Field project tutorials 2002 - Day 5

Day 5: Notebook entries






Warm & humid but overcast; no wind; cloud base well above peaks


Steep grassy slopes (slippery in wet) and precipitous cliffs; several stream/river sections with fast-flowing water and waterfalls/rapids.

Humidity; midges/mosquitoes, especially near water &/or at lower levels; flies at mid levels.


Dr. Geoff Lloyd




Collection of fault rock microstructural data and interpretation via optical thin sections in terms of the field area, to:

  • recognise and distinguish cataclastic and mylonitic fault rocks
  • understand the rheological and geological implications of both types of fault rock
  • understand the distinction between brittle and ductile deformation in fault rocks

Submission of final map, cross-section and strain analysis data.

  1. GR 040 080. The first specimen (No. 53837) shows only slight deformation and can be regarded as the protolith for the other two rocks.
  2. The second specimen (53838) was collected from locality GR 020 050.
  3. The third specimen (53839) was collected from locality GR 084 051.

Using direct observations and information from your mapping, strain analysis and lecture notes etc., describe the deformation features you observe in the three thin-sections. Be sure to make plenty of diagrams and to illustrate your answer with comparisons between the three thin-sections. In particular, how do the two deformed rocks differ from each other, what rock names would you give to them, and how are their conditions of formation likely to differ?

Daily Summary

(remember to summarise your observations & to begin to evolve ideas about this region).












Last update: 23rd January 2002
Copyright © Dr G. Lloyd, School of Earth Sciences, Leeds University, 2002