A 50,000 year insect record from Rancho La Brea, Southern California: Insights into past climate and fossil deposition

2017 ◽  
Vol 168 ◽  
pp. 123-136 ◽  
Author(s):  
Anna R. Holden ◽  
John R. Southon ◽  
Kipling Will ◽  
Matthew E. Kirby ◽  
Rolf L. Aalbu ◽  
...  
2004 ◽  
Vol 205 (3-4) ◽  
pp. 199-219 ◽  
Author(s):  
Joan Brenner Coltrain ◽  
John M. Harris ◽  
Thure E. Cerling ◽  
James R. Ehleringer ◽  
Maria-Denise Dearing ◽  
...  

2018 ◽  
Vol 2 ◽  
pp. e25980
Author(s):  
Elizabeth Ellwood ◽  
Kathryn Estes-Smargiassi ◽  
Noel Graham ◽  
Gary Takeuchi ◽  
Austin Hendy ◽  
...  

The School and Teacher Programs of the Natural History Museum of Los Angeles County have partnered with the La Brea Tar Pits and Museum (LBTPM) and the Invertebrate Paleontology (LACMIP) collection to create two “citizen curation” exercises dubbed “Project Paleo”. Classroom kits were created with unsorted fossils from either LBPTM or from a local invertebrate paleontological field site, to be sorted and identified by local elementary and middle school students and then returned to the museum for curation, analysis, and research purposes. Each kit contains background information about the project and fossils, and an identification guide to assist the students and teachers. The “Project Paleo: Rancho La Brea” kit contains three tablespoons of unsorted fossil matrix from LBTPM’s Project 23. Groups of students learn about past and present food webs of the Los Angeles Basin, then sort the matrix into several categories (bones, plants, other fossils, and rocks) using a guide with drawn examples of each. An online iNaturalist (inaturalist.org) project also serves as an identification resource as well as a platform by which students can contribute photos for identification by staff researchers. This project is aimed at middle schoolers and over 700 students have used the sorting kits. Results will help to recreate past ecosystems of Southern California and help to inform a National Science Foundation (NSF) funded project, “A Mouse’s Eye View of Rancho La Brea”. The “Project Paleo: Marine Invertebrates of Southern California” kit produced by LACMIP, contains approximately two cups of washed but unsorted coarse fossil matrix from a salvaged (now destroyed) construction site. This kit is aimed at 5th grade Los Angeles Unified School District classrooms and homeschooling families. Students are asked to sort fossils by species and use included identification cards to identify the sorted fossils to the best of their ability. Results of this project will be included in an NSF funded digitization project and will contribute to research on the paleoecology of Pleistocene Southern California. Early evaluation of both kits has shown positive feedback from students and educators, as well as some room to improve instructions to students. These kits are designed to conform to Next Generation Science Standards while generating useful data for museum scientists. Collections staff are able to outsource the curation of critical data to students who get the experience of handling real museum fossils and contributing to the body of paleontological research.


Radiocarbon ◽  
2016 ◽  
Vol 58 (1) ◽  
pp. 99-113 ◽  
Author(s):  
A R Holden ◽  
J R Southon

AbstractThis paper presents the first successful methods for accelerator mass spectrometry (AMS) dating of asphalt-impregnated insect chitin from the Rancho La Brea Tar Pits in southern California. A persistent problem with stratigraphic correlation at this site is that asphalt flows are characteristically intermittent and are really discontinuous, which can result in mixing fossils of quite different ages. Direct14C dating of specimens circumvents this difficulty but requires a pretreatment method that can produce dates from relatively small samples (<10 mg) of insect cuticle, while successfully removing residual asphalt and sample preparation solvents as well as soil carbon contamination.14C dating accuracy was verified by comparing dates on insect chitin with ages for seeds and twigs compacted during a rapid entrapment event within a separately dated skull of the Western Camel,Camelops hesternusLeidy. All dates fell within a relatively narrow range of ~40,000–44,00014C yr BP, suggesting that such methods can be used with confidence on other insect material from this site. Insects are often superior paleoenvironmental indicators for establishing precise data points for climate fluctuations. This is because their lifecycles and present-day climate-restricted geographic distributions are well documented, and unlike migrating mammals and birds, insects offer crucial information about the local environment. Our results are therefore potentially significant for studies of paleoecological and paleoclimatic change within the Los Angeles Basin and coastal southern California, as well as reconstruction of entrapment events at Rancho La Brea.


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