Field project tutorials 2002 - Day 2

Day 2: Notebook entries






OK: overcast but dry; slight breeze; mild


Steep grassy slopes (slippery in wet) to /river section with flowing water and waterfalls/rapids.


Dr. Geoff Lloyd




In general

  • to collect two and three dimensional strain data at specific outcrops
  • to analyse these data using methods explained in class, in terms of the structural geological history of the field area


  • to follow a structural traverse, approximately at right angles to the overall structural trend, from 050 066 to 069 052 along the central part of the main river valley
  • to compare the strain data with undeformed examples, either observed or anticipated
  • to provide the basis for determining the progressive deformation history of the sedimentary rocks
  1. Walk from the field camp (grid reference 003 072) up the hill to the south. At 012 045, horizontally bedded thin limestones and shales occur with abundant fossils, both on and normal to bedding. On the bedding plane, belemnites show slight fracturing (figure 20a). Normal to bedding planes, solitary corals are slightly flattened (figures 20b,c).

Return to main river valley & walk upstream to 050 066 to begin the strain analysis traverse.

  1. 050 066 Well bedding quartzite (167/35E), with no cleavage, is observed. Worm tubes intersect bedding planes with a circular outline and are perpendicular to bedding in cross-section.
  1. Continue walking up river until 060 056 (Fig. 21), where a junction between bedded quartzite and shales is observed. Bedding in both rocks is parallel to the boundary: 169/32E. The shales have a strong cleavage, which is only weakly developed in the quartzite: 020/55E. The cleavage plane has a stretching lineation (43/159) and a cleavage-bedding intersection lineation (27/041). Reduction spots occur in the shales (Fig. 22).
  2. At 069 052 the junction between limestone-shales and massive shales occurs. Both rock types are fossiliferous and heavily cleaved. Deformed Oxytoma cygnipes are observed on a plane oriented 070/47W, on which a reference direction pitches 90° E (see Fig. 23). Deformed solitary fossils are seen on a plane oriented 020/56E on which a stretching lineation plunges 43/159 (see Fig. 24)

Strain analysis methodologies

  1. Breddin
  2. Fry
  3. Rf/phi
  4. When to use which methodology

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