACT
Despite early interest in Neogene floras, primarily Miocene sites associated with Mio–Pliocene volcanic
deposits of the Interior Plateau of British Columbia, few systematic accounts of the Miocene macrofloras of
British Columbia – or elsewhere in non-Arctic Canada – have been published since the pioneering studies of J.W.
Dawson and his contemporaries in the late 19th century. In this report, the Red Lake macroflora from sediments
of the middle Miocene Deadman River Formation exposed in the Red Lake diatomite mine north of Kamloops,
British Columbia, is illustrated, and a preliminary assessment presented, along with a brief review of Miocene
floras from British Columbia and the U.S. Pacific Northwest. The Red Lake macroflora contains rare Ginkgo
leaves, shoots of Cupressaceae (Cupressinocladus, Metasequoia, Taxodium) and shoots and seeds of Pinaceae
(Pseudotsuga, Tsuga), maple (Acer) seeds and leaves, Liquidambar (fruit), Trochodendraceae (Zizyphoides auriculata
leaves, Nordenskioeldia interglacialis fruits), leaves of 4 species of red and white oaks (Quercus columbiana,
Q. prelobata, Q. pseudolyrata, Quercus sp.), leaves of an alder (Alnus harneyana) and birch (Betula thor), chestnut
(Castanea spokanensis), beech (Fagus pacifica), sycamore (Platanus dissecta), elm (Ulmus speciosa), leaves of
unidentified taxa, fruits of Tilia pedunculata (Malvaceae) and fruits and inflorescences of other unidentified taxa,
and leaves of a reed or rush (indet. monocot). The Red Lake middle Miocene climate reconstructed from leaf physiognomy
was temperate and mesic, with mean annual temperature ~11–13°C, mild winters (coldest month mean
temperature ~3°C), mean annual precipitation 170 −51/+73 cm/yr, and growing season precipitation ~92 cm, with
moderate seasonality of precipitation (three wettest months ~51 cm vs. three driest months ~25 cm). The Red Lake
flora shows similarities to middle to late Miocene floras from the U.S. Pacific Northwest (i.e., richness in oaks) but
is of much lower diversity and lacks key elements common to many of the contemporaneous U.S. Miocene floras
(e.g., foliage of Pinaceae esp. Pinus), and is missing taxa detected in the microflora, a pattern likely due to sampling
effectiveness at the Red Lake Mine and sampling of different lithofacies for macro- and microfloras.
RELATED ARTICLE