Logging: Beds and What They Record
Everything a bed on a geological log can carry, and the faster ways to enter it. Digitising a log and editing its beds is in Geological Logging.
The Bed Table
Bed Table on the 2D Log tab, or on a bed's or a log header's right-click menu, lists every bed of the log you clicked last in a grid. The top bed comes first, as on the log.
| Column | What it holds |
|---|---|
| Thickness | Metres, in the panel's depth mode (TVT, TST or MT). |
| Facies, Grain Size Base, Grain Size Top, Base Contact | Chosen from the project's lists. |
| Certainty, Bioturbation, Covered, Munsell | As in the bed's Properties (see What a bed records). |
| Lithologies, Structures, Fossils | Names from the project's lists, separated by ;. A lithology's share or a fossil's abundance follows its name after :, as in Sandstone:0.7; Shale:0.3 or Bivalves:Common. |
| Name, Comment | Text. |
| Dip, Azimuth | Degrees. |
| Interval | Shown only. Assign intervals on the log, which keeps each interval one unbroken run of beds. |
Press Enter to finish a cell. OK applies every change as one step of undo. The messages panel lists any name the project's lists do not have.
On a log that is a straight vertical column (one typed in, or imported from a bed table, SedLog or StraboSpot) you can also add and delete beds and change thicknesses:
- Add Above and Add Below put a new bed next to the selected one, as thick as it and at its dip.
- Delete Bed removes the selected bed. Its samples and palaeocurrent readings join its neighbour, as Delete bed on the log does.
- Type a new Thickness.
OK then restacks the column up from its base. A log picked on an outcrop keeps its beds where they were picked. Its thicknesses are greyed out, and the table cannot add or delete its beds.
Pasting beds
Paste Beds, or Ctrl+V with a row selected, takes beds from the clipboard: rows copied from a spreadsheet, or a notebook typed up, one bed a line with the fields separated by tabs (or commas when a line has no tab).
- The columns are the table's own, from Thickness on — Thickness, Facies, Name, Grain Size Base, Grain Size Top, Base Contact, Certainty, Bioturbation, Covered, Munsell, Lithologies, Structures, Fossils, Dip, Azimuth, Interval, Comment — so two columns, thickness and facies, are enough, and a copy of the table pastes back.
- A first line of column names (the table's headings, in any order and any case) says otherwise. A Bed column is passed over.
- On a straight column the rows go in as new beds above the selected row, in the order pasted — top first, as the table is. Hold Shift to paste a list that runs from the base up.
- On a log picked on an outcrop the rows fill the existing beds from the selected row down; their thicknesses are left as picked.
- A line with no thickness is skipped, and the messages panel says which.
Nothing changes on the log until OK.
Beds from field notes
Beds from Field Notes on a bed's or a log header's right-click menu turns notes you type, paste or dictate into the log's beds, using Athos. Write them as you would in a notebook, for example "0.4 m medium sst, trough x-bedded, erosive base; 1.2 m grey mudstone, laminated, plant debris common".
- On a straight vertical column, choose whether the notes are for the log's beds, from its base up, or for new beds on top of the log. On a log picked on an outcrop they always describe its beds.
- Type or paste the notes, and choose OK. Athos reads them in the background; the messages panel says so.
- The log's Bed Table opens with what Athos read, in TST, since a measured section's thicknesses are measured across the beds. Nothing has changed yet: check it, correct it, and choose OK to apply it as one step of undo, or Cancel to drop it.
Athos takes every facies, grain size, lithology, structure, fossil and contact from your project's lists. It does not invent a name: a word that fits none of them goes into the bed's comment, and the messages panel lists anything that could not be used, including parts of the notes Athos could not place on a bed. When the notes describe the log's own beds, a bed keeps whatever the notes do not mention, and the panel warns when the notes give a bed a thickness well off the log's, which usually means the notes and the log are out of step. New beds need a thickness each.
Athos must be connected; it uses the provider chosen in the Athos panel.
Recently used names first
A project's lists can run to hundreds of names: every fossil, every sedimentary structure, every pattern tile. Each list keeps the names you used most recently, for the session, and puts them first:
- The right-click menus on the lithology, structures, fossils, grain-size and base-contact tracks, and on a generic class track, start with the names you chose last, then a separator, then the whole list in its own order. The facies menu starts with the facies on the number keys instead.
- The Pattern Fill list on a facies' properties starts with the tiles chosen most recently on any facies.
- The Log Palette puts them first in each section, marked with a dot.
They are saved with the project (in ProjectPrefs.json, with which palette
sections you have folded away), so a section logged over several days starts
each day where it left off. A new project starts with none.
Annotations
An annotation is a symbol or a short note put at a height on any track, where you saw it: a structure, a fossil, covered, sample 12.
- Turn on Annotate on the 2D Log tab, or press A.
- Click a track at the height you want. A menu offers the symbols you used last, Note... for a line of text, and the project's Sedimentary Structures, Palaeontology and Lithology entries that have symbols.
- The annotation is placed where you clicked.
In Annotate mode, drag an annotation to move it along its track, hold Ctrl while you drag to put a copy where you drop it, and press Delete to remove the one you picked. The picked symbol shows a box with a handle at each corner: drag a corner to make the symbol bigger or smaller.
Right-click an annotation in any mode for:
- Edit Annotation Text... (a symbol can carry a note too).
- Duplicate, which puts a copy just below it, ready to drag.
- Anchor > Top, Centre or Base, for a symbol.
- Reset Size, for a symbol you have resized.
- Delete Annotation.
Each change is a step of undo.
A symbol stays the same size on the page whatever the vertical scale, while the beds round it stretch and shrink. Its anchor is the edge of the symbol that sits at the height you clicked, so that edge stays on the contact at every scale: roots hang from the top of their bed, and flame structures stand on its base. A new symbol takes its anchor from its name: Top for roots and root traces, desiccation cracks, raindrop impressions, hardgrounds, firmgrounds and palaeosols; Base for flame structures, load casts, flute, groove, gutter and tool marks, and other sole marks; Centre for the rest. Use Anchor to change it. Annotations made before anchors existed stay centred, as they were drawn. The picked symbol shows its anchor as a tick on each side of its box, and resizing it keeps that edge where it is.
An annotation stays on its bed in every depth mode, and moves up with the beds when a bed is added below the base. It belongs to the kind of track it was put on, so it shows in any template that has that kind of track. It is saved with the log, printed with the panel and written to the SVG export.
Base contacts
The Grain Size track draws the base of each bed as the line of its base contact, so you can tell an erosive base from a sharp or a gradational one at a glance:
| Line | Drawn as | Default for |
|---|---|---|
| Straight | A plain line. | Sharp, and any contact not listed here. |
| Scalloped | Scours cut down into the bed below. | Erosive, erosional, scoured. |
| Wavy | A heavier wavy line right across the track. | Unconformity, disconformity. |
| Dashed | A dashed line. | Gradational, transitional. |
| Dotted | A dotted line. | Amalgamated. |
| Zigzag | A sawtooth line. | Irregular, undulating. |
| Loaded | A flat line sagging into load casts. | Loaded. |
The line is part of the bed's outline: an erosive base's fill reaches down into its scours, and the bed below gives up the part of its top that the base covers. A bed with no profile still shows a contact other than straight, across the track.
Each entry of the Base Contacts list picks its line under Line in the Properties panel. Its name chooses one until you do. Changing it redraws every open log, and the project saves the choice. A contact you add with New on the branch header draws straight until you pick its line. The SVG export draws the same lines as the screen.
On the Sedimentary Structures and Palaeontology tracks, each log gives a column to each entry its units hold, in the collection's order. A long collection does not narrow the columns.
To draw them as a hand-drawn log does, turn on Symbols in Beds in the grain-size track's Properties. Each bed's structures, then its fossils, are drawn as a row of symbols across the middle of the bed. Where the bed's profile is too narrow for them they go just beyond its widest point instead. A symbol is as tall as the bed allows, and a very thin bed shows none. The key then lists them too, and the SVG export and print draw them the same way.
A few tracks worth knowing:
- Comment shows each bed's comment, wrapped to the track and cut off at the bed's top.
- Bed Orientation draws a dip tadpole only for beds whose dip or azimuth has been set. A bed nobody measured shows nothing, rather than a flat bed dipping north.
- JSON Log curves (LAS or JSON) draw in TST as well as TVT and MT. Each reading is placed through the bed it falls in, as picks are.
- Sample Count counts the samples on the log, such as veins or fractures logged as sample points. It counts bed by bed, or in windows of its Count Window (metres) when that is set in the track's properties. The bars show the count per metre against the most in any bed or window, with the count beside each bar. The header gives that most, for example a P10 for fractures.
Grain-size profiles keep to the grain sizes of their anchors between them. A bed fining from coarse sand to clay no longer dips below clay on screen, in the SVG or in the 3D column.
What a bed records
As well as its facies, grain size and lists, each bed holds what a published log shows of it. Set these in the bed's Properties. Bioturbation, certainty and covered are also on the bed's right-click menu in the 2D log view, which sets every selected bed when the bed you clicked is one of them.
| Property | Values | How it is shown |
|---|---|---|
| Bioturbation Index | Not recorded, or 0 - Absent to 6 - Complete on Taylor and Goldring's scale (1 Sparse, 2 Low, 3 Moderate, 4 High, 5 Intense). | A bar on the Bioturbation track, scaled 0 to 6 across the track. |
| Covered | On or off. | A covered (not exposed) bed keeps its thickness but has no profile. The Grain Size track draws it as a crossed box a third of the track wide. Log statistics leave it out of the logged thickness and the facies shares and report its thickness separately. |
| Base Contact Certainty | Certain, Probable or Inferred. | A probable or inferred base has a ? at the right of the Grain Size track, and an inferred base is drawn in grey. |
| Munsell Colour | A Munsell notation such as 10YR 6/4, in any case: 10yr 6/4 is read as the same colour. | Written in the bed on the Munsell Colour track. |
| Fossil Abundance | For each fossil in the bed: Present, Rare, Common or Abundant. | A letter (r, c or a) beside the fossil's symbol, on the Palaeontology track and with Symbols in Beds. |
Carbonate beds: the profile scale
A bed's profile is logged on one of two scales, chosen bed by bed, so a mixed section can change scale as often as it changes rock:
- Siliciclastic (grain size) — the project's grain-size classes, as every bed has been until now.
- Carbonate (Dunham texture) — Mudstone, Wackestone, Packstone and Grainstone (Dunham 1962), Floatstone and Rudstone (Embry and Klovan 1971), then Boundstone and Crystalline.
Both draw on the one profile axis of the Grain Size track, as a mixed log has them: each texture takes a span of grain sizes (mudstone the clays and silts, wackestone very fine sand, packstone fine to medium sand, grainstone coarse and very coarse sand, floatstone and rudstone the gravels, boundstone cobbles, crystalline boulders). A carbonate bed between two sandstones therefore sits in line with them, and a profile keeps its shape when its scale changes.
- Right-click a bed on the grain-size track and choose a texture under Carbonate Texture to put the selected beds on the carbonate scale. Choosing a grain size puts them back on grain size.
- Profile Scale on the same menu switches the selected beds' scale but keeps their profiles: each end is renamed for the class it falls in on the new scale.
- A bed's Profile Scale is also on its Properties, which then offer textures for its Texture Base and Texture Top.
- In the Bed Table, a texture's name in the grain-size columns (Packstone) puts the bed on the carbonate scale, and a grain size's name puts it on grain size. The Quick Log and Athos take texture names too. Mudstone in the Quick Log is still the lithology; choose a carbonate mudstone from the menu.
When a log has carbonate beds, its grain-size track adds a second row under the grain-size names, with each texture's abbreviation (Mdst, Wkst, Pkst, Grst...) over its span, on screen and in the SVG and PDF.
Bioturbation and Munsell Colour are track types: add them to a template like any other track. When a displayed log has a covered bed, the key lists Covered (not exposed) under Base Contacts. The SVG export and the printout draw all of these as the screen does.
Samples on the log
Sample Point adds a sample where you click, in any depth mode, and links it to the bed there. On the samples track:
- Click a sample to select it. It turns red, and the sample point's own properties show in the property pane.
- Drag a sample with Sample Point active to move it along the log. It moves into the bed under the cursor, and its point in the 3D view follows, unless the sample is Placed in 3D (below). Clicking on an existing sample never adds another on top of it.
- Delete, or Delete Sample on the right-click menu, deletes the selected sample. Ctrl+Z brings it back.
A bed's properties list its samples from bottom to top, each with its Name and its height above the log's base (TVT from base). A new name typed there renames the sample point everywhere: in the tree, in the 3D view and on every log that links it. A sample renamed in the tree shows its new name on the log too.
Where a sample was taken need not be on the log's track. Once a sample has been placed or moved in the 3D view (Move Vertices, 3D Translate, or its X/Y/Z typed in), its Placed in 3D property is ticked, and moving it on the log changes only its place on the log, not its point in 3D. A sample added with Sample Point on the log starts unticked and follows the log's path. Untick Placed in 3D to let the log move the point again.
A sample point already in the project can be tied to a bed without placing another. Right-click a bed on the Grain Size or Samples track and choose it under Link Sample Points, which lists the project's samples shown in the view, the nearest to the click first. Unlink Sample Points, on a bed that holds any, undoes it.
Show Outcrop Points, on the same menu, draws a line across each track at the log's base and at the top of every bed, in TVT and MT, as a check of where the beds fall.