Changes

The steps of the workflow we recommend for examining mudstones in outcrops, cores, and thin sections are:

The steps of the workflow we recommend for examining mudstones in outcrops, cores, and thin sections are:

# ‘’Make observations’’

# '''Make observations'''

## ‘’Establish stratigraphic context’’

## '''Establish stratigraphic context'''

### Step back, examine, and photograph the entire exposure, walking the section several times.

### Step back, examine, and photograph the entire exposure, walking the section several times.

### Check core depths and core box order, clean the core, and photograph the entire core. Step back, examine, and walk the section several times with well logs in hand.

### Check core depths and core box order, clean the core, and photograph the entire core. Step back, examine, and walk the section several times with well logs in hand.

### Look for changes in texture, bedding, composition, thickness, continuity, and stacking; and presence of erosional surfaces. Tentatively identify stratigraphic packages.

### Look for changes in texture, bedding, composition, thickness, continuity, and stacking; and presence of erosional surfaces. Tentatively identify stratigraphic packages.

### Make note of weathering characteristics and their vertical and lateral distribution.

### Make note of weathering characteristics and their vertical and lateral distribution.

## ‘’Start at the base of the section or core, identify, examine, and describe stratigraphic packages and surfaces as you proceed up-section. Integrate outcrop or core observations with thin-section observations.’’ Observe and take pictures of stratigraphic features at all scales (laminae, laminasets, beds, bedsets, parasequences, parasequence sets, and sequences).

## '''Start at the base of the section or core, identify, examine, and describe stratigraphic packages and surfaces as you proceed up-section. Integrate outcrop or core observations with thin-section observations.''' Observe and take pictures of stratigraphic features at all scales (laminae, laminasets, beds, bedsets, parasequences, parasequence sets, and sequences).

### Examine a fresh face of rocks from each potential stratigraphic package; sample each significant facies; mudstones tend to weather deeply and may require much digging to remove the weathered rock and to obtain fresh exposure and samples ([[:file:M91Ch6FG47.JPG|Figure 1]]).

### Examine a fresh face of rocks from each potential stratigraphic package; sample each significant facies; mudstones tend to weather deeply and may require much digging to remove the weathered rock and to obtain fresh exposure and samples ([[:file:M91Ch6FG47.JPG|Figure 1]]).

### Describe the mudstones: ‘’texture, bedding,’’ and ‘’composition’’. Figure 1A–D in [[Mudstone nomenclature]] summarize the terms and definitions we recommend for texture, bedding, and composition. A practical, proxy method, the “scratch test,” we recommend to use to determine the dominant grain size at hand specimen scale is detailed in [[:file:M126Ch3-Table10.jpeg|Table 10]]. Fine-tune outcrop and core estimations of texture, bedding, and composition by integrating observations under optical and electronic microscopes and analytical data obtained on samples taken in sedimentologic and stratigraphic context.

### Describe the mudstones: '''texture, bedding,''' and '''composition'''. Figure 1A–D in [[Mudstone nomenclature]] summarize the terms and definitions we recommend for texture, bedding, and composition. A practical, proxy method, the “scratch test,” we recommend to use to determine the dominant grain size at hand specimen scale is detailed in [[:file:M126Ch3-Table10.jpeg|Table 10]]. Fine-tune outcrop and core estimations of texture, bedding, and composition by integrating observations under optical and electronic microscopes and analytical data obtained on samples taken in sedimentologic and stratigraphic context.

### Describe biogenic sedimentary structures and characterize the degree of bioturbation using a 0–5 scale (figure 1E of [[Mudstone nomenclature]]).

### Describe biogenic sedimentary structures and characterize the degree of bioturbation using a 0–5 scale (figure 1E of [[Mudstone nomenclature]]).

### Describe the type, size, diversity, abundance (figure 1F of [[Mudstone nomenclature]]), preservation, and taphonomy (figure 1G of [[Mudstone nomenclature]]) of body fossils. Similarly, describe trace fossils.

### Describe the type, size, diversity, abundance (figure 1F of [[Mudstone nomenclature]]), preservation, and taphonomy (figure 1G of [[Mudstone nomenclature]]) of body fossils. Similarly, describe trace fossils.

### Describe the type, size, composition, and abundance of diagenetic products (figures 1C, F of [[Mudstone nomenclature]]).

### Describe the type, size, composition, and abundance of diagenetic products (figures 1C, F of [[Mudstone nomenclature]]).

### Organize recurring, representative, and diagnostic facies attributes into ‘’facies associations’’.

### Organize recurring, representative, and diagnostic facies attributes into '''facies associations'''.

### Identify and describe ‘’stratal packages and key surfaces’’ (sequence boundaries and flooding surfaces; [[:file:M126CH03-Figure3.jpeg|Figure 3]]; Tables 7, 11). Obtain a spectral gamma-ray profile to further characterize stratigraphic units ([[:file:M126CH03-Figure4.jpeg|Figure 4]]).

### Identify and describe '''stratal packages and key surfaces''' (sequence boundaries and flooding surfaces; [[:file:M126CH03-Figure3.jpeg|Figure 3]]; Tables 7, 11). Obtain a spectral gamma-ray profile to further characterize stratigraphic units ([[:file:M126CH03-Figure4.jpeg|Figure 4]]).

### Record all information consistently in an appropriate format, designed for your particular setting or unit.

### Record all information consistently in an appropriate format, designed for your particular setting or unit.

# ‘’Make interpretations’’

# '''Make interpretations'''

## ‘’Integrate’’ outcrop, core, or thin-section observations with analytical, well-log, and seismic data as available. Make a hierarchical interpretation of stratal units (laminae, laminasets, beds, bedsets, parasequences, parasequence sets, sequences; significant stratal boundaries).

## '''Integrate''' outcrop, core, or thin-section observations with analytical, well-log, and seismic data as available. Make a hierarchical interpretation of stratal units (laminae, laminasets, beds, bedsets, parasequences, parasequence sets, sequences; significant stratal boundaries).

## ‘’Make interpretations’’ of dominant sediment provenance, input mode, physical reworking, sediment accumulation rate, completeness of sedimentary record, bottom-water redox conditions, and environment of deposition<ref name=Bhcsea2005 /><ref name=Bhcsea2014 /><ref name=Lzrea2015a /><ref name=Lzrea2015b /> (e.g., [[:file:M126Ch3-Table2|Table 2]] ; see also [[Laminasets, beds, and bedsets]], [[Parasequences]], and [[Parasequence sets and depositional sequences]]).

## '''Make interpretations''' of dominant sediment provenance, input mode, physical reworking, sediment accumulation rate, completeness of sedimentary record, bottom-water redox conditions, and environment of deposition<ref name=Bhcsea2005 /><ref name=Bhcsea2014 /><ref name=Lzrea2015a /><ref name=Lzrea2015b /> (e.g., [[:file:M126Ch3-Table2|Table 2]] ; see also [[Laminasets, beds, and bedsets]], [[Parasequences]], and [[Parasequence sets and depositional sequences]]).

[[file:M126Ch3-Table10.jpeg|thumb|300px|’’Table 10.’’ Scratch Test (After Lazar et al.<ref name=Lzrea2015a /><ref name=Lzrea2015b />).]]

[[file:M126Ch3-Table10.jpeg|thumb|300px|'''Table 10.''' Scratch Test (After Lazar et al.<ref name=Lzrea2015a /><ref name=Lzrea2015b />).]]

[[file:M126Ch3-Figure3.jpeg|thumb|300px|{{figure number|3}}Accommodation succession showing key stratigraphic surfaces, stacking patterns, and depositional sequence expression using definitions outlined in [[:file:M126CH03-Table7.jpeg|Tables 7]] and [[:file:M126Ch3-Table11.jpeg|11]]<ref name=Abrea2010 /> (after Neal and Abreu<ref name=NlABr>Neal, J., and V. Abreu, 2009, Sequence stratigraphy hierarchy and the accommodation succession method: Geology, v. 37, p. 779–782.</ref>, and Abreu et al.<ref name=Abrea2014>Abreu, V., K. Pederson, J. Neal, and K. M. Bohacs, 2014, A simplified guide for sequence stratigraphy: Nomenclature, definitions and method: Geological Society of America Annual Meeting, 19–22 October 2014, Vancouver, British Columbia, Abstracts with Programs, v. 46, no. 6, p. 832.</ref>).]]

[[file:M126CH03-Figure3.jpeg|thumb|300px|{{figure number|3}}Accommodation succession showing key stratigraphic surfaces, stacking patterns, and depositional sequence expression using definitions outlined in [[:file:M126CH03-Table7.jpeg|Tables 7]] and [[:file:M126Ch3-Table11.jpeg|11]]<ref name=Abrea2010 /> (after Neal and Abreu<ref name=NlABr>Neal, J., and V. Abreu, 2009, Sequence stratigraphy hierarchy and the accommodation succession method: Geology, v. 37, p. 779–782.</ref>, and Abreu et al.<ref name=Abrea2014>Abreu, V., K. Pederson, J. Neal, and K. M. Bohacs, 2014, A simplified guide for sequence stratigraphy: Nomenclature, definitions and method: Geological Society of America Annual Meeting, 19–22 October 2014, Vancouver, British Columbia, Abstracts with Programs, v. 46, no. 6, p. 832.</ref>).]]

[[file:M126Ch3-Table11.jpeg|thumb|300px|’’Table 11.’’ Definitions of Systems Tracts With Stacking Patterns and Recognition Criteria (after Abreu et al.<ref name=Abrea2014 />).]]

[[file:M126Ch3-Table11.jpeg|thumb|300px|’’Table 11.’’ Definitions of Systems Tracts With Stacking Patterns and Recognition Criteria (after Abreu et al.<ref name=Abrea2014 />).]]

[[file:M126Ch3-Figure4.jpeg|thumb|300px|{{figure number|4}}Schematic diagram of using a gamma-ray spectrometer in the field (after Schwalbach and Bohacs<ref name=SchwlbchBhcs1992 /><ref>Schwalbach, J. R., and K. M. Bohacs, 1995, Stratigraphic sections and gamma-ray spectrometry from five outcrops of the Monterey Formation in southwestern California; Naples Beach, Point Pedernales, Lion’s Head, Shell Beach, and Point Buchon: US Geological Survey Bulletin 1995, p. Q1–Q39.</ref>).]]

[[file:M126CH03-Figure4.jpeg|thumb|300px|{{figure number|4}}Schematic diagram of using a gamma-ray spectrometer in the field (after Schwalbach and Bohacs<ref name=SchwlbchBhcs1992 /><ref>Schwalbach, J. R., and K. M. Bohacs, 1995, Stratigraphic sections and gamma-ray spectrometry from five outcrops of the Monterey Formation in southwestern California; Naples Beach, Point Pedernales, Lion’s Head, Shell Beach, and Point Buchon: US Geological Survey Bulletin 1995, p. Q1–Q39.</ref>).]]

===Introduction to Sequence Stratigraphy===

===Introduction to Sequence Stratigraphy===

This chapter introduced key tools and techniques that provide data about texture, bedding, composition, and grain origin. Such data enable characterization of mudstone strata at lamina to sequence-set scales. The application of such tools and techniques to decipher depositional conditions and construct sequence-stratigraphic frameworks was specifically addressed. Outlines of our approach to making detailed and systematic observations of key attributes of mudstones in outcrops, cores, and thin sections as well as an introduction to key sequence-stratigraphic concepts that we find useful for studying mudstones were included for quick reference. Our approach is elaborated and illustrated in all of the following chapters.

This chapter introduced key tools and techniques that provide data about texture, bedding, composition, and grain origin. Such data enable characterization of mudstone strata at lamina to sequence-set scales. The application of such tools and techniques to decipher depositional conditions and construct sequence-stratigraphic frameworks was specifically addressed. Outlines of our approach to making detailed and systematic observations of key attributes of mudstones in outcrops, cores, and thin sections as well as an introduction to key sequence-stratigraphic concepts that we find useful for studying mudstones were included for quick reference. Our approach is elaborated and illustrated in all of the following chapters.

[[file:M126Ch3-Figure5.jpeg|thumb|300px|{{figure number|5}}Figure 5. Illustration of the sequence-stratigraphic approach in siliciclastic nearshore strata (after Bohacs and Schwalbach<ref name=BhcSchwlbch1992 />). The stratigraphic section is divided into large-scale stratal packages bounded by significant surfaces that are identified by their characteristics and stratigraphic context (place in stacking patterns, etc.). See [[:file:M126Ch3-Table12.jpeg|Table 12]] for more details. MFS = maximum flooding surface; SB = sequence boundary; TS = transgressive surface.]]

[[file:M126CH03-Figure5.jpeg|thumb|300px|{{figure number|5}}Figure 5. Illustration of the sequence-stratigraphic approach in siliciclastic nearshore strata (after Bohacs and Schwalbach<ref name=BhcSchwlbch1992 />). The stratigraphic section is divided into large-scale stratal packages bounded by significant surfaces that are identified by their characteristics and stratigraphic context (place in stacking patterns, etc.). See [[:file:M126Ch3-Table12.jpeg|Table 12]] for more details. MFS = maximum flooding surface; SB = sequence boundary; TS = transgressive surface.]]

==See also==

==See also==