Raymond’s Geology Blog
May 11, 2026

Geology and Mineral Resources – Peru

Introduction

Figure 1 – Peru
Credit: Mapsland, Creative Commons Attribution-Share Alike 3.0 Licence

The Republic of Peru is a country of 32,440,172 people on the west coast of South America. The country has an area of 1,285,216 square kilometres and borders on: the Pacific Ocean, to the west; Ecuador, to the north; Columbia, to the northeast; Brazil, the east; Bolivia, to the southeast; and Chile, to the south.

Peru is a modestly prosperous country with a per capita GDP (PPP) of $20,116 and a high Human Development Index of 0.794.The country has a mixed economy made up of services, manufacturing, agriculture, and extractive industries such as mining. The top exports of Peru were copper ore, gold, grapes, precious metal ore, and refined copper. The top imports of Peru were refined petroleum, crude petroleum, cars, delivery trucks, and telephones. As of January 2026, Peru exported mostly to China, the United States, India, Canada, and Japan, and imported mostly from China, the United States, Brazil, Argentina, and Mexico.

Peru has an interesting, and tragic, history that is worth reading about to understand the country. For more details on Peru, check out the Wikipedia and Grokipedia articles on the country.

Geology

Figure 2 – Tectonic Background of Peru
Credit: Eric Gaba, Creative Commons Attribution-Share Alike 2.5 Generic license

Peru sits on the South American Plate. To the west, across a convergent boundary and subduction zone, is the Nazca Plate. The collision of the Nazca and South American plates has created the Andes Mountains through the current, ongoing, Andean Orogeny. Two smaller microplates are present: in the north is the North Andes Plate and in the south is the Altiplano Plate. Figure 3 links to an interactive geological map of Peru.

Figure 3 – Interactive Geological Map of Peru
Credit: Macrostrat, CC BY 4.0

The geology of Peru is fairly complex, reflecting a complex geological history, much of which has been volcanism and tectonism during the Cenozoic.

The youngest deposits in Peru are from the current Quaternary Period. These deposits include sedimentary terrace deposits, glacial deposits, and volcanic rocks. The USGS has compiled a Database and Map of Quaternary Faults and Folds in Peru and its Offshore Region.

Next older are rocks that date from the Neogene and Paleogene periods (a.k.a. Tertiary). These include Neogene and Paleogene aged volcanic and intrusive igneous rocks. Some of the Neogene volcanic rocks in Peru have been explored for lithium. Neogene and Paleogene aged sedimentary rocks include those of the continental margin, the Huallaga Basin of northern Peru, and the Pisco Basin.

Figure 4 - Vinicunca, Rainbow Mountain, Peru
Credit: Yifan Wang, Creative Commons Attribution 2.0 Generic license

Mesozoic aged deposits in Peru include Cretaceous and Jurassic aged sedimentary rocks, volcanic rocks and intrusive rocks. The volcanic and intrusive sequences include those associated with the now extinct Farallon Plate, coastal batholiths including the Ilo Batholith, and intrusive deposits from Central Peru. Mesozoic sedimentary deposits include those of the coastal basins, the Arequipa-Tarapacá Basin, and the famous Vinicunca Formation of Rainbow Mountain.

Late Paleozoic deposits include metamorphic rock and back arc deposits from the Carboniferous and Permian periods. Older still are sedimentary rocks dating from the Devonian, Silurian, and Ordovician periods.

The oldest rocks in Peru date from the Neoproterozoic and Paleoproterozoic eras. These include the Proterozoic basement rocks of the Arequipa Massif. These rocks reflect the tectonic evolution in western South America together with the history of Proterozoic terrane accumulation in South America including the development of Rodinia and the creation of Gondwana.

Paleontology

Peru has a wide variety of fossils; a catalogue of fossil finds can be found here. Here are a few examples.

Hoekaspis sp.

Figure 5 - Hoekaspis sp.Credit: Tiia Monto, Creative Commons Attribution-Share Alike 3.0 Unported license.

Hoekaspis sp. was a genus of trilobite from the family Asaphidae that lived during the Floian Age of the Ordovician Period approximately 478 to 471 million years ago (Mya). In Peru, fossils of Hoekaspis sp. are found in the San José Formation and were first described by Teiichi Kobayashiin1937.

Prolyelliceras perucianum

Figure 6 - Prolyelliceras perucianumCredit: Ryan Somma, Creative Commons Attribution-Share Alike 2.0 Generic license

Prolyelliceras perucianum was an ammonite that lived during the Albian Age of the Early Cretaceous. Also called Prolyelliceras prorsocurvatum, was a predatory cephalopod and have been found in the Chulec Formation near Cajamarca. A fossil Prolyelliceras perucianum was offered for sale here.

Cetaceans: Samaydelphis chacaltanae and Brachydelphis mazeasi

Figure 7 – Fossil Skulls of Samaydelphis chacaltanae (a, b),
Brachydelphis mazeasi (c) and an unknown species of Ziphiidae (d)
Credit: Figure 6 in Bosio et al, 2024

Excavations in the East Pisco Basin, published in 2024, have revealed many fossils from the Miocene Epoch, including the cetaceans (whales and dolphins) in the Tortonian aged Pisco Formation. Among the many fossils recovered are those of two beaked whales (Ziphiidae): Samaydelphis chacaltanaeandBrachydelphis mazeasi. BothSamaydelphisandBrachydelphiswere toothed whales of the Pontoporiidae family. Both were related to the only remaining Pontoporiid whale, the La Plata dolphin (Pontoporia blainvillei).

Acrophoca longirostris

Figure 8 - Acrophoca longirostrisCredit: Jonathan Chen, Creative Commons Attribution-Share Alike 4.0 International license

Another marine mammal from the Pisco Formation was the Archaic southern seal, Acrophoca longirostris. A member of the Monachinae family, Acrophocawas a marine predator. It was first found in 1981 by Leonard Dewaele and Christian de Muizon and more recently referenced in their 2025 publication.

Mineral Resources

Figure 9 - Intergrowth of quartz, sphalerite and pyrite from a hydrothermal deposit in Peru
Credit: UND Mineralogy Collection, Creative Commons CC0 1.0 Universal Public Domain Dedication

According to the USGS Minerals Yearbook for Peru, the country has a diverse minerals industry including metallic minerals, industrial minerals and fuel minerals. Also, according to the USGS, in 2019 Peru was the second largest world producer of copper, silver, and zinc; third for lead, fourth of tin and molybdenum; fifth for boron; and the eighth largest global producer of gold. The most recent statistics for mineral production in Peru from the USGS are here and more up to date statisitics from the Peruvian government can be found here.

Metallic Minerals

Metallic minerals mined in Peru include:

Industrial Minerals

A wide variety of industrial minerals are produced in Peru. For construction materials, cement is made at 16 plants in Peru. Bentonite, diatomaceous earth, gravel, gypsum, kaolin, sand, crushed stone, and dimension stone are also produced in Peru. Other industrial minerals mined in Peru include:

Mineral Fuels and Related Materials

Peru produces coal, natural gas, and petroleum. Ammonia fertilizers are also produced from natural gas in Peru.

The main coal mines in Peru include:

Figure 10 – Oil and gas Basins in Peru
Credit: Figure 2 in Chavez-Rodriguez et al, 2015

Figure 10 shows the locations of the major petroleum basins in Peru; these include: the Lima Basin; the Madre de Dios Basin; the Mollendo-Tarapaca Basin; the Pisco Basin; the Progreso Basin; the Putamayo-Orient-Maranon Basin; the Salaverry Basin; the Santiago Basin; the Sechura Basin; the Talara Basin; the Trujillo Basin; and the Ucayali Basin.

Summary

Figure 11 – Machu Picchu, Peru
Credit: Diego Delso, Creative Commons Attribution-Share Alike 4.0 International license

For geologists, Peru still has challenges and opportunities. New technologies, such as AI, are already being used to identify potential plays and Peru has an abundance of critical minerals. Just be careful if you go to work there, not all Peruvians are friendly.

There is a lot more that could be said about Peru. Historically, silver from Bolivia, Mexico and Peru made the Spanish Empire rich. The access to easy money then helped bankrupt them as their ambitions outran their finances. It makes for a sobering story of human suffering and wasted opportunities.

The story of New World silver and the Spanish Empire reminds me of what happens when an individual gets rich through a windfall, such as winning a lottery. In most cases they rarely change their lifestyle, and sometimes they simply go on a spending spree with their money and have little to show for it in the end. In the case of the Spanish Empire, their lifestyle involved conducting the interstate wars of the Early Modern Period. Silver and gold from the New World enabled them to simply buy whatever they needed for their wars. Spain consequently ignored and failed to develop the Spanish domestic economy; why bother when we have all this silver and gold from the colonies? Meanwhile, their rivals, England, France and Holland, did develop their domestic economies, in part because they had no easy money to pay for their part in the wars. In the end, logistics wins wars and no matter how brilliant the tactics of the Spanish Tercio, their opponents wore them down through the superior logistics of their better developed economies. That the whole business of taking gold and silver from the New World involved immense human suffering was not a consideration. It gives you something to think about.

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.