21 Banded Iron Formations: What Are They, and Why Should We Care? Johanna Wood, johannawood@cedarville.edu | Department of Science and Mathematics | Cedarville University | 251 N. Main St., Cedarville, OH 45314 USA Banded iron formations (BIFs) are anomalous iron-rich chemical sedimentary and metamorphic deposits that occur in Precambrian strata around the world. As a general standard, they should contain at least 15 wt% iron and display distinct micro-, macro-, and mesobanded textures. As they tend to lie at the bottom of most stratigraphic sequences, they often undergo extensive metamorphic overprinting processes, which makes determination of their original sedimentary signatures somewhat challenging. However, conventional geologists have established 3 primary types through REE studies, mineralogy, and field comparison: Algoma: Archean volcanogenic exhalatives, often sulfur-rich, have been traditionally interpreted as anoxic and deep marine, laterally extensive and voluminous Superior: Paleoproterozoic storm-reworked continental shelf and carbonate platform, less laterally extensive but often thicker, somewhat granular texture, primary proposed cyanobacteria fossil host Rapitan: Neoproterozoic redox-stratified glaciomarine deposits, often thinner, usually interbedded with diamictites, sometimes phosphorus-rich These progressive changes in depositional style have resulted in several deep-time models for BIF genesis. However, recent laboratory experiments are indicating that BIF mineral assemblages may be generated more rapidly than previously imagined through microbial input and potential secondary replacement of a preexisting carbonate protolith. This is exciting news for creationists. Furthermore, BIFs are often used to interpret former climates. If Biblically-based scientists evaluated these rocks more rigorously, they could gain new insights into what Precambrian depositional environments looked like. So far, creation authors such as Snelling (2009), Clarey (2020), and Dickens (2018) have offered numerous thoughts regarding a time frame for their genesis, classifying them as Creation Week rocks, initial Flood deposits, or a mixture of both. However, further geochemical and stratigraphic analysis is necessary to determine which depositional interpretations are plausible in each classification. Introduction Exposure of the Superior-type Paleoproterozoic Negaunnee BIF at Jasper Knob in Ishpeming, Michigan. Banded jaspilite, differential weathering patterns, and dramatic folds and faults were observed. BIFs in a Biblical Model Acknowledgements Why Should We Care about BIFs? Conclusion Early Life and Oxygen Implications. Conventionally, Precambrian oceans are believed to have hosted significant microbial colonies, which would have participated in carbonate, phosphorus, sulfur, and iron biogeochemical cycling. We see possible evidence of these colonies in BIFs through proposed fossilized cyanobacteria sheaths (such as Gunflintia), trichomes, and organic residues such as C13-depleted graphite. New interpretations for Precambrian glaciation events. Neoproterozoic Rapitan-type BIFs have often been tied to the Snowball Earth glaciations in the Cryogenian period, conventionally dated from about 640 – 720 Ma. Some criteria cited for this classification include dropstone inclusions, interbedding with interpreted diamictites, and trace element concentrations. However, data may more closely line up with a debris flow or turbidite depositional model, as has been Flood Boundary Signficance. In a traditional Biblical geology model, the North American lower Flood boundary has often been placed at the Neoproterozoic-Cambrian transition. However, it is possible that Precambrian BIFs indicate biological and chemical conditions associated with the Flood, in which case the Neoproterozoic-Cambrian boundary would need to be reevaluated. 78 BIFs were sampled for data collection purposes, and analysis revealed that potential organic indicators have been reported in all 3 types. These results appear to support a biotic role in BIF genesis. It is worth noting that some of these indicators, particularly certain types of microfossils, could be interpreted as abiotic. I would like to thank Dr. John Whitmore for his guidance throughout the course of this project. I would also like to thank Dr. Aaron Hutchison for providing relevant scholarly articles and Mr. Tom Rice for encouraging my passion for BIFs. 1). They could be Creation Week, or simply Pre-Flood, rocks. Day 3 of Creation Week would have been quite chaotic, and dramatic chemical conditions associated with the land rising up from the sea could have precipitated these rocks. If varying degrees of organic indicators among different BIF types can be rigorously confirmed, however, then it could be possible that both Creation Week and its continuing pre-Flood processes were responsible for depositing them. A Creation-Week interpretation appears to be the most consistent with a Proterozoic-Cambrian Flood boundary. 2). They could be Flood rocks. Field work in the Canadian Mackenzie Mountains has revealed that barium sulfate caps can cover BIFs. Barium sulfate is supposed to be more soluble than hematite, yet the barium sulfate layers occur stratigraphically above the BIFs. It is geochemical evidence like this that prompted creation authors Dickens and Hutchison (2021) to propose that those conventionally-interpreted glacial Rapitan-type BIFs in the Mackenzie Mountains actually formed rapidly as debris flows in Flood conditions. 3). They could be Creation Week and Flood rocks. There is a dramatic shift in depositional environment from the Archean to Paleoproterozoic, with Algoma-type greenstone and volcanic successions giving way to Superior-type reworked continental shelf and carbonate platforms. Conventional interpretations have cited greater microbial diversity and the subsequent Neoproterozoic 2.41 Ga Neoproterozoic Oxygenation Event as a trigger, but the Flood’s initiation may have flipped depositional conditions instead. Either way, BIF deposition appears to peak twice at conventional dates of around 2.6 and 1.89 Ga. These peaks could indicate both Creation Week activity and Flood initiation (Dickens 2018). Creationists have expended much effort in building Flood sedimentation and post-Flood climatic models, but detailed explanations of Precambrian processes in a Biblical model remain rather sparse. BIF is only one category of Precambrian chemical sediments that hold exciting implications for creationists, and much more technical work needs to be compiled before we can interpret their appropriate place in geologic history Such work might include chemical experiments to determine possible formation conditions, paleontological study to verify and categorize organic content, and consideration of REE diagrams to verify iron sources. References Aftabi, A., Atapour, H., Mohseni, S., and Babaki, A. 2021. Geochemical discrimination among different types of banded iron formations (BIFs): A comparative review. Ore Geology Review 136. https://doi.org/10.1016/j.oregeorev.2021.104244 Clarey, T. 2020. Carved in Stone: Geological Evidence of the Worldwide Flood. Dallas, Texas: Institute for Creation Research. Dickens, H. 2017. Banded iron formations formed rapidly. Journal of Creation 31, no. 2:14-16. Dickens, H. 2018. North American Precambrian geology–A proposed young earth biblical model. In Proceedings of the International Conference on Creationism, vol. 8, pp. 389-403. Pittsburgh, Pennsylvania: Creation Science Fellowship. 10.15385/jpicc.2018.8.1.34. Dickens, H., and Hutchison, A. 2021. Geochemical and related evidence for early Noah’s Flood year. Journal of Creation 35, no. 1:78-88. Smith, A.J.B. 2018. The Iron Formations of Southern Africa. In: Siegesmund, S., Basei, M., Oyhantçabal, P., Oriolo, S. (editors) Geology of Southwest Gondwana. Regional Geology Reviews. Springer, Cham. https://doi.org/10.1007/978-3-319-68920-3_17 Snelling, A. A. 2009. Earth’s Catastrophic Past: Geology, Creation, and the Flood, pp. 362, 637. Dallas, Texas: 2025 International Conference on Creationism New Scholar’s Conference Worldwide BIF Distribution. Taken from Aftabi et al. 2021. Abstract Wood, J. 2025. Banded Iron Formations: What are they, and why should we care? In J.H. Whitmore (editor), Proceedings of the 2025 New Scholars International Conference on Creationism, pp. 20-21. Cedarville, Ohio: Cedarville University International Conference on Creationism [poster presentation]. Proposed BIF depositional models. (a) and (d) describe different Superior-type depositional models. (c) describes a Rapitan-type depositional model. Adapted from Smith, A.J.B. 2018. 2025 New Scholars Wood, J. 2025. Banded Iron Formations: What are they, and why should we care? In J.H. Whitmore (editor), Proceedings of the 2025 New Scholars International Conference on Creationism, pp. 20-21. Cedarville, Ohio: Cedarville University International Conference on Creationism [poster presentation]. New Scholars 2025
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