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Climate Change (Oxygen isotope stratigraphy (Pioneered by Emiliani in 50s,…

- - - - In order to produce peat in sufficient thickness to be composed into economic coal seams, there has to be highly productive ecosystem, Rapid plat growth requires high rainfall and temps such as in tropical rainforests in equatorial regions
    - - Sands exposed to the air develop a red colour as the iron hydroxides oxidise to haematite, Desert sands are fine grained, very well sorted, with well rounded grains consisting of mostly quartz, They are transported by wind to produce spectacular dunes, Sune-forming desert latitudes generally around 20-30 S or N of equator
    - - These deposits from where rainfall is low and evaporation is high, Evaporites today are found at latitudes of about 20-30 S and N so same is likely for ancient deposits
    - - These are ancient boulder clay deposits, which are most commonly formed at high latitudes of more than 60 N or S of equator, However there are glacial deposits in low latitudes as small areas of high-altitude glaciers
    - - Today reef limestone is built mainly of colonial corals which are restricted to latitudes of less than 30 N or S of equator so reef structures most likely formed at these latitudes
  - - - Modern reef corals live in narrow range of water depths and temperatures, only thrive and build reefs where they can successfully exploit their symbiotic relationship with algae, This means they are restricted to the warm tropics mostly within 30N and 30S
      - Recent stable isotope analyses have shown that most Palaeozoic corals had O18 to O16 ratio similar to those of modern corals, so it is safe to assume that fossil reef building corals required same tropical conditions, Fossil coral reefs are found in Silurian and lower Carboniferous rocks so must have formed when the British Isles was in the tropical region
    - - Excellent indicators of climate in the past, The use of tree rings, leaf size and shape are good climate indicators, The lack of tree rings in Carboniferous plant fossils indicates a non-seasonal equatorial climate, as those current day tropics do not have seasonal rings, Upper Carboniferous plants grew up to heights of 40m which suggests they grew in hot, humid equatorial climate and latitude to accumulate such biomass