Post By: Lily Francis, Kaydence Monson, Helen Myers, and Oyinkansola Tunji-Ogunsanya

GPS coordinates: +44.046193714415445, -123.07375911454125

Location and general description: 

This feature is located on the ground level of Cascade Hall, towards the north side of the University of Oregon campus. Both figures show a piece of wood that has been petrified. This means it has undergone a change in mineral composition during a process known as fossilization. This feature, shown in Figures 1 and 2, was originally part of the Haase Collection and was donated to the University of Oregon in 2002. Our group was initially interested in this feature because we wanted to learn more about the factors that contribute to the preservation of this fossil and its mineral makeup.

Geological Observations: 

The petrified wood piece has a rougher exterior and a glossy finish on the top due to human intervention and polishing. The top face of the feature shown in Figure 1 is roughly 27 inches wide, as estimated by the pen included for scale, and is characterized by its differing colors. The differing colors are a result of the feature’s mineral composition. The red, brown, and yellow colors seen in Figure 1 are a result of the presence of iron. Copper and cobalt contribute to the green and blue colors, while manganese contributes to the pink. Over time the cavities of the log were filled by quartz, a mineral with high silica content. Ash, silt, and other debris from a volcanic eruption worked to fossilize the original piece of wood and caused it to be petrified. This feature is not in situ, meaning it isn’t in its natural site, because the fossil was moved from its original location to the University of Oregon campus.

Google Earth Location (Site 1)

 

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What are the Perfect Conditions to Ensure Wood becomes Petrified?

Contributed by: Lily Francis

Geological Question: This question, What are the Perfect Conditions to Ensure Wood becomes Petrified?, will help highlight the environments that wood is petrified in, the specific processes of petrification, and the ways that minerals interact with the cellular structure of wood. By researching this question and the processes in which petrification occurs, it would be interesting to harness these processes for ourselves (possibly for aesthetic or scientific purposes). Answering this question will also give context on how our feature formed and to which standard of “perfection” it is held.

Description of Article: My chosen article, Mustoe (2017), describes to processes of petrification, permineralization and replacement. With the described processes and environments in this article, I may be able to apply this to finding the perfect conditions for petrification. Permineralization describes the filling of sediments into the spaces in between the cells of the wood, while replacement describes minerals slowly replacing the tissue of the wood (Mustoe, 2017). These two processes are used in unison with each other to petrify the wood, with varying rates of each leading to differing results (Mustoe, 2017). Bog and hot spring environments for petrification are discussed, with bogs being an incredibly good environment and hot springs being very quick but destructive for preservation (Mustoe, 2017).

Intersection Between Peer-Research and Observations on Campus: The plaque accompanying our petrified log feature gives some information on how it was formed. During the Triassic period, the log was washed down stream and then covered up by mud and volcanic ash. This can be compared to the petrification processes described in the article. The conditions needed for good petrification is warmth with a neutral pH and a high permineralization rate, just like in a bog (Mustoe, 2017). Conditions for a quick but terrible petrification, have very high temperatures, either very high or very low pH (which will destroy cell tissue too quickly to be replaces accurately), and a quick permineralization rate, like in a hot spring (Mustoe, 2017). As shown in Figures 1 and 2, this feature has survived 220 my and is in good condition with many bright colors (shown in figure 1) and only a few cracks (shown in figure 2). Due to our feature’s well-preserved nature, the mixture of volcanic ash and mud preservation might have similar conditions to that found in bogs, like having a neutral pH and providing warm insulation. The permineralization rate cannot be observed by the naked eye, but again due to our features very good preservation, one could assume that the permineralization rate was high.

An Answer to the Question?: This article gave examples of good and bad petrification, as well as the cellular structure of petrified wood. It did not explicitly state the exact conditions needed to perfectly petrify wood, but it did state some conditions needed. Petrification requires a permeable wood that is in a environment of high temperature, neutral pH, and high permineralization rate. This article was also able to give more insight into the petrification of our feature. A microscope could investigate our feature further, by examining if there is more mineral content surrounding the plant cell (showing permineralization) or inside the actual cell (showing replacement).

What I learned and Future Questions: I learned that petrification using permineralization is practiced for industrial and commercial purposes. This makes me wonder what use petrified wood has in the industrial and commercial sector, unrelated to collection or research purposes.

Sources Cited:

Mustoe, G. E. (2017). Wood Petrifaction: A New View of Permineralization and Replacement. Geosciences, 7(4), 119. https://doi.org/10.3390/geosciences7040119

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Which tree species are most commonly represented in petrified wood formations, and what factors influence their preservation?

Contributed by: Oyinkansola Tunji-Ogunsanya

Geological Question:

Petrified wood is a fascinating geological phenomenon that offers a glimpse into the Earth’s ancient forests. The process of permineralization ( a fossilization process where minerals fill the pores and spaces within organic material, such as wood or bone, preserving its structure over time) preserves cellular details of trees, transforming organic material into stone over millions of years. Understanding which tree species are commonly represented in petrified wood formations can help us reconstruct pre-historic ecosystems and climate conditions. It’s incredible to think about how a living tree once swaying in the wind can become a fossilized record, frozen in time.

 Which tree species are most commonly represented in petrified wood formations, and what factors influence their preservation? This question is particularly intriguing because it combines aspects of paleobotany, geochemistry, and geology. I’m excited to explore how specific environmental conditions and biological characteristics contribute to the preservation of different species in petrified wood.

Description of scientific article:

To answer my question, I chose to read an article by Moore and Wallace (2000) that investigates petrified wood from the Miocene (a geological epoch that occurred about 23 to 5 million years ago) volcanic sequence on the Coromandel Peninsula in New Zealand. This article focuses on identifying the tree species found in these formations and exploring the geological and environmental conditions that led to their preservation. I believe this article will help me answer my question because it examines how factors like volcanic activity and burial environments contribute to fossilization, shedding light on the processes that influence the types of trees commonly preserved as petrified wood. Moore and Wallace (2000) detail how specific mineralization conditions, such as silica deposition from volcanic fluids, play a critical role in preserving wood tissue, providing a clear connection to my inquiry about the preservation of prehistoric plant life.

Intersection between peer-reviewed research and observations on campus:

The petrified wood feature at the University of Oregon and the petrified wood described in Moore and Wallace’s (2000) research share several geological similarities that provide insight into their formation and preservation. Both examples demonstrate the process of permineralization, where mineral-rich fluids infiltrate the cellular structure of organic wood, depositing minerals like silica that replace the original organic material over time.

The volcanic context described in the Moore and Wallace (2000) study highlights the role of volcanic ash and silica-rich groundwater in fossilizing the Miocene wood of New Zealand. Similarly, the UO campus fossil feature likely underwent a comparable process, where volcanic activity deposited ash and minerals that catalyzed the permineralization process.

Additionally, both the Coromandel wood and the UO campus feature show color variations caused by mineral impurities. For example, Moore and Wallace (2000) note that iron, manganese, and other trace elements contribute to colorations in the petrified wood they studied. These same minerals are responsible for the red, yellow, green, and pink hues observed in the campus feature, linking its appearance to the geochemical processes outlined in the article.

However, while the UO campus feature has been relocated to its current site at Cascade Hall, the Coromandel wood described in the article remains in situ (in its original location). This distinction provides valuable context for interpreting the environmental history of each sample and the geological processes that contributed to their preservation. Despite the UO feature’s relocation, its mineralogical composition and preservation offer a comparable snapshot of ancient geological activity.

An answer to the question? Does the science article you chose help you answer your initial science question? Yes or No or Partially? Why or why not?

Yes, the article by Moore and Wallace (2000) significantly helps answer the initial science question about the tree species commonly represented in petrified wood formations and the factors influencing their preservation. The article highlights that Miocene petrified wood formations include diverse species such as Nothofagus (southern beeches), members of the Casuarinaceae family (she-oaks), and conifers like Agathis (a type of kauri tree) and Podocarpaceae (a family of southern hemisphere conifers).

The preservation of these species is influenced by specific geological conditions, such as volcanic ash deposits (layers of fine material from eruptions), silica-rich groundwater (water containing high amounts of silicon dioxide), and rapid burial, which prevents decay and promotes fossilization. This process involves mineral replacement, where the original organic material of the wood is gradually replaced with minerals like quartz while retaining its structure. I hypothesized that the geological processes preserving petrified wood are more significant than the specific tree species typically found in petrified wood formations.

These findings directly address both parts of the question, providing concrete examples of tree species and explaining the preservation mechanisms. However, because the study focuses on a specific Miocene formation in New Zealand, further research from other regions would be needed to generalize these conclusions globally.

What I learned and future questions:

From the article by Moore and Wallace (2000), I learned that the mineralization process of petrified wood often preserves fine anatomical details of the original wood, such as growth rings (annual rings formed by the tree’s growth) and cellular structures. This preservation allows scientists to gain insights into the paleoclimate (the climate of a particular period in the geological past) and paleoecology (the study of ecosystems and interactions of organisms in ancient times) of the time when the tree lived. For example, changes in the width of the growth rings can indicate seasonal changes (differences between dry and wet seasons) or environmental stresses, such as periods of drought or volcanic eruptions, in the Miocene environment (a geological epoch that occurred about 23 to 5 million years ago).

This discovery led me to a new question: How can detailed analysis of preserved growth rings in petrified wood be used to reconstruct specific environmental events, such as volcanic eruptions or droughts, in the geological past? I wonder if this data from petrified wood could be used alongside other paleoclimate proxies (indicators like ice cores or sediment layers that help reconstruct past climates) to create a more complete picture of Earth’s historical climate.

Source Cited

Moore, P. R., & Wallace, R. (2000). Petrified wood from the Miocene volcanic sequence of Coromandel Peninsula, northern New Zealand. Journal of the Royal Society of New Zealand, 30(2), 115–130. https://doi.org/10.1080/03014223.2000.9517612

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How do trees become preserved in pyroclastic flows?

Contributed by: Helen Myers

Geological Question: 

To be honest, before this project, I didn’t know exactly what petrification was. I remember finding a piece of petrified wood on the beach when I was younger, and my dad was far more ecstatic about it than I was, as I didn’t understand the significance. As with most things, after doing research and informing myself on the matter, I find it far more interesting than before. I find it fascinating that through petrification, organic material can transform into something completely different from before. A lot of our information about the history of the earth comes from fossils that have stood the test of time, and petrification is a window into what the world was like when that tree was still living. These time capsules should not be taken for granted. After I looked more into petrification and silicification I wondered: How do trees become preserved in pyroclastic flows?

Description of scientific article: 

To help me answer this question, I turned to a paper by Ballhaus et al. (2012) who ran a study on the silicification of trees specifically in volcanic ash. To start, they explained that silicification is a type of petrification where silica invades the cellular tissues of organic material such as wood. Over thousands of years, silica (or SiO2) fills the pores of the wood and replaces the cells so that the material is almost 100% composed of silica (Ballhaus et al., 2012). These transformed pieces are useful because they still retain the same shape and cellular structure as before, which can inform scientists about the climates and ecology of the past. Pyroclastic flows are essentially just rapidly moving masses composed of volcanic material such as rocks, ash, and gas. When volcanos erupt, these flows can cover the surrounding environment. This creates the perfect conditions for silicification and entire forests can fight decomposition and be preserved over time (Ballhaus et al., 2012). Ballhaus et al. have simulated silicification to study the process in a controlled environment. I chose this article as it gave good insight into silicification and how it functions in the context of pyroclastic flows. Their specific study tested how long this petrification process takes, and they concluded that silicification is very efficient when it comes to preventing decomposition in wood.

Intersection between peer-reviewed research and observations on campus:

Our feature is directly connected to my geological question as well as the scientific paper from Ballhaus et al. (2012) as this specific piece of wood was preserved from a volcanic eruption. During the Late Triassic period, the tree fell and was gathered in a log jam in modern-day Arizona. A nearby volcano erupted and the wood was covered with ash, silt, and other debris from a pyroclastic flow, preserving the log and fighting decomposition. In roughly 5,000-10,000 years the tree underwent silicification and the tree became more rock-like and petrified. The rings of the tree are still visible after all these years, as seen in Figure 1. As mentioned before, this preservation can inform scientists about past conditions, even hundreds of millions of years ago. Tree rings can reflect the entire lifetime of a tree and tell whether there was a significantly high or low temperature for the season, and also reflects precipitation levels. Because of the content of pyroclastic flows, there was mineral impurities, which resulted in the various colors in the fossil. Ballhaus et al. (2012) replicated the conditions of pyroclastic flows to measure the efficiency of silicification in a lab. They used information from previous silicification experiments and tested how the different materials such as gas, ash, and silt influence tree preservation on a microscopic level.

An answer to the question?

My geological question was how do trees become preserved in pyroclastic flows? Ballhaus et al. (2012) were able to replication pyroclastic flow conditions in a lab to test the efficiency of silicification. This informed me that silicification is one way that trees can become fossilized in pyroclastic flows, providing one answer to my question. This article also described the specific processes which preserved our feature and allow us to still view this tree millions of years later. Learning the science behind this feature make me appreciate it, along with other petrified wood samples, even more. Humans use written language and artifacts to preserve our stories, while trees use fossilization and petrification.

What I learned and future questions: 

After reading the paper by Ballhaus et al. (2012), I also learned that water is one of the main elements which accelerates the decomposition of organic material such as wood. This makes it all the more fascinating that a tree caught in a water log jam was able to stand the test of time and be transported to the University of Oregon hundreds of millions of years later. After observing our feature and reading this paper, another question I have is if petrification is the only way that wood can become fossilized, or if there are other natural conditions that can lead to preservation?

Sources Cited: 

Ballhaus, C., Gee, C., & Greef, K. (2012, January 27). The silicification of trees in volcanic ash – an experimental study. Geochimica et Cosmochimica Acta. https://www.sciencedirect.com/science/article/pii/S0016703712000415 

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How does the composition of petrified wood inform us about climate change?

Contributed By: Kaydence Monson

Geological Question: Climate change isn’t something that just started recently– it has been shaping Earth’s environment for millions of years. There are many ways that modern-day scientists can investigate how exactly our climate has changed. One particularly interesting process is the analysis of petrified wood. This fossilization of wood allows us to look back in time to see how Earth has transformed. By understanding past climate changes, we can gain valuable insights into how our current climate might evolve and what impact that could have on the ecosystems around us. That’s why I find the question “How does the composition of petrified wood inform us about climate change?” so fascinating. 

Description of Scientific Article: To help me answer this question, I read an article by Elliot and Foster (2014) about how petrified wood has informed us about climate change and what implications it may have for the future. In this study, researchers collected over 1900 petrified wood samples from Jackson County, Oregon (a region in the southwestern part of the state) and measured the amount of argon in each of the samples to estimate their ages (Elliot and Foster, 2014). After estimating the ages of each of the samples, the researchers examined their growth rings to determine the climate conditions at the time the trees were growing, and to track changes in those conditions over time (Elliot and Foster, 2014). This analysis showed a shift in climate from a tropical to a cooler climate over the past 40 million years or so in southwestern Oregon (Elliot and Foster, 2014). This shift was reflected in the types of petrified wood found, with an increase in distinct growth rings in the petrified wood specimens the younger they got (Elliot and Foster, 2014). In terms of my research question, the findings from the study conducted by Elliot and Foster (2014) suggest that examining the growth rings of petrified wood can tell us about past climate shifts, which may help us understand current climate trends and better predict future environmental changes. 

Intersection between peer-reviewed research and observations on campus:

This article provides more information about how climate change can be assessed through analyzing petrified wood. This relates to the petrified wood shown in Figures 1 and 2 because, by using the information presented in the article by Elliot and Foster (2014) we could analyze the growth rings of this piece of wood, and learn more about the climate around the time this tree was grown. Since the petrified wood, shown in Figures 1 and 2, came from northeastern Arizona, we would be able to learn more about how the climate in that region of Arizona has changed over the years by comparing it to other pieces of petrified wood from the area. In doing so, we would also be able to compare how different regions of the United States differ in their ecological reactions to climate change, providing more information about future climate change implications.

An answer to the question? My initial question was: How does the composition of petrified wood inform us about climate change? After learning more about how growth rings in petrified wood reflect climate conditions at the time the tree was standing, and how we can use this information to draw conclusions about climate change, I would say that my peer-reviewed article did answer my question. Using the results from the study conducted by Elliot and Foster (2014), I believe that the composition of petrified wood can inform us about Earth’s climatic changes by allowing us analyze the growth rings. This enables us to look into the past, understand the climate conditions when the wood was originally formed, and compare samples from different time periods to track how the climate has changed. This comparison may be able to help us predict how climate change may continue in the future.

What I learned and future questions: I mainly learned about how growth rings of petrified wood can inform us about climate change, however, in addition to this, I also learned that some of the more tropical petrified wood samples that were analyzed were identified as Maureroxylon (a type of petrified wood and an extinct relative of the modern-day cashew tree), which were previously only known to be found in eastern Oregon, which made this the first discovery of Maureroxylon in southwestern Oregon (Elliot and Foster, 2014). Although I learned a lot from this article, I still wonder: What does this shift from a tropical to a cooler climate in southwestern Oregon indicate about future climate change in the region?

Sources cited: 

Elliot, W. S., Jr., & Foster, D. (2014). Petrified wood of southwestern Oregon: Implications for Cenozoic climate change. Palaeogeography, Palaeoclimatology, Palaeoecology, 42, 1-11. https://doi.org/10.1016/j.palaeo.2014.03.004