Anthraxolite Pyrobitumen Sudbury [44 Grams]

Anthraxolite: Rare Carbonaceous Pyrobitumen From Sudbury

Discover the unique allure of anthraxolite, also known as pyrobitumen. This rare carbonaceous material is found in select geological settings, with this specimen sourced from the Sudbury Impact Structure, Ontario, Canada. Its distinctive properties and significant geological history make anthraxolite a rare addition to any collection.

Origin and Specifications

Origin: Sudbury Impact Structure, Onwatin Formation, Balfour Township, Sudbury District, Ontario, Canada.

Specimen Size: 73mm X 72mm X 7mm, Weight: 44 grams

Included with Purchase

• Certificate of Authenticity
• Tag and tag stand
• Detailed information about anthraxolite
• Copy of related scientific paper

Note: Negligible radioactivity (uranium/thorium content <5)

Historical Significance

Anthraxolite

Named by Chapman in 1888 and Coleman in 1896 to describe anthracite-like material in Precambrian sedimentary rocks in northern Ontario.

Pyrobitumen

Defined by Hunt in 1979 as solid bitumen that is infusible and less than 2% soluble in carbon disulfide.

Geological Setting and Age

Since the end of the global glaciation period (~600 Ma), hydrocarbons from living organisms settled together with fine mineral mud. Becoming buried deeper over time and exposed to Earth’s upper mantle temperatures and high pressure, some hydrocarbons became petroleum. Being lighter than water, petroleum migrates more easily into cracks, slowly moving upward to accumulate in reservoirs.

In the rare case of anthraxolite, its already heavy petroleum became trapped in the veins created by the 1.85 Ga Sudbury Impact Event. Immobilized, and over time with modest temperatures caused the heavy petroleum to crack, release gases, and form the unique, brittle pitch known as anthraxolite.

Petrology

Anthraxolite from Sudbury appears as small globular blebs, ranging from 1 to 10 mm, with shapes varying from round to discoid, kidney to saddle, twisted or elongated. These blebs have shiny surfaces with vesicles and are predominantly composed of carbon with a hydrogen-to-carbon (H/C) ratio of 0.57.

The formation of anthraxolite is attributed to Precambrian petroleum's natural migration and maturation (>750 million years ago) through fissures and cracks, influenced by the Sudbury Impact. The tarry masses in the veins are organic. Over time, heavy petroleum components accumulated in the cracks and were altered to form pyrobitumen (anthraxolite). Due to its lack of crystalline structure, pyrobitumen is not the same as graphite or anthracite.

Visual Characteristics

Under magnification, the sample is dominated by anthraxolite blebs flattened into overlapping plates with typical conchoidal fracturing of brittle petroleum pitch. This suggests the specimen underwent metamorphic forces, such as shear movement. The plates are shiny with a purplish “ oil slick” sheen, and native sulfur and pyrite add distinctive yellow colors.

Unique for Geology Collections

Enhance your collection with this rare and scientifically significant anthraxolite specimen. It will likely be one of the most unusual specimens in your scientific collection!