The technofossil record of humans

March 27, 2014
HayleyKeen

 

Can you spot the techno fossil?

Can you spot the technofossil?

Hayley Keen on:

Zalasiewicz, J., Williams, M., Waters, C.N., Barnosky, A.D. & Haff, P. (2014) The technofossil record of humans. The Anthropocene Review, 1, 34-43.

An interesting research article introducing a stratigraphy (technostratigraphy) for and within the Anthropocene, stratigraphic markers are defined as “fossils” left behind by humans (technofossils); for example Iron Age tools from around 1000 BC. The article is driven by the need to:

  1. characterise the deposits, and
  2. date and correlate strata,

of (and within) the Anthropocene in a similar manner to other periods of geological time. By using technofossils from the different stages of homonid technological development Zalasiewicz et al. argue that a chronology can be developed and applied to the Anthropocene concept. Furthermore, Zalasiewicz et al. provide examples of how technofossils, such as pottery and mobile phones, could be used to produce a high resolution (sub-centennial) dating and correlation of strata; so far an unreachable target for other periods of geological time. The paper provides a thought provoking insight the definition of strata throughout geological time, and a novel technique into how this could be done in the Anthropocene.

 

 

Royal Geographical Society (with IBG) annual international conference – 2013

August 30, 2013
HayleyKeen

Palaeo-people at the RGS-IBG meeting plotting future papers and grants.

Palaeo-people at the RGS-IBG meeting plotting future papers and grants. Left-right: Encarni Montoya, Joe Williams, Hayley Keen and Frazer Bird.

RGS – IBG Annul International Conference 2013
27th – 30th August, London

Yesterday (29th August) four members of the Palaeoenvironmental Change Research Group (PCRG) went down to London for the third day of the Royal Geographical Society with IBG (RGS – IBG) international conference for a day of informative talks. Two of the morning sessions were of particular interest to us with the sessions entitled ‘Human – environment interactions in the Neotropics: historical impact to current challenges’ organised by John Carson, Lizzy Rushton and Sarah Metcalfe.

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Sediment sampling on the Andean flank, Ecuador

October 10, 2012
HayleyKeen

One of the key goals of the fieldtrip to Ecuador (August-September) was to sample organic and volcanic (tephra) layers from sedimentary exposures with the aim of obtaining new information about past envrionmental change in the region. Our Ecuadorian collaborator, Dr Patricia Mothes (Instituto Geofisico), had identified four of sites she thought might be useful too us: El Fatima Dique, Mera “2” Dique, El Rosol and Vinillos. 

Fatima section

At the Fatima site, near Puyo, a thin organic bed was sampled sandwiched between volcanic ash deposits. Wood macrofossils from this deposit have been dated to the last glacial period.

For further descriptions of what we found and field photos read on…

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Number crunching in palynology

May 10, 2012
HayleyKeen

Simulated pollen counts

Simulated pollen counts

HOW DO WE UNDERSTANT PAST VEGETATION CHANGE?
Our understating of vegetation in the past, and how it has changed through time, comes mainly from the examination of macrofossils (e.g. wood and leaves) and microfossils (e.g. pollen and spores) found in the sedimentary record. The potential for microscopic fossils to provide an insight into past vegetation change on a landscape scale was pioneered by von Post (Von Post, 1916, reprinted 1967) and has been subsequently used to understand changes in regional floras (Godwin, 1956), and address conservation issues (Willis et al., 2007). Analysis of fossil pollen and spores (palynology) is now widely used on late Quaternary timescales to answer ecological questions linking vegetation and wider environmental/climatic change; these include:

  • Has there been a change in major vegetation type (biome)? For example a change between woodlands and grassland vegetation.
  • How have the ecosystem dynamics altered? For example the presence or absence of fire.
  • How has the diversity within the ecosystem changed? For example increase or decrease in sample richness.

Palynological analysis relies on obtaining a sub-sample of the pollen contained within the sediment at a specific depth (time) which allows the vegetation at that time to be reconstructed. This sub-sample is known as a pollen count. To build up a picture of vegetation change through time it is necessary to generate a sequence of pollen counts. The size of the sub-sample (pollen count) required from any particular depth (time period) is dependent on the nature of the vegetation association being investigated and the ecological question being addressed . For example, the amount of pollen analysed to determine if the vegetation was predominantly wooded or grassland is different to that required to provide information on the biological diversity within the vegetation assemblage.

Discussed below are some of the conventions related to choosing an appropriate pollen count size within palynology, with particular reference to the challenges of dealing with diverse tropical floras.

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