A11: UNITED ARAB EMIRATES

This page authored by Steve Kershaw


This page shows what is probably the world’s thinnest post-mass extinction microbialite, in Wadi Shahha in United Arab Emirates. The thrombolite is 1 m thick at its thickest point, but the sample displayed here is 6cm thick, and represents the entire microbialite.

Go to Microbialite Atlas Contents PageGA3_Microb_Contents.htmlGA3_Microb_Contents.htmlshapeimage_1_link_0
Go to PTB map pageGA5_P-T_Boundary.htmlGA5_P-T_Boundary.htmlshapeimage_2_link_0

This log shows the thrombolite as a thin red-coloured bed, and occurs some metres above the extinction level. It also occurs some metres above the level of significant shift in Uranium level of the sediment, showing that the microbialite does not correspond with onset of low oxygen conditions, and therefore was not governed by low oxygen levels, at least in this area.


Ref: Maurer et al. (2009)  ; Kershaw et al. (2012).

The fulll thickness of the micronbialite in this sample is 6cm. It is thrombolite, shows no vertical change in character, and suggests that it was switched on and off without gradual change. Thin section photos below all come from this sample, and show it is largely recrystallised, but has some partial preservation, demonstrating that it is thrombolite. It has lobate margins, rather like the South China renalcid-group thrombolites.


Sample provided by Florian Maurer.

Photo: Steve Kershaw

Photo: Steve Kershaw

Photo: Steve Kershaw

Photo: Steve Kershaw

Photo: Steve Kershaw

Photo: Steve Kershaw

Photo: Steve Kershaw

Photo: Steve Kershaw

Photo: Steve Kershaw