5/1/18

Due to various conflicts I haven't been in the lab since before the symposium, so this will be a short report on the symposium instead! It was a really neat trip and getting to talk to people about the fossils project was really interesting. I feel it helped me understand the field at large a lot better, as well as on a small scale, to understand the project here better as well.

            Some of the other attendees had suggestions for our research - one suggested to look into some research done in the 60's - all I managed to scribble down is "Axelrod 60s, published Batista look up for plant fossils", which is somewhat cryptic but something I'm probably going to be looking into in the future. I also wrote "Sebolba flora" (which unfortunately only yields images of Sebulba from Star Wars), so this too is something I'll likely be looking into in the future.

            Another attendee mentioned, I believe, the San Mateo formation - he had noticed that the sandstone of our fossils appeared very similar to another layer of rock found in San Bernadino County. Jess told me this and said it would be the first thing I'd do when we went back, so I'm sure I'll be hearing more about it a week from now when I go in next. I'm planning on doing research on those beds and if there's any possible correlation between our plant fossils' sandstone and siltstone and the rock layer that man believed could possibly be related.

            Other than this, not much to report! We're still talking about carbon dating the samples, but I'm not sure when that will be sent out. I'm excited to know if the fossils really are Late Pleistocene or not.

3/16/18

As mentioned previously, the sandstone and siltstone in the fossils is very fine - it definitely would have been formed in a low energy environment and not some sort of event like a flash flood. The road underneath which the fossils were found seems to run through a natural gulley, so the assumption can be made that there was some sort of small stream there that came to a stop in the small dip in the ground where our fossils were found.

            I have been taking photos of the fossils and editing them to make them brighter and more clean. Currently, we're preparing our poster to present at the Desert Symposium to report on the fossils, and I've been helping Jess with the poster file. Last time I made the pictures transparent, and today Lido and I worked on finalizing the layout of  the photos section. The symposium is this weekend, so we're working to get it done. I'll be sending Jess the references for the reports that Rich has sent me during these last few months within the next couple days.

            Work on the project has been going well overall! I'm excited to present it this weekend. It'll be my first symposium, so I'm excited to be able to go to represent this project, since it's really cool!

 

2/14/18

I talked to Rich yesterday & further emailed him today to clarify some of what he's said about scrub oak and the surrounding area. For self-reference clarification: Chaparral is an umbrella term for evergreen shrubs, such as scrub oak. Coastal sage scrub are also shrubs, but they are drought deciduous. The 13,000 year old Palmer oak in Jurupa Hills is not actually scrub oak. We talked about different distributions of scrub oak throughout southern California and throughout the Baja as well, in both past and present times in order to give context to the late Pleistocene climate. In relation to the project, we have a fossil of a scrub oak found in an area where only coastal sage scrub grows now. Climate change and a shift in vegetation are important facets to consider throughout this project.

He showed me an aerial shot of Joshua Tree National Park and how there were some flourishing tree populations at the bases of the large, fractured rocks found there. While there is little rainfall, it all collects on the rocks and runs off to the base, where these plants flourish. Likewise, rainfall can be absorbed by the rocks and precipitated out. This is directly relevant to the Box Springs area, where, true to the name, there are a couple streams emanating from the granitic bedrock. He showed me the aerial shots of these two stream areas and how there are sycamore and willows growing there, two of the specimens found in the fossils. He also showed me the only two (perhaps three) scrub oak known to be in the entire area, also near these stream areas, seeing as all three of these are stream plants and require plenty of water to flourish.

In direct correlation to the project, it got me thinking specifically about how the fossils came to rest there. The original assumption was that they were growing there, especially since the place in which the road is now happens to be a stream bed for water (as it is lower than the surrounding areas). However, Rich mentioned something that caught my attention. He mentioned that maybe the Sycamore leaf could've blown in from far away and become fossilized with the others despite not having been present in that location - but because they are all stream plants that can coexist in the same type of environment, it seems to me that they are all most likely from the same location and that they could not have all blown in on their own.

This lead me to think of something else: as I mentioned, the original assumption was that they were growing there together. However, seeing as they were fossilized all at the same time in an instant burial event, I still find it strange that we could not find any other indication of sandstone in the area. This would seem to imply, at least to me, that it's plausible these plants were actually washed into the lower area by the stream of water during the flooding event. If there was a dip in the ground, the water could have brought the leaves from further upstream and dumped them into a puddle all together, where they mixed with the sediment and became fossilized. Their proximity to each other may not actually be indicative of dense foliage in that specific area during LGM conditions, but actually of denser scrub oak and willow/sycamore communities at a slightly higher elevation in the Box Springs hills (which would still be consistent with what we know, but could indicate the fossils are from later in the Pleistocene or early Holocene). If sandstone only formed in small pockets in the Box Springs hills where the sediment deposition rates are higher, it would coincide with the fact that most of the geology of the area is granitic without enough topsoil or proper conditions to form sandstone atop the granite.

The sandstone containing the fossils is also very fine. Outside of the flooding event, it means that location in particular had to be very low energy. The other piece of sandstone we found higher up in the hills is less fine, and gives the impression that it's an unrelated piece of sandstone - if it is indeed from Box Springs, it's possible that multiple pockets of sandstone were formed in different locations, possibly some not now covered by the road. I'm curious if it would be possible to find any of these places and find more clues as to how these pockets of sedimentary rock were able to form.

I feel it's important not only to put the climatic context of these fossils into place, but to also consider all methods and possibilities of how they came to rest there and what processes had to take place in order to ensure their fossilization. As I continue to do more literary research into Pleistocene climate and the plant content of ancient pack rat middens, I will also be attempting to put my knowledge of the geology of Box Springs to  think of all the possible pieces to the puzzle we can put together.

2/12/18

When presented with the topic of plant fossils, I honestly wondered if I had the qualifications, even as an intern, to work on something so important. Especially such a rare find - out of Box Springs, no less. But as it goes, I had come to learn - and the learning began almost immediately.

The fossils consist of one sycamore leaf, a willow leaf, and scrub oak. They are embedded in sandstone, which is all the more baffling - not only are plant fossils a rare enough find, but Box Springs is mostly granite. To have been preserved the way they are, it would have had to have been instant burial. In addition, having been found in a lower area between two hills (where the road was built), it's a relatively safe assumption that because no other sandstone was found in the area besides one seemingly unrelated piece further up the hills, this particular portion of rock was only formed in a small pocket in that one location.

The florule fossils found are stream plants, and having been there now I can say with absolute certainty I can't even imagine a stream running through there. It is absolutely barren, desolate, and extremely hot. These plants, which require lots of water and less arid conditions, are a clear sign that things were not always the way they are now. They're likely to be Pleistocene, as conditions during that time allowed flora such as the evergreen scrub oaks to flourish at lower altitudes, such as the Box Springs hills in the late glacial period. The scrub oak fossil is found where only coastal sage shrub grows now (which is deciduous and goes dormant during drought months), giving a clear visual into a time when water was more abundant in the area. Scrub oak has been recorded to have been at lower altitudes during the late glacial period, as well as many other plants that now only live at higher, cooler altitudes.

Although it seems clear that the fossils should date to be Pleistocene, should they be found to be Holocene, we will have quite the mystery on our hands. They have yet to be dated. For now, though, they fit right into what we know about the last glacial maximum in southern California. This, of course, does not make them any less of a significant find - it only strengthens what we know, and it's extremely exciting.

As for the project, this is where we're beginning. In order to assess the Box Springs plant fossils properly, it's important to put them into context with the rest of what we know about paleoflora in the Pleistocene. That being said, I'm going to be researching climate conditions and the effect on plant growth during the Pleistocene and putting it together to build a background around the plant fossils we found.

In addition, as a more personal approach to the topic, I'm hoping to also look into possible causes for the burial event. Finding sandstone in a pocket such as that in an otherwise granitic landscape is interesting - although the event was likely a flash flood, possibly by thunderstorm (as Rich suggested), I'm still curious to look into the area more and see if it's possible to find anything else that might give us a clue on the geological processes that might have contributed to the fossil's formation and preservation.