Paleontological Fieldwork: 2014

Roland Springs Ranch Locality 1, an earliest Pleistocene fauna
from the Rolling Plains of Scurry County, Texas

Session: June 1st - July 13th

Introduction
Investigations at Roland Spring Ranch represent an aspect of the Lubbock Lake Landmark's regional research program. The regional goal is to understand the dynamics of the interface of grassland faunas and climate reflected in adaptive responses and climate change detected in the paleontological record. Annual excavations at Roland Springs Ranch Locality 1 (RSR-1) have produced a record of the rich diversity of ancient life that existed on the Southern Plains from a time period currently estimated to be earliest Pleistocene (2.0 - 2.6 million years ago).

Fieldwork is based out of a small camp located on the ranch, from which excavations and laboratory work is carried out. Volunteers are trained in field and laboratory methodology, use of surveying equipment, and bone stabilization/conservation. Volunteers are included as members of the research field crew and participate in every aspect of the daily discovery of a wide range of extinct animal remains. Regular trips to Lubbock are made for days off where volunteers stay at the Lubbock Lake Landmark camp and interact with volunteers from the other research stations.

Physiographic Setting
The Roland Springs Ranch is located on the western Rolling Plains, just east of Snyder, Texas. This working ranch is relatively undeveloped and has preserved a number of paleontological as well as archaeological localities. The most prominent features of the landscape are the numerous tributaries of the Brazos River, including the local Clear Fork tributary. Turtle Creek, an ephemeral tributary to the Clear Fork of the Brazos River, has exposed multiple paleontological localities, including RSR-1. The stratigraphy present in Turtle Creek records a dynamic history of several cross-cutting erosional channels and subsequent episodes of deposition. The excavated deposits are contained within an ancestor of the modern drainage channel.

 

Previous Investigations
Exploration on the ranch began in 2005 with the discovery of RSR-1 by the landowners and have continued annually since. The investigations have resulted in the identification of over 50 taxa from a collection of well over 10,000 individual specimens. These faunal remains include representatives of all vertebrate classes (amphibians, birds, reptiles, mammals, and fish) ranging in size from Proboscidenas (elephants and their relatives) to the smallest frogs, songbirds, and mice. The abundance, diversity, and quality of these animal remains make RSR-1 an excellent and important locality for understanding the fauna and environment of the region broadly and, more specifically, the taxonomy and ecology of individual species.

The overwhelming majority of animals documented are extinct species and genera. Notable among the taxa identified from the locality are the remins of giant tortoises (Hesperotestudo), gazelle-horses (Nannippus peninsulatus), rabbits (Leporidae), ancestral coyote (Canis lepophagus), North American cheetah-like cat (Miracinonyx cf. trumani), small carnivores (Procyon, Buisnictis breviramus), and large birds such as the extinct turkey (Meleagris), an extinct eagle (Accipitridae), and a heron/crane (Ardeidae). This diverse fauna, combined with geomorphologic evidence, indicates a riparian setting within a grassland environment, likely lacking seasonal extremes and perhaps with an increased moisture regime relative to today's continental climate. The assemblage of taxa identitifed suggests an approximate age for the locality of earliest Pleistocene, 2.0 million to perhaps as old as 2.6 million years ago, within the Blancan Land Mammal Age.

2014 Fieldwork
Fieldwork for the 2014 season at RSR-1 focuses on both excavation and geological exploration. The broad current objective is to establish the past Pleistocene animals, environment, and climate of the region and secure a better age estimate of the locality. Excavation continues to recover faunal material and trace the eroded contact of the underlying sedimentary unit. Discitntive in color, this unit, apparently Pliocene in age, represents the eroded, oxidized surface of an ancient stream bed within which the faunal material was deposited by later fluvial actions. Excavation seeks to understand the taphonomic processes involved in the deposition, the geomorphology of the deposits, and the identity and paleoecology of the faunal remains.

 

 

Methodology

Field. Primary components of the fieldwork consist of:

- Hand excavation of 1m X 1m units in 10cm levels and 2.5cm sublevels within the defined stratigraphy;
- Recording, mapping, and photographing of material found in situ;
- Recovery of micromaterials from provenienced sediments by water washing through nested fine-mesh screen;
- Fragile bone stabilized initially in the field with conservation grade resin solution prior to removal;
- Plaster jacketing employed for very fragile large specimens;
- Use of standardized Museum forms to record all information.

Laboratory. The on-site lab involves all crew members checking in objects, crosschecking of field forms, and sorting of all resultant concentrates from the water screening of excavated sediments. All recovered objects and documentation are transported to the Landmark's Quaternary Research Center (QRC) for additional processing and analysis.