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PrecambrianThe Precambrian is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic eon,

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PrecambrianThe Precambrian is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic eon,

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The Precambrian Era lasted for 4 billion years. It is the longest period in Earth's history. It consists of the Archaean eon and the Proterozoic eon. At the end of the Precambrian (the Proterozoic) life began to appear and to evolve. But the fossils from most of the Precambrian era are very few in number and very rare, so little is known about life on Earth at that time still.

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The Precambrian Era lasted for 4 billion years. It is the longest period in Earth's history. It consists of the Archaean eon and the Proterozoic eon. At the end of the Precambrian (the Proterozoic) life began to appear and to evolve.

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The Mesozoic Era is an interval of geological time from about 252 to 66 million years ago. It is also called the Age of Reptiles, a phrase introduced by the 19th century paleontologist Gideon Mantell .

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The Mesozoic era saw the rise of some of the most iconic animals, from Tyrannosaurus rex to birds and mammals.

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Fossil Group, Inc. is an American fashion designer and manufacturer founded in 1984 by Tom Kartsotis and based in Richardson, Texas. Their brands include Fossil, Relic, Abacus, Michele Watch, Skagen Denmark, Misfit, WSI, and Zodiac Watches.

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Taphonomy - the soft parts of organisms need certain conditions in order to become fossils

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Fossils are formed in a number of different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.

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Explore the ancient Earth with videos from BBC programmes.

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Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy.

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When we observe the intersection in this diagram depicting these two dating techniques, we can conclude that they both have two things in common:

1.Provide an idea of the sequence in which events have occurred.
2.Determine the age of fossils, rocks, or ancient monuments.

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Relative Vs. Absolute Dating: The Ultimate Face-off

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Our planet inherits a large number of artifacts and monuments bestowed upon us by older historic civilizations. These remains are subjected to dating techniques in order to predict their ages and trace their history. This Buzzle post enlists the differences between the absolute and relative dating methods.

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Paleontology or palaeontology is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene Epoch.

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Ice Age Mammoth Remains Unearthed in Southern California

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A paleontologist digs up a fossilized mammoth skeleton from the Ice Age. The skeleton is 50-70% complete with 6-7 foot long tusks and is estimated to be 400,000 to 1.8 million years old. The remains are encased in plaster and burlap and removed from the site after excavation.

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The Holocene is the current geological epoch. It began after the Pleistocene, approximately 11,700 years before present. The Holocene is part of the Quaternary period.

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The largest defined unit of time is the supereon, composed of eons.Eons are divided into eras, which are in turn divided into periods,epochs and ages. The terms eonothem, erathem, system, series, and stage are used to refer to the layers of rock that correspond to these periods of geologic time.

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In physics and systems theory, the superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually.

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When two or more than two waves travelling through a medium at the same time, the resultant displacement at any point is equal to the vector sum of their individual displacement caused by each wave separately at that point.

y = resultant

y n = individual displacement

If the displacement are along the same direction we can write,

If two waves each of same amplitude undergo superposition, the result displacement is:

y = a + a = 2a (Constructive interference)

y = a - a = 0 (Destructive interference)

This principle is used to explain different wave phenomenon such as interference, beats etc as:

When two waves having same frequency are moving in a same direction superpose, constructive interference is produced.

When two waves in the opposite direction superpose, stationary waves are formed.

When two waves of slightly different frequencies are travelling in the same direction, beats are formed.

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Principle of Superposition of Wave | Lets Learn Nepal

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When two or more than two waves travelling through a medium at the same time, the resultant displacement at any point is equal to the vector sum of their individual displacement caused by each wave separately at that point. i.e., y = y1 + y2 +......

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Throw (something) forcefully in a specified direction.

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Orthopedic cast as treatment for scaphoid fracture

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View Stock Photo of Cast. Find premium, high-resolution photos at Getty Images.

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Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface. The magma, which is brought to the surface through fissures oror volcanic eruptions, solidifies at a faster rate.

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Home " Rocks " Igneous Rocks

Photos and Descriptions of Common Intrusive and Extrusive Igneous Rock Types

What are Igneous Rocks?

Igneous rocks are formed from the solidification of molten rock material. Some form below Earth's surface. Some form on or above Earth's surface. We describe these two basic types:

Intrusive igneous rocks crystallize below Earth's surface, and the slow cooling that occurs there allows large crystals to form. Examples of intrusive igneous rocks are: diabase, diorite, gabbro, granite, pegmatite, and peridotite.

Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals. Some cool so quickly that they form an amorphous glass. These rocks include: andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff.

Pictures and brief descriptions of some common igneous rock types are shown on this page.

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Photographs and descriptions of intrusive and extrusive igneous rocks with photos and links to detailed articles by Geology.com

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Rock that has formed through the deposition and solidification of sediment, especially sediment transported by water (rivers, lakes, and oceans), ice ( glaciers ), and wind. Sedimentary rocks are often deposited in layers, and frequently contain fossils. Note :Limestone and shale are common sedimentary rocks.

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Home " Rocks " Sedimentary Rocks

Photos of Common Clastic, Chemical, and Organic Sedimentary Rock Types.

What Are Sedimentary Rocks?

Sedimentary rocks are formed by the accumulation of sediments. There are three basic types of sedimentary rocks.

Clastic sedimentary rocks form from the accumulation and lithification of mechanical weathering debris. Examples include: breccia, conglomerate, sandstone, siltstone, and shale.

Chemical sedimentary rocks form when dissolved materials preciptate from solution. Examples include: chert, some dolomites, flint, iron ore, limestones, and rock salt.

Organic sedimentary rocks form from the accumulation of plant or animal debris. Examples include: chalk, coal, diatomite, some dolomites, and some limestones.

Photos and brief descriptions of some common sedimentary rock types are shown on this page.

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Sedimentary Rocks | Pictures, Characteristics, Textures, Types

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A photo gallery of sedimentary rocks. Breccia, caliche, chalk, chert, coal, conglomerate, coquina, diatomite, dolomite, flint, iron ore, limestone, oil shale, rock salt, sandstone, shale, siltstone.

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Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock is subjected to heat and pressure, causing profound physical or chemical change.

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Check out this Metamorphic Rock Biotite Gneiss in the Q?rius collection!

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A trace fossil, also ichnofossil, is a geological record of biological activity. Trace fossils may consist of impressions made on the substrate by an organism: for example, burrows, borings, urolites, footprints and feeding marks, and root cavities.

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Associated Press

Footprints found on a sandy plain in eastern Africa have been hailed by scientists as the earliest evidence of modern upright walking.

The footprints, dated to between 1.51m and 1.53m years ago, were discovered in sedimentary rock at Ileret, Kenya, researchers report in today's edition of the journal Science.

The findings mark one of the most important discoveries in recent years regarding the evolution of human walking.

With a large toe parallel to the other toes, the prints indicate a modern upright stride, the researchers said. They are likely to have been made by the early hominid Homo ergaster or early Homo erectus.

The series of footprints, including one apparently from a child, were left by individuals walking on a muddy river bank. Judging from stride length, they estimated the individuals were about 5ft 9in tall.

"It was kind of creepy excavating these things to see all of a sudden something that looks so dramatically like something that you yourself could have made 20 minutes earlier in some kind of wet sediment just next to the site," one of the researchers, archaeologist David Braun of the University of Cape Town in South Africa, told Reuters. "These could quite easily have been made on the beach today," he said.

These are the second-oldest known footprints of human ancestors. Older footprints, dating to 3.6m years ago found in Tanzania have been attributed to the less advanced Australopithecus afarensis. Those prints indicate an upright posture but with a shallower arch and a more ape-like, divergent big toe.
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Earliest human footprints found in Kenya

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Associated Press Footprints found on a sandy plain in eastern Africa have been hailed by scientists as the earliest evidence of modern upright walking. The footprints, dated to between 1.51m and 1.53m years ago, were discovered in sedimentary rock at Ileret, Kenya, researchers report in today's edition of the journal Science.

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Petrified fossils form when minerals replace all or part of an organism. Water is full of dissolved minerals. It seeps through the layers of sediment to reach the dead organism. When the water evaporates, only the hardened minerals are left behind.

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What Is a Fossil Fossils for Sale Fossil Excavation Block Ultra Fossil Excavation Block Contact Us

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The Cenozoic Era is the current geological era, covering the period from 66 million years ago to the present day. The Cenozoic is also known as the Age of Mammals, because of the large mammals that dominate it.

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The Cenozoic is divided into three periods: the Paleogene, Neogene, and Quaternary; and seven epochs: the Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene. The Quaternary Period was officially recognized by the International Commission on Stratigraphy in June 2009, and the former Tertiary Period was officially disused in 2004 because of the necessity to divide the Cenozoic into periods more like that of the previous Paleozoic and Mesozoic eras.[why?

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a proposed amendment to the US Constitution stating that civil rights may not be denied on the basis of one's sex.

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The paleolithic era and the neolithic era

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Paleolithic Era to Neolithic Era. Created for a sixth grade social studies classroom. Contains information about the transition from hunting and gathering to...

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law of superposition. noun. Geology. a basic law of geochronology, stating that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom, each layer being younger than the one beneath it and older than the one above it.

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Ordering of Rock Layers Scientists read the rock layers knowing that each layer is deposited on top of other layers. The law of superposition states that each rock layer is older than the one above...

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Rock that has formed through the deposition and solidification of sediment, especially sediment transported by water (rivers, lakes, and oceans), ice ( glaciers ), and wind. Sedimentary rocks are often deposited in layers, and frequently contain fossils. Note :Limestone and shale are common sedimentary rocks.

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Home " Rocks " Sedimentary Rocks

Photos of Common Clastic, Chemical, and Organic Sedimentary Rock Types.

What Are Sedimentary Rocks?

Sedimentary rocks are formed by the accumulation of sediments. There are three basic types of sedimentary rocks.

Clastic sedimentary rocks form from the accumulation and lithification of mechanical weathering debris. Examples include: breccia, conglomerate, sandstone, siltstone, and shale.

Chemical sedimentary rocks form when dissolved materials preciptate from solution. Examples include: chert, some dolomites, flint, iron ore, limestones, and rock salt.

Organic sedimentary rocks form from the accumulation of plant or animal debris. Examples include: chalk, coal, diatomite, some dolomites, and some limestones.

Photos and brief descriptions of some common sedimentary rock types are shown on this page.

Find Other Topics on Geology.com:

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Sedimentary Rocks | Pictures, Characteristics, Textures, Types

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A photo gallery of sedimentary rocks. Breccia, caliche, chalk, chert, coal, conglomerate, coquina, diatomite, dolomite, flint, iron ore, limestone, oil shale, rock salt, sandstone, shale, siltstone.

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mber is sticky, like honey or glue. The insects land on tree sap either intentionally or by accident, and can't exert enough force to remove themselves from it. The tree sap continues to flow and coats the insect. The sap hardens into amber, preserving the now dead insect forever.

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Over a hundred million years ago, tree resin dripped from the trees in a forest. As it dripped and fell to the ground, it covered some insects as they went about their daily life. Not even the dinosaurs roamed then; we have to wonder what the insects saw, what was life like on earth at the time? And we can get a little hint because the insects or "inclusions" be it debris or a rare flower to a spider and its prey are frozen forever in time, trapped in amber.

We also have something very special for you, only the second snail ever found in Burma Amber and we are the ones showing it to the world. It has not been published until now.

This snail is extremely rare. Before this find, there was only one other Burma snail in the world, this makes the second. Anders Damgaard took a perfect photograph to let us share this amazing discovery with you, the only people to have seen it since the T. Rex.

As you can see, the snail looks as if it has a lot of iridescence in its shell. Perfectly preserved, we wonder what it ate and if it was terrestial or an aqua snail that got washed up as the waters shifted? How amazing to look at something never before seen for 100 million years.

Amber itself is formed from tree resin that, over thousands of years, fossilizes to produce first copal and then thousands or millions of years after that, amber. The sticky resin traps anything in its way, preserving it for millennia.

As it dries and hardens, the resin becomes copal, which is a greasy, clearish substance sometimes called (and is if you see it sold as amber) fake amber. Copal is a constant stage after the sticky resin that all amber goes through and can be as old as recent years to 20 million years old.

That doesn't mean that amber can't be less than 20 million years old; some tree resins harden much faster than others and so would go through the copal stage more quickly and become amber in 10 million years, while another amber may take 50 million years.
Cretaceous New Jersey amber (90-94 MYO) with inclusions (huge beetle, spider web, 2 midge, 2 ants (one perfect perserved), part of
leaf, coprolite and debris).
Once the polymerization of amber starts from the copal stage, it starts to fully harden and will get harder with time. The above image with its many pieces trapped inside also includes some dinosaur poop (coprolite).

There are two types of amber that are most often discussed and known for the inclusions or for jewelry: Dominican, which is much paler than the deep yellow to burnished golds we often think amber to be like (even though some of the rarest is Dominican blue amber), and Baltic amber, which is yellow. The color gauges are not hard and fast rules though.

The oldest amber ever found is 300 million years old from the Upper Carboniferous era. The oldest amber pieces that have insect inclusions came from the Lower Cretaceous era approximately 150 million years ago.

Damgaard talks about the meaning of amber to him: "Thinking philosophically about amber and time is interesting. Ever since I was little I've believed that it was not possible to look back in time, but amber serves as the window into a vanished world - a second as forever frozen in time. It provides a wider perspective on our lives, the earth and evolution - how short life is and how small our problems are compared with the big issues. I always have a piece of amber in my pocket as it reminds me how small and unimportant my problems are when it all gets too much."

The life trapped in amber is critical to our understanding of life long ago before humans even existed. It can help scientists tell what sort of climate there was or even the landscape.

Insects from Baltic amber show that it was produced in a subtropical forest
with mixed trees while Dominican amber was produced in a tropical forest area. A book written by George Poinar Jr. and Roberta Poiner called "The Amber Forest" reconstructs a forest from amber specimens discovered in the last 20 years and shows how it can be done.

The authors state in the book: "As we discuss the natural history of the extinct animals in amber, we will draw heavily on the principle of behavioral fixity in the fossil record. This principle is an important concept in the reconstruction of ancient worlds and states that the behavior, ecology, and climatic preferences of fossil organisms will be similar to that found in their present-day descendants at the generic and often family level. This well-documented principle is very helpful in deciphering the behavior of ancient organisms."

The authors continue: "Thus it may be possible to indirectly infer the presence of a plant or animal that existed long ago by finding an organism that today is intimately associated with it. When we discover fig wasps, for example, we can be certain that fig trees existed even though we have not found their actual remains, since it is known that fig wasps can develop only inside the fruits of this tree."

One reason amber is critical to understanding the world humans never saw is that most fossils are 2D dimensions but amber is 3D, with the most minute hairs able to be seen. This magnificent spider, for example, looks as if it made an attempt to extricate itself as there are what seems to be movement waves next to the body.

One of the very rare finds in amber is a flower, a whole one. This shows a fine example of one, it is interesting to think about what animals may have smelt its blooms as they made their way along? Or if it a food source for the bees or wasps of the time? How many dinosaurs may have walked past it?

Amber and its inclusions are not just beautiful, they are a fascinating study into the life of the past...a veritable window into the past. A past that is hard for us to even comprehend as much of it was formed when no humans walked the earth. Yet the clues the pieces give allow scientists and then the public to better understand the world we live in and the world that came before.

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15 Incredible Images of Prehistoric Creatures Trapped in Amber

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Photo: Anders DaamgaardBaltic amber ball - very rare Cerambycidae - body 6 mm Over a hundred million years ago, tree resin dripped from the trees in a forest. As it dripped and fell to the ground, it covered some insects as they went about their daily life.

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Earth is 4.54 billion years old, with an error range of 50 million years.

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Fossils are fundamental to the geologic time scale. ... Rocks formed during the Phanerozoic Eon may have fossils of complex animals and plants such as dinosaurs, mammals, and trees. We study Earth's history by studying the record of past events that is preserved in the rocks.

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The assumptions and correlations within the 'geologic column' are largely make-believe and wishful-thinking and cannot be substantiated by empirical science; despite this, many under-knowledged school and college teachers teach this system verbatim.

The ten strata systems that geologists use (Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, and Tertiary) compose the "standard geologic column" and are claimed by many to contain the major proof of evolutionary theory. Several erroneous notions have been attached to the geologic column. The following are the ten most common misconceptions.

Misconception No. 1. The geologic column was constructed by geologists who, because of the weight of the evidence that they had found, were convinced of the truth of uniformitarian theory and organic evolution.

It may sound surprising, but the standard geologic column was devised before 1860 by catastrophists who were creationists.1 Adam Sedgewick, Roderick Murchison, William Coneybeare, and others affirmed that the earth was formed largely by catastrophic processes, and that the earth and life were created. These men stood for careful empirical science and were not compelled to believe evolutionary speculation or side with uniformitarian theory. Although most would be called "progressive creationists" in today's terminology, they would not be pleased to see all the evolutionary baggage that has been loaded onto their classification of strata.

Misconception No. 2. Geologists composed the geologic column by assembling the "periods" and "eras" which they had recognized.

The geologic column was not composed by assembling a chronology of "periods," "eras" or other supposed measures of time, but by superposition of objectively defined sequences of sedimentary strata called "systems." The "periods" and "eras" were later appended to the system nomenclature of the "geologic Column" transforming it into a "geologic time scale."

Misconception No. 3. The strata systems of the geologic column are worldwide in their occurrence with each strata system being present below any point on the earth's surface.

The notion that the earth's crust has on "onion skin" structure with successive layers containing all strata systems distributed on a global scale is not according to the facts. Data from continents and ocean basins show that the ten systems are poorly represented on a global scale: approximately 77% of the earth's surface area on land and under the sea has seven or more (70% or more) of the strata systems missing beneath; 94% of the earth's surface has three or more systems missing beneath; and an estimated 99.6% has at least one missing system.2 Only a few locations on earth (about 0.4% of its area) have been described with the succession of the ten systems beneath (west Nepal, west Bolivia, and central Poland). Even where the ten systems may be present, geologists recognize individual systems to be incomplete. The entire geologic column, composed of complete strata systems, exists only in the diagrams drawn by geologists!

Misconception No. 4. Strata systems always occur in the order required by the geologic column.

Hundreds of locations are known where the order of the systems identified by geologists does not match the order of the geologic column. Strata systems are believed in some places to be inverted, repeated, or inserted where they do not belong. Overturning, overthrust faulting, or landsliding are frequently maintained as disrupting the order. In some locations such structural changes can be supported by physical evidence while elsewhere physical evidence of the disruption may be lacking and special pleading may be required using fossils or radiometric dating.

Misconception No. 5. Because each strata system has distinctive lithologic composition, a newly discovered stratum can be assigned easily to its correct position in the geologic column.

Sandstone, limestone, dolomite, shale, chert, salt, conglomerate, coal and other rock types are not diagnostic of specific strata systems. Therefore, a rock's physical appearance cannot, with certainty, distinguish the system or strata level to which a rock may belong. The sequence of rock types is more useful, but hardly an infallible guide to correlation. Thus, the Cambrian System on an intercontinental scale is typically composed of quartzose sandstone, overlain by glauconitic sandstone with dark-brown shale, overlain by impure, light-brown limestones.3 The correlation of "Cambrian" strata is further strengthened by the presence on an intercontinental scale of an unconformity (surface of erosion) at or near the base of the system. Each rock type is not distinctive of the Cambrian, and neither is the unconformity, but the sequence may be.

Misconception No. 6. Fossils, especially the species distinctive of specific systems, provide the most reliable method of assigning strata to their level in the geologic column.

Bed-to-bed correlation of strata to their "type system" area is the most reliable method of assigning strata to a system. The data from oil well drilling, seismic surveys, and surface geologic mapping is of such character that subsurface correlation of lithostratigraphic units of the thickness of systems is possible on a continental scale. Although some fossils appear to be distinctive of certain systems (most fossil taxa range through a few to several systems), care must be exercised in correlation by fossils. First, the stratigraphic range of a fossil type is always open to extension as new fossils are discovered. Second, when an extension of a fossil's range may be required, geologists may call upon erosion (reworking fossils into younger strata or leaking fossils into older strata) and structural events (overturning or faulting strata and fossils). An example of the first problem is the monoplacophoran mollusk Pilina, which might otherwise be considered diagnostic of the Silurian System, except for the startling discovery that Neopilina lives today, and, therefore, would be expected in any system overlying the Silurian. For these reasons correlation by fossils must always remain tentative awaiting further confirmatory evidence from lithostratigraphy. We should look very skeptically at strata correlations which rely solely on fossils.

Misconception No. 7. Sedimentary evidence proves that periods of millions of years duration were required to deposit individual strata systems.

Before radiometric dating was devised, uniformitarian geologists postulated "periods" of millions of years duration to slowly deposit the strata systems. A single sedimentary lamina, or bed, was supposed by uniformitarian geologists to represent typically a year or many years duration. It was concluded, therefore, that multiplied thousands of laminae and beds superimposed required millions of years. Recently, however, geologists have discovered that laminae and beds form quickly on floodplains of rivers during floods, in shallow marine areas during storms, and in deep water by turbidity currents. The evidence of rapid sedimentation is now so easily recognized that geologists observing a strata system these days often ask where to insert the "missing time" of which the strata do not show sedimentary evidence. Catastrophism, quite naturally, is making a come-back. There is good reason to believe that entire strata systems, and even groups of systems, were accumulated in a hydraulic cataclysm matching the description of Noah's Flood in the Bible.

Misconception No. 8. Radiometric dating can supply "absolute ages" in millions of years with certainty to systems of the geologic column.

Geologists and geochronologists assert that radiometric dating verifies that individual strata systems and their strata are millions of years old. When asked to document the most reliable radiometric age dates, geologists usually point to isochron and concordia plots which employ multiple isotopic analyses, which they claim will remove the effects of original "contaminants," and display the "age" of a rock in graphical form. However, we find geologists often reporting isochron plots which are discordant with the accepted "ages" of strata systems.4 Frequently, these discordant isochron plots "date" strata systems much older than even the accepted old ages customarily assigned to the systems of the geologic column. Geologists should be asking which, if any, of the isochron plots should be accepted as "absolute ages," and if the discordances do not falsify the assumptions upon which radiometric dating is based. Geologists need to consider radiometric methods which indicate ages of thousands of years for strata systems,5 as well as general indicators supporting young age.

Misconception No. 9. The environmental "pictures" assigned to certain portions of the geologic column allow us to accurately visualize what its "geologic ages" were like.

Books, films and museum displays contain illustrations asking us to visualize what earlier "geologic ages" were like. These "pictures" show supposed primitive earth conditions, specific environments with sediments being slowly deposited, inferred "transitional organisms" evolving toward familiar forms, and whole communities of organisms "at home" with other organisms absent. Perhaps the most blatant environmental picture" has been assigned to lower Precambrian strata, formed when the earth supposedly had a reducing atmosphere and an "organic soup" in which life evolved. Yet, geologists have yet to find sedimentary evidence for the reducing atmosphere and the soup.6 This reminds us that accepting an environmental "picture" requires much imagination from a meager supply of facts.

Misconception No. 10. The geologic column and the positions of fossils within the geologic column provide proof of amoeba-to-man evolution.

All the animal phyla, including chordate fish, are now known as fossils in the Cambrian System. No ancestral forms can be found for the protozoans, arthropods, brachiopods, mollusks, bryozoans, coelenterates, sponges, annelids, echinoderms or chordates. These phyla appear in the fossil record fully formed and distinct, in better agreement with the concept of "multiple, abrupt beginnings" (creation) than with the notion of "descent from a common ancestor" (evolution).

REFERENCES

1. R.Ritiand, "Historical development of the current understanding of the geologic column: part II," Origins, Vol. 9, 1982, pp. 28-47.
2. Estimated by the author using data from J. Woodmorappe, "The essential nonexistence of the evolutionary-uniformitarian geologic column: a quantitative assessment," Creation Res. Soc. Quarterly, Vol. 18, 1981, pp. 46-71.
3. D.V. Ager, The Nature of the Stratigraphical Record, 2nd ed. (New York: John Wiley, 1981), P. 11.
4. C. Brooks, D.E. James and S.R. Hart, "Ancient lithosphere: its role in young continental volcanism," Science, Vol. 193, 1976, pp. 1086-1094.
5. R.V. Gentry, et al., "Radiohalos in coalified wood: new evidence relating to the time of uranium introduction and coalification," Science, Vol. 194, 1976, pp. 315-318.
6. S.A. Austin, "Did the early earth have a reducing atmosphere?" ICR Impact 109, July 1982, 4 pp.

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Ten Misconceptions About the Geologic Column

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The assumptions and correlations within the 'geologic column' are largely make-believe and wishful-thinking and cannot be substantiated by empirical science; despite this, many under-knowledged school and college teachers teach this system verbatim. The ten strata systems that geologists use (Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, and Tertiary) compose the "standard geologic column" and are claimed by many to contain the major proof of evolutionary theory.

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Relative Dating of rock layers tells us that the deeper we dig - the older the rock gets.

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Relative Dating of rock layers tells us that the deeper we dig - the older the rock gets.

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These rock layers formed from sediments deposited in a lake. ... In the same way, geologists figure out the relative ages of fossils and sedimentary rock layers; rock layers, and the fossils they contain, toward the bottom of a stack of sediments are older than those found higher in the stack.

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Relative dating determines the relative age of fossils according to

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Observation of modern marine and non-marine sediments in a wide variety of environments supports this generalization although cross-bedding is inclined, the overall orientation of cross-bedded...

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Fossil is an impression left by the original organism - mold

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Fossil is an impression left by the original organism - mold

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A mold is the impression and void (space, hole) that an organism or organism's body or body part leaves in the sediment. ... A cast is made of different material than a mold.

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Under certain conditions, living things can leave behind fossils. Certain kinds of fossils are referred to as "molds" or "casts". These are usually impressions left in rock, which fill with sediment. Fossils are useful tools for biologists studying how ancient animals evolved and lived.

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A fossil consisting of an imprint of or a mark left by an organism, as opposed to physical remains. Trace fossils are produced in soft sediments and include surface tracks, molded impressions left by organisms or tissues that later decayed, and subsurface burrows or tunnelings.

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On August 23, 1966, fossil tracks were uncovered during excavation for a state building. When Edward McCarthy turned over a slab of gray sandstone with his bulldozer, he saw a large footprint with three toes. The news of the discover spread quickly as more tracks were uncovered.

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Petrified wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization.

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Petrified Forest of Lesvos | a tourist holiday travel guide from Greek Islands Postcards.

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Organisms buried in sediment may decay or dissolve away leaving a cavity or mold. If the space is subsequently filled with sediment, an external cast can be made.Molds and casts are three dimensional and preserve the surface contours of the organism.

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Petrified Fossil.Petrified fossil.Petrified fossil.Petrified Fossil.mold and cast fossils..mold fossil.carbon film fossil.carbon film fossil.trace fossil.trace fossils.preserved remains.preserved remains...law of superposition.relative age of rock.relative age of rock.....15 Unbelievable Fossil Discoveries.Geologic Time.Geological Time Scale.EYEWITNESS | Prehistoric Life.25 Strangest Prehistoric Creatures To Roam The Earth.Prehistoric shark captured on film

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In physics and systems theory, the superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually.

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The superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually. So that if input A produces response X and input B produces response Y then input ( A + B) produces response ( X + Y).

A function that satisfies the superposition principle is called a linear function. Superposition can be defined by two simpler properties; additivity and homogeneity

Additivity

Homogeneity

for scalar a.

This principle has many applications in physics and engineering because many physical systems can be modeled as linear systems. For example, a beam can be modeled as a linear system where the input stimulus is the load on the beam and the output response is the deflection of the beam. The importance of linear systems is that they are easier to analyze mathematically; there is a large body of mathematical techniques, frequency domain linear transform methods such as Fourier, Laplace transforms, and linear operator theory, that are applicable. Because physical systems are generally only approximately linear, the superposition principle is only an approximation of the true physical behaviour.

The superposition principle applies to any linear system, including algebraic equations, linear differential equations, and systems of equations of those forms. The stimuli and responses could be numbers, functions, vectors, vector fields, time-varying signals, or any other object that satisfies certain axioms. Note that when vectors or vector fields are involved, a superposition is interpreted as a vector sum.

By writing a very general stimulus (in a linear system) as the superposition of stimuli of a specific and simple form, often the response becomes easier to compute.

For example, in Fourier analysis, the stimulus is written as the superposition of infinitely many sinusoids. Due to the superposition principle, each of these sinusoids can be analyzed separately, and its individual response can be computed. (The response is itself a sinusoid, with the same frequency as the stimulus, but generally a different amplitude and phase.) According to the superposition principle, the response to the original stimulus is the sum (or integral) of all the individual sinusoidal responses.

As another common example, in Green's function analysis, the stimulus is written as the superposition of infinitely many impulse functions, and the response is then a superposition of impulse responses.

Fourier analysis is particularly common for waves. For example, in electromagnetic theory, ordinary light is described as a superposition of plane waves (waves of fixed frequency, polarization, and direction). As long as the superposition principle holds (which is often but not always; see nonlinear optics), the behavior of any light wave can be understood as a superposition of the behavior of these simpler plane waves.

Waves are usually described by variations in some parameter through space and time-for example, height in a water wave, pressure in a sound wave, or the electromagnetic field in a light wave. The value of this parameter is called the amplitude of the wave, and the wave itself is a function specifying the amplitude at each point.

In any system with waves, the waveform at a given time is a function of the sources (i.e., external forces, if any, that create or affect the wave) and initial conditions of the system. In many cases (for example, in the classic wave equation), the equation describing the wave is linear. When this is true, the superposition principle can be applied. That means that the net amplitude caused by two or more waves traversing the same space is the sum of the amplitudes that would have been produced by the individual waves separately. For example, two waves traveling towards each other will pass right through each other without any distortion on the other side. (See image at top.)

Wave diffraction vs. wave interference

With regard to wave superposition, Richard Feynman wrote:

No-one has ever been able to define the difference between interference and diffraction satisfactorily. It is just a question of usage, and there is no specific, important physical difference between them. The best we can do, roughly speaking, is to say that when there are only a few sources, say two, interfering, then the result is usually called interference, but if there is a large number of them, it seems that the word diffraction is more often used.

Other authors elaborate:

The difference is one of convenience and convention. If the waves to be superposed originate from a few coherent sources, say, two, the effect is called interference. On the other hand, if the waves to be superposed originate by subdividing a wavefront into infinitesimal coherent wavelets (sources), the effect is called diffraction. That is the difference between the two phenomena is [a matter] of degree only, and basically they are two limiting cases of superposition effects.

Yet another source concurs:

In as much as the interference fringes observed by Young were the diffraction pattern of the double slit, this chapter [Fraunhofer diffraction] is therefore a continuation of Chapter 8 [Interference]. On the other hand, few opticians would regard the Michelson interferometer as an example of diffraction. Some of the important categories of diffraction relate to the interference that accompanies division of the wavefront, so Feynman's observation to some extent reflects the difficulty that we may have in distinguishing division of amplitude and division of wavefront.

Wave interference

The phenomenon of interference between waves is based on this idea. When two or more waves traverse the same space, the net amplitude at each point is the sum of the amplitudes of the individual waves. In some cases, such as in noise-cancelling headphones, the summed variation has a smaller amplitude than the component variations; this is called destructive interference. In other cases, such as in a line array, the summed variation will have a bigger amplitude than any of the components individually; this is called constructive interference.

combined
waveform

wave 1

wave 2

Two waves in phase

Two waves 180° out
of phase

Departures from linearity

In most realistic physical situations, the equation governing the wave is only approximately linear. In these situations, the superposition principle only approximately holds. As a rule, the accuracy of the approximation tends to improve as the amplitude of the wave gets smaller. For examples of phenomena that arise when the superposition principle does not exactly hold, see the articles nonlinear optics and nonlinear acoustics.

Quantum superposition

In quantum mechanics, a principal task is to compute how a certain type of wave propagates and behaves. The wave is described by a wave function, and the equation governing its behavior is called the Schrödinger equation. A primary approach to computing the behavior of a wave function is to write it as a superposition (called " quantum superposition") of (possibly infinitely many) other wave functions of a certain type- stationary states whose behavior is particularly simple. Since the Schrödinger equation is linear, the behavior of the original wave function can be computed through the superposition principle this way.

The projective nature of quantum-mechanical-state space makes an important difference: it does not permit superposition of the kind that is the topic of the present article. A quantum mechanical state is a ray in projective Hilbert space, not a vector. The sum of two rays is undefined. To obtain the relative phase, we must decompose or split the ray into components

where the and the belongs to an orthonormal basis set. The equivalence class of allows a well-defined meaning to be given to the relative phases of the .[6]

There are some likenesses between the superposition presented in the main on this page, and quantum superposition. Nevertheless, on the topic of quantum superposition, Kramers writes: "The principle of [quantum] superposition ... has no analogy in classical physics." According to Dirac: " the superposition that occurs in quantum mechanics is of an essentially different nature from any occurring in the classical theory [italics in original]."

A common type of boundary value problem is (to put it abstractly) finding a function y that satisfies some equation

with some boundary specification

For example, in Laplace's equation with Dirichlet boundary conditions, F would be the Laplacian operator in a region R, G would be an operator that restricts y to the boundary of R, and z would be the function that y is required to equal on the boundary of R.

In the case that F and G are both linear operators, then the superposition principle says that a superposition of solutions to the first equation is another solution to the first equation:

while the boundary values superpose:

Using these facts, if a list can be compiled of solutions to the first equation, then these solutions can be carefully put into a superposition such that it will satisfy the second equation. This is one common method of approaching boundary value problems.

Consider a simple linear system :

By superposition principle, the system can be decomposed into

with
Superposition principle is only available for linear systems. However, the Additive state decomposition can be applied not only to linear systems but also nonlinear systems. Next, consider a nonlinear system

where is a nonlinear function. By the additive state decomposition, the system can be 'additively' decomposed into

with

This decomposition can help to simplify controller design.

In electrical engineering, in a linear circuit, the input (an applied time-varying voltage signal) is related to the output (a current or voltage anywhere in the circuit) by a linear transformation. Thus, a superposition (i.e., sum) of input signals will yield the superposition of the responses. The use of Fourier analysis on this basis is particularly common. For another, related technique in circuit analysis, see Superposition theorem.

In physics, Maxwell's equations imply that the (possibly time-varying) distributions of charges and currents are related to the electric and magnetic fields by a linear transformation. Thus, the superposition principle can be used to simplify the computation of fields which arise from a given charge and current distribution. The principle also applies to other linear differential equations arising in physics, such as the heat equation.

In mechanical engineering, superposition is used to solve for beam and structure deflections of combined loads when the effects are linear (i.e., each load does not affect the results of the other loads, and the effect of each load does not significantly alter the geometry of the structural system). Mode superposition method uses the natural frequencies and mode shapes to characterize the dynamic response of a linear structure.

In hydrogeology, the superposition principle is applied to the drawdown of two or more water wells pumping in an ideal aquifer. This principal is used in the analytic element method to develop analytical elements capable of being combined in a single model.

In process control, the superposition principle is used in model predictive control.

The superposition principle can be applied when small deviations from a known solution to a nonlinear system are analyzed by linearization.

In music, theorist Joseph Schillinger used a form of the superposition principle as one basis of his Theory of Rhythm in his Schillinger System of Musical Composition.

According to Léon Brillouin, the principle of superposition was first stated by Daniel Bernoulli in 1753: "The general motion of a vibrating system is given by a superposition of its proper vibrations." The principle was rejected by Leonhard Euler and then by Joseph Lagrange. Later it became accepted, largely through the work of Joseph Fourier.

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The superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually.

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Uniformitarianism is defined in the authoritative Glossary of Geology as "the fundamental principle or doctrine that geologic processes and natural laws now operating to modify the Earth's crust have acted in the same regular manner and with essentially the same intensity throughout geologic time

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chapter 3 the rock and fossil record sections 1-5 pages 58-89.

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Chapter 3 The Rock and Fossil Record Sections 1-5 Pages ppt download

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Uniformitarianism vs. Catastrophism Uniformitarianism did not gain acceptance until Charles Lyell published Principle of Geology in 1833 to prove Hutton correct with his new evidence Catastrophism: principle that states: Remained Geology's guided principle until 1830's