International Geological Congress

Learn about the International Geological Congress and the rocks in the MGMH's collections from past congresses

By Mineralogical and Geological Museum, Harvard University

Diorite (2024-07-17) by Lucille EwingMineralogical and Geological Museum, Harvard University

What is the International Geological Congress?

The International Geological Congress (IGC) was formed by the community of geoscientists in North America and Europe who felt they needed a platform to share findings and create a framework for geological classification and nomenclature. The first IGC was held in 1878.

Mica Crystals (2024-07-17) by Lucille EwingMineralogical and Geological Museum, Harvard University

The International Geological Congress has met at 3-5 year intervals to discuss matters of geology and to encourage the advancement of research in Earth sciences. 36 meetings of the IGC have been held in 24 countries and attendance continues to grow each time.

Front Cover of Field Trip Guide. (1910) by A. E. TornebohmMineralogical and Geological Museum, Harvard University

Harvard at the IGC

Dr. John Eliot Wolff attended a few Geological Congresses during his time as a curator at the MGMH and the rocks he collected at these Congresses are now a part of the MGMH's collection. The MGMH houses many rocks from the 8th and 11th congresses specifically.

Map of excursions of the Eighth International Geologic Congress (1900) by AnonymousMineralogical and Geological Museum, Harvard University

8th International Geological Congress

The 8th International Geological Congress was held in 1900 and attended by Dr. John Eliot Wolff. It was hosted in Paris, France, with excursions to other areas around France to collect rock samples to study, mainly around the Pyrenees Mountains.

Amphibolite thin section (2024-07-19) by Lucille EwingMineralogical and Geological Museum, Harvard University

Amphibolite

This is a thin section of amphibolite from Etang de l'Estagnet near the Pyrenees Mountains collected during the 8th IGC. A thin section is a very thin slice of rock that geologists look at under a microscope to help determine the mineralogy of the rock.

Tuff Background Removed (2024-10-02) by Rachel GnieskiMineralogical and Geological Museum, Harvard University

Tuff

This tuff was collected in Puy-de-Dome, France. Tuff is made of volcanic ash that comes out of a vent during an eruption. After it is deposited, it lithifies into solid rock. Tuff is a very porous rock and is also quite soft.

Norite Background Removed, Rachel Gnieski, 2024-10-02, From the collection of: Mineralogical and Geological Museum, Harvard University

Norite thin section, Lucille Ewing, 2024-07-19, From the collection of: Mineralogical and Geological Museum, Harvard University

Show lessRead more

This is a rock of norite and its thin section, collected from the Ariege region of the Pyrenees mountains. Norite is a coarse-grained igneous rock.

Geologic Map of the Scandinavian Peninsula with excursion routes. (1910) by A. E. TornebohmMineralogical and Geological Museum, Harvard University

11th International Geological Congress

The 11th International Geological Congress was held in 1910 in Stockholm, Sweden. Excursions were taken to many other areas in Sweden and rocks were collected. This map shows the path of the Congress' excursions.

Gabbro-Granite Background Removed (2024-10-02) by Rachel GnieskiMineralogical and Geological Museum, Harvard University

Monzonite

This rock is a monzonite and was collected in Nordingra, Sweden. Monzonite is a coarse-grained rock that forms from slow-cooling magma in the Earth's crust.

Gneiss thin section (2024-07-24) by Lucille EwingMineralogical and Geological Museum, Harvard University

Gneiss

This is a thin section of gneiss from Malmberget, Sweden. Gneiss is a metamorphic rock which means it forms from high pressure or high temperature changing a preexisting rock. Mineral grains recrystallize under these conditions, forming a new kind of rock.

Soapstone with Background Removed, Rachel Gnieski, 2024-10-02, From the collection of: Mineralogical and Geological Museum, Harvard University

Soapstone thin section, Lucille Ewing, 2024-07-24, From the collection of: Mineralogical and Geological Museum, Harvard University

Show lessRead more

This is a soapstone rock and its thin section, collected from a quarry in Handol, Sweden. The rectangular cut in the bottom of the rock is where the thin section was cut from.

Credits: Story

Story by Lucille Ewing

Credits: All media

The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.

Mineralogical and Geological Museum, Harvard University

Stories from Mineralogical and Geological Museum, Harvard University

Online Exhibit