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--- paleoenv_typical [20/03/2023 10:25] – created mike_gss
+++ paleoenv_typical [10/05/2023 14:53] (current) – mike_gss
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 Predominantly based on benthonic organisms as these are more responsive to substrate conditions. However, the planktonic component of a fossil assemblage is useful for estimating paleodepths.
-Foraminifera (both benthonic and planktonic varieties) are the best microfossils to evaluate paleoenvironments.
+Foraminifera (both benthonic and planktonic varieties) are the best microfossils to evaluate paleoenvironments. Many foraminifera have reasonably well-known environmental and bathymetric distributions.
+{{:paleoenv03.jpg?nolink|}}
+//Distribution of living foraminifera in the hydrosphere. Proportions of the three main foraminiferal groups in fossil assemblages are shown in the bottom strip.//
+{{:paleoenv06.jpg?nolink|}}
+//Different shell shapes of planktonic forams (keeled or non-keeled) reflect habitat-differences in relative water depth.//
 Groups such as ostracods can also be useful. Other planktonic microfossils can give more generalised information. Combination studies of various palynomorphs (often referred to as “palynofacies”) can also give useful paleoenvironmental and paleoclimate information.
+{{:paleoenv05.jpg?nolink|}}
+//Details of palynological components and their proportions in terrestrial and marine settings (courtesy of Katrin Ruckwied, Shell).//
+**Palynofacies** - A term often seen in conjunction with typical biostratigraphic reports is "palynofacies". This is a quantitative technique which examines not only the various species of palynomorph that make up an assemblage, but also the other organic matter (kerogen) contained within a palynological preparation. It also assesses - by means of measuring the colour of certain palynological objects such as spores - the degree of thermal change that the sample has undergone during burial. Palynofacies can provide a detailed paleoenvironmental breakdown of a succession when trends in these signals can be plotted.
+The uses of colour in fossils to determine thermal maturity is covered in more detail here [**NEED LINK**]
 A combination of data based on different microfossil (or macrofossil) groups is the most powerful tool for determining paleoenvironments.
-Many foraminifera have reasonably well-known environmental and bathymetric distributions.
+{{:paleoenv04.jpg?nolink|}}
+//Summary chart of the broad distribution patterns of the main microfossil groups (courtesy of Dr Jonathan Bujak, the Azolla Foundation).//
+In addition, numerous statistical methods can be applied to fossil assemblages.
+{{:paleoenv07.jpg?nolink|}}
-Numerous statistical methods can be applied to fossil assemblages.
+//Shape variation in Operculina ammonoides is related to depth of habitat. Measuring the dimensions of a species assemblage can be applied statistically to paleoenvironmental interpretations.//
 **The Composition of Some Typical Environments**