[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-649777-105":59,"doc-detail-649777-en":129},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":122,"head_meta":124,"extra_data":126,"updated_unix":128},105,"en","lab-4-introduction-to-cross-sections-fall-2005","Lab 4 - Introduction to cross sections - Fall 2005","","Lab 4 introduces cross-section construction in structural geology, explaining how subsurface geometry must be inferred from surface observations, maps, and well-log data. It discusses selecting a representative section line, plotting topographic profiles with or without vertical exaggeration, projecting contacts and dip data, and drawing faults, folds, and lithologic units while preserving thickness constraints. The lab also emphasizes interpretive reasonableness through balance, requiring admissibility and retrodeformability, and revisits balanced cross sections in later work.",{"@graph":69,"@context":121},[70,84,104],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":20,"@type":76,"position":81},"https://docshare.wps.com/document/exam/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/lab-4-introduction-to-cross-sections-fall-2005/649777/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":98,"encodingFormat":97,"isAccessibleForFree":99,"interactionStatistic":100},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/lab-4-introduction-to-cross-sections-fall-2005/649777.png","ImageObject",300,407,{"name":92,"@type":93},"Terk","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-24",true,{"@type":101,"interactionType":102,"userInteractionCount":4},"InteractionCounter",{"@type":103},"ViewAction",{"@type":105,"mainEntity":106},"FAQPage",[107,113,117],{"name":108,"@type":109,"acceptedAnswer":110},"Why are cross sections needed in structural geology?","Question",{"text":111,"@type":112},"Because only limited information is directly observable at the Earth’s surface (or in 1D well-log data), the subsurface shape must be inferred. Cross sections provide geologic interpretations along a chosen plane that are consistent with the available data.","Answer",{"name":114,"@type":109,"acceptedAnswer":115},"What factors should be considered when selecting the line for a cross section?",{"text":116,"@type":112},"The section should be representative of the studied area and cross major structural features such as faults or folds. 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Unfortunately, all that can be directly observed are rocks at the Earth’s surface or, in special cases, one dimensional information obtained from well logs. The shape of the structures below the surface and the projection of those features into the air (before they were eroded) must be inferred. Cross sections are 2 D educated guesses at the geology along a plane different from the surface of the earth. Although this plane is almost always vertical, there are instances where it is desirable to project geologic structure into a dipping plane. As is true of many problems in geology, there are numerous possible interpretations ofthe same data. The best we can hope to doin drawing a cross section is to come up with an interpretation that is consistent with all the available data.  \nThis lab is designed introduce you to the basic techniques of building cross sections. The last problem asks you to “balance” a cross section, and we will revisit balanced cross sections in the fold and thrust belt lab.  \nConstructing a Cross Section.  \n1. Determine the line along which you are going to draw the section. Although this is trivial when it is assigned to you, as a geologist, several considerations must go into selecting an appropriate section. Things to consider might include:  \na. The section should be representative of the area being studied, and should cross major structural features such as faults, fold, etc. A section through a structurally non complex area might be easy to draw, but it will not help anyone understand the area you are working on. However, drawing a section through the most complex area, where there is a lot of room for subjective interpretation, may not be the best approach either. It may be necessary to draw an easier section first, get a feeling for how structures are projecting to depth, and then move on to more complex areas.  \nb. There should be appropriate data on the map or in a well log to draw a complete section.  \nc. One of the most common ways to draw cross sections is to orient them perpendicular to major structural features. Sections drawn perpendicular to planar features avoid the problem of determining apparent dips.  \n2. Plot a topographic profile along the cross section. For a horizontal scale, it is easiest to use the map scale. The vertical scale is usually the same as the horizontal scale, in which case you say that the cross section has “no vertical exaggeration.” In some cases, however, you may want to exaggerate the vertical. This is useful for some applications, but has the handicap that angles on the map (such as topography, dip of beds, faults, etc.) are not preserved. If you are going to then use angular relations from the map, they will be exaggerated as well, although in a non linear fashion. A cross section without vertical exaggeration will allow you to determine structures at depth much more quickly and will present an accurately scaled representation of features at depth.  \n3. Mark contacts on the topographic profile where the particular feature crosses the line of the section. Project dip data onto the line of the cross section and then to the topographic profile. Projections can usually be made from several km distance, depending on the scale of heterogeneity of the structures. There is no good rule for how far dips may be projected, but as long as you feel that there is no good reason for a dip to change between its location and the line of cross section, it maybe projected. If the dip does not project perpendicularly into the line (if the strike is not perpendicular), you must determine the apparent dip of the feature. You can use the methods we developed in Lab 2 or you can use the handy chart provided with this lab.  \n4. Draw in structures (faults, folds) and the lithologic units on the cross section so that","cbCailBmHmMjVKwY","https://ap.wps.com/l/cbCailBmHmMjVKwY","pdf",222808,"English","# 1 Introduction\n##  Constructing a Cross Section\n##  1.1 Balanced cross sections","[{\"question\":\"Why are cross sections needed in structural geology?\",\"answer\":\"Because only limited information is directly observable at the Earth’s surface (or in 1D well-log data), the subsurface shape must be inferred. Cross sections provide geologic interpretations along a chosen plane that are consistent with the available data.\"},{\"question\":\"What factors should be considered when selecting the line for a cross section?\",\"answer\":\"The section should be representative of the studied area and cross major structural features such as faults or folds. It should also have appropriate map or well-log data to draw a complete section, and it is often oriented perpendicular to major structural features to avoid apparent-dip problems.\"},{\"question\":\"What makes a balanced cross section acceptable?\",\"answer\":\"A balanced cross section must be admissible (structures are reasonable for the geological setting) and retrodeformable (after removing shortening from faults and folds, layers restore to a reasonable predeformation configuration without significant gaps).\"}]","Lab 4 - Introduction to cross sections - Fall 2005 | PDF",23]