The Snowmastodon site, also known as the Ziegler Reservoir fossil site, is the location of an important
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
excavation near
Snowmass Village, Colorado
Snowmass Village is a home rule municipality in Pitkin County, Colorado, United States. The population was 2,826 at the 2010 census. A popular winter resort location for skiing and snowboarding, the town is well known as the location of the Sno ...
. Fossils were first discovered on October 14, 2010, during the construction of a reservoir to supply Snowmass Village with water.
Over the subsequent weeks, after an agreement had been reached to allow paleontological excavation, crews from the
Denver Museum of Nature & Science
The Denver Museum of Nature & Science is a municipal natural history and science museum in Denver, Colorado. It is a resource for informal science education in the Rocky Mountain region. A variety of exhibitions, programs, and activities help mus ...
and the
U.S. Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...
worked along with the construction crews as more fossil material was uncovered.
The site closed for five months over the winter, reopening May 15, 2011. Between May 15 and July 4, 2011, crews from the Denver Museum of Nature & Science conducted a large scale fossil excavation alongside construction crews building a dam for the reservoir. In total over 36,000
vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
fossils (including
mammoths
A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks and, ...
,
mastodons
A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of th ...
,
ground sloths
Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. The term is used to refer to all extinct sloths because of the large size of the earliest forms discovered, compared to existing tree sloths. The Carib ...
,
horses
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...
,
camels
A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. C ...
and
deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...
), more than 100 species of fossil
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s and over 100 species of fossil plants were found in sediments deposited by an alpine lake during the last
interglacial period
An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene in ...
.
Discovery
![Mammut americanum Sergiodlarosa](https://upload.wikimedia.org/wikipedia/commons/0/04/Mammut_americanum_Sergiodlarosa.jpg)
The fossil site was discovered on October 14, 2010, by Gould Construction Inc. crews who had been employed by the Snowmass Water and Sanitation District (SWSD) to expand the
Ziegler Reservoir and provide additional water supplies to the nearby town of
Snowmass Village
Snowmass Village is a home rule municipality in Pitkin County, Colorado, United States. The population was 2,826 at the 2010 census. A popular winter resort location for skiing and snowboarding, the town is well known as the location of the Sn ...
.
[
][
][
]
While clearing the perimeter of the reservoir,
bulldozer
A bulldozer or dozer (also called a crawler) is a large, motorized machine equipped with a metal blade to the front for pushing material: soil, sand, snow, rubble, or rock during construction work. It travels most commonly on continuous track ...
operator Jesse Steele unearthed the first animal bones.
[
]
Recognizing them as possible fossils, Steele informed project foreman, Kent Olson. Olsen took the bones home and identified them as belonging to a mammoth using sources he found on the internet. The next morning, Kit Hamby, the district manager for the Snowmass Water and Sanitation District (SWSD), contacted a contractor from the Colorado Geological Survey who contacted the Denver Museum of Nature & Science (DMNS).
The DMNS reached an agreement with the SWSD to allow the museum to excavate the fossils.
Crews from the Denver Museum, U.S. Geological Survey, and several other institutions work alongside bulldozers for two weeks in order to salvage the increasing number of fossils being unearthed.
The onset of winter caused the site to be closed for five months beginning November 15.
When the excavation resumed on May 15, 2011, museum crews had 7 weeks to complete the excavation in order for the reservoir project to be completed on time.
By the time excavation had been completed, the team consisting of more than 250 volunteers and 40 project scientists removed approximately 8000 cubic meters of sediment.
Thousands of fossils were collected along with stratigraphic, geochronologic, palynologic, paleoentomologic, and paleobotanic data that was subsequently used to reconstruct the paleoecosystem at ancient Lake Ziegler.
Snowmastodon Project
A $10.5 million dam for the reservoir was scheduled to be completed by mid-October 2011, with the site was expected to be underwater by November 2011.
For that reason, any paleontological excavation had to be done quickly.
The excavations were led by the Denver Museum of Nature & Science, together with the U.S. Geological Survey and scientists from at least 19 institutions.
The Snowmastodon Project, as the efforts had been dubbed, cost approximately $1 million, including public outreach programs.
Half of the costs were covered by grants and gifts to the museum, while the rest came from donations.
The first scientific excavation officially began on November 2, 2010. It involved 67 workers from the Denver Museum of Nature & Science, and lasted 12 days. Preliminary efforts concluded on November 14, 2010, when the arrival of winter prevented any further excavation.
[
] The site and fossils left ''in situ'' were protected with frost-free barrier and the recovered fossils taken to the conservation laboratory of the DMNS. More than 600 bones and 130 plant, rock, and invertebrate samples were recovered, including the first mastodon skull ever recovered in Colorado (unearthed a mere day after the beginning of the excavation) and the first remains of a Jefferson's ground sloth to be found in the state. Other
megafauna
In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common threshold ...
recovered included
giant bison
''Bison latifrons'', also known as the giant bison or long-horned bison, is an extinct species of bison that lived in North America during the Pleistocene epoch ranging from Alaska to Mexico. It was the largest and heaviest bovid ever to live in ...
, two
deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...
-like animals, and more mammoths.
Excavations resumed during spring of 2011, from May 15 to July 4, with the support and permission of SWSD and the State of Colorado.
By the end of July, the total number of bones recovered was around 36,000, from at least 52 different Ice Age vertebrate animals.
Approximately 3,000 of them are believed to come from
mastodon
A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of th ...
s of both sexes and of varying ages, from infants to full adults.
Other new animals recovered included an Ice Age camel, a horse, and various smaller vertebrates.
A small excavation crew from the museum remained at the site, in the event further discoveries were made in the course of the dam construction.
The speed at which the fossils were recovered (more or less seven weeks) is remarkable for a scientific dig of this size. Kirk R. Johnson, leader of the Snowmastodon Project on behalf of the Denver Museum of Nature & Science, told the New York Times, ''"The speed of this thing is so unlike normal science — from discovery to completion of one of the biggest digs ever in less than nine months."''
[
Scientists are not concerned now that the site is covered by water after completion of the reservoir expansion. Being underwater helps preserve the fossils and the reservoir can be drained if ever the need arises for additional excavations.]
Importance
The Ziegler Reservoir fossil site is one of the few localities in North America from the Sangamonian Stage, and the only one at high elevation. This site preserves multiple alpine ecosystems stacked on top of each other within sediments of ancient alpine lake. Among the vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
fauna, this site represents highest known elevations of a number of species. Additionally, this site holds the record for the most mastodons preserved in a single location, including the largest mastodon ever found. The fossil flora offer unprecedented insights into plant biogeography of the Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
during the last interglacial period.
The site is also important for the exceptional preservation of fossil material. Fossil sedge and willow leaves were still green, conifer cones were still intact, and large driftwood logs were preserved. In addition, the mollusks and gastropods showed color, and beetle parts were still iridescent. Vertebrate fossil material was in excellent condition as well.
The National Geographic Society
The National Geographic Society (NGS), headquartered in Washington, D.C., United States, is one of the largest non-profit scientific and educational organizations in the world.
Founded in 1888, its interests include geography, archaeology, and ...
, which donated a $55,000 grant to the project, featured the site in the ''National Geographic Magazine
''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
'' . The science television series ''Nova
A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramati ...
'' broadcast an episode about the site in February, 2012.
Geologic setting and geochronology
The Ziegler Reservoir occupies an unusual geologic setting on top of a ridge above sea level. The lake basin was formed when a glacier flowing down Snowmass Creek Valley became thick enough to overtop the adjacent ridgeline. As the glacier retreated, a moraine impounded a 5 hectare alpine lake that was initially 10 meters deep. Over time, the lake filled in with wind-blown sediments until it became a marshland and ultimately an alpine meadow. After Doug Ziegler and his family purchased the land that now contains the Ziegler Reservoir, they commissioned the construction of a small earthen dam in 1961 to block the meadow drainage and form a shallow, private lake that persisted until the Snowmass Water and Sanitation District bought the water rights in 2010.
Several dating techniques were employed in order to determine the age of the ancient lake sediments. Attempts at radiocarbon
Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ...
dating of lake organics, bone collagen and shell carbonate, revealed that the site was radiocarbon dead or greater than 45,000 years old. ''In situ'' cosmogenic beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form mi ...
and aluminum
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
from a boulder that was part of the bounding moraine yielded an age of approximately 140,000 years old. Uranium-series dating of vertebrate fossils confirmed the age range of 45,000-140,000 years; however, the extremely low uranium concentrations limited the utility of that method. Optically stimulated luminescence
In physics, optically stimulated luminescence (OSL) is a method for measuring doses from ionizing radiation. It is used in at least two applications:
* Luminescence dating of ancient materials: mainly geological sediments and sometimes fired pott ...
(OSL) ages obtained from the fine-grained quartz provided reliable, replicable ages for the sediments within the established 45,000 – 140,000 time frame. The dates obtained via OSL correlate with the end of the Bull Lake glaciation and the Sangamon interglacial stage, spanning marine isotope stage
Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data reflecting changes in temperature derived from data ...
s 6 through 4.
Vertebrate fauna
Over 36,000 bones and teeth belonging to 52 taxa
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...
of macro- and microvertebrates were uncovered during the construction of Ziegler Reservoir. These taxa represent a diverse assemblage of fauna belonging to the Rancholabrean
The Rancholabrean North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from less than 240,000 years to 11,000 years BP, a p ...
North American Land Mammal Age
The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when ref ...
. The smaller vertebrate species include: trout
Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salmoni ...
, frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
, salamander
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten ...
, snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
, lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
, duck
Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form t ...
, goose
A goose ( : geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera ''Anser'' (the grey geese and white geese) and '' Branta'' (the black geese). Some other birds, mostly related to the ...
, pheasant
Pheasants ( ) are birds of several genera within the family (biology), family Phasianidae in the order (biology), order Galliformes. Although they can be found all over the world in introduced (and captive) populations, the pheasant genera na ...
, crane, finch
The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where they are usua ...
, shrew
Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different fa ...
, river otter, bear
Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Nor ...
, coyote
The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...
, rabbit
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...
, chipmunk
Chipmunks are small, striped rodents of the family Sciuridae. Chipmunks are found in North America, with the exception of the Siberian chipmunk which is found primarily in Asia.
Taxonomy and systematics
Chipmunks may be classified either as ...
, squirrel
Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...
, beaver
Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...
, mice
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
and other small rodents
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...
. The most abundant species found throughout the site is the tiger salamander
The tiger salamander (''Ambystoma tigrinum'') is a species of mole salamander and one of the largest terrestrial salamanders in North America.
Description
These salamanders usually grow to a length of with a lifespan of around 12–15 years. ...
.
Also represented in the Ziegler Reservoir are the remains of seven megafauna taxa. These taxa include:
* Columbian mammoth
The Columbian mammoth (''Mammuthus columbi'') is an extinct species of mammoth that inhabited the Americas as far north as the Northern United States and as far south as Costa Rica during the Pleistocene epoch. It was one of the last in a line ...
(''Mammuthus columbi''): Four individuals, including the first fossil recovered from the site (a juvenile nicknamed 'Snowy') were collected.
* American mastodon
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
(''Mammut americanum''): The Ziegler Reserver is the largest site for mastodons in the world with at least 35 individuals present. Approximately 60% of the total number of vertebrate elements recovered belong to the American mastodon.
* Jefferson's ground sloth (''Megalonyx jeffersonii''): Three individuals, one adult and two juveniles, were found at the site. This marks the first time this species has been found in Colorado.
* Giant bison
''Bison latifrons'', also known as the giant bison or long-horned bison, is an extinct species of bison that lived in North America during the Pleistocene epoch ranging from Alaska to Mexico. It was the largest and heaviest bovid ever to live in ...
(''Bison latifrons''): At least 10 individuals were found making the Ziegler Reservoir one of only three sites to produce multiple individuals of ''B. latifrons'' and the highest known elevation for this species.
* Deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...
: At least two individuals of indeterminate species.
* Camelops
''Camelops''Being occasionally called ''Western Camel'' or ''Yesterday's Camel''. is an extinct genus of camels that lived in North and Central America, ranging from Alaska to Guatemala, from the middle Pliocene to the end of the Pleistocene. It ...
: A single tooth belonging to the extinct camel genus ''Camelops'' was found in lake-center deposits. This is the highest known elevation for this genus.
* Horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million y ...
: A single foot bone from an indeterminate species of '' Equus''.
Invertebrate fauna
; Fossil insects
A total of 99 taxa of insect were identified from samples spanning the interval of 125,000 to 77,000 years ago. These fossils are the oldest known Pleistocene high elevation insect faunas from the Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
. The fossil assemblages were dominated by beetles
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
, ants
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,00 ...
, midges
A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some midg ...
, and caddisflies
The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the b ...
, which were used to document the climatic oscillations during the time represented by the samples.
; Mollusks and ostracodes
Sediments containing terrestrial and aquatic mollusks
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
and ostracods
Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typical ...
span 130,000 to 87,000 years ago. These sediments produced 12 identifiable taxa of terrestrial gastropods, 5 taxa of aquatic bivalves, 8 taxa of aquatic gastropods, along with 7 taxa of ostracodes. These taxa indicate that the ancient lakeshore was a shallow, well-vegetated, fresh water wetland during the time periods sampled.
Fossil flora
A diverse assemblage of plant macrofossils and pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
was collected during Snowmastodon. Approximately 99 taxa of plant macrofossil, including seeds
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...
, leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
, needles, cones
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines conn ...
, twigs
A twig is a thin, often short, branch of a tree or bush.
The buds on the twig are an important diagnostic characteristic, as are the abscission scars where the leaves have fallen away. The color, texture, and patterning of the twig bark are ...
and wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...
were identified. Over 300 specimens of fossil wood were collected ranging in size from small stems to logs greater than 50 cm in diameter and more than 10 m in length. The majority of wood fossils came from the “beach” horizon at the lake margin. Species of fir
Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family (biology), family Pinaceae. They are found on mountains throughout much of North America, North and Central America, Europe, Asia, and North Africa. The ...
, Douglas fir
The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...
, spruce
A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...
and pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...
were represented. The pollen collected includes species of sagebrush
Sagebrush is the common name of several woody and herbaceous species of plants in the genus ''Artemisia''. The best known sagebrush is the shrub ''Artemisia tridentata''. Sagebrushes are native to the North American west.
Following is an alph ...
, spruce, pine, oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
, Douglas fir, fir, juniper
Junipers are coniferous trees and shrubs in the genus ''Juniperus'' () of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere, from the Arcti ...
, as well as herbaceous
Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.
Definitions of "herb" and "herbaceous"
The fourth edition of t ...
and aquatic plants
Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...
.
See also
* Denver Museum of Nature and Science
The Denver Museum of Nature & Science is a municipal natural history and science museum in Denver, Colorado. It is a resource for informal science education in the Rocky Mountain region. A variety of exhibitions, programs, and activities help mus ...
* List of fossil sites
This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there. Many of t ...
* Pitkin County, Colorado
Pitkin County is a county in the U.S. state of Colorado. As of the 2020 census, the population was 17,358. The county seat and largest city is Aspen. The county is named for Colorado Governor Frederick Walker Pitkin. Pitkin County has the sev ...
* Pleistocene megafauna
Pleistocene megafauna is the set of large animals that lived on Earth during the Pleistocene epoch. Pleistocene megafauna became extinct during the Quaternary extinction event resulting in substantial changes to ecosystems globally. The role of hu ...
* Snowmass Village, Colorado
Snowmass Village is a home rule municipality in Pitkin County, Colorado, United States. The population was 2,826 at the 2010 census. A popular winter resort location for skiing and snowboarding, the town is well known as the location of the Sno ...
* Southern Rocky Mountains
The Southern Rocky Mountains are a major subregion of the Rocky Mountains of North America located in the southeastern portion of the U.S. state of Wyoming, the central and western portions of Colorado, the northern portion of New Mexico, and ex ...
References
{{Reflist, 30em
External links
"Ice Age Death Trap"
Episode of PBS
The Public Broadcasting Service (PBS) is an American public broadcasting, public broadcaster and Non-commercial activity, non-commercial, Terrestrial television, free-to-air television network based in Arlington, Virginia. PBS is a publicly fu ...
's ''Nova
A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramati ...
'' on the Snowmastodon excavation project, broadcast February 1, 2012 (archive; introduction only)
2010 in paleontology
Cenozoic paleontological sites of North America
Geography of Pitkin County, Colorado
Paleontology in Colorado