K–Pg Boundary Layer Sample

K–Pg Boundary Layer — Resin-Cast Sample Mixture (Display Card)

Accession Number: 2025-KPG-RES-01
Object Type: Geological reference specimen (resin-cast boundary layer sample)
Date: ~66 million years ago
Origin: K–Pg Boundary layer, Montana, United States
Material: Resin-cast mixture containing representative boundary sediments and iridium-rich material
Dimensions: Small composite sample; varies by specimen
Provenance: Resin-cast representation of material from the K–Pg Boundary layer; prepared for educational and curatorial reference
Acquisition: Mini Museum
Collection Status: Permanent Collection

What This Artifact Represents

The K–Pg Boundary marks one of the most consequential moments in the history of life on Earth. Approximately 66 million years ago, a sudden global event brought the Cretaceous Period to an abrupt end — extinguishing nearly three-quarters of all species, including every non-avian dinosaur.

This thin geological layer, found worldwide, represents a literal line in Earth’s history: the boundary between worlds. Below it lies the age of dinosaurs; above it, a planet reshaped by catastrophe and recovery, eventually giving rise to mammals, birds, and modern ecosystems.

The discovery of anomalously high concentrations of iridium — a rare element on Earth but common in asteroids — provided the first compelling evidence that a massive extraterrestrial impact was responsible. That hypothesis, proposed by Luis and Walter Alvarez in 1980, transformed our understanding of mass extinction and planetary vulnerability.

This artifact represents that moment of transition — not as a single fossil, but as a global signature of sudden change.

About This Specific Piece

This specimen is a resin-cast sample mixture representing material from the K–Pg Boundary layer as documented in Montana, where the boundary sits between the Hell Creek Formation and the Fort Union Formation.

Because authentic boundary material is both rare and scientifically protected, resin-cast composites are used to convey the physical composition and visual character of the layer without disturbing critical geological sites. The sample reflects the fine-grained sediments, impact debris, and trace elements associated with the extinction event.

While not a single intact slice of boundary rock, this specimen faithfully represents the material reality of the extinction horizon — the narrow interval in which Earth’s biological trajectory changed forever.

Interpretive Note

Unlike fossils, which preserve life, the K–Pg Boundary preserves absence.

It is a layer defined not by what it contains, but by what disappears above it. In geological terms, it is remarkably thin. In evolutionary terms, it is immeasurable.

This sample reminds us that Earth’s history is not a steady ascent, but a series of ruptures and recoveries — moments when dominance gives way to opportunity, and when survival depends not on strength alone, but adaptability.

In this boundary layer, the age of dinosaurs ends — and the long path toward the modern world begins.