Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism

Abstract The earliest named stromatolite Cryptozoon Hall, 1884 (Late Cambrian, ca. 490 Ma, eastern New York State), was recently re-interpreted as an interlayered microbial mat and non-spiculate (keratosan) sponge deposit. This “classic stromatolite” is prominent in a fundamental debate concerning t...

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Main Authors: Fritz Neuweiler, Mathias Mueller, Benjamin F. Walter, Ed Landing, Aratz Beranoaguirre, Consuelo Sendino, Lisa Amati, Stephen Kershaw
Format: Article
Language:English
Published: Nature Portfolio 2024-12-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-024-83359-7
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author Fritz Neuweiler
Mathias Mueller
Benjamin F. Walter
Ed Landing
Aratz Beranoaguirre
Consuelo Sendino
Lisa Amati
Stephen Kershaw
author_facet Fritz Neuweiler
Mathias Mueller
Benjamin F. Walter
Ed Landing
Aratz Beranoaguirre
Consuelo Sendino
Lisa Amati
Stephen Kershaw
author_sort Fritz Neuweiler
collection DOAJ
description Abstract The earliest named stromatolite Cryptozoon Hall, 1884 (Late Cambrian, ca. 490 Ma, eastern New York State), was recently re-interpreted as an interlayered microbial mat and non-spiculate (keratosan) sponge deposit. This “classic stromatolite” is prominent in a fundamental debate concerning the significance or even existence of non-spiculate sponges in carbonate rocks from the Neoproterozoic (Tonian) onwards. Cryptozoon has three types of microbially-induced carbonate layers: clotted-pelletoidal micrite with microbial filaments, clotted-pelletoidal micrite with vesicular structure, and dense microcrystalline laminae. A fourth, stratiform to patchy fabric comprises suspect sponges. Using contextual fabric analysis, elemental mapping, cathodoluminescence, fluid inclusions, electron backscatter diffraction, U–Pb dating, and burial history, the sponge interpretation is denied. Neither a distinct sponge body outline nor a canal system is identifiable. Instead, the suspect fabric is secondary in origin, and best explained as a product of Carboniferous (Mississippian) deep burial alteration associated with basement reactivation. Key petrographic observations include heterogenous recrystallization via aggrading Ostwald ripening with interfingering reaction fronts typical for partially miscible fluids, a granoblastic calcite texture (incipient metamorphism), and subsequent hypidioblastic white mica (arguably Carboniferous/Permian, Alleghenian orogeny). Topotype Cryptozoon is a stromatolite altered to sub-greenschist metacarbonate. The published Tonian to Phanerozoic record of interpreted non-spiculate sponges requires reassessment.
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spelling doaj-art-4202e0b6c25e4fd38ec5d3b9c690bf312025-08-20T02:39:38ZengNature PortfolioScientific Reports2045-23222024-12-0114111310.1038/s41598-024-83359-7Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphismFritz Neuweiler0Mathias Mueller1Benjamin F. Walter2Ed Landing3Aratz Beranoaguirre4Consuelo Sendino5Lisa Amati6Stephen Kershaw7Département de Géologie et de Génie géologique, Université LavalInstitute of Geology, Mineralogy and Geophysics, Ruhr-University BochumKarlsruhe Institute for Technology (KIT)New York State MuseumKarlsruhe Institute for Technology (KIT)Collections Department, National Museum of Natural SciencesNew York State MuseumScience Group, Natural History MuseumAbstract The earliest named stromatolite Cryptozoon Hall, 1884 (Late Cambrian, ca. 490 Ma, eastern New York State), was recently re-interpreted as an interlayered microbial mat and non-spiculate (keratosan) sponge deposit. This “classic stromatolite” is prominent in a fundamental debate concerning the significance or even existence of non-spiculate sponges in carbonate rocks from the Neoproterozoic (Tonian) onwards. Cryptozoon has three types of microbially-induced carbonate layers: clotted-pelletoidal micrite with microbial filaments, clotted-pelletoidal micrite with vesicular structure, and dense microcrystalline laminae. A fourth, stratiform to patchy fabric comprises suspect sponges. Using contextual fabric analysis, elemental mapping, cathodoluminescence, fluid inclusions, electron backscatter diffraction, U–Pb dating, and burial history, the sponge interpretation is denied. Neither a distinct sponge body outline nor a canal system is identifiable. Instead, the suspect fabric is secondary in origin, and best explained as a product of Carboniferous (Mississippian) deep burial alteration associated with basement reactivation. Key petrographic observations include heterogenous recrystallization via aggrading Ostwald ripening with interfingering reaction fronts typical for partially miscible fluids, a granoblastic calcite texture (incipient metamorphism), and subsequent hypidioblastic white mica (arguably Carboniferous/Permian, Alleghenian orogeny). Topotype Cryptozoon is a stromatolite altered to sub-greenschist metacarbonate. The published Tonian to Phanerozoic record of interpreted non-spiculate sponges requires reassessment.https://doi.org/10.1038/s41598-024-83359-7CambrianSpongesAppalachian mountainsFluid inclusionsU–Pb datingReactive fluid flow
spellingShingle Fritz Neuweiler
Mathias Mueller
Benjamin F. Walter
Ed Landing
Aratz Beranoaguirre
Consuelo Sendino
Lisa Amati
Stephen Kershaw
Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism
Scientific Reports
Cambrian
Sponges
Appalachian mountains
Fluid inclusions
U–Pb dating
Reactive fluid flow
title Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism
title_full Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism
title_fullStr Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism
title_full_unstemmed Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism
title_short Spongy-looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism
title_sort spongy looking microfabrics in the earliest named stromatolite represent deep burial alteration and incipient metamorphism
topic Cambrian
Sponges
Appalachian mountains
Fluid inclusions
U–Pb dating
Reactive fluid flow
url https://doi.org/10.1038/s41598-024-83359-7
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