Cretaceous Scleractinian Coral with a Calcitic Skeleton

• Published in: Science (American Association for the Advancement of Science) Vol. 318; no. 5847; pp. 92 - 94
• Main Authors: Stolarski, Jarosław, Meibom, Anders, Przeniosło, Radosław, Mazur, Maciej
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 05-10-2007; The American Association for the Advancement of Science
• Subjects: Animals; Anthozoa - anatomy & histology; Anthozoa - chemistry; Aragonite; Calcification, Physiologic; Calcite; Calcium; Calcium Carbonate; Carbon; Chemical composition; Coelosmilia; Coral reefs; Corals; Crystallization; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fossils; Geologic Sediments; Invertebrate paleontology; Marine; Mass extinction events; Mineralogy; Paleontology; Polymorphism; Scleractinia; Sea water; Skeleton; Synchrotron radiation; Trace Elements - analysis; Mesozoic; Anthozoa; X-ray diffraction; SEM data; calcite; polymorphism; Scleractinia; chemical ratios; Coelenterata; calcium carbonate; Upper Cretaceous; synchrotron radiation; high resolution; diagenesis; scanning electron microscopy; corals; aragonite; Zoantharia; Cretaceous; ion probe data; carbonates; crystal structure; alteration; microstructures; calcification; powder diagrams; Invertebrata; Phanerozoic; invertebrates; chemical composition
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1149237

It has been generally thought that scleractinian corals form purely aragonitic skeletons. We show that a well-preserved fossil coral, Coelosmilia sp. from the Upper Cretaceous (about 70 million years ago), has preserved skeletal structural features identical to those observed in present-day scleractinians. However, the skeleton of Coelosmilia sp. is entirely calcitic. Its fine-scale structure and chemistry indicate that the calcite is primary and did not form from the diagenetic alteration of aragonite. This result implies that corals, like other groups of marine, calcium carbonate-producing organisms, can form skeletons of different carbonate polymorphs.