Radiocarbon Dating and Stable Isotopic Analysis of Insect Chitin from the Rancho La Brea Tar Pits, Southern California

Radiocarbon ◽  
2016 ◽  
Vol 58 (1) ◽  
pp. 99-113 ◽  
Author(s):  
A R Holden ◽  
J R Southon
Keyword(s):  
Los Angeles ◽  
Southern California ◽  
Local Environment ◽  
Isotopic Analysis ◽  
Small Samples ◽  
Stratigraphic Correlation ◽  
Persistent Problem ◽  
Climate Fluctuations ◽  
La Brea Tar Pits ◽  
Rancho La Brea

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.

scholarly journals Leveraging Collective Experience to Digitize the Fossil Insects of Los Angeles

2018 ◽  
Vol 2 ◽  
pp. e26385
Author(s):  
Lindsay Walker ◽  
Erica Krimmel ◽  
Jann Vendetti ◽  
Austin Hendy
Keyword(s):  
United States ◽  
Los Angeles ◽  
The United States ◽  
Fossil Insects ◽  
Test Case ◽  
History Museum ◽  
Fossil Insect ◽  
Research And Education ◽  
La Brea Tar Pits ◽  
Rancho La Brea

The Invertebrate Paleontology Collection at the Natural History Museum of Los Angeles County (NHMLA) has received support from the United States National Science Foundation (NSF DBI 1702342) to digitize the museum’s unique and historic collection of 28,000+ fossil insects. The primary goal of this project, “Fossil Insects of L.A.”, is to increase access to these collections for both research and education. Key collections to be become discoverable through iDigBio and iDigPaleo include the Georg Statz Collection (Oligocene, Rott Formation, Germany) and three faunas from Southern California: Barstow (Miocene), Rancho La Brea (Pleistocene), and McKittrick (Pleistocene). Fossil Insects of L.A. constitutes the final contribution to the Fossil Insect Collaborative Thematic Collections Network (TCN), a consortium of institutions that have been digitizing the largest fossil insect collections in the United States. As a project beginning at the tail-end of the TCN’s active funding, Fossil Insects of L.A. is actively leveraging existing TCN knowledge and resources to streamline workflows and efficiently achieve project goals. In addition to basing imaging and preservation protocols on those designed by TCN partners, Fossil Insects of L.A. is using a layered approach to provide high-quality taxonomic information without sacrificing the pace of specimen digitization. Previously unidentified specimens are initially identified only to Order, allowing them to quickly continue through the digitization process; specimens can then be re-examined by experienced project participants and external experts, who are able to reference the specimen images generated during digitization. A critical and novel aspect of this component of the project’s workflow is the concurrent digitization of the literature associated with the Statz Collection. These data will be used as a test case for the "Enhancing Paleontological and Neontological Data Discovery API" (ePANDDA) project (NSF ICER 1821039), which seeks to associate related datasets found in iDigBio, iDigPaleo, and the Paleobiology Database. Fossil Insects of L.A. will digitize and make 10,960 specimens publically available online, of which over 6,200 will include images. An additional 15,684 specimen records from the Rancho La Brea Tar Pits will also be included in the data mobilization. In doing so, Fossil Insects of L.A. intends to dramatically enhance the research potential of these formerly hidden collections, as well as synthesize and demonstrate digitization best practices generated through the TCN.

scholarly journals Microbial Diversity in Natural Asphalts of the Rancho La Brea Tar Pits

2007 ◽  
Vol 73 (14) ◽  
pp. 4579-4591 ◽  
Author(s):  
Jong-Shik Kim ◽  
David E. Crowley
Keyword(s):  
Los Angeles ◽  
Microbial Diversity ◽  
Rrna Gene ◽  
Dna Encoding ◽  
Phylogenetic Groups ◽  
Wide Range ◽  
Genes Encoding ◽  
Cell Densities ◽  
La Brea Tar Pits ◽  
Rancho La Brea

ABSTRACT Bacteria commonly inhabit subsurface oil reservoirs, but almost nothing is known yet about microorganisms that live in naturally occurring terrestrial oil seeps and natural asphalts that are comprised of highly recalcitrant petroleum hydrocarbons. Here we report the first survey of microbial diversity in ca. 28,000-year-old samples of natural asphalts from the Rancho La Brea Tar Pits in Los Angeles, CA. Microbiological studies included analyses of 16S rRNA gene sequences and DNA encoding aromatic ring-hydroxylating dioxygenases from two tar pits differing in chemical composition. Our results revealed a wide range of phylogenetic groups within the Archaea and Bacteria domains, in which individual taxonomic clusters were comprised of sets of closely related species within novel genera and families. Fluorescent staining of asphalt-soil particles using phylogenetic probes for Archaea, Bacteria, and Pseudomonas showed coexistence of mixed microbial communities at high cell densities. Genes encoding dioxygenases included three novel clusters of enzymes. The discovery of life in the tar pits provides an avenue for further studies of the evolution of enzymes and catabolic pathways for bacteria that have been exposed to complex hydrocarbons for millennia. These bacteria also should have application for industrial microbiology and bioremediation.

Ultrafiltration for asphalt removal from bone collagen for radiocarbon dating and isotopic analysis of Pleistocene fauna at the tar pits of Rancho La Brea, Los Angeles, California

2014 ◽  
Vol 22 ◽  
pp. 85-98 ◽  
Author(s):  
Benjamin T. Fuller ◽  
Simon M. Fahrni ◽  
John M. Harris ◽  
Aisling B. Farrell ◽  
Joan B. Coltrain ◽  
...  
Keyword(s):  
Los Angeles ◽  
Radiocarbon Dating ◽  
Isotopic Analysis ◽  
Bone Collagen ◽  
Rancho La Brea

scholarly journals Project Paleo: Citizen Curation and Community Science at the Natural History Museum of Los Angeles County

2018 ◽  
Vol 2 ◽  
pp. e25980
Author(s):  
Elizabeth Ellwood ◽  
Kathryn Estes-Smargiassi ◽  
Noel Graham ◽  
Gary Takeuchi ◽  
Austin Hendy ◽  
...  
Keyword(s):  
Los Angeles ◽  
Natural History ◽  
Los Angeles County ◽  
Southern California ◽  
The Body ◽  
Natural History Museum ◽  
Background Information ◽  
History Museum ◽  
Identification Guide ◽  
Rancho La Brea

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.

The Sunland Grizzly

2014 ◽  
Vol 91 (4) ◽  
pp. 56-63
Author(s):  
Josh Sides
Keyword(s):  
Los Angeles ◽  
Los Angeles County ◽  
Southern California ◽  
Grizzly Bear ◽  
Science And Art ◽  
Founding Director

In 1916, Cornelius Birket Johnson, a Los Angeles fruit farmer, killed the last known grizzly bear in Southern California and the second-to last confirmed grizzly bear in the entire state of California. Johnson was neither a sportsman nor a glory hound; he simply hunted down the animal that had been trampling through his orchard for three nights in a row, feasting on his grape harvest and leaving big enough tracks to make him worry for the safety of his wife and two young daughters. That Johnson’s quarry was a grizzly bear made his pastoral life in Big Tujunga Canyon suddenly very complicated. It also precipitated a quagmire involving a violent Scottish taxidermist, a noted California zoologist, Los Angeles museum administrators, and the pioneering mammalogist and Smithsonian curator Clinton Hart Merriam. As Frank S. Daggett, the founding director of the Los Angeles County Museum of History, Science and Art, wrote in the midst of the controversy: “I do not recollect ever meeting a case where scientists, crooks, and laymen were so inextricably mingled.” The extermination of a species, it turned out, could bring out the worst in people.

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