Rapa Nui 2005

 

1. History of Dissertation Research

 

Fall of 2002 I was in correspondence with Irving Friedman about his work with climate change and obsidian. He had found that obsidian contained deuterium that could be used to detect a climate snapshot at the time the glass was formed. What I wanted to know was if the obsidian could possibly retain a signature over time. More particularly did it show a change in moisture over time? Hydration dating was already a successful method of dating human use of obsidian as an artifact, therefore if the obsidian could keep a moisture record then perhaps it could be a tool to understanding human impact and climate change. Afterall I was searching for the connection between deforestation, climate change and humans.

 

Dr. Friedman referred me to Christopher Stevenson and in September 2002 I contacted Chris in Virginia about his upcoming Earthwatch group at Easter Island. Chris’s research with obsidian was well known and I wanted to see what he was doing on the island to unravel the questions about deforestation, moisture change and the human impact on the island. I decided to join his group in December.

 

Upon returning Chris and I planned to run a dynamic SIMS analysis on a few obsidian samples at Evans Northeast in New Jersey. The samples consisted of H in obsidian (SiO2). The purpose of this analysis was to measure the concentration change from the top layer of hydration down to baseline using H. In addition, the 16O to 18O ratios were analyzed.

 

Although some sensitivity was detected it was not significant enough to base the type of questions we were looking for. We then switched our thinking to lake sediments after review of Flenley and Dumont’s previous coring at the island.

 

In May of 2004 I applied to the National Science Foundation for a Dissertation Improvement Grant in the sum of $12,000. This initial proposal included joining Chris Stevenson at the island in November 2004 for 3 weeks and coring 3 crater lakes at the island and doing some small sample coral coring. The NSF grant was declined and I resubmitted in November 2004 for a new proposal to begin March 2005.

 

Before the second NSF proposal was declined I had already made plans with John Flenley and David Feek to join then at the island in March and collaborated to join Rob Dunbar and his group from Stanford as they were working on an NSF grant themselves on coral coring at the island.

 

From March 6 – 25 I worked at Rapa Nui and obtained 19 meters of sediment cores both from Rano Kao and Rano Raraku. Upon return to the United States the cores were sent to the LRC at the University of Minnesota at Minneapolis. On April 19-22 I visited the lab and conducted the initial analysis of the cores. The preliminary report follows:

2. Summary of Coring

2.1 LCR

 

Amy Myrbo at The Limnological Research Center at the University of Minnesota was contacted to rent a Livingstone corer and 20 meters of rods to bring with me as carry on baggage to the island. The equipment arrived a few days before my departure on March 6 from Portland via FedEx Ground. A total weight of 98 pounds contained 1 Livingstone corer, barrel with serrated [peat] cutting end, 1m square rod, Piston, Cable, 10x 2m drive rods in ski bag, 40x 1m split PVC pieces and a“Almendinger” extruder yoke. Rental of the Livingstone corer: $25/week, drive rods: $1/rod-week ($20/week total) for a grand total of $180 for 4 weeks. The shipping cost $57 via FedEx Ground from Minnesota to Portland.

 

            2.2 Travel

 

On March 6 I left from Portland Oregon en route to Dallas Texas via American Airlines. In Dallas I transferred again via American for a direct flight to Santiago Chile arriving the next morning on the 7th of March. I had one day delay in Santiago and retrieved my equipment and stayed at the Vitoria in downtown Santiago. On March 8th I met Rob Dunbar, David Mucciarone and Sarah at the Santiago airport for a flight to Isla de Pascua, better known as Easter Island, and to the local people at Rapa Nui. We all arrived at the island after a 5 hour flight to a quite pleasant 80 degree sunny day.

 

            2.3 Stanford and Massey

 

Over the course of the year 2004 I corresponded with John Flenley and David Feek of Massey University in New Zealand and Rob Dunbar at Stanford University, California.

Professor Flenley and David Feek were at the island previous to our arriving as they were participating in another coring attempt with Professor Yasuda of Japan. We arranged to meet up for 2 days of coring, one at Rano Raraku, and another at Rano Kao. During the 18 days that I was at the island, I lodged with Rob, David and Sarah and was able to dive one day of reconnaissance with them.

 

           

2.4 Coring

2.4a Rano Raraku

 

Rano Raraku is a volcanic crater lake of asymmetry and complex geological origin. It is famous for the moai sculptures that face the south and south-east rims of the cliff tuff that form the crater rims. Both the inner and outer walls were quarried and have left behind much lithic debris that has been washed into the lake. The asymmetry of the lake suggests a large amount of filling-in of the quarry walls with this very same debris that continues to wash into the lake with soil erosion.

 

 

 

 

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The first day of coring included Candace Gossen, John Flenley and David Feek at Rano Raraku. David had constructed a small platform in the lake at Rano Raraku and we were able to get to the platform via a 2 person inflatable boat that they had brought over from New Zealand. The platform was moved to the center of lake and tied off from the available totora to the south and anchored in the 3 meters of water in the lake on the other sides.

 

We began coring in the middle of the day and as always the winds were mainly calm on the lake in the morning hours, but were very strong in the afternoon. For most of the coring time we were challenged with a “drifting platform” from the strong wind gusts as the cord that I brought was not truly static but stretched.

 

Using a Russian D-Section corer that John and David had brought with them were able to obtain 5 meters of core at a center of lake destination. The total water depth at center of lake was 10.7 feet noted with a scuba ecosounder that was borrowed from the ORCA diving shop on the island and 3.1 meters with tape measure. The eco sounder also located an underwater horizontal distance of 226 feet from the south bank of totoras as well as 160 feet to the east totoras.

 

The D-Section corer worked very well with the densely fibrous sediments as it was able to cut and turn into the sections at each meter. The sediments were mostly fibrous and had very little decomposition. The 1 meter sections were very watery and some fine sediments were lost through the equipment. The D-Section is very good for peat and fibrous materials, but fine sediments may be lost as the corer does not have a very tight seal when closed.

 

The D-Section corer was very easy to push by hand into the sediment and was able to penetrate a meter at a time by adding more rods. The core dimension was 40mm halves, and we placed them into the pvc halves that were brought from LCR. A sheet of heavy saran wrap was placed first into the pvc and the core wrapped well for transport back to the van.

 

Once the 5 meters were obtained we pulled ourselves back to the totora and back to the edge of the lake, deconstructed the platform and carried everything out over the quarry’s rim.

 

Upon initial inspection the cores were reddish brown in color, showing the heavy roots and fibers of the totora reeds. The cores were densely fibrous and not very cohesive. They contained by weight at least 50% water, which later in the lab at LCR was mostly evaporated. The cores varied in consistency as the tops of the cores were more wet than the bottoms due to the coring device. We called this core RKU1

 

 

 

 

 

 

 

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2.4b Rano Kao

            2.4b1 KAO3

 

Rano Kao is the largest of the crater lakes on the island. It is 1 kilometer in diameter at the lake level and nearly 2km at rim level. This lake has never been irrigated and is the last area where many species of trees were last seen before going extinct. The environment within the crater is temperate and has a very stable microclimate that lends to plant growth very well. It is not affected by wind surges like Rano Raraku is, but it is downwind of the island and is a good depository for pollen and charcoal that is airborne.

There is much evidence of erosion into this lake that continues today. At 300 meters elevation at the rim, and 100 meters approx. at lake level it is quite steep making bringing gear and coring materials in and out quite difficult.

 

Another challenge was manuvering the floating mat surface of the lake. On the surface of Rano Kao is a more than 90% cover of totora (scirpus californicus) and polygonum species that vary from 1 to 3 meters in thickness. Although firm enough to walk on in places, it is quite a challenge to move towards the middle of the lake. The eco sounder was also used in this lake to verify depth ranges along the way. At the time of coring, at varying places in the lake, we found anywhere from 9 meters of water to 20 meters of water depth. A GPS reading of 110 meters was taken at the surface of the totora mat of the KAO3 borehole, 552 meters horizontal direction from the mirador to the coring spot also noted as 400 meters from the north edge of the lake in the due north direction, and 350-400 meters in the west direction to the edge of lake. Latitude 27.11.37 South, and Longitude 109.26.40 West.

 

According to the Chilean Hydrological and Oceanographic Map of the Armada de Chile of 1967 updated by aerial photography in 1992 the lake level reads at 104 meters. In John Flenley’s report he also states the elevation of the totora mat at 104 meters. This lends a difference of 6 meters higher than in 1981.

 

image003.gif (29146 bytes)We attempted 4 borings at Rano Kao. Over many days, we successfully obtained 3 coring depths with a total of 14 meters of sediment cores from Rano Kao. The lake depths were recorded at KAO3 with 9 meters of water depth. At KAO4 14 meters of water, KAO5 the water depth was beyond our 19 meters of rods, and at KAO6 there was 14 meters of water depth. On a side note, after interviewing a Rapa Nui man that worked at Rano Kao for 17 years planting, he swears that the lake has never had more than 5 meters of water. Flenley reported 8 meters of water in the 1980s, and now we have 2 indicators that the water depth has increased by 6 meters both in the increased elevation reading from the totora mat at 110 meters, and in the depth of sediment in the coring attempts at 14 meters of water. It is unknown whether there is groundsource water input into the lake.

 

The first day of coring at Rano Kao John Flenley and David Feek were available to core. This was a special treat as John had cored the very same lake 25 years earlier and I was very interested in his expertise and comparing what we would find now as compared to earlier.

 

The adventure down the 300 meter crater walls was very exhausting carrying the ski bag weighing 78 pounds, the dry bag with the 40 pounds of pvc and the tools, Rob’s videocamera for the event, and the D-Section corer that David had brought as backup. The coring team for this day included Rob Dunbar, Yan Araki, John Flenley, David Feek and Candace Gossen.

 

The objective for the first coring site was to come somewhere between KAO1 and KAO2, the two boreholes that John Flenley had obtained in the 1980s to give a better profile of the bottom of the lake. Also we wanted to be out of the vicinity of where the Japanese team had cored just days before. We walked approximately 400 meters from the south and east towards the center of the lake. We found a patch of newly growing vegetation and found the water depth at this site to be approximately 9 meters.

 

Using the D-Section corer we cored the first 3 meters of the floating mat. These were obtained in 1 meter sections and placed into the channel tubes that John Flenley brought with him. The mat was not difficult to core and presented a dense fibrous material with sediment mixed in.

 

Once the D-Section hit the water beneath we inserted a 110mm x 12m long pvc pipe for stability with the corer. We switched equipment to use the Livingstone corer and about 9.5 to 10 meters of water depth we begin to hit sediment. Although the sediment being really fine was not able to stay in the piston corer we came up with nothing until the 12.5 – 13.5 meter section which was soupy with a large organic plug of totora with roots at the end of 13.5 meters. Again the next meter was soupy and mostly water with a totora plug at the bottom of 14.5 meters. At 14.5-15.5 meters the fibrous cores became more consistent. 15.5 – 16.5 meters had good consistency, watery on top but still not full 40mm rounded cores. 16.5 – 19.5 meters were well formed, consistent, mixed fibrous and deitritus. At the depth of 19.5 – 20.5 meters we had a natural separation angle at about 20 meters that showed the incline of the lake approximately a 12 degree angle.

 

We were limited to 20 meters of rods, for a total length with corer of 21.5 meters. It was this last meter that hit a clay layer at about 21 meters. We were very happy to have found a full core down to the clay layer which should give some really good dating.

 

The cores were mostly dense to medium detritus. Some had mild to moderate smells, and were mostly watery at the top few meters. The Livingston corer was very important in this extraction as if it had not been for the piston creating a nice seal we would have lost many meters of sediment.

 

            2.4b2 KAO4

 

image004.gif (22671 bytes)The second day of coring at Rano Kao the team included Yan Araki, Francisco Rapu, Jon, and Candace Gossen. The objective of KAO4 was to find a continuous sediment core, one that was not broken between the floating mat and the sediment beneath. We walked down the approach from the Northwest and headed south. The totora around the perimeter of the lake was 7 – 8 feet in height and it was quite an adventure to maneuver through it. We did some poking around with the rods and seemed to find floating mat almost to the edge of the lake. We attempted one core some 75 meters from the edge of the lake with what we thought continuous sediment, and at 3 meters hit water that continued to 14 meters. We moved and attempted a second spot approx. 100 meters from a small patch of maize growing on the side of the crater wall on the west side of the lake. The mat where we cored was one of the anomalous patches of dead totora which cannot be determined the cause of. So we began coring KAO4. 14 meters of water we obtained the first core14-15 meters which was a grey/green clay consistency with some organic mixed in. No laminations and no smell. At 60 centimeters the core stopped, it had fractured and had become incredibly difficult to go deeper. We gave it a second attempt and at the 15-16 meter level we pulled up 15cm of brown to light grey fibrous to grey clay with volcanic rock at the end. It was very obvious that we were at basalt rock and were not going any further.

 

            2.4b3 KAO5

 

For KAO5 we attempted a walk to near center of lake directly from the KAO4 borehole. We were greeted with a huge water hole and were not able to continue our path. The adventure in coring this lake is that from top you can see how all of the floating mats fit together and can plan your movement, but once in the totora and walking on the mats it becomes not obvious at all. There is great manuvering across the patches, sometimes we used the rods as a walking ladder between the mats. Often we plunged in through the mat to our knees, waist and I fell in to my neck once! It was a muddy muddy day.

 

We traveled around the mats to a location more north east and decided to core next to an open area of water. The ecosounder at this area showed 14 meters of water. Over the full 20 meters of rods we were not able to bring up any sediment, and finally determined that the water depth was greater than 14 meters and what did come up occasionally was too fine for the piston corer to keep. KAO5 has no sediment cores.

 

            2.4b4 KAO6

 

image005.gif (14853 bytes)From KAO5 we traveled in a north direction to about 200-250 meters from the north side of the lake. At this borehole reached 16 meters of water. The first sediment we obtained was 17-18 meter depth. The color of the fibrous, coarse detritus was a deep chocolate brown with reddish hue from the totora roots. The sediment expanded when released from the chamber due to gases in the sediment. The core had noticeable fibers and was not totally consolidated, the last 5 cm was firm, round but slumpy. There was no smell. At 18-19 meters the color became darker chocolate brown with the top 20 cm firm, and watery between, the bottom 5 cm was firm. 19 – 20 meters the color was chocolate with grey/yellow clay mixed in at the end of 20 meters. This core was consolidated well.

We noticed with this depth that it was incredibly difficult to keep the corer from bouncing back out of the hole. When we did get it to stick at the depth we wanted we noticed a buzzing sound coming out of the rods. Clearly there was gas being released from our corer up through the rods. There was no smell and noone lit any fire at the time, which thinking back we weren’t sure at the time this was gas so I am glad we were working hard and not taking a cigarette break. At 20 meters we could not go further, the resistance in the hole was too great.

 

This was the last attempted bore on Rano Kao. We had obtained 14 meters total of 3 boreholes in the lake, all of which were very different at varying levels, that had their own independent features.

2.5 Processing and travel with the cores

 

image006.gif (20222 bytes)After each field day I would take the cores back to our room and photograph and document each meter of the cores. The cores were well wrapped again in saran wrap, then the 2 halves taped with duct and electrical tape for their final transport to the United States.

 

Transporting was tricky as I had to bring the cores with me on the plane. Transporting by ship was not possible as time was critical to get the cores back to the lab in Minnesota as soon as possible. Therefore a dry bag was purchased before leaving Portland that was used both in the field to get cores transported up and out of the crater and was used as the flying vessel for the 19 meters of core.

 

LanChile charged 123,000 pesos equivalent to $217 to bring the 67 kilos (147 lbs) back to Santiago. The coring equipment was 78 of the total while the cores weighed 69 lbs.

Soil export permits were obtained from the SAG office at the island, and soil import permits to the United States were already laminated and in the bag which had been sent via Chris Stevenson.

 

In Santiago I had to retrieve the bags and bring through customs. The first pass through kept me stalled for over 30 minutes telling me that I needed a permit from Santiago and the country of Chile to import the cores. After explaining that I was getting on another plane, and they could not find a number to the SAG office on the island, they gave up and told me that the USA would deal with me, it wasn’t their problem.

 

Once entering Dallas and passing through customs, there was no soil to be found, it was lake sediments and they were sealed so I walked right through. No problem.

 

Once in Portland, the cores were repacked in a wooden box and the Livingstone corer and the 19 meters of core were off to the LCR lab in Minneapolis.

 

 

3. Analyses at the Limnological Research Center, University of Minnesota.

 

The Limnological Research Center Core Facility is an open laboratory operating with funds from the National Science Foundation and the University of Minnesota. The mission of the Core Facility is to provide expertise, equipment, and instrumentation in support of the collection and study of lake sediment cores to the University, North American, and international communities.

 

In 2004, with NSF funding, the LRC acquired both a new Geotek Multi-Sensor Core Logger (MSCL) with tremendous capabilities for logging and imaging both whole and split cores, and the first Geotek XYZ core logger in the Western Hemisphere, which automates the measurement of high-resolution magnetic susceptibility by point-sensor, color analysis by spectrophotometry, and detection of natural gamma emissions.

 

 

Analysis completed April 19-22, 2005:

Whole-core multisensor logging

Core splitting into working and archive halves

Core surface preparation

Digital whole-core imaging

ICD sheet production

Split core multisensor logging

Macroscopic sediment description

Microscopic sediment description (smear slides and coarse fractions)

Cold storage in D-tubes

Data archiving and curation

 

Whole-core logging on the Geotek Multisensor Core Logger (MSCL) track was the first

step in analyzing the cores and developing the ICD. Anders Noren, curator and Amy Myrbo, lab manager, received the cores via UPSGround and placed them in situ, without removing or unwrapping the cores in the pvc, into the whole-core logger and the following graphs below were a result of the first run. The automated track features sensors that non-destructively measure sediment density, acoustic wave velocity, electrical resistivity, and loop-sensor magnetic susceptibility at any resolution (typically 1 cm).

 

The resulting graphs of the data are as follows:

 

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The cores were then put into the cooler for storage until I arrived two weeks later.

 

The first step was to unwrap the cores one by one, removing the saran wrap and splitting the cores in half using a sharp knife. One important note when I opened the cores was the actual size decrease from the field size to the refridgerated size. The original coring contained mostly water, and over time there was both evaporation and leakage through transport. Comparing photographs from infield cores to scanned cores show size shrinkage as well as obvious water discrepancies. Amy and Anders both told me when the cores arrived at the lab in the wooden box, when opened all of the packing rags were wet. I noticed the same once I had transported the cores from the field by airplane to Portland.

 

Once the cores were split one half was placed into an archive tube called a D-tube that was labeled and replaced in the cooler, while the working core was also labeled, observed, commented on and then placed into the photoscanner.

 

Imaging used at LCR includes:

 

DMT CoreScan Colour

Digital linescan camera, resolution: 10 pixels/mm. Orthogonal polarizing filters over light source and lens

 

Geotek Corescan-V

Digital linescan camera, resolution: 20 pixels/mm. Orthogonal polarizing filters over light source and lens

 

The digital line scanner produces a ~50 MB single image per 1.5 m core section at a

resolution of 10 pixels per millimeter (~300 dpi). Polarizers on the light source and the

camera lens completely eliminate glare from the core and allow fine details to be seen. A color card in each file allows for color correction after the fact, and the D-tube endcap for the core is included in the picture for identification. 10 pixels/mm is sufficient for almost all cores; however, in special cases such as microlaminated cores, another camera, mounted on the Geotek MSCL track, collects images at a resolution of 20 pixels/mm.

 

Once the cores were scanned and photographed, a semiautomated production of ICD sheets (also called “barrel sheets”) were created to facilitate sediment description. Logger data (typically magnetic susceptibility) and the core image are placed on an electronic standard core description sheet that is printed within minutes of the completion of the digital scan. The core descriptions and notes made on this sheet can then refer to the logger and image data, and point to, rather than simply describe, particular features.

 

The cores were moved to a description area whereupon core description was noted by hand on the printed sheets for each meter of core. Characteristics included in the description were, depth, description of texture, color, smell, laminations, wet-dry, elasticity, humification and noted changes or points of interest.

 

Random and specific smear slides were made at various intervals of each core. A total of 100 slides for the 19 meters of core were created and brought back to Portland with me. A smear slide would incorporate Smear slides taken at regular intervals and in anomalous layers are used to identify minerals and organic components that make up the sediment, to make an initial estimate of relative abundance of each sedimentary component, and to estimate grain size distribution. Smear slide compositional information is combined with macroscopic structural description to classify and name sedimentary units (Schnurrenberger et al.,2003). The practice of naming sediments in a way that includes compositional information and according to uniform guidelines enables comparison of sediment descriptions between researchers and provides information supplementary to the core image that can be made available through the LRCVault database.

 

Random and quick viewing of the smear slides from Rano Kao showed no diatoms. This was a bit disappointing but perhaps the anoxic and anaerobic conditions of the lake dissolve the diatoms and we could not find them upon first glance. Flenley had noted same findings in his written descriptions of his core findings back in the 1980s.

Although Dumont found both diatoms and ostracoda at Rano Raraku, there wasn’t any time to view the Raraku slides before I departed. I am anxious to have a look to see what we find there. One important criteria is the need for a base set of slides/photographs to detect pollen, diatoms and other materials in the cores. I will be in contact with Flenley and Christine Cocquyt of Belgium who created a library from their previous research.

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image013.gif (14187 bytes)Once the descriptions and smear slides were made, the core was rewrapped and placed on the newest piece of equipment in the facility, the Geotek XYZ core scanner, which is used primarily for measurement of high-resolution point-sensor magnetic susceptibility on split cores. This analysis is slow relative to other steps (~2.5 hours per 1.5 m section),but the XYZ can be loaded with up to nine core sections at a time and left to run unattended, even overnight. When each section finishes, it can be replaced with another section for non-stop continuous logging. Typically the archive half of the core is placedon the XYZ, and the working half is imaged and then placed in a core cradle for visual description.

 

image014.gif (13485 bytes)Sediment description (Valero-GarcŽs and Kelts, 1995, Schnurrenberger et al., 2003)

begins without genetic attribution (i.e., without interpretation of the depositional

environment), but with the goal of ultimately building a facies model for the basin. Lake sediments are highly variable between basins and over time within a given basin, so the level of detail of description is dictated by the nature of the sediments themselves (i.e., laminated, massive, etc.).

 

With these cores obtained from Rapa Nui there were some noted differences which altered the settings of the XYZ. The Raraku cores once split only covered the area of 1/4 to 1/2 of the pvc tube. They were mostly fibrous and had lost most of its water content. So we had to levelize the cores using “elephant gut” a grey rounded stuffing material to center in the tube and sometimes only using 1 wrap of saran wrap to make sure the scanner was able to get to appropriate depth. The negative factor in this that due to the small amount of matter, the laser would often pick up the metal structural beam beneath the core and therefore you will notice the negative numbers in the graphs. This can be altered by adjusting into positive values.

 

KAO4 was also very different in that it consisted of grey/green clays with volcanic rock which had very high magnetic feedback and the scanner had to be adjusted accordingly. These 2 meters of core were run alone.

 

KAO3 and KAO6 were very similar and were run as a whole batch.

 

Once the XYZ was finished the section of core was replaced in its D-tube and stored in the cooler.

 

Over the course of 3 days we spent about 8 hours of lab time per day analyzing the 19 meters of core. Anders, Amy, myself and 2 students that periodically helped, conducted all of the analysis. There were periodic drop ins by various people including Paul Glaser and Herb Wright from the National Academy of Science, that had heard about the Rapa Nui cores and wanted to see what they were like.

 

The cores are presently sitting in cold storage awaiting my return. Determining the next step in sampling is what we need to figure now.

 

 

 

Graphs from XYZ:

 

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4. Dating and Analysis – where to go from here?

 

The objective of this PhD dissertation is find indicies of moisture change. Testing for moisture as an inferential of isotopes was one way we had hoped. Ostracods or any calcium carbonate organism would merge the 018 data between the lake sediment core findings and the coral coring that Dunbar and his team had performed at the same time I was at the island.

 

Pollen and fibrous plant materials are plentiful and can be used as a subjective count for indicating climate specific species and their change over time as well as pollen counting to give ideas of quantity.

 

There is also great need for some secure carbon dates and Rano Kao being downwind of the island should have great quantity of both pollen rain and airborne charcoal which will be helpful.

 

 

4.1 Carbon Dating

 

As we have the experience of Flenley and Dumont, there have been anomalous dates for both Rano Kao and Rano Raraku. Predominately bulk sediment dating has been used and as they have found there is quite a range in difference between the samples.

Therefore the chosen method for dating of these cores shall be AMS Radiocarbon dating.

 

Optimally I would like to have at least one date per meter core, which would total 19 samples to date. At approximately $500 per sample, we have approximately $10.000 needed to sample each meter. The Easter Island Foundation has very kindly supported this research along the way, and even though their grant to me in the amount of $2,000 was contingent on the NSF grant, they have confidence in my ability, the people that I am working with as being highly credible, and the lab having a good history of success.

Therefore 4 AMS samples will be paid for by the EIF.

 

The question is where to get the remaining $8.000?

 

Rob Dunbar has suggested a laboratory in California to run the AMS dates as one option. There are several places in the United States that we could chose to run the samples. Using charcoal or some form of carbon would be optimal.

 

            4.2 Diatoms and Ostracoda

 

During some very quick review of the smear slides, we were not able to locate any diatoms on the Rano Kao slides. The first assumption is that we may not find any due to the anaerobic conditions of the lake. Although Rano Raraku was noted by Dumont has having diatoms, and we have yet to review the slides to determine whether we have found such. A high profile pollen microscope is needed for viewing these slides before sampling.

 

Dumont found 38 diatom species out of what he called 70 extant species including brackish-water forms, one sponge, one cladoceran, and one ostracod (out of 3 extant species). He claims that diatoms were not very plentiful below his zone 4 which is the top 135 centimeters. In this zone he also found 3 cold water forms which he claims are sub-antartic. In the upper zone 5 he found the microfossils of 2 crustaceans: alona weinecki a chydorid cladoceran and an ostracod from subantartic which he claims are in the freshwaters of the island. So there is still hope that Rano Kao will contain something.

 

Flenley’s information on diatoms include 14 samples at Rano Raraku and 3 at Rano Aroi. They did not find any diatoms, and claim it was post-depositional solution which is unfavorable as a living habitat.

 

Comparing numerical analyses of pollen and diatom data from the same sequences have been used successfully before in separating different forcing factors such as volcanic influence and climate change. Therefore we will hope to find diatoms upon further analysis.

 

 

            4.3 Plant fibers

 

The cores are all mostly fibrous with the exception of KAO4 which is mostly clay, but still has nice organic contribution. Therefore major focus should take advantage of both pollen species identification to support Flenley’s previous work on species identification and climate specific species as well as pollen counting.

 

Aquatic cellulose testing is also an option if we can find plants that were growing in isolated situations mainly in the water, and not in the sediment as a fallen and decomposing product of the totora mat.

 

Fungi spores may also be an option.

 

 

5. Need to haves

 

1.    funding for data analysis, next trip july 2005

 

At present moment the total cost to date of my expenses is $6,700. Aslam Khalil and PSU has offered a travel reimbursement of $5,000 that I hope to get any day to pay the brunt of these costs.

 

The LCR lab has a running tab of my costs including rental of the equipment to the island at approximately $200, D-tubes for archiving $200, lab incidentals in the 4/19-22 analysis, and shipping costs for equipment approx. $57.

 

My hope is to return to the lab end of June and for the month of July to perform what analysis I can on the cores.

 

My 2nd NSF proposal has been declined, I did not received the award of the $20.000 SWG fellowship, nor the $1,500 Explorer’s club grant all of which I have received confirmation letters from.

 

PSU’s grant that Aslam and I put together is still outstanding. It is based on exploratory research but is specific that it is not for funding of a PhD, so we are not sure whether this $10.000 will be an option.

 

The Easter Island Foundation has sent a check for $2,000, which is posted on my wall in front of me, for AMS dating.

 

I am currently looking for more funds and finding little that hasn’t already been awarded for the 2005 year.

 

2.    pollen microscope

 

I need to secure a good microscope with pollen capabilities to use at PSU and a lab to look at the smear slides for further analyses.

 

3.    diatom, ostracoda and pollen slide library for comparison

 

In order to properly identify the species I need to acquire a library of photos/slide copies of Flenley’s identified pollens, and Christine Cocquyt’s diatom and ostracod libraries.

Both will be contacted shortly.

 

Photo documentation of the coring/analysis process is available upon request