Raymond’s Geology Blog

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November 3, 2025

News and notes

Día de los Muertos, Day of the Dead
Credit: 5chw4r7z, Creative Commons Attribution-Share Alike 2.0 Generic license

Now that my computer is working again, can publish this week’s blog. From now on I will publish Monday afternoons rather than Sunday night/Monday morning.

This past week saw both Halloween and the Day of the Dead, so that makes it a perfect time to discuss the geology and mineral resources of Mexico, where the Day of the Dead is a national celebration. However, before going on to that, we will first look at some news items I thought were interesting. If you enjoy my blogs, bookmark the site, and check Monday afternoon rather than relying on social media postings which can get lost in the shuffle.

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November 3, 2025

Geology and Mineral Resources – Mexico

Introduction

Figure 1 – Mexico
Credit: CIA World Factbook, public domain

Mexico, officially called the Estados Unidos Mexicanos, is a country of 130,739,927 people that is the bridge between North America and Central America. Culturally, Mexico is the northernmost country in Latin America.

Mexico has an area of 1,964,375 square kilometres and borders on the United States, to the north and Guatemala and Belize, to the south. Also, to the west of Mexico is the Pacific Ocean, to the northeast is the Golfo de Mexico (a.k.a the Gulf of America), and to the southeast is the Caribbean Sea. Other significant oceanic seas are the Mar de Cortes (Gulf of California), and the Golfo de Tehuantepec in the Pacific, and the Bahia de Campeche in the Gulf of Mexico.

Mexico is a moderately prosperous country with a per capita GDP (PPP) of $25,463 and a high Human Development Index of 0.789.

For more details on the country, check out the CIA World Factbook on Mexico as well as the Wikipedia and Grokipedia articles on the country.

Geology

Figure 2 – Tectonic Framework of Mexico
Credit, extract: Eric Gaba ( Sting – fr:Sting), Creative Commons Attribution-Share Alike 2.5 Generic license

Tectonically, Mexico sits on the North American Plate. Significant boundaries with neighbouring plates include:

Figure 3 – Tectonic Map of Mexico
Credit: Padilla y Sánchez et al, AAPG Open File Series

The tectonic history of Mexico goes back to the Precambrian and continues to the present day Quaternary. This almost continuous tectonic activity assembled the mosaic of tectonic terranes that makes up modern day Mexico. These terranes reflect a complex interaction between Laurentia, Gondwana, and the ancient versions of the Pacific Plate that took place during the Paleozoic, Mesozoic, and present-day Cenozoic eras. To get an idea of the complexity of this tectonic history, study the Tectonic Map of Mexico shown in Figure 3 for an hour or so to give it the study it deserves.

Figure 4 – Six Volcanoes in Mexico, From left to right: Iztaccíhuatl, Popocatépetl,
Matlalcueitl, Nauhcampatépetl (most distant), Citlaltépetl, and Sierra Negra
Credit: David Tuggy, Creative Commons Attribution-Share Alike 2.5 Generic license

If you think that all this tectonic activity leads to widespread volcanism and earthquakes in Mexico, you’d be right. The six volcanoes in Figure 4 are part of the Trans-Mexican Volcanic Belt. Volcano Discovery lists 150 active volcanoes in Mexico. Earthquakes are a daily occurrence somewhere in Mexico, here is a link to the latest ones.

Figure 5 – Interactive Geologic Map of Mexico
Credit: Macrostrat, Creative Commons Attribution-Share Alike 4.0 International license

Figure 5, above, links to an interactive geologic map of Mexico, this is another map that can occupy a lot of your time if you want to study it.

Mineral Resources

Figure 6 - Native silver bisecting bornite, from the San Martín Mine, Zacatecas,
Credit: Robert M. Lavinsky, Creative Commons Attribution-Share Alike 3.0 Unported license

The USGS Minerals Yearbook on Mexico indicates that the country has a huge natural endowment of metallic minerals, energy minerals and industrial minerals. The USGS site The Diggings lists 2,012 records of mines in Mexico. Metallic minerals minerals mined in Mexico include: antimony, cadmium, cobalt, copper, gold, iron, lead, manganese, mercury, molybdenum, mine, silver, and zinc. Industrial minerals produced in Mexico include: barite, celestite, cement, various kinds of clay (bentonite, common clay, fullers earth, kaolin, diatomaceous earth), feldspar, fluorspar, graphite, gypsum & anhydrite, magnesite, mica, ammonia nitrogen, perlite, phosphate rock, salt, construction stone, sand & gravel, quartz & quartzite, sulfur, talc, vermiculite, and wollastonite. The latest production statistics can be found here.

Figure 7 – 8 Reales Coin of Carlos III
Credit: Heritage Auctions, Creative Commons Attribution-Share Alike 4.0 International license

Silver production from Mexico and Peru funded the Spanish empire in the 16th and 17th centuries. This silver mining, had a huge effect on Mexico and the whole world economy. Spanish silver dollars, the famous Pieces of Eight, became the world currency. In the end, the Spanish overextended themselves; no amount of silver could match their ambitions, and Spain slid into second-rate status. However, they still mine the silver to this day.

Figure 8 – Offshore Oil Platform near Ciudad del Carmen,
Credit: Chad Teer, Creative Commons Attribution 2.0 Generic license

Fuel mineral production in Mexico includes coal, natural gas and petroleum. There are approximately 48 coal mining centres in Mexico, most of which are located in Coahuila State.

For petroleum and natural gas, Mexico is the eleventh largest producer of oil in the world, the thirteenth largest in terms of net exports and has the seventeenth largest oil reserves in the world. Much of the oil production in Mexico comes from the Bahia de Campeche in the Gulf of Mexico. The latest statistics on production from the USGS can be found here. The USGS also recently released Assessment of undiscovered conventional oil and gas resources in Mexico, Belize, and Guatemala, 2024.

I worked in Mexico 1980-81 and part of my work was in oil fields in the Bahia de Campeche. The geology of the Campeche Bay includes Jurassic and Cretaceous aged carbonate rocks deposited in an oceanic rift basin formed during the breakup of the supercontinent Pangaea in the Late Triassic period. These carbonate rocks are generally fractured, probably a buried karst topography. Overlying these carbonate rocks are Paleogene and Neogene clastic deposits, mostly shales and mudstones. This situation is the perfect one for creating dangerous overpressures in the subsurface and the danger of lost circulation. In Campeche, these conditions lay behind the Ixtoc disaster of 1979.

Figure 9 - Chicxulub Impact Structure
Credit: NASA/JPL-Caltech, public domain

Another, related, feature of the geology of Campeche is the Chicxulub Impact Structure. The cause of this structure is an asteroid impact that occurred approximately 66 million years ago, an event that led to the K/Pg Extinction Event, an hypotheses first proposed by Luis and Walter Alvarez in 1980. An interesting connection between the oil resources and the Chicxulub Impact Structure is that the geology suggesting the presence of an impact structure had been uncovered during petroleum exploration activities, it wasn’t until Alvarez père et fils looked at the previously hidden drill core that the recognized that an impact had taken place. So, don’t throw out your rock collection. Here is a link to a recent paper on the Chicxulub crater.

Summary

Figure 10 – Quote Attributed to Porfirio Díaz, 33rd President of Mexico
Credit: AZ Quotes

That winds up this short look at Mexico. It is a beautiful place with great potential for future mineral development, especially in the offshore petroleum industry. The main problem they face is resolution of the ongoing conflict between the narcotics trafficking cartels and the government. The Jalisco Cartel New Generation (CJNG) is a typical example of these cartels. This resolution could be difficult, as in this story:

Standard Caveat

J. Robert Oppenheimer on freedom and scientific inquiry

The purpose of my weblog postings is to spark people's curiosity in geology. Don't entirely believe me until you've done your own research and checked the evidence. If I have sparked your curiosity in the subject of this posting, follow up with some of the links provided here. If you want to, go out into the field and examine some rocks on your own with the help of a good field guide. Follow the evidence and make up your own mind.

In science, the only authority is the evidence.