3171: Geologic Core Sample

2025-11-22T01:06:31Z

2600:1700:94A0:6BE0:ACA1:6215:6E6A:1924: /* Explanation */

{{comic
| number = 3171
| date = November 21, 2025
| title = Geologic Core Sample
| image = geologic_core_sample_2x.png
| imagesize = 493x789px
| noexpand = true
| titletext = If you drill at the right angle and time things perfectly, your core sample can include a section of a rival team's coring equipment.
}}

==Explanation==
{{incomplete|This page was created BY A RIVAL GEOLOGY TEAM. Don't remove this notice too soon.}}

This image presents a core sample taken by a slightly chaotic team of geologists.

A {{w|core sample}} is a cylindrical piece of something's core, in this case the rock of Earth's crust, obtained with special drills in order to see the layers within. In typical xkcd fashion, the core sample depicted here contains a mix of real rocks found in core samples alongside many humorous or fictional additives. In addition it's shown that the coring drills have hit many, many obstacles on the way down they really shouldn't have impacted, culminating in a punchline the geologists have drilled straight through the Earth to the opposite hemisphere, far deeper than any core sample could be taken in reality.

Contained within it are fairly normal ground matter such as "topsoil" and "granite" but also such things as "bottomsoil", which has no IRL parallel, parts of subway cars, arms of a spelunker most likely amputated by the sample, netherrack (a dark red stone appearing in the Nether in {{w|Minecraft}}), a "balrog" wing (referencing a fictional animal from {{w|Lord of the Rings}} which first made an appearance in xkcd in [[730: Circuit Diagram]]).

After a discontinuity in the diagram, that would cover whatever might appear having driven through the core of the earth, there is a reversal of the more 'standard' layers and then some equally nonstandard layers. These indicate that it has tunneled up into the home of someone else, starting with cement (the foundation), floorboards and carpet, then their posessions.

While still on the side that is heading down, it also mentions other rocks that are "basically granite". As in the idea that many rocks are similar, but are called "{{w|diorite}}" or "andalite". Diorite is a real rock, but an Andalite is an alien from the Animorphs book series, which Randall enjoys and has referenced before.

The title text humorously refers to a "rival team" and their coring equipment — implying that (with the correct angle) you can meddle with their own coring experiment. This is, outside of cold war-type pettiness, not considered a constructive approach to science.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}
[This shows a drill sample with various labels]

Topsoil

Till

Granite Bedrock

Bottomsoil

Roof of Subway Car

Floor of Subway Car

More Granite

Municipal water main

Slightly different granite

Piece of screaming spelunker's arm

Cool Crystals with no resale value

Mangled Fragments of drillbit from previous attempt

Some boring intrusive rock that's basically granite but has a name like "diorite" or "andalite" that you always have to look up

Netherrack

Balrog wing

Granite

Topsoil

Cement

Floorboards

Carpet

Possesions of a confused and angry homeowner in the other hemisphere

{{comic discussion}}<noinclude>
[[Category:Geology]]
[[Category:Charts]]
[[Category:LOTR]]
[[Category:Animorphs]]
[[Category:Minecraft]]

explain xkcd - User contributions [en]

3171: Geologic Core Sample