Serpentine soil
Encyclopedia
A serpentine soil is derived from ultramafic rocks, in particular serpentinite
, a rock formed by the hydration and metamorphic
transformation of ultramafic rock from the Earth's mantle
.
The soils derived from ultramafic bedrock give rise to unusual and sparse associations of edaphic
(and often endemic) plants that are tolerant of extreme soil conditions, including:
These plants are commonly called serpentine endemics, if they grow only on these soils. Serpentinite is composed of the mineral serpentine, but the two terms are often both used to mean the rock, not its mineral composition.
For instance, in areas where these ultramafic rocks are patchy, such as the Klamath Basin
region of northern California, the areas of serpentine soil can be clearly seen as sparsely covered areas bounded by forest on the normal soils.
s, many of which are rare
or endangered species
such as Acanthomintha duttonii
, Pentachaeta bellidiflora
, and Phlox hirsuta
. In California, shrubs such as leather oak (Quercus durata
) and coast whiteleaf manzanita (Arctostaphylos viscida ssp. pulchella) are typical of serpentine soils.
has a mottled, greenish-gray color with a waxy feel to it. These rocks form by the reaction of olivine
-rich rock, peridotite
, with water.
It forms in oceanic crust
near the surface of the earth, particularly where water circulates in cooling rock near mid-ocean ridge
s: masses of the resulting ultramafic rock are found in ophiolites incorporated in continental crust
near present and past plate tectonic
boundaries.
of eastern North America.
. As those plants developed specialized processes to exist in a metal-saturated environment, the process (also known as bioremediation
) utilizes them to treat environmental problems by consuming those minerals from polluted soil.
found in parts of the United States
in small but widely-distributed areas of the Appalachian Mountains
and the Coast Ranges of California
, Oregon
, and Washington. The barrens occur on outcrops of altered ultramafic ophiolites.
They are named for minerals of the serpentine group, resulting in serpentine soils, with unusually high concentrations of iron
, chromium
, nickel
and cobalt
. Serpentine barrens often consist of grassland
or savannas in areas where the climate
would normally lead to the growth of forests.
The ecology of serpentine barrens is poorly understood: the evolution of plants adapted to such areas and the relationship between the soil geology and ecology, particularly the ways in which plants handle high concentrations of metals such as nickel, is largely unexplored.
and skippers
.
In Chester County, PA, the Nottingham Park Serpentine Barrens was recommended by UMCES as deserving of National Natural Landmark
designation, on numerous grounds, including supporting a number of rare and endemic species, an intact population of pitch pine
, and also the site having historic significance.
Serpentinite
Serpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle...
, a rock formed by the hydration and metamorphic
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
transformation of ultramafic rock from the Earth's mantle
Mantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....
.
The soils derived from ultramafic bedrock give rise to unusual and sparse associations of edaphic
Edaphic
Edaphic is a nature related to soil. Edaphic qualities may characterize the soil itself, including drainage, texture, or chemical properties such as pH. Edaphic may also characterize organisms, such as plant communities, where it specifies their relationships with soil...
(and often endemic) plants that are tolerant of extreme soil conditions, including:
- low calcium-to-magnesium ratio
- lack of essential nutrients such as nitrogenNitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, potassiumPotassiumPotassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
, and phosphorusPhosphorusPhosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks... - high concentrations of the heavy metals (more common in ultramafic rocks).
These plants are commonly called serpentine endemics, if they grow only on these soils. Serpentinite is composed of the mineral serpentine, but the two terms are often both used to mean the rock, not its mineral composition.
As ecologic indicator
Excellent examples of serpentine soils and the distinctive ecologic communities associated with them have been described in western North America.For instance, in areas where these ultramafic rocks are patchy, such as the Klamath Basin
Klamath Basin
The Klamath Basin is the region in the U.S. states of Oregon and California drained by the Klamath River. It contains most of Klamath County and parts of Lake and Jackson counties in Oregon, and parts of Del Norte, Humboldt, Modoc, Siskiyou, and Trinity counties in California. The drainage basin...
region of northern California, the areas of serpentine soil can be clearly seen as sparsely covered areas bounded by forest on the normal soils.
Botany
Areas of serpentine soil are also home to diverse wildflowerWildflower
A wildflower is a flower that grows wild, meaning it was not intentionally seeded or planted. Yet "wildflower" meadows of a few mixed species are sold in seed packets. The term "wildflower" has been made vague by commercial seedsmen who are interested in selling more flowers or seeds more...
s, many of which are rare
Rare species
A rare species is a group of organisms that are very uncommon or scarce. This designation may be applied to either a plant or animal taxon, and may be distinct from the term "endangered" or "threatened species" but not "extinct"....
or endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
such as Acanthomintha duttonii
Acanthomintha duttonii
Acanthomintha duttonii is a species of annual plant endemic to San Mateo County, California in the Lamiaceae family. It is commonly called San Mateo Thornmint or Dutton's acanthomintha and is found growing on Serpentine soils near the Crystal Springs Reservoir in a six mile long strip on the east...
, Pentachaeta bellidiflora
Pentachaeta bellidiflora
Pentachaeta bellidiflora is a Californian wildflower in the genus Pentachaeta of the family. It is included in both the state and federal lists of endangered species....
, and Phlox hirsuta
Phlox hirsuta
Yreka phlox is a species of phlox. It is a small flowering plant that grows in the serpentine soils of Siskiyou County, California and is the official city flower of Yreka, California, after which it is named.-Description:Yreka phlox plants grow to a height of up to six inches, with thick hairy...
. In California, shrubs such as leather oak (Quercus durata
Quercus durata
Quercus durata is an oak endemic to California.Quercus durata var. durata is a strict serpentine endemic that occurs in the Coast Range and northern Sierra Nevadas. It is often a component of serpentine chaparral...
) and coast whiteleaf manzanita (Arctostaphylos viscida ssp. pulchella) are typical of serpentine soils.
Parent rock
Serpentine-rich rock or serpentiniteSerpentinite
Serpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle...
has a mottled, greenish-gray color with a waxy feel to it. These rocks form by the reaction of olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....
-rich rock, peridotite
Peridotite
A peridotite is a dense, coarse-grained igneous rock, consisting mostly of the minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica. It is high in magnesium, reflecting the high proportions of magnesium-rich olivine, with appreciable iron...
, with water.
It forms in oceanic crust
Oceanic crust
Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium...
near the surface of the earth, particularly where water circulates in cooling rock near mid-ocean ridge
Mid-ocean ridge
A mid-ocean ridge is a general term for an underwater mountain system that consists of various mountain ranges , typically having a valley known as a rift running along its spine, formed by plate tectonics. This type of oceanic ridge is characteristic of what is known as an oceanic spreading...
s: masses of the resulting ultramafic rock are found in ophiolites incorporated in continental crust
Continental crust
The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to more felsic, or granitic, bulk composition, which lies in...
near present and past plate tectonic
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
boundaries.
Distribution
Serpentine soils are widely distributed on Earth, in part mirroring the distribution of ophiolites. Although it covers only about 1 percent of the state's surface, the state rock of California is serpentine. One such area in California is the Edgewood Park and Natural Preserve. Serpentine soils also are present in small but widely distributed areas within the Appalachian mountainsAppalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
of eastern North America.
Serpentine endemism and bioremediation
The unique plants that survive in serpentine soils have been used in the process of phytoremediationPhytoremediation
Phytoremediation Phytoremediation Phytoremediation (from the Ancient Greek , and Latin (restoring balance or remediation) describes the treatment of environmental problems (bioremediation) through the use of plants that mitigate the environmental problem without the need to excavate the...
. As those plants developed specialized processes to exist in a metal-saturated environment, the process (also known as bioremediation
Bioremediation
Bioremediation is the use of microorganism metabolism to remove pollutants. Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated...
) utilizes them to treat environmental problems by consuming those minerals from polluted soil.
Serpentine barrens
Serpentine barrens are a unique ecosystemEcosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
found in parts of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in small but widely-distributed areas of the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
and the Coast Ranges of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
, and Washington. The barrens occur on outcrops of altered ultramafic ophiolites.
They are named for minerals of the serpentine group, resulting in serpentine soils, with unusually high concentrations of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
, nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
and cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....
. Serpentine barrens often consist of grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
or savannas in areas where the climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
would normally lead to the growth of forests.
The ecology of serpentine barrens is poorly understood: the evolution of plants adapted to such areas and the relationship between the soil geology and ecology, particularly the ways in which plants handle high concentrations of metals such as nickel, is largely unexplored.
Examples
Rock Springs Nature Preserve in Lancaster County, PA is a 176 acre (0.71224736 km²) property conserved by the Lancaster County Conservancy that is a prime example of a serpentine barren. It was originally a grassland, but fire suppression led to the conversion of the area to forest. This barren contains the rare serpentine aster, as well as a number of rare species of mothMoth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
and skippers
Skipper (butterfly)
A skipper or skipper butterfly is a butterfly of the family Hesperiidae. They are named after their quick, darting flight habits. There are more than 3500 recognized species of skippers and they occur worldwide, but with the greatest diversity in the Neotropical regions of Central and South...
.
In Chester County, PA, the Nottingham Park Serpentine Barrens was recommended by UMCES as deserving of National Natural Landmark
National Natural Landmark
The National Natural Landmark program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only natural areas program of national scope that identifies and recognizes the best examples of biological and geological features in...
designation, on numerous grounds, including supporting a number of rare and endemic species, an intact population of pitch pine
Pitch Pine
The Pitch Pine, Pinus rigida, is a small-to-medium sized pine, native to eastern North America. This species occasionally hybridizes with other pine species such as Loblolly Pine , Shortleaf Pine , and Pond Pine The Pitch Pine, Pinus rigida, is a small-to-medium sized (6-30 meters or 20-100 feet)...
, and also the site having historic significance.
See also
- Pygmy forestPygmy forestA pygmy forest is a forest which, for pedological and geological reasons, contains only miniature trees. Pygmy forests may occur over various world locations with notable occurrences being noted in the literature of the: California coastal terraces and inner coastal mountains of Northern...
- Serpentine
- SerpentiniteSerpentiniteSerpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle...
- Ultramafic rock