**Mundrabilla (meteorite)**
**Definition**
Mundrabilla is a large and scientifically significant iron meteorite found in Western Australia, notable for its size, composition, and contribution to meteoritics. It is classified as a medium octahedrite and is one of the largest meteorite finds in Australia.
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# Mundrabilla (meteorite)
## Introduction
The Mundrabilla meteorite is a prominent iron meteorite discovered in the Nullarbor Plain region of Western Australia. It is renowned for its considerable mass, distinctive composition, and the insights it provides into the early solar system. The meteorite belongs to the IAB complex group of iron meteorites and has been extensively studied for its mineralogy, isotopic composition, and structural features.
## Discovery and Location
The Mundrabilla meteorite was first identified in 1911 near the Mundrabilla homestead, located approximately 100 kilometers east of Eucla on the Nullarbor Plain. The region is characterized by its arid climate and flat limestone terrain, which has preserved many meteorite fragments over time. The initial discovery was made by a local prospector who noticed large metallic masses on the surface.
Subsequent expeditions and surveys in the area uncovered numerous fragments, with the total known weight of the meteorite exceeding 22 tonnes. The largest individual piece, known as the „Mundrabilla Mass,” weighs approximately 12.4 tonnes, making it one of the largest meteorite masses ever recovered.
## Classification and Composition
Mundrabilla is classified as an iron meteorite of the IAB complex, specifically a medium octahedrite. Iron meteorites are primarily composed of iron-nickel alloys, and the octahedrite structure refers to the crystalline pattern revealed when the meteorite is etched and polished.
### Chemical Composition
The meteorite consists predominantly of kamacite and taenite, two iron-nickel alloys. Kamacite contains about 5-7% nickel, while taenite has a higher nickel content, typically 20-50%. The Mundrabilla meteorite also contains trace amounts of other elements such as cobalt, phosphorus, and sulfur.
### Mineralogy
In addition to the iron-nickel alloys, Mundrabilla contains inclusions of silicate minerals, graphite, and troilite (iron sulfide). These inclusions provide valuable information about the conditions in the early solar system and the processes that led to the formation of iron meteorites.
## Physical Characteristics
The meteorite exhibits a distinctive Widmanstätten pattern, a unique intergrowth of kamacite and taenite crystals that form during slow cooling in the parent body’s core. This pattern is a hallmark of iron meteorites and is used to classify and study them.
The surface of Mundrabilla fragments often shows regmaglypts, or thumbprint-like indentations, formed during atmospheric entry. The meteorite’s density is approximately 7.8 g/cm³, consistent with other iron meteorites.
## Scientific Significance
Mundrabilla has been the subject of numerous scientific studies due to its size, composition, and well-preserved structure. It provides critical insights into the formation and differentiation of planetary bodies in the early solar system.
### Parent Body and Formation
The IAB complex meteorites, including Mundrabilla, are believed to originate from a partially differentiated parent body. Unlike fully differentiated iron meteorites, which come from the cores of large asteroids, IAB meteorites contain silicate inclusions and show evidence of complex thermal histories.
Studies of Mundrabilla’s isotopic ratios and mineralogy suggest that its parent body underwent partial melting and mixing of metal and silicate phases. This process likely occurred in the early solar system, around 4.5 billion years ago.
### Cosmogenic Studies
Analysis of cosmic ray exposure ages indicates that Mundrabilla was exposed to cosmic radiation for several million years before falling to Earth. This data helps reconstruct the meteorite’s journey through space and its collisional history.
## Recovery and Distribution
Since its discovery, many fragments of the Mundrabilla meteorite have been recovered, ranging from small chips to massive blocks. The largest pieces are held in museums and research institutions worldwide, including the Western Australian Museum.
Smaller fragments have been distributed to collectors and researchers, facilitating a broad range of studies. The meteorite’s size and accessibility have made it a valuable resource for meteoritic research.
## Cultural and Historical Context
The Mundrabilla meteorite holds a place of significance in Australian meteoritics. Its discovery contributed to the understanding of meteorite distribution in the Nullarbor region, an area now known for numerous meteorite finds.
The meteorite has also been a subject of public interest and education, featuring in exhibitions and scientific outreach programs. Its large mass and distinctive appearance make it an iconic specimen.
## Preservation and Conservation
Efforts have been made to preserve the Mundrabilla meteorite fragments, particularly the largest masses. Conservation techniques include controlled storage environments to prevent oxidation and corrosion.
Museums housing Mundrabilla specimens employ specialized display cases and environmental controls to maintain the meteorite’s condition for future study and public viewing.
## Conclusion
The Mundrabilla meteorite is a key specimen in the study of iron meteorites and planetary formation. Its large size, complex composition, and well-preserved structure provide valuable information about the early solar system and the processes that shaped planetary bodies. Ongoing research continues to uncover new insights from this remarkable meteorite.
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**Meta Description:**
Mundrabilla is a large iron meteorite found in Western Australia, notable for its size, composition, and scientific importance. It offers valuable insights into the early solar system and planetary formation.