Tropidoceras Golden Pyrite Ammonite Fossil Jurassic Lyme Regis Dorset UK Lower Lias

Description

Authentic Tropidoceras Golden Pyrite Ammonite from the Jurassic Coast

Offered here is a genuine Tropidoceras golden pyrite ammonite fossil recovered from the Black Ven Marls at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, along England’s world-famous Jurassic Coast. This carefully chosen specimen displays striking pyrite preservation that highlights the ammonite’s natural form and ornamentation. The photographs show the exact fossil you will receive, allowing complete confidence in quality and appearance. Full sizing details are shown in the photos.

This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card, ensuring lasting confidence in provenance and collectability.

Provenance and Preparation

This specimen was discovered by our own team members, Alister and Alison, on 18 December 2025, during fieldwork at Stonebarrow Cliff. Following recovery, the ammonite was cleaned, prepared, and stabilised by Alison, ensuring the pyritised surface is clearly visible while preserving the fossil’s natural integrity. Direct team-collected provenance provides a strong, traceable history that is highly valued by collectors and institutions.

Geological Formation and Age

The fossil originates from the Lower Lias Group, deposited during the Early Jurassic Period, approximately 199–191 million years ago, within the Sinemurian Stage. The Black Ven Marls consist of fine-grained marine mudstones and marls laid down in a shallow epicontinental sea that covered much of southern Britain. Stonebarrow Cliff is a classic Lower Jurassic locality, internationally known for producing ammonites preserved in exceptional detail, including rare and visually impressive pyritised examples.

Fossil Species and Scientific Context

Tropidoceras is a distinctive Early Jurassic ammonite genus belonging to the Order Ammonitida, Superfamily Eoderoceratoidea, and Family Eoderoceratidae. Tropidoceras is recognised for its importance in Lower Lias biostratigraphy and is associated with specific ammonite biozones used to correlate Early Jurassic marine sediments. Specimens from the Jurassic Coast are well-documented in scientific literature and are prized by collectors for their clear diagnostic features.

Morphology and Pyrite Preservation

This Tropidoceras ammonite displays characteristic planispiral coiling with a pronounced keeled venter and strong, well-defined ribbing across the flanks. These ribs often terminate at the keel, giving the genus its distinctive angular appearance. The fossil has undergone pyrite replacement, where iron sulphide minerals formed under low-oxygen conditions shortly after burial. This process preserves fine morphological detail while imparting a rich golden metallic lustre that dramatically enhances visual appeal.

Depositional Environment

During the Early Jurassic, the Stonebarrow and Charmouth area lay beneath a warm, shallow marine environment rich in cephalopods, fish, and marine reptiles. Periodic storm events and rapid sedimentation led to the burial of ammonite shells on the sea floor. Low-oxygen conditions within the sediments promoted pyrite formation, resulting in the exceptional golden preservation seen in this specimen. This ammonite represents a genuine snapshot of Early Jurassic marine life and sedimentary processes.

Collecting, Display, and Educational Value

This Tropidoceras golden pyrite ammonite fossil is ideal for serious fossil collectors, museums, educational institutions, or statement interior display. Its rare pyrite preservation, precise team-collected provenance, and classic British Jurassic origin make it both scientifically informative and visually striking. Pyritised ammonites from the Jurassic Coast are increasingly scarce and highly sought after. Each specimen we offer is individually selected, ensuring you receive an authentic and carefully curated piece of Early Jurassic marine history from one of the world’s most important fossil localities.