John Muir, Alaska, and A Tree Mountain Chronology

June 12th, 2015

Guest Blogger: Audrey Steiner-Malumphy

In 2011, Dr. Wiles and his advisees Lauren Vargo and Jennifer Horton cored dozens of trees from Tree Mountain in Alaska’s Glacier Bay National Park and Preserve. Muir Glacier is located northwest of this mountain, named after the esteemed naturalist and preservationist John Muir.

John Muir in Sierra Nevada, courtesy of PBS.

John Muir in Sierra Nevada, photo courtesy of PBS.

Muir first traveled to the area in 1879 with a particular interest in Alaska’s glaciers. He returned many times, continually fine-tuning his preservationist vision while drawing from theistic and transcendentalist ideas to transform the public’s perception of wilderness. Muir’s published works recalling these expeditions sparked national interest in Alaska’s wilderness and its preservation, laying the foundation for environmental debates yet to come.

Map of Glacier Bay, edited by John Muir. Published in the book Alaska Days With John Muir.

Map of Glacier Bay, edited by John Muir. Published in the book Alaska Days With John Muir.

Though the Tlingit lived in the Glacier Bay region for centuries, and others explored the area before him, Muir was the first distinguished scientist to map it and record his observations.

map

Above is a present-day map of Glacier Bay, courtesy of Google Earth. Tree Mountain is marked in red on the southern border of Adams Inlet, which feeds into Muir Inlet. Muir Glacier lies at its base. Note the altered position and size of the glacier in comparison to Muir’s map.comparison

Photographs from the National Snow and Ice Data Center famously portray Muir Glacier’s retreat. Between 1941 (left) and 2004 (right), the tidewater glacier retreated more than seven miles, though it has been rapidly retreating since the end of the Little Ice Age in the mid 1800s.

Photograph of Muir Glacier from Alaska Days With John Muir.

Photograph of Muir Glacier from Alaska Days With John Muir.

Muir observed the rapid retreat of glaciers, expressing concern for Alaska’s changing climate and frustration with potential anthropogenic causes, specifically deforestation. In October of his 1879 expedition, he wrote in his journal, “That the climate is warmer is shown by the melting shrinking condition of the glaciers… where formerly much snow fell to thaw off gradually, incessant flood-rains fall, saturating the soil, causing it to decay and become slippery and wash off… It was not in this condition while the forests existed.”

Muir’s 1895 journal sketch of Muir Glacier from Tree Mountain.

Muir’s 1895 journal sketch of Muir Glacier from Tree Mountain.

To learn more about the climate in the Glacier Bay area when Muir recorded his observations, I measured the tree-ring widths of the Tree Mountain cores. Twenty of the Tree Mountain samples dated back to the mid 1800s or later, allowing me to compare tree-ring records with John Muir’s notes from his 19th century expeditions.

core

The growth patterns of tree-rings vary based on the species, age of the tree, and other environmental factors. However, tight growth patterns, representing little growth, are typically an indication of stress. Increased growth usually reflects temperature, precipitation, the availability of nutrients.

ring width

This figure above shows the standardized raw ring widths of the twenty cores from Tree Mountain. The growth trend has been removed. The blue line beneath the raw data represents the number of cores measured each year.

charttA 2014 study headed by Dr. Wiles provides a chronology and climate reconstruction for the entire Gulf of Alaska over the past 1200 years.

According to my Tree Mountain findings, John Muir’s 19th expeditions in Alaska occurred during a period of gradual warming, aligning with the chronology provided in Dr. Wiles’ study. However, the small Tree Mountain sample size poses difficulties in making significant comparisons, as well as the complexities of the numerous factors that influence both ring width and temperature, which are not accounted for in this post. Further comparisons of the paleoclimate record and the writings of John Muir in Glacier Bay continue..

Russian Birch Climate Reconstruction- Part 2

June 12th, 2015

Guest blogger- Clara Deck

This summer, I am working with Dan Misinay to continue a dendrochronology project focused on Kamchatka, Russia. We have been working with birch tree cores (Bertula ermanii) collected from the region by Dr. Wiles and I.S. student Sarah Frederick in the summer of 2014.

DSC_0015

Our goal is to use the cores to gather information about the climate. By counting, measuring and comparing different cores, Dan and I developed separate tree ring width chronologies from different areas in Kamchatka.

Kamchatka Peninsula GE

My samples are labeled NR in the northern part of the Kamchatka peninsula, while Dan’s are labeled UG. SANO represents birch cores in a study by Sano et al, 2009. The UG and SANO data correlates very well together, but the NR data is in a much different latitudinal location, and does not correlate. With the Sea of Okhotsk to the east, the Pacific Ocean to the West, and numerous mountain ranges and volcanoes, there are many climate factors that may influence the growth of these trees along the peninsula. The following work deals solely with my samples (NR).fulltabs

Shown here in green is the standardized data for the entire chronology (1823-2014). Trends in this graph may indicate climate signal and will be further analyzed this summer. The blue line represents the number of samples for each given year.

mintemp

I compared my tree ring data with meteorological data from a nearby weather station in Kljuci, Russia (also spelled Klyuchi). This graph shows the correlation of the tree rings with the minimum temperatures for each month. Months from the previous year are labeled t-1, while the present is year t. High positive correlations are shown during March through August of the present year, indicating that minimum temperatures in these months primarily influence the tree ring widths. Though this graph only shows correlations with minimum temperatures, I found the same trend with maximum and mean temperatures.

shiveluch

The map above shows a zoomed in region of northeast Kamchatka with spruce (Picea) and larch (Larix gmelinii) samples from a study called Constraining recent Shiveluch volcano eruptions (Kamchatka, Russia) by means of dendrochronology (Solomina, et al 2008). Shiveluch volcano is adjacent to the site where the birch tree samples were collected, and all of the samples shown could be affected by its volcanic activity. It is one of the most active volcanoes in Kamchatka, and a significant eruption was recorded in 1964 (Solomina, et al 2008). The tree ring record should show evidence of this eruption in the year 1965. The study indicated that although a slight decrease was shown in their cores, it was of negligible scale and does not provide clear evidence of the eruption. I am interested to see if my samples show evidence of the eruption, because of its different position relative to the volcano.

1965

Shown here is isolated data from 1950-1980 from the above shown chronology, and shows a drop off in ring width growth in 1965. This could be evidence of a volcanic eruption, but as you can see even in this small data set, variability like this is not uncommon. More work needs to be done to determine the significance of this decrease.

 

References:

Sano, M., Furuta, F., and Sweda, T., 2010, Summer temperature variations in southern Kamchatka as reconstructed from a 247-year tree-ring chronology of Betula ermanii: Journal of Forest Research, v. 15, p. 234–240, doi: 10.1007/s10310-010-0183-z.

Solomina, O., Pavlova, I., Curtis, A., Jacoby, G., Ponomareva, V., and Pevzner, M., 2008, Constraining recent Shiveluch volcano eruptions (Kamchatka, Russia) by means of dendrochronology: Natural Hazards Earth Systems Sciences, doi: 10.5194/nhess-8-1083-2008

Goodygoody Girdwood Chronology Construction

June 12th, 2015

 Guest bloggers: Kaitlin Starr and Maddie Happ
BLOG4

Forest surrounding Girdwood, Alaska. Living mountain hemlock trees were cored from this site (Wiles, 2014).

    During the summer of 2014, the Columbia Bay team (Dr.Wiles, Nick Wiesenberg, Kaitlin Starr and Jesse Wiles) cored numerous trees near the town of Girdwood, Alaska. The collection is primarily made up of cores taken from living Mountain Hemlock trees from the surrounding forest. In addition to the living forests a few cores were taken from subfossil wood at Turnagain Arm.
DSC_0064

Kaitlin Starr coring a living Western Hemlock found in the forests surrounding the town of Girdwood (Starr, 2014).

    The Girdwood living tree collection was brought back to the Wooster Tree Ring Lab where the cores were mounted, sanded, counted and measured. Students, Maddie Happ and Kaitlin Starr constructed a chronology out of 38 cores sampled. The chronology spans 342 years, beginning at 1672 and extending to 2014. When compared to the established Turnagain Pass chronology by Jacoby, G.C., D’Arrigo, R.D., Buckley, B., our new Girdwood chronology correlated well. In addition, our chronology extends the known database for the region by contributing an additional 85 years of data.
Blog2

Girdwood core sample illustrating both tight and normal growth patterns. Growth patterns may vary due to shifting climates. Tight growth often occurs during periods of distress, such as drought or storms.

    The graph below illustrates the standardized tree ring measurements by removing biological growth trends from   the series. Removing growth trends allows us to view the desired climate signal.
Blog4

Standardized Girdwood chronology note the upward trend in the series . The red line indicates the sample size.

The chronology was compared with meteorological data from the nearest station, Anchorage (International Airport) and correlations are plotted below. We found an unexpected high negative correlation between our chronology and the minimum temperature data, specifically throughout the summer months (June, July and August). The possible cause of this correlation is unknown at the moment.

Screen Shot 2015-06-12 at 11.21.19 AM

This graph illustrates the overall correlation between tree ring width and mean temperature and precipitation in Girdwood, Alaska for the dendroclimatic year.

Screen Shot 2015-06-12 at 11.21.43 AM

The above graph displays the overall minimum temperature compared to the tree ring widths for Girdwood, Alaska. A clear significant negative correlation exists for the months of May, June, July, and August.

 

 

Taking a break to see York

June 12th, 2015

1 Mae Meredith SW York MinsterSCARBOROUGH, ENGLAND (June 12, 2015) — Team Yorkshire went on a holiday today with a visit to York, only a short train ride inland from Scarborough. We needed a break, and in any case the tides were not in our favor at Meredith’s Independent Study field site. It was another extraordinarily warm, clear and dry day. (Unlike the cold, foggy and damp Scarborough we returned to in the evening.)

Above Meredith and Mae stand in front of the southwestern portion of the iconic York Minster.

2 Mae Meredith York StreetHere we are walking down a York street. The city felt very large and busy after our days in Scarborough.

3 River Ouse in York from Skeldergate Bridge 585The River Ouse in York from Skeldergate Bridge. This river divides the city and has been an important transportation and trade route for centuries.

4 Constantine 061215This statue of the Roman Emperor Constantine the Great is a monument to his accession to the office in 306 CE while in York, then known as Eboracum.

We spent time at the Viking archaeological center (Jorvik) and the York Castle Museum before taking the train back “home” to Scarborough. It was a great cultural excursion as we prepare for our last days of fieldwork.

Wooster’s Fossils of the Week: Chaetetids from the Upper Carboniferous of Liaoning Province, North China

June 12th, 2015

1 Benxi chaetetid 2a 585Last year I had a short and painful trip to China to meet my new colleague and friend Yongli Zhang (Department of Geology, Northeastern University, Shenyang). The China part was great; the pain was from an unfortunately-timed kidney stone I brought with me. Nevertheless, I got to meet my new colleagues and we continued on a project involving hard substrates in the Upper Carboniferous of north China. Above is one of our most important fossils, a chaetetid demosponge from the Benxi Formation (Moscovian) exposed in the Benxi area of eastern Liaoning Province. We are looking at a polished cross-section through a limestone showing the tubular, encrusting chaetetids.
2 Chaetetid Benxi Formation (Moscovian) Benxi Liaoning China 585This closer view shows two chaetetids. The bottom specimen grew first, was covered by calcareous sediment, and then the system was cemented on the seafloor. After a bit of erosion (marked by the gray surface cutting across the image two-thirds of the way up), another chaetetid grew across what was then a hardground that partially truncated the first chaetetid. This little scenario was repeated numerous times in this limestone, producing a kind of bindstone with the chaetetids as a common framework builder.
3 Chaetetid Benxi cross-section 585Here is the closest view of the chaetetids, showing the tubules running vertically, each with a series of small diaphragms as horizontal floors.

Last week’s fossil was a chaetetid, introducing the group. They are hyper-calcified demosponges, and the classification of the fossil forms is still not clear. Their value for paleoecological studies, though, is clear. This particular chaetetid from the Benxi Formation preferred a shallow, warm, carbonate environment, and it was part of a diverse community of corals, fusulinids, foraminiferans, brachiopods, crinoids, bryozoans, gastropods, and algae. Such hard substrate communities are not well known in the Carboniferous, and this is one of the best.

References:

Gong, E.P, Zhang, Y.L., Guan, C.Q. and Chen, X.H. 2012. The Carboniferous reefs in China. Journal of Palaeogeography 1: 27-42.

West, R.R. 2011a. Part E, Revised, Volume 4, Chapter 2A: Introduction to the fossil hypercalcified chaetetid-type Porifera (Demospongiae). Treatise Online 20: 1–79.

West, R.R. 2011b. Part E, Revised, Volume 4, Chapter 2C: Classification of the fossil and living hypercalcified chaetetid-type Porifera (Demospongiae). Treatise Online 22: 1–24.

Zhang, Y.L., Gong, E.P., Wilson, M.A., Guan, C.Q., Sun, B.L. and Chang, H.L. 2009. Paleoecology of a Pennsylvanian encrusting colonial rugose coral in South Guizhou, China. Palaeogeography, Palaeoclimatology, Palaeoecology 280: 507-516.

Zhang, Y.L., Gong, E.P., Wilson, M.A., Guan, C.Q.. and Sun, B.L. 2010. A large coral reef in the Pennsylvanian of Ziyun County, Guizhou (South China): The substrate and initial colonization environment of reef-building corals. Journal of Asian Earth Sciences 37: 335-349.

Museum work and a castle visit in Scarborough

June 11th, 2015

1 Scarborough museum workSCARBOROUGH, ENGLAND (June 11, 2015) — It is always useful when doing paleontological fieldwork to visit the local museum to see what specimens they’ve curated over the years. Today Team Yorkshire explored the collections at the Scarborough Museums Trust Woodend storage facility, courtesy of Jennifer Dunne, Collections Manager. Above are Mae Kemsley (’16) and Meredith Mann (’16) examining boxes of specimens from the Speeton Clay and Coralline Oolite, the two units they’re working with.

2 Peltoceras williamsoniThis specimen of the ammonite Peltoceras williamsoni is an example of the kind of material we find in museum collections. It comes from the Passage Beds of the Coralline Oolite — Meredith’s unit. We are not likely to come across such a well-preserved fossil in our short interval of fieldwork. This is not the first Peltoceras in this blog.

3 Peltoceras noteThis note that accompanied the above specimen is from J.K. Wright, an expert with these fossils.

4 Scarborough castle keepAfter our museum work, we took an opportunity to visit Scarborough Castle. (We couldn’t do more fieldwork this afternoon because of the high tides.) This is a spectacular place with over 3000 years of history. It was the site of settlements in about 800 BCE and 500 BCE, and then a Roman signalling station around 370 CE. The castle itself dates back to the 12th Century. In 1645 it was the subject of a long Civil War siege, with Parliamentarians on the outside shelling Royalists on the inside. (The cannonades broke the above castle keep in half.) In December 1914, German battleships fired over 500 shells into it.

5 Team Yorkshire castle 061115Mae and Meredith with the castle keep in the background. Note the fantastic weather!

6 St Marys chapel castleThe remains of St. Mary’s Chapel within the castle walls were built on the site of the Roman signals station. Resident of the castle took shelter here during the 1914 German bombardment.

7 Scarborough from castleA view of Scarborough from the castle walls. We could see all of our field areas along the coast from this vantage point.

Another gorgeous day on the Yorkshire coast

June 10th, 2015

Dismantled pillbox Filey BeachSCARBOROUGH, ENGLAND (June 10, 2015) — We certainly can’t complain about the weather for our fieldwork in Yorkshire this year. Today was spectacular with blue skies and cool sea breezes. It made the long beach hikes very pleasant.

1 Mae on Speeton 061015This was our first day without our English colleague (and Yorkshire native) Paul Taylor, so we were on our own for transportation. We figured out the bus system, though, and made it to the Lower Cretaceous Speeton Clay at Reighton Sands in good time. Here is the last view you’ll have of Mae Kemsley (’16) working on her outcrops of this gray, mushy unit. We collected sediment samples this morning, along with a few last fossils.

2 Meredith on Speeton 061015Here is Meredith Mann (’16) doing the same. We finished all of our fieldwork for Mae’s project by 10:30 a.m., so we could make a long beach hike from the Speeton Cliffs northwards to Filey.

3 Meredith waiting on tide

4 Mae waiting on tideWe hiked as far as we could on Filey Brigg, but had to chill because our sites were still cut off by the high tide. Waiting for a tide to drop is tedious, but the students had plenty of patience.

5 Thalassinoides 061015We reached the large slabs of Hambleton Oolite Member (Upper Jurassic, Oxfordian) with Thalassinoides burrows to begin Meredith’s data collection. These are impressive trace fossils, with numerous shelly fossils in the surrounding matrix. We took reference photos and collected what we could. Unfortunately only three slabs met our criteria for measurements, so we moved to a unit exposed just below the Hambleton.

6 Cannonball concretionsOn the north side of Filey Brigg there are these large “cannonball” concretions, which were excellent stratigraphic markers for us. They are in the Saintoft Member of the Lower Calcareous Grit Formation. They told us that the units above were the Passage Beds Member of the Coralline Oolite Formation.

7 Passage Beds 061015Mae and Meredith are here collected fossils from the Passage Beds above the concretions. This unit is interesting to us because it contains shelly debris that was apparently washed onto shore during storms. These shells are often heavily encrusted with oysters and serpulids. Such sclerobionts have been little studied in this part of the section.

8 MMbus 061015On our sunny ride home the students sat in the front of the top section of our double-decker bus. Not a bad commute for a day’s work!

 

Russian Birch Climate Reconstruction

June 9th, 2015

Guest blogger – Dan Misinay

During the summer of 2014 Dr. Wiles and I.S. student Sarah Fredrick traveled to Kamchatka, Russia. While there, they cored hundreds of birch (Bertula ermanii) and larch (Larix gmelinii) trees to bring back to the tree ring lab and be analyzed. The cores were mounted, sanded, counted, and measured. This study is important because very little work has been done with Russian birch regarding climate reconstruction. The work that I have been doing so far this summer has been strictly with the birch trees.

DSCN1084a

Hard at work with COFECHA and measuring cores.

IMG_1400a

The birch forest growing on steep slopes in Kamchatka.

Image_2041

Photo of sample UG05 of normal growth rings in the birch.

Image_2038

Rapid growth occurring in 90 percent of the samples. Possibly caused from warming or increased precipitation.

Image_2037

One of the many challenges with the birch trees were these patches of narrow rings. This growth occurred from 1990-2013 and or 1930-1960 in many of the cores. This growth could be caused from climate change or pollution in the surrounding environment. Additionally the rings at this site may be reacting to being on a slope, or the tree is slowly dying.

Image_2043

Birch with small rings, notice one of the rings is much lighter than the rest of the wood. These changes occur between 1825 and 1875 in some of the samples.

IMG_1403a

Another photo of birch trees growing in Kamchatka. Some of the abnormal ring growth could be linked to the growing conditions. Trees the grow on slopes generally have reaction wood which will cause the ring to grow much larger on side of the tree than the other. The side opposite of the reaction wood is generally very narrow and rings are pinched out.

 

ug vs sono

UG site from Kamchatka plotted against results from Sano et al, 2009. These are raw ring width measurements correlated with one another. UG site measurements are represented by the green line and Sano’s data is the blue line.

STD PLOTn

The above graph is the UG site chronology after being standardized. The growth trend is removed so that the desired climate signal is only showing. There are many trends through out the graphed that will be addressed later in the summer when the climate reconstruction is completed. The blue line on the bottom represents the number of samples at each given year.

References

Sano, M., Furuta, F., and Sweda, T., 2009, Tree-ring-width chronology of Larix gmelinii as an indicator of changes in early summer temperature in east-central Kamchatka: J For Res, v. 14, p. 147-154.

A coincidence?

June 9th, 2015

a Shoe Zone SmithSCARBOROUGH, ENGLAND (June 9, 2015) — Why do these geologists look so pleased to be standing in front of a nondescript shoe store? The answer is on the blue plaque above their heads.

b Smith plaque 060915Turns out we’ve been eating breakfast every morning next to the Scarborough home of the heroic geologist William Smith. Auspicious!

Return to the Speeton Clay

June 9th, 2015

1 Mae on Speeton 060915SCARBOROUGH, ENGLAND (June 9, 2015) — Team Yorkshire returned to the Speeton Clay today to begin the fieldwork for Mae Kemsley’s Senior Independent Study project. Mae chose to work on the incredible diversity of belemnites found in this Lower Cretaceous unit. There are two aspects to her study: the paleoecology of the belemnites themselves, and the taphonomy of their distinctive bullet-shaped calcitic rostra (guards). We hope that Mae will be able to do some stable isotope work to help elucidate the paleoenvironments these pelagic creatures lived in. Oxygen isotopes in particular may indicate the seawater temperatures when the belemnites were forming their skeletons. The Speeton Clay has faunas from alternating Boreal (northern, colder) and Tethyan (southern) regions, so this will be interesting.

2 Middle Cliff SpeetonHere is the Speeton Clay forming the Middle Cliff along the shoreline. Virtually every outcrop of this unit is slumped from above, so sorting out the stratigraphy is a challenge.

3 Mae working 060915Here is Mae again working through a small patch of the Speeton Clay. There are four broad intervals of the unit (A, B, C, D) that we must recognize by the fossil content and the position of the outcrop relative to various field markers like abandoned pillboxes, breakwaters, and large rocks.

5 SS Laura boilersOne of our intertidal landmarks is a set of boilers from the 1897 wreck of the SS Laura, an Austro-Hungarian cargo ship that ran aground near Filey Brigg. The heavy boilers have stayed in essentially the same place for over a century.

4 Speeton work 060915The weather could not have been better today. We got Mae’s project off to a fine start with several sets of samples collected from the four primary units of the Speeton Clay.

Paul Taylor returned to his home in Epsom at the end of the day, leaving the three Americans to their own devices. He was essential in our first week, getting us oriented to the local geology, expertly driving us around to the various sites, and entertaining us with his trademark puns. He trained us well to carry on into week two of the Yorkshire Expedition.

« Prev - Next »