absolute dating - Dating methods that determine time without ambiguity
to a known level of accuracy. Most radioactive decay-based methods are
accumulation - Used in Paleoclimatology to describe the deposition
of sediment or other material over time. Accumulation rates are usually
measured as mass/time, volume/time, or mass/length2/time. aerosols - A suspension of solid or liquid
particles in a gas, for example sulfate molecules (SO4-)
found in the earth atmosphere.
albedo - The percentage of solar radiation that is reflected relative
to the total incoming radiation.
alkaline - A substance which, when added to water, decreases the
hydrogen-ion concentration; a solution containing a base, a substance
that combines with a hydrogen ion in solution.
altithermal - A period of high temperature; a postglacial thermal
algae - Single-celled, multi-celled or colonial marine or freshwater
plants that contain chlorophyll; they don't have true roots, stems or
leaves and also do not flower or contain seeds
altiplano - A high elevation plateau in southeastern Peru and western
Bolivia, elevation about 3500 m.
angiosperms - The flowering seed plants, as differentiated from
gymnosperms, the non-flowering seed plants.
anthropogenic - Generated by the actions of humans.
aphelion- The point
in the earth's orbit furthest away from the sun.
aquatic macrophytes - Aquatic plants that are found in the near-shore
arid - Lacking
moisture, especially having insufficient rainfall to support trees or
- The whole mass of gases surrounding the earth or other celestial
bodies. Today's atmosphere is made up primarily of nitrogen (78%), free
oxygen (21%) and greenhouse gases which can capture solar radiation: water
vapor, which ranges from less than 1% in arid regions to over 3% in moist
areas, carbon dioxide (0.035%) and methane (0.00018%). In the past the
composition of the Earth's atmosphere has varied.
that are able to produce their own food through processes such as photosynthesis.
B basal sediments - Till carried at or deposited from the under
surface of a glacier.
bedrock substrate - Solid, in place rock underlying unconsolidated
sediments or other superficial material
- Single-celled amimals that live near the sediment water interface and
have calcium carbonate skeletons. The skeletons of benthic foraminifers
are often preserved in ocean sediments, providing a rich fossil record
of the environmental conditions of the lake.
Bergmann's Rule - An ecological theory that proposes there is
an inverse relationship between environmental temperature and an organism's
carbon dating - A dating method that uses the disintegration of the
14C atom to determine the age of sample containing carbon.
14C is produced in the atmosphere by cosmic ray bombardment,
and has a half-life of 5570 years, making it useful for dating samples
in the range of 0-40,000 years.
celestial equator - The great circle on the celestial sphere midway
between the celestial poles (the projection of the north and south pole
onto the celestial sphere).
celestial sphere - An imaginary sphere of infinite radius, on
which the stars appear to be placed.
calcium carbonate(CaCO3) - A molecule consisting
of calcium, carbon and oxygen that is secreted by corals, forming their
skeleton; it also secreted by mollusks (clams, oysters, etc.), forming
their protective shells.
calcium concentrations - Concentration (units mass/mass) of the
calcium ion (Ca+), often found in layers of ice, and derived
from atmospheric transport of dust.
calving - To separate or break so that a part becomes detached.
chronology - A general term for the age-depth relationship in ice,
sediment, or another deposit. Ages are usually measured for discrete samples,
and the ages of intermediate samples is interpolated between samples with
Classic Collapse - Collapse of the Maya civilization that occurred
between 800 and 900 A.D.. Symptoms of the collapse included abandonment
of the countryside and ceremonial centers as well as a cessation of cultural
clast - Fragment of rock.
climate - Long term characteristics of weather.
climatic feedback mechanisms - A feedback is an enhancement (positive feedback)
or a damping (negative feedback) of an initial change, in this case in
the climate system. For example, when less energy reaches the earth, temperature
decreases and the area covered by snow increases. The albedo of the planet
increases, reflecting more solar energy back into space. Consequently
less energy is absorbed at the surface, and temperature further decreases.
The whole "cycle" from the initial cooling to the further cooling is a
feedback. It is a positive feedback in this example.
clone - An individual, identical to the parent organism, created
by the splitting or budding of cells from the parent organism.
processes - tectonic movements that relate to the continental land
coral bleaching - An environmental stress indicator for coral; if
conditions for corals are not optimum, the corals will expel the algae
that live among the living polyps, therefore giving the colony a bleached
crossdating - The procedure of matching and synchronizing ring-width
variations and other structural characteristics among trees that have
grown in nearby areas, allowing the identification of the exact year in
which the ring was formed.
- The portion of the world's climate system which consists of snow and
D Dansgaard-Oeschger cycles - Climate oscillations averaging a few
thousand years in duration that dominate Greenland ice-core records.
debris slide - Downward movement of unconsolidated mass of mud,
sediment, and rock.
dendrochronology - A science based on the exact calendar dating
of annual growth rings in wood.
dendroclimatology - A subfield of dendrochronology, which
investigates the climatic effect on tree growth, and uses dated tree rings
to reconstruct and study past and present climate.
density - The mass per unit volume of a substance under specified
conditions of pressure and temperature.
detrital carbonate - Crystalline calcium carbonate found in ocean
sediments, usually derived from continental weathering of carbonate rock.
Detrital carbonate is more resistant to dissolution compared to the calcium
carbonate produced by plankton that falls directly to the seafloor.
diatom - Single celled phytoplankton that produce silica skeletons.
Diatoms are one of the most abundant, widely distributed primary producers
in the ocean. Different species of diatoms living in ocean and lakes have
affinities for different environmental conditions such as alkalinity,
available nutrients, salinity and acidity.
Diluvian Theory - Theory that attributed most geological features
of the earth to the great flood described in the Bible.
cycle - Mean solar day occurring as Earth rotates from east to west
on its axis.
dolomite - Mineral consisting of calcium, magnesium carbonate
found in crystals, and in extensive beds as a compact limestone -- CaMg(CO3)2.
Dreizack seamounts - A chain of extinct underwater volcanoes rising
1000m or higher above the sea floor, either flat-topped or peaked and
located in the eastern North Atlantic.
earlywood - The portion of the annual ring produced early in the growing
season, characterized by large, thin-walled cells. Earlywood is
more porous than latewood, and often lighter in color. Also known
eccentricity - The amount that the
earth's revolution deviates from a circular path; the variation of an
ellipse from a circle, where a circle has an eccentricity of 0.
ecliptic - The apparent path of the sun on the celestial sphere,
also used for the plane in which the motion of the earth around the sun
ecosystem - Relationships between and among living organisms and
their non-living environment.
El Niño - The appearance of unusually warm waters in the
eastern Pacific; termed the "Christ child," because of the time of year
it effects the South American coastline.
ENSO - An acronym for
El Niño Southern Oscillation
epidermis - The outermost layer of skin cells.
equinox - Either of two points on the celestial sphere where the
celestial equator intersects the ecliptic; either of the two times each
year when the sun crosses the equator, and day and night are of equal
length (spring equinox, fall equinox).
erratics - Large boulders displaced from their natural geologic
location by glaciers.
evolutionary change - Either phenotypic or genetic changes that
occur in an organism from generation to generation through the exchange
exine - The outer wall layer of a spore or pollen grain.
false ring - A change in cell structure within an annual growth layer,
which resembles the boundary of a true annual ring, making it appear to
be two or more growth layers instead of one. Also known as a double
ring or an intra-annual ring.
fault depression - Basin formed by the downward movement of the
earth's crust at a geological fault.
fault line- A brittle fracture across which relative movement of
rocks has occurred.
firn - Granular, partially consolidated snow that has passed through
one summer melt season but is not yet glacial ice. Also called old snow.
fossil air - A sample of air that preserves the composition of the
environment at the time it was deposited. Bubbles found in ice cores are
one example of fossil air that records the atmospheric composition of
the atmosphere at the time the ice was formed.
gamete - Egg or sperm cell that combines with a gamete of the opposite
sex to form a zygote cell.
gastropods - Class of mollusks that includes snails.
glacier - River of ice that under pressure can deform
and flow plastically.
geologic time scale - Relative time scale based onstratigraphic
position and correlation, and many different types of chronologic evidence.
Geologic time is broken down into eons, eras, periods and epochs.
GISP2 - Greenland Ice Sheet Project 2, the second phase of an effort
by a group of scientists to produce long records of climate by drilling
into the Greenland Ice Sheet from the surface to bedrock.
global warming - an increase in temperature that occurs globally such
as the interglacial warming period the earth experienced after the last
Ice Age, or that predicted to result from human increases in greenhouse
greenhouse gases - Any one of the gases found in the atmosphere
(including CO2, H2O, CH4) that act to
allow short wave radiation from the sun to reach the earth, but which
absorbs outgoing long wave radiation from the earth surface.
"greenhouse effect" - The process by which the equilibrium
temperature of the earth is increased due to presence of gases in the
atmosphere that absorb outgoing longwave radiation.
growth band - The secretion of CaCO3 by coral forms
yearly growth bands; one yearly growth band contains two smaller bands
representing winter growth and summer growth.
gymnosperms - The non-flowering seed plants, as differentiated from angiosperms,
the flowering seed plants.
habitat - Location where a plant or animal species naturally lives
half-life - The time required for half the nuclei in a sample
of a specific isotopic species to undergo radioactive decay.
hemipelagic sediments - Deep-sea sediment in which more than 25% of
the fraction coarser than 5 microns is of terrigenous, volcanogenic, and/or
neritic origin. Such deposits usually accumulate near the continental
heterotrophs - Organisms that are unable to produce their own food,
therefore they consume other organisms (plants or animals) to obtain energy.
Holocene epoch - An epoch of the Quaternary
period dating from the end of the Pleistocene approximately 11,000 years
ago until the present.
- Any of a family (Hominidae) of erect bipedal primate mammals comprising
recent humans together with extinct ancestral and related forms
I Ice Age - Period during which polar ice extends to much lower
latitudes than normal.
ice rafted detritus - Continental material transport within a matrix
of ice and deposited in marine sediments when the ice matrix melts.
ice sheet margin - Edge of the ice sheet where melting and calving
of icebergs occurs.
ice streams - Rapidly flowing ice generally in the bottom of an
ice sheet and flowing from the middle to the ice sheet margin.
increment borer - A manual tool used to bore and extract a thin cylinder
of wood from tree stems.
Indonesian Low - The low pressure, or cyclonic air circulation, normally
found in the western tropical Pacific and Indonesia, associated with a
large, deep layer of warm ocean water.
insolation - Amount of solar radiation
received on a given body or in a given area.
Intertropical Convergence Zone - The region that circles the Earth,
near the equator, where the trade winds of the Northern and Southern Hemispheres
ion - Atoms that have either a positive or negative charge.
isotope - A form of a specific element that has the same number
of protons, but differs in the number of neutrons; forms of the same element
that have different mass numbers.
Jurassic period - The second period of the Mesozoic era, thought
to have covered the span of time between 190 and 135 million years ago.
karstic - Comprised of limestone.
keystone species - A species that exerts a major influence on
the composition and dynamics of the community in which it lives.
latewood - Dense, often dark, and heavily lignified wood produced in the
annual ring during the later part of the growing season, characterized
by small, thick-walled cells. Also known as summerwood.
littoral zone - Area of shore between mean high water and mean
lithic - Made of rock.
locally absent ring - A growth ring that is discontinuous around the
stem so that it is absent along certain radii; also referred to as a partial ring or missing ring.
A wind-deposited sediment consisting mostly of silt, the silt commonly
derived from finely ground rock washed out of continental glaciers.
of fresh water derived from the melting of glacial ice that floats in
large bodies of salt water.
Mesoamerica - Continental
North America south of Mexico that is usually considered to comprise the
present day countries of Guatemala, Belize, El Salvador, Honduras, Nicaragua,
Costa Rica, and Panama.
methane (CH4) - An odorless, colorless, flammable gas,
the major constituent of natural gas, and produced by a variety of natural
Miocene epoch - An epoch of the early Tertiary period, found in-between
the Oligocene and the Pliocene eras.
morphology - The scientific study of organic form, including both
its development and its function.
natural climate record - A record of climatic events found by examining
the natural environment (tree rings, coral growth bands, layers of ice in
nepheloid layer - Layer of seawater containing a high concentration
of suspended sediment that may reach heights of several hundred meters above
the ocean floor.
nitric acid (HNO3) - A highly reactive oxidizing agent
obtained by distilling a nitrate with sulfuric acid.
normal faulting - A fault in which the hanging wall moves downward relative
to the footwall, in response to extensional stress.
obliquity - The angle between the planes
of the celestial equator and the ecliptic, currently the earth has a 23.4
degree obliquity cycle.
orbital forcing - Theory that proposes large scale climate changes
are due in part to the variations in precession, eccentricity and obliquity
that affects the amount of solar radiation received by the earth.
ostracods - Marine and
fresh-water crustaceans that have their body enclosed in a bi-valved shell.
oxygen isotopes - Oxygen atoms having the same atomic number (protons)
but different mass numbers (and different numbers of neutrons). The two
stable isotopes of oxygen are 16O and 18O.
oxidation - Relative loss of electrons in a chemical reaction; usually
associated with the liberation of energy.
oxygen isotope ratio (d18O) -
An expression for the ratio of the 18O to 16O atoms
in a sample relative to a standard, defined as:D18O= (18O/16Osample
- 18O/16Ostandard)/ 18O/16Ostandard
pack rat middens
- Remains of food and other materials left in caves inhabited by pack
rats which are preserved and serve as a "time capsule" of the vegetation
of the time and, by extension, the climate.
Past or ancient climates.
paleoclimatologist - One who studies
ancient (paleo-) climate.
environmental remnant of the past (pollen grains, tree rings, lake sediments,
pack rat middens, ice cores, coral skeletons) that assist researchers
in deciphering past climate conditions through the use of scientifically
proven dating techniques.
Paleozoic - An era of geological
history which extends from the beginning of the Cambrian to the close
of the Permian and is marked by the culmination of nearly all classes
of invertebrates except the insects and in the later epochs of which seed-bearing
plants, amphibians, and reptiles first appeared.
palynology - The study of
pollen analysis; used to determine past environmental conditions.
particulate - Material made
up of small pieces.
chain reaction) -
A technique used to rapidly reproduce
millions of copies of a particular stretch of DNA.
pelagic - Primary division
of the sea that includes the whole
mass of water subdivided into neritic and oceanic zones.
pharynx - The section of
the digestive system that extends from the mouth and nasal cavities to
the larynx, where it becomes continuous with the esophagus.
ability of an organism to adapt to a changing environment through the
manipulation of its phenotype, without the alteration of its genotype.
In trees, the region containing food-conducting tissue in the
photosynthesis - The process in
green plants and certain other organisms by which carbohydrates are synthesized
from carbon dioxide and water using light as an energy source.
(CO2 ) and water (H2 O) are combined in the presence
of sunlight and the green pigment chlorophyll, to produce food (C6
H12 O6 ) and oxygen (O2 ).
plankton - Small or microscopic organisms, including algae and protozoan,
that float or drift in great numbers in fresh or salt water, especially
at or near the surface, and serve as food for fish and other larger organisms.
planktonic Foraminifera - Marine zooplankton
that passively float or weakly swim, and have calcium carbonate skeletons
that are present in large numbers on the surface of the ocean. The skeletons
of planktonic foraminifers are preserved in large numbers in deep-sea sediments,
providing a rich fossil record of the environmental conditions of the upper
ocean. The size of the shells is typically from 50 to 100 microns.
Pleistocene epoch - An interval of the Quaternary period, from 1.8
million years before present to 10 thousand years before present.
Pliocene - An epoch of the late Neogene period, from 5.3 to 1.8
million years before present.
pluvial pharynx - The part of the gut between the mouth and the
esophagus, the throat.
polyp - The fleshy, living portion of coral; they are permanently
fixed to the reef in which they are attached.
pollen - Pollen grains that are made up of microspores containing
a mature or immature male gametophyte.
precession (of the equinoxes) - A measure
of the slow clockwise motion of the equinoxes along the ecliptic due to
the motion of the earth's axis of rotation around the pole of the ecliptic;
the angular movement of the spin axis of an object around an axis fixed
proxy signals - A general term for paleoclimate evidence that
can be used to indirectly infer or estimate some aspect of the environment
such as precipitation or temperature.
Quaternary period - The second period of the Cenozoic era containing
the Pleistocene epoch and the Holocene epoch and dating from 1.8 million
years to the present.
radiocarbon age - The age of plant or animal remains determined
by measuring the remaining activity of the 14C atoms in the sample:
A=A0e-ltwhere A is the measured activity,
A0 isthe initial activity, l is the decay constant,
and t is the sample age.
radiocarbon time - The use of the regular known rates of radiocarbon
decay to determine the exact ages of carbon-based life.
relative dating - Dating methods that determine time with respect to
stratigraphic position, for example deeper layers being older, or with respect
to some changing quantity or property, such as magnetic polarity.
rock varnish - A dark, manganese coating that forms on top of rocks,
usually paper-thin. The amount of moisture affects the amount of manganese,
so the thicker the varnish the wetter the climate was.
sea surface temperatures - Temperature of the ocean's surface used in
collaboration with other data to predict an El Nino occurrence.
seismic profile - A
two dimensional picture of the geophysical properties of layers of the
earth reflecting differences in arrival time of energy waves as they propagate
through the earth.
shelf break - The transition between the gently sloping continental
shelf and the much steeper continental slope that descend to ocean depths.
skeleton plot - A graphical representation of ring width patterns, used in
variability - changes in the sun's radiation due to the sun's internal
Southern Oscillation (ENSO) - Shifting of pressure zones in the
Pacific during an El Nino event.
spring tide - Tide that occurs when the sun, moon and earth are
aligned either at a new moon or a full moon; these tides have the greatest
range from low to high tide.
stable isotope - Different species of an element that have the
same atomic number, but different atomic mass, that are not affected by
standardization - The removal of growth trends due to the effects
of increasing tree age and circumference. Standardized ring width time
series are designed to have a stationary mean and variance.
stomata - A minute opening bordered by guard cells in the epidermis
of leaves and stems through which gases pass.
striations - Small-scale grooves cut into rock by the rasping
action of rock-laden glaciers.
symbiosis - A relationship between two organisms in which one
or both of the organisms benefit from the other.
teleconnection - Ripples of change that occur far away from the source;
wildfires in the Australian Outback and flooding in the Peruvian Andes
are teleconnections caused by El Nino.
tentacles - Structures located at the opposite end of the attached
coral, used for capturing and swallowing their prey.
thermohaline circulation (THC)- Density-driven
circulation system for the world's oceans. Warm Atlantic water moves northward
along the axis of the Gulf Stream, evaporation makes the water more and
more dense while releasing heat to the colder atmosphere in the North
Atlantic. Once dense enough, the water sinks into the deep ocean, forming
a downward limb of a giant conveyor-like circulation that extends around
the world's oceans.
tracheid - In gymnosperms, dead, vertically oriented tubular cells that make
up the xylem.
tradewinds - A system of low-level winds occurring in the tropics;
the tradewinds blow from the northeast to the equator in the Northern
Hemisphere and from the southeast to the equator in the Southern Hemisphere.
tree-ring chronology - The averaged standardized ring-width indices from
a number of trees sampled from a particular site that can be used for
crossdating and estimating past climate.
tree-ring indices - Dimensionless values, generated through the process of
standardization, that represent annual departures in tree growth
compared to mean growth at the site over time.
turbidite - A fast moving sediment-rich density current. The resulting
sediment deposits are characterized by graded bedding, moderate sorting,
and well-developed primary structures, especially laminations.
upwelling - Rising of cold, nutrient-rich water towards the surface.
varves - Lake or ocean annual layers of finer and coarser silt/clay
that represent the annual cycles of deposition in that lake or ocean.
vascular cambium - The thin living sheath of meristematic tissue between
the wood and the bark which differentiates into xylem on the inside and
phloem on the outside and produces the annual ring.
vessel - Large, tube-like water-conducting element in the wood of angiosperms.
visual stratigraphy -The process of identifying different
layers in ice, rock, sediment, or another paleo deposit, based on visually
apparent distinctions such as color or other properties. The identified
stratigraphic layers are usually assigned different ages or age intervals.
weather - Temperature, precipitation and wind speed and direction that occur
on a daily basis.
xylem - The water-conducting tissue of plants, which makes up the wood cylinder
of a tree, located inside the vascular cambium and surrounding
zooxanthellae - Microscopic phytoplankton that have a symbiotic
relationship with coral; they are also responsible for giving coral their
slightly brown color.