Palaeoenvironment, palaeoclimate and age of the Brassington Formation (Miocene) of Derbyshire, UK

Abstract

The Brassington Formation is the most extensive Miocene sedimentary succession onshore in the UK. Because of its unique position at the margin of NW Europe, the pollen from this lithostratigraphical unit provides evidence on the development of vegetation affected by North Atlantic currents and hypothesized atmospheric circulation changes during the Middle to Late Miocene climate cooling. Palynostratigraphy suggests that the uppermost Kenslow Member of the Brassington Formation is not coeval. Previously, all occurrences of the Kenslow Member were assumed to be contemporary. The oldest pollen assemblage is from the more southern Bees Nest Pit, which represents a subtropical conifer-dominated forest of late Serravallian age ( c . 12 Ma). A younger assemblage was observed from the more northern Kenslow Top Pit; this indicates that a subtropical mixed forest was present during the early Tortonian (11.6–9 Ma). The shift from a conifer-dominated to a mixed forest was related to precipitation. Although the total precipitation did not change between the two assemblages, the younger assemblage had more uniform rainfall throughout the year. The diachronous nature of the Kenslow Member means that the depositional model of the Brassington Formation needs revising, and this will have implications for Neogene to recent uplift of the southern Pennines. Supplementary material: All valid formally defined palynomorph taxa below the generic level that are mentioned in this paper, with full author citations, are available at http://www.geolsoc.org.uk/SUP18889 .

Three new Miocene fungal palynomorphs from the Brassington Formation, Derbyshire, UK

“…The Bees Nest Member comprises vari-coloured clays and has also proven unfossiliferous to date, though ongoing exploration has returned samples that show promise of yielding palynomorphs (Boulter et al, 1971;Walsh et al, 1972;1980). It is the Kenslow Member that has yielded fossil plant material (Boulter, 1971;Pound et al, 2012;Pound & Riding, 2016). Fossil wood, leaves and seeds have been reported, but represent a low diversity assemblage (Boulter & Chaloner, 1970;Boulter, 1971).…”

“…Fossil wood, leaves and seeds have been reported, but represent a low diversity assemblage (Boulter & Chaloner, 1970;Boulter, 1971). The fossil pollen has not only revealed a greater diversity of plant species, but has been the only means to date the formation (Boulter, 1971;Pound et al, 2012;Pound & Riding, 2016). Recent re-analysis of the Kenslow Member has shown that its deposition was diachronous; in the Bees Nest Pit, it is Serravallian in age, whereas in the Kenslow Top Pit, it is Tortonian in age (Pound et al, 2012;Pound & Riding, 2016).…”

A biography and obituary of William G. Chaloner FRS (1928–2016)

“…Boulter and Chaloner (1970) proposed a Pliocene age for this unit, which had been previously attributed to the Carboniferous, Permian and Triassic. The age of the Brassington Formation was subsequently revised to Miocene-Pliocene (Boulter 1971) and, more recently, to Middle-Late Miocene (Pound et al 2012;Pound and Riding 2016;Walsh et al 2018).…”

Early and Middle Pleistocene environments, landforms and sediments in Scotland

“…The latest phase of uplift commenced at ~4 Ma, prior to the onset of extensive glaciation, and may have extended into the Pleistocene (Stoker et al, 2010). In the English Peak District uplift has been estimated at 300 m since 12 Ma (Pound & Riding, 2015) or ~3 Ma (Westaway, 2009). Evidence from caves of valley incision and from raised beaches suggests uplift of the Alston Block in northern England at rates of 0.2 mm/yr over the last 0.8 Ma (Westaway, 2016).…”