98
with care, and no single vertical profile across the
outcrop will contain a complete sequence of surface
and element notations. Proflles of this type can provide a graphic illustration of the lengthy process of
channel migration and bar accretion that can occur
within a single mobile channel before it is finally
abandoned.
4.9 Summary of Methods
The field methods described in this chapter are
designed to lead to detailed descriptions of stratigraphic architecture for purposes of resource exploration and production, and to facilitate the
interpretation of sedimentary controls. Observation
leads to interpretation by inductive reasoning. Baker
( !978a), in an examination of the methods of fluvial
geomorphology, illustrated the links between sedimentary controls and the real-world outcome by
using a flow chart (Fig. 4.14). Architectural methods
for detailed outcrop study, which form the basis for
inductive reasoning, contain the following components, to be carried out in essentially the order given.
References are made to the chapters where the relevant detail is provided. A typical example of a completed, annotated photomosaic is illustrated in Fig.
4.!5.
!. Photograph the outcrop and construct a photomosaic.
2. Document the scale and orientation of the profile.
3. Enter all visible bounding surfaces on a profile
overlay.
4. Check the correctness of the surface drawings in
the field, and carry out preliminary element interpretation. This can be done by viewing the
Methods of Architectural�Element Analysis
outcrop from the same place as the photographs
were taken. It is particularly useful to distinguish the major lithosomes by defining fifthand higher-order surfaces wherever possible.
5. Commence traverses of the outcrop, making
detailed observations of lithofacies (Chap. 5)
and paleocurrent directions. Mark observation
points precisely on the profile overlay, if necessary 'With the assistance of a second worker located at the photo site (who has a better overview
of the outcrop). Attempt to complete the tracing
of bounding surfaces left "hanging" following
the preliminary photointerpretation. Attempt to
obtain a representative suite of readings of current indicators and dipping bounding surfaces
for at least each fifth-order lithosome, and preferably for third- and fourth-order units as well.
6. Carry out element interpretation using the architectural details obtained from facies and orientation data (Chaps. 6, 7).
7. Annotate elements and bounding surfaces.
8. Correlate adjacent outcrops. If possible, correlate specific major lithosomes and bounding
surfaces by walking them out or by visual tracing
from a distance, but be particularly cautious of
attempting to correlate units and surfaces lower
than fifth-order in rank (Chap. 9).
9. Synthesize lithofacies, element, and paleocurrent data to arrive at interpretations of fluvial
style and channel pattern (Chaps. 8, 9).
10. Where appropriate, develop a regional allostratigraphic and sequence framework from
such regional correlations (Chap. 13).
11. Where required, measure the scale and geometry of lithosomes at each level of the hierarchy,
for the purpose of documenting reservoir het�
erogeneities (Chap. 10).
with care, and no single vertical profile across the
outcrop will contain a complete sequence of surface
and element notations. Proflles of this type can provide a graphic illustration of the lengthy process of
channel migration and bar accretion that can occur
within a single mobile channel before it is finally
abandoned.
4.9 Summary of Methods
The field methods described in this chapter are
designed to lead to detailed descriptions of stratigraphic architecture for purposes of resource exploration and production, and to facilitate the
interpretation of sedimentary controls. Observation
leads to interpretation by inductive reasoning. Baker
( !978a), in an examination of the methods of fluvial
geomorphology, illustrated the links between sedimentary controls and the real-world outcome by
using a flow chart (Fig. 4.14). Architectural methods
for detailed outcrop study, which form the basis for
inductive reasoning, contain the following components, to be carried out in essentially the order given.
References are made to the chapters where the relevant detail is provided. A typical example of a completed, annotated photomosaic is illustrated in Fig.
4.!5.
!. Photograph the outcrop and construct a photomosaic.
2. Document the scale and orientation of the profile.
3. Enter all visible bounding surfaces on a profile
overlay.
4. Check the correctness of the surface drawings in
the field, and carry out preliminary element interpretation. This can be done by viewing the
Methods of Architectural�Element Analysis
outcrop from the same place as the photographs
were taken. It is particularly useful to distinguish the major lithosomes by defining fifthand higher-order surfaces wherever possible.
5. Commence traverses of the outcrop, making
detailed observations of lithofacies (Chap. 5)
and paleocurrent directions. Mark observation
points precisely on the profile overlay, if necessary 'With the assistance of a second worker located at the photo site (who has a better overview
of the outcrop). Attempt to complete the tracing
of bounding surfaces left "hanging" following
the preliminary photointerpretation. Attempt to
obtain a representative suite of readings of current indicators and dipping bounding surfaces
for at least each fifth-order lithosome, and preferably for third- and fourth-order units as well.
6. Carry out element interpretation using the architectural details obtained from facies and orientation data (Chaps. 6, 7).
7. Annotate elements and bounding surfaces.
8. Correlate adjacent outcrops. If possible, correlate specific major lithosomes and bounding
surfaces by walking them out or by visual tracing
from a distance, but be particularly cautious of
attempting to correlate units and surfaces lower
than fifth-order in rank (Chap. 9).
9. Synthesize lithofacies, element, and paleocurrent data to arrive at interpretations of fluvial
style and channel pattern (Chaps. 8, 9).
10. Where appropriate, develop a regional allostratigraphic and sequence framework from
such regional correlations (Chap. 13).
11. Where required, measure the scale and geometry of lithosomes at each level of the hierarchy,
for the purpose of documenting reservoir het�
erogeneities (Chap. 10).