https://docs-vrgeo-version3.netlify.app/assets/js/5e4ac23b.ca1d8c95.js

1"use strict";(globalThis.webpackChunkvrgs_docs_v_3_1=globalThis.webpackChunkvrgs_docs_v_3_1||[]).push([[724],{4302(e,t,n){n.r(t),n.d(t,{assets:()=>h,contentTitle:()=>o,default:()=>d,frontMatter:()=>a,metadata:()=>r,toc:()=>l});const r=JSON.parse('{"id":"general/fractures-structure/stratigraphy","title":"Stratigraphy & the Stratigraphic Column","description":"Give objects an age in VRGS \u2014 pick ICS units with the System / Series / Stage cascade, name your own group, formation and member, place stratigraphic markers, and read it all against the stratigraphic column overlay.","source":"@site/docs/general/fractures-structure/stratigraphy.md","sourceDirName":"general/fractures-structure","slug":"/general/fractures-structure/stratigraphy","permalink":"/docs/next/general/fractures-structure/stratigraphy","draft":false,"unlisted":false,"editUrl":"https://github.com/vrgeoscience/vrgs_docs_v3/tree/master/docs/general/fractures-structure/stratigraphy.md","tags":[],"version":"current","sidebarPosition":13,"frontMatter":{"id":"stratigraphy","title":"Stratigraphy & the Stratigraphic Column","sidebar_label":"Stratigraphy","description":"Give objects an age in VRGS \u2014 pick ICS units with the System / Series / Stage cascade, name your own group, formation and member, place stratigraphic markers, and read it all against the stratigraphic column overlay.","keywords":["stratigraphy","stratigraphic column","ICS","chronostratigraphy","lithostratigraphy","age","Ma","stratigraphic marker","system","series","stage","formation"],"sidebar_position":13},"sidebar":"docs","previous":{"title":"Slope Stability \u2014 Method","permalink":"/docs/next/general/fractures-structure/slope-stability-method"},"next":{"title":"Importing LAS Well Logs","permalink":"/docs/next/general/wells-seismic/las-well-log-import"}}');var s=n(74848),i=n(28453);const a={id:"stratigraphy",title:"Stratigraphy & the Stratigraphic Column",sidebar_label:"Stratigraphy",description:"Give objects an age in VRGS \u2014 pick ICS units with the System / Series / Stage cascade, name your own group, formation and member, place stratigraphic markers, and read it all against the stratigraphic column overlay.",keywords:["stratigraphy","stratigraphic column","ICS","chronostratigraphy","lithostratigraphy","age","Ma","stratigraphic marker","system","series","stage","formation"],sidebar_position:13},o=void 0,h={},l=[{value:"Giving an object a stratigraphy",id:"giving-an-object-a-stratigraphy",level:2},{value:"Chronostratigraphy \u2014 picked from the ICS chart",id:"chronostratigraphy--picked-from-the-ics-chart",level:3},{value:"Lithostratigraphy \u2014 your own naming",id:"lithostratigraphy--your-own-naming",level:3},{value:"Measured ages",id:"measured-ages",level:3},{value:"Two ends, for an object that spans an unconformity",id:"two-ends-for-an-object-that-spans-an-unconformity",level:3},{value:"Stratigraphic markers",id:"stratigraphic-markers",level:2},{value:"The stratigraphic column overlay",id:"the-stratigraphic-column-overlay",level:2},{value:"What it shows",id:"what-it-shows",level:3},{value:"Choosing the age window",id:"choosing-the-age-window",level:3},{value:"How the age is resolved",id:"how-the-age-is-resolved",level:2},{value:"Stratigraphy and Athos",id:"stratigraphy-and-athos",level:2},{value:"Tips and troubleshooting",id:"tips-and-troubleshooting",level:2},{value:"See also",id:"see-also",level:2}];function c(e){const t={a:"a",admonition:"admonition",code:"code",em:"em",h2:"h2",h3:"h3",li:"li",ol:"ol",p:"p",strong:"strong",table:"table",tbody:"tbody",td:"td",th:"th",thead:"thead",tr:"tr",ul:"ul",...(0,i.R)(),...e.components};return(0,s.jsxs)(s.Fragment,{children:[(0,s.jsxs)(t.p,{children:["VRGS can attach a ",(0,s.jsx)(t.strong,{children:"stratigraphy"})," to an object \u2014 an internationally recognised\nchronostratigraphic unit, your own group / formation / member naming, and\nmeasured ages where you have them \u2014 and draw a ",(0,s.jsx)(t.strong,{children:"stratigraphic column"})," beside\nthe 3D view showing where everything sits in geological time."]}),"\n",(0,s.jsx)(t.p,{children:"Two things carry a stratigraphy today:"}),"\n",(0,s.jsxs)(t.table,{children:[(0,s.jsx)(t.thead,{children:(0,s.jsxs)(t.tr,{children:[(0,s.jsx)(t.th,{}),(0,s.jsx)(t.th,{})]})}),(0,s.jsxs)(t.tbody,{children:[(0,s.jsxs)(t.tr,{children:[(0,s.jsx)(t.td,{children:(0,s.jsx)(t.strong,{children:"A triangulated mesh"})}

1),(0,s.jsxs)(t.td,{children:["What a whole outcrop ",(0,s.jsx)(t.em,{children:"is"}),"."]})]}),(0,s.jsxs)(t.tr,{children:[(0,s.jsx)(t.td,{children:(0,s.jsx)(t.strong,{children:"A stratigraphic marker"})}),(0,s.jsxs)(t.td,{children:["An age pinned to ",(0,s.jsx)(t.strong,{children:"one location"})," \u2014 a measured horizon, a dated sample, a picked contact."]})]})]})]}),"\n",(0,s.jsx)(t.h2,{id:"giving-an-object-a-stratigraphy",children:"Giving an object a stratigraphy"}),"\n",(0,s.jsxs)(t.p,{children:["Select the object and open the ",(0,s.jsx)(t.strong,{children:"Stratigraphy"})," group in its property sheet. It\noffers three independent descriptions, any of which you can leave blank."]}),"\n",(0,s.jsx)(t.h3,{id:"chronostratigraphy--picked-from-the-ics-chart",children:"Chronostratigraphy \u2014 picked from the ICS chart"}),"\n",(0,s.jsxs)(t.p,{children:["Chosen as a ",(0,s.jsx)(t.strong,{children:"cascade"}),": ",(0,s.jsx)(t.strong,{children:"System \u2192 Series \u2192 Stage"}),", each list filtered by the\none above. Choosing the Cretaceous drops the stage list from 102 entries to\ntwelve, which is what makes it usable \u2014 a flat chart dropdown is 171 units and\nnobody can find anything in it."]}),"\n",(0,s.jsxs)(t.table,{children:[(0,s.jsx)(t.thead,{children:(0,s.jsxs)(t.tr,{children:[(0,s.jsx)(t.th,{children:"Row"}),(0,s.jsx)(t.th,{children:"What it is"})]})}),(0,s.jsxs)(t.tbody,{children:[(0,s.jsxs)(t.tr,{children:[(0,s.jsx)(t.td,{children:(0,s.jsx)(t.strong,{children:"System"})}),(0,s.jsx)(t.td,{children:"Period / System. Narrows the two lists below it."})]}),(0,s.jsxs)(t.tr,{children:[(0,s.jsx)(t.td,{children:(0,s.jsx)(t.strong,{children:"Series"})}),(0,s.jsx)(t.td,{children:"Epoch / Series within the chosen System."})]}),(0,s.jsxs)(t.tr,{children:[(0,s.jsx)(t.td,{children:(0,s.jsx)(t.strong,{children:"Stage"})}),(0,s.jsx)(t.td,{children:"Age / Stage within the chosen Series (or System)."})]})]})]}),"\n",(0,s.jsxs)(t.p,{children:["You do not have to fill all three: ",(0,s.jsx)(t.strong,{children:"the most specific level you have chosen is\nthe one that counts"}),", so a System on its own is perfectly valid. Choosing a\nblank clears that level and everything below it."]}),"\n",(0,s.jsx)(t.admonition,{title:"The lists re-filter as you go",type:"note",children:(0,s.jsx)(t.p,{children:"Changing a level rebuilds the rows below it, so pick top-down. If you switch the\nSystem from Cretaceous to Jurassic, a stale Turonian in the Stage row is cleared\nrather than left sitting there meaning nothing."})}),"\n",(0,s.jsx)(t.h3,{id:"lithostratigraphy--your-own-naming",children:"Lithostratigraphy \u2014 your own naming"}),"\n",(0,s.jsxs)(t.p,{children:[(0,s.jsx)(t.strong,{children:"Group"}),", ",(0,s.jsx)(t.strong,{children:"Formation"})," and ",(0,s.jsx)(t.strong,{children:"Member"})," are free text: what ",(0,s.jsx)(t.em,{children:"you"})," call the rock.\nThey are deliberately ",(0,s.jsx)(t.strong,{children:"never"}),' matched against the ICS chart \u2014 "top unit 1" is a\nperfectly good formation name and means nothing to the chart. They are purely\ndescriptive and never move the column.']}),"\n",(0,s.jsx)(t.h3,{id:"measured-ages",children:"Measured ages"}),"\n",(0,s.jsxs)(t.p,{children:[(0,s.jsx)(t.strong,{children:"Age (Ma)"})," \u2014 millions of years before present \u2014 ",(0,s.jsx)(t.strong,{children:"refines"})," that end rather than\nreplacing it. So an object can say ",(0,s.jsx)(t.em,{children:'"Turonian, but I have dated the base at\n92.1 Ma"'})," and get a tighter interval than the stage alone would give."]}),"\n",(0,s.jsx)(t.h3,{id:"two-ends-for-an-object-that-spans-an-unconformity",children:"Two ends, for an object that spans an unconformity"}),"\n",(0,s.jsxs)(t.p,{children:["Meshes get ",(0,s.jsx)(t.strong,{children:"Top (younger)"})," and ",(0,s.jsx)(t.strong,{children:"Base (older)"})," groups, each carrying the full\nset \u2014 chronostratigraphy, lithostratigraphy and a measured age \u2014 because an\noutcrop spanning an unconformity really is different rock at the top than at the\nbase."]}),"\n",(0,s.jsxs)(t.p,{children:[(0,s.jsx)(t.strong,{children:"Leave the Base group blank"})," for anything sitting within a single unit."]}),"\n",(0,s.jsxs)(t.p,{children:["A read-back row at the bottom of the group shows the ",(0,s.jsx)(t.strong,{children:"resolved age range"})," \u2014\n",(0,s.jsx)(t.code,{children:"66 \u2013 100.5 Ma"})," \u2014 or says ",(0,s.jsx)(t.em,{children:'"no age (descriptive only)"'})," when only\nlithostratigraphy was given, or ",(0,s.jsx)(t.em,{children:'"not set"'}),". That row is how you catch a unit\nname the chart does not recognise, rather than only noticing later that the\ncolumn is quietly ignoring the object."]}),"\n",(0,s.jsx)(t.h2,{id:"stratigraphic-markers",children:"Stratigraphic markers"}),"\n",(0,s.jsxs)(t.p,{children:["A marker is a point in the model carrying an age. Place one from the\n",(0,s.jsx)(t.strong,{children:"Interpretations"})," tab's ",(0,s.jsx)(t.strong,{children:"Strat Marker"})," command: click the spot on the\noutcrop, then say what it is in its property sheet \u2014 the same way samples and\nwaypoints are placed."]}),"\n",(0,s.jsxs)(t.ul,{children:["\n",(0,s.jsxs)(t.li,{children:["A marker is a ",(0,s.jsx)(t.strong,{children:"single point in t

1ime"})," by default, so it gets one ",(0,s.jsx)(t.strong,{children:"Age"})," group\nrather than Top and Base. Mark it as spanning an unconformity to get both."]}),"\n",(0,s.jsxs)(t.li,{children:["The marker ",(0,s.jsx)(t.strong,{children:"captions itself with the most specific stratigraphy it carries"})," \u2014\nmember, else formation, else group, else the ICS unit \u2014 because that is what\nidentifies it on the outcrop. Its object name (",(0,s.jsx)(t.em,{children:"Strat Marker_3"}),") says nothing.\nA marker with no stratigraphy yet falls back to its name."]}),"\n",(0,s.jsxs)(t.li,{children:["Markers ",(0,s.jsx)(t.strong,{children:"take their colour from the official CGMW colour of the ICS unit"}),"\nthey carry, so a scene of markers reads as the same palette as the column\nbeside it."]}),"\n",(0,s.jsxs)(t.li,{children:["They are listed under ",(0,s.jsx)(t.strong,{children:"Stratigraphic Markers"})," in the Data tree, with the\nusual point-annotation group options: ",(0,s.jsx)(t.strong,{children:"Show Labels"}),", ",(0,s.jsx)(t.strong,{children:"Label Size"}),",\n",(0,s.jsx)(t.strong,{children:"Maintain Size"}),", ",(0,s.jsx)(t.strong,{children:"Display Size"})," and LOD."]}),"\n"]}),"\n",(0,s.jsx)(t.h2,{id:"the-stratigraphic-column-overlay",children:"The stratigraphic column overlay"}),"\n",(0,s.jsxs)(t.p,{children:["Switch it on from ",(0,s.jsx)(t.strong,{children:"Home \u2192 Options \u2192 Overlays \u2192 Strat Column"}),". It draws a\ncolumn of geological time down the side of the 3D view, with each unit in its\nofficial ",(0,s.jsx)(t.strong,{children:"CGMW"})," colour."]}),"\n",(0,s.jsxs)(t.p,{children:["The chart is generated from the ",(0,s.jsx)(t.strong,{children:"Macrostrat international timescale"})," (CC-BY\n4.0, ICS-derived): 171 units from Eon down to Stage, including all 102 stages."]}),"\n",(0,s.jsx)(t.h3,{id:"what-it-shows",children:"What it shows"}),"\n",(0,s.jsxs)(t.ul,{children:["\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"Bands"})," at the finest rank that is legible at the current size. Where stages\nfit, the column draws up to three strips \u2014 ",(0,s.jsx)(t.strong,{children:"Period | Epoch | Stage"})," \u2014 because\na bare Epoch beside a stage is not enough context."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"Markers for the objects in the scene"})," that carry a stratigraphy, at the ages\nthey resolve to."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"The picked object's own range."})," Click a mesh or a marker in the 3D view and\nthe column ",(0,s.jsx)(t.strong,{children:"brackets"})," where it sits, captioned with the object's name. A\nbracket rather than a filled band, because filling would hide the very bands\nthe selection is meant to be read against; a caret in the left margin keeps a\nselection only a pixel or two tall findable."]}),"\n"]}),"\n",(0,s.jsx)(t.h3,{id:"choosing-the-age-window",children:"Choosing the age window"}

1),"\n",(0,s.jsx)(t.p,{children:"Priority, highest first:"}),"\n",(0,s.jsxs)(t.ol,{children:["\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"Mouse-wheel zoom"})," over the column. It zooms the age axis ",(0,s.jsx)(t.strong,{children:"about the\ncursor"}),", so the age under the pointer stays put across notches. It is clamped\nto the chart at one end and to the shortest stage at the other, and slides\nrather than truncating at the ends."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"The project's age range"}),", if you set one. In the project property grid's\n",(0,s.jsx)(t.strong,{children:"Stratigraphy"})," group: tick ",(0,s.jsx)(t.strong,{children:"Set Age Range"})," and give ",(0,s.jsx)(t.strong,{children:"Top Age (Ma)"})," (the\n",(0,s.jsx)(t.em,{children:"younger"})," end) and ",(0,s.jsx)(t.strong,{children:"Base Age (Ma)"}),". A Book Cliffs project is Top 66, Base\n100.5. It is the opening view, ",(0,s.jsx)(t.strong,{children:"not a limit"})," \u2014 the wheel can still take you\noutside it."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"Worked out from the model"})," \u2014 the span of whatever stratigraphy the visible\nobjects carry."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"The whole chart"}),", when nothing else applies."]}),"\n"]}),"\n",(0,s.jsx)(t.admonition,{title:"Getting back to auto-ranging",type:"tip",children:(0,s.jsxs)(t.p,{children:["There is no reset button. ",(0,s.jsx)(t.strong,{children:"Switching the column off clears the wheel zoom"}),", so\nturning it off and on again returns it to the project range or to the model's own\nextent."]})}),"\n",(0,s.jsx)(t.admonition,{title:"Renderer differences",type:"note",children:(0,s.jsxs)(t.p,{children:["Wheel zoom over the column is ",(0,s.jsx)(t.strong,{children:"Vulkan only"}),". The OpenGL view still draws the\ncolumn and still honours the project age range."]})}),"\n",(0,s.jsx)(t.h2,{id:"how-the-age-is-resolved",children:"How the age is resolved"}),"\n",(0,s.jsx)(t.p,{children:"For each end of an assignment:"}),"\n",(0,s.jsxs)(t.ol,{children:["\n",(0,s.jsxs)(t.li,{children:["If a ",(0,s.jsx)(t.strong,{children:"measured age"})," was given, that is the age."]}),"\n",(0,s.jsxs)(t.li,{children:["Otherwise the ",(0,s.jsx)(t.strong,{children:"most specific chronostratigraphic level"})," filled in supplies\nthe boundary \u2014 its younger boundary for the top, its older boundary for the\nbase."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"Lithostratigraphy never contributes an age."})," An object described only by\nformation name has no age and does not appear on the column; the read-back row\nsays ",(0,s.jsx)(t.em,{children:'"no age (descriptive only)"'})," so you can see that is what happened."]}),"\n"]}),"\n",(0,s.jsx)(t.h2,{id:"stratigraphy-and-athos",children:"Stratigraphy and Athos"}),"\n",(0,s.jsxs)(t.p,{children:["An object's stratigraphy is appended to its description in the same tagged form\nthe rest of VRGS uses, so it reads as prose ",(0,s.jsx)(t.strong,{children:"and"})," is findable \u2014 a question like\n",(0,s.jsx)(t.em,{children:'"which surfaces are Turonian?"'})," has something to match. Any free text you have\nalready written in the object's ",(0,s.jsx)(t.strong,{children:"LLM Context"})," row is kept; the stratigraphy is\nadded to it, not substituted for it."]}),"\n",(0,s.jsx)(t.h2,{id:"tips-and-troubleshooting",children:"Tips and troubleshooting"}),"\n",(0,s.jsxs)(t.ul,{children:["\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"The object does not appear on the column."})," It has no resolvable age \u2014 check\nthe read-back row in its ",(0,s.jsx)(t.strong,{children:"Stratigraphy"})," group. Lithostratigraphy alone is\ndescriptive and carries no age."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"A unit name is not recognised."})," The read-back row says so. Names are matched\nagainst the shipped ICS chart; re-pick the unit from the cascade rather than\ntyping it."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"The Stage list is enormous."})," Pick a ",(0,s.jsx)(t.strong,{children:"System"})," first \u2014 that is what the\ncascade is for."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"The column shows a range I did not ask for."})," Something has priority over the\nproject range: you have wheel-zoomed. Switch the column off and on again."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.strong,{children:"A marker is grey."})," It has no ICS unit yet \u2014 markers take their colour from\nthe chart."]}),"\n"]}),"\n",(0,s.jsx)(t.h2,{id:"see-also",children:"See also"}),"\n",(0,s.jsxs)(t.ul,{children:["\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.a,{href:"/docs/next/general/setup-system/project-properties",children:"Project Properties"})," \u2014 where the project age range is set."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.a,{href:"/docs/next/general/viewing-collaboration/display-properties",children:"Display Properties"})," \u2014 the overlay toggles."]}),"\n",(0,s.jsxs)(t.li,{children:[(0,s.jsx)(t.a,{href:"/docs/next/general/fractures-structure/stereonet-user-guide",children:"Stereonet User Guide"})," \u2014 colouring orientations by stratigraphy."]}),"\n"]})]})}function d(e={}){const{wrapper:t}={...(0,i.R)(),...e.components};return t?(0,s.jsx)(t,{...e,children:(0,s.jsx)(c,{...e})}):c(e)}},28453(e,t,n){n.d(t,{R:()=>a,x:()=>o});var r=n(96540);const s={},i=r.createContext(s);function a(e){const t=r.useContext(i);return r.useMemo(function(){return"function"==typeof e?e(t):{...t,...e}},[t,e])}function o(e){let t;return t=e.disableParentContext?"function"==typeof e.components?e.components(s):e.components||s:a(e.components),r.createElement(i.Provider,{value:t},e.children)}}}]);