Fossil - Wikipedia

Creation vs. Evolution

are fossil dating methods accuracy

This is the saturation point. The dip of the beds from which the trees arise seldom exceeds 7 degrees, which is not enough to cause all the trees to fall downhill. A First Overview , , Koninklijke Brill nv:

0. Introduction and table of contents

This error may exceed the measured value when dealing with younger uranium minerals containing even small amounts of original lead, as clearly recognized by Holmes when the method was first proposed. Others that this technique doesn't work for the Qur'an. This includes factoring in many variables, such as the amount of radiation the object was exposed to each year. Gathering fossils dates at least to the beginning of recorded history. Permineralization is a process of fossilization that occurs when an organism is buried.

Index fossils also known as guide fossils, indicator fossils or zone fossils are fossils used to define and identify geologic periods or faunal stages. They work on the premise that, although different sediments may look different depending on the conditions under which they were deposited, they may include the remains of the same species of fossil.

The shorter the species' time range, the more precisely different sediments can be correlated, and so rapidly evolving species' fossils are particularly valuable. The best index fossils are common, easy to identify at species level and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is poor. Trace fossils consist mainly of tracks and burrows, but also include coprolites fossil feces and marks left by feeding. Many traces date from significantly earlier than the body fossils of animals that are thought to have been capable of making them.

Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour in this case, diet rather than morphology. They were first described by William Buckland in Prior to this they were known as "fossil fir cones " and " bezoar stones. A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group.

Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation.

Microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye.

Microfossils may either be complete or near-complete organisms in themselves such as the marine plankters foraminifera and coccolithophores or component parts such as small teeth or spores of larger animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in the correlation of rock units. Fossil resin colloquially called amber is a natural polymer found in many types of strata throughout the world, even the Arctic.

The oldest fossil resin dates to the Triassic , though most dates to the Cenozoic. The excretion of the resin by certain plants is thought to be an evolutionary adaptation for protection from insects and to seal wounds. Fossil resin often contains other fossils called inclusions that were captured by the sticky resin. These include bacteria, fungi, other plants, and animals.

Animal inclusions are usually small invertebrates , predominantly arthropods such as insects and spiders, and only extremely rarely a vertebrate such as a small lizard.

Preservation of inclusions can be exquisite, including small fragments of DNA. Fossil wood is wood that is preserved in the fossil record. Wood is usually the part of a plant that is best preserved and most easily found. Fossil wood may or may not be petrified. The fossil wood may be the only part of the plant that has been preserved: This will usually include "xylon" and a term indicating its presumed affinity, such as Araucarioxylon wood of Araucaria or some related genus , Palmoxylon wood of an indeterminate palm , or Castanoxylon wood of an indeterminate chinkapin.

The term subfossil can be used to refer to remains, such as bones, nests, or defecations, whose fossilization process is not complete, either because the length of time since the animal involved was living is too short less than 10, years or because the conditions in which the remains were buried were not optimal for fossilization.

Subfossils are often found in caves or other shelters where they can be preserved for thousands of years. Additionally, isotope ratios can provide much information about the ecological conditions under which extinct animals lived. Subfossils are useful for studying the evolutionary history of an environment and can be important to studies in paleoclimatology. Subfossils are often found in depositionary environments, such as lake sediments, oceanic sediments, and soils.

Once deposited, physical and chemical weathering can alter the state of preservation. Chemical fossils, or chemofossils, are chemicals found in rocks and fossil fuels petroleum, coal, and natural gas that provide an organic signature for ancient life.

Molecular fossils and isotope ratios represent two types of chemical fossils. It has been suggested that biominerals could be important indicators of extraterrestrial life and thus could play an important role in the search for past or present life on the planet Mars. Furthermore, organic components biosignatures that are often associated with biominerals are believed to play crucial roles in both pre-biotic and biotic reactions.

Pseudofossils are visual patterns in rocks that are produced by geologic processes rather than biologic processes. They can easily be mistaken for real fossils. Some pseudofossils, such as dendrites , are formed by naturally occurring fissures in the rock that get filled up by percolating minerals. Other types of pseudofossils are kidney ore round shapes in iron ore and moss agates , which look like moss or plant leaves.

Concretions , spherical or ovoid-shaped nodules found in some sedimentary strata, were once thought to be dinosaur eggs, and are often mistaken for fossils as well.

Gathering fossils dates at least to the beginning of recorded history. The fossils themselves are referred to as the fossil record. The fossil record was one of the early sources of data underlying the study of evolution and continues to be relevant to the history of life on Earth. Paleontologists examine the fossil record to understand the process of evolution and the way particular species have evolved.

Many early explanations relied on folktales or mythologies. In China the fossil bones of ancient mammals including Homo erectus were often mistaken for " dragon bones" and used as medicine and aphrodisiacs. In the West fossilized sea creatures on mountainsides were seen as proof of the biblical deluge. If what is said concerning the petrifaction of animals and plants is true, the cause of this phenomenon is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquake and subsidences, and petrifies whatever comes into contact with it.

As a matter of fact, the petrifaction of the bodies of plants and animals is not more extraordinary than the transformation of waters.

Greek scholar Aristotle realized that fossil seashells from rocks were similar to those found on the beach, indicating the fossils were once living animals. Aristotle previously explained it in terms of vaporous exhalations , which Avicenna modified into the theory of petrifying fluids succus lapidificatus , later elaborated by Albert of Saxony in the 14th century and accepted in some form by most naturalists by the 16th century.

More scientific views of fossils emerged during the Renaissance. Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life. If the Deluge had carried the shells for distances of three and four hundred miles from the sea it would have carried them mixed with various other natural objects all heaped up together; but even at such distances from the sea we see the oysters all together and also the shellfish and the cuttlefish and all the other shells which congregate together, found all together dead; and the solitary shells are found apart from one another as we see them every day on the sea-shores.

And we find oysters together in very large families, among which some may be seen with their shells still joined together, indicating that they were left there by the sea and that they were still living when the strait of Gibraltar was cut through.

In the mountains of Parma and Piacenza multitudes of shells and corals with holes may be seen still sticking to the rocks Robert Hooke included micrographs of fossils in his Micrographia and was among the first to observe fossil forams. His observations on fossils, which he stated to be the petrified remains of creatures some of which no longer existed, were published posthumously in William Smith — , an English canal engineer, observed that rocks of different ages based on the law of superposition preserved different assemblages of fossils, and that these assemblages succeeded one another in a regular and determinable order.

He observed that rocks from distant locations could be correlated based on the fossils they contained. He termed this the principle of faunal succession.

This principle became one of Darwin's chief pieces of evidence that biological evolution was real. Georges Cuvier came to believe that most if not all the animal fossils he examined were remains of extinct species.

This led Cuvier to become an active proponent of the geological school of thought called catastrophism. Near the end of his paper on living and fossil elephants he said:. Early naturalists well understood the similarities and differences of living species leading Linnaeus to develop a hierarchical classification system still in use today. Darwin and his contemporaries first linked the hierarchical structure of the tree of life with the then very sparse fossil record.

Darwin eloquently described a process of descent with modification, or evolution, whereby organisms either adapt to natural and changing environmental pressures, or they perish. He worried about the absence of older fossils because of the implications on the validity of his theories, but he expressed hope that such fossils would be found, noting that: Since Darwin's time, the fossil record has been extended to between 2. However, macroscopic fossils are now known from the late Proterozoic.

The fossil record and faunal succession form the basis of the science of biostratigraphy or determining the age of rocks based on embedded fossils. For the first years of geology , biostratigraphy and superposition were the only means for determining the relative age of rocks. The geologic time scale was developed based on the relative ages of rock strata as determined by the early paleontologists and stratigraphers.

Radiometric dating has shown that the earliest known stromatolites are over 3. Paleontology has joined with evolutionary biology to share the interdisciplinary task of outlining the tree of life, which inevitably leads backwards in time to Precambrian microscopic life when cell structure and functions evolved. Earth's deep time in the Proterozoic and deeper still in the Archean is only "recounted by microscopic fossils and subtle chemical signals.

The study of fossils, on the other hand, can more specifically pinpoint when and in what organism a mutation first appeared. Phylogenetics and paleontology work together in the clarification of science's still dim view of the appearance of life and its evolution. Niles Eldredge 's study of the Phacops trilobite genus supported the hypothesis that modifications to the arrangement of the trilobite's eye lenses proceeded by fits and starts over millions of years during the Devonian. This and other data led Stephen Jay Gould and Niles Eldredge to publish their seminal paper on punctuated equilibrium in Synchrotron X-ray tomographic analysis of early Cambrian bilaterian embryonic microfossils yielded new insights of metazoan evolution at its earliest stages.

The tomography technique provides previously unattainable three-dimensional resolution at the limits of fossilization. Fossils of two enigmatic bilaterians, the worm-like Markuelia and a putative, primitive protostome , Pseudooides , provide a peek at germ layer embryonic development. These million-year-old embryos support the emergence of some aspects of arthropod development earlier than previously thought in the late Proterozoic.

The preserved embryos from China and Siberia underwent rapid diagenetic phosphatization resulting in exquisite preservation, including cell structures. This research is a notable example of how knowledge encoded by the fossil record continues to contribute otherwise unattainable information on the emergence and development of life on Earth.

For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida , Nematoda and Arthropoda. Fossil trading is the practice of buying and selling fossils. This is many times done illegally with artifacts stolen from research sites, costing many important scientific specimens each year.

Fossil collecting some times, in a non-scientific sense, fossil hunting is the collection of fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many still collect fossils and study fossils as amateurs. Professionals and amateurs alike collect fossils for their scientific value.

Three small ammonite fossils, each approximately 1. The reason for this is also at least partly due to the fact that the actual rate of fission track production.

Some experts suggest using a rate constant of 6. Wagner, Letters to Nature , June 16, In other words, the actual rate of fission track production isn't really known, nor is it known if this rate can be affected by various concentrations of U or other physical factors. For example, all fission reactions produce neutrons. What happens if fission from some other radioactive element, like U or some other radioisotope, produces tracks?

Might not these trackways be easily confused with those created by fission of U ? The human element is also important here. Fission trackways have to be manually counted. This is problematic since interpreting what is and what is not a true trackway isn't easy.

Geologists themselves recognize the problem of mistaking non-trackway imperfections as fission tracks. For example, it is recommended that one choose samples with as few vesicles and microlites as possible. But, how is one to do this if they are so easily confused with true trackways? Fortunately, there are a few other "hints". True tracks are straight, never curved. They also tend to show characteristic ends that demonstrate "younging" of the etched track.

True tracks are thought to form randomly and have a random orientation. Therefore, trackways that show a distribution pattern tend not to be trusted as being "true". Certain color and size patterns within a certain range are also used as helpful hints.

This is yet another reason why calibration with other dating techniques is used in fission track dating. It just isn't very reliable or accurate by itself. And, it gets even worse. Fairly recently, Raymond Jonckheere and Gunther Wagner American Minerologist, published results showing that there are two kinds of real fission trackways that had "not been identified previously. As it turns out, the "stable tracks do not shorten significantly even when heated to temperatures well above those normally sufficient for complete annealing of fission tracks.

The tracks through fluid are also interesting. They are "excessively long". This is because a fission fragment traveling through a fluid inclusion does so without appreciable energy loss. Such features, if undetected, "can distort the temperature-time paths constructed on the basis of confined fission-track-length measurements. These problems have resulted in several interesting contradictions, despite calibration.

For example, Naeser and Fleischer Harvard University showed that, depending upon the calibration method chosen, the calculated age of a given rock from Cerro de Mercado, Mexico in this case could be different from each other by a factor of " sixty or more " - - "which give geologically unreasonable ages. In addition, published data concerning the length of fission tracks and the annealing of minerals imply that the basic assumptions used in an alternative procedure, the length reduction-correction method, are also invalid for many crystal types and must be approached with caution unless individually justified for a particular mineral.

No wonder the authors recommend only going with results that do not provide "geologically unreasonable ages". Another example of this sort of aberrancy comes in the form of glass globs known as "tektites". Tektites are thought to be produced when a meteor impacts the Earth. When the massive impact creates a lot of heat, which melts the rocks of the Earth and send them hurtling through the atmosphere at incredible speed.

As these fragments travel through the atmosphere, they become superheated and malleable as they melt to a read-hot glow, and are formed and shaped as they fly along. It is thought that the date of the impact can be dated by using various radiometric dating methods to date the tektites.

For example, Australian tektites known as australites show K-Ar and fission track ages clustering around , years. The problem is that their stratigraphic ages show a far different picture. Edmund Gill, of the National Museum of Victoria, Melbourne, while working the Port Campbell area of western Victoria uncovered 14 australite samples in situ above the hardpan soil zone. This zone had been previously dated by the radiocarbon method at seven locales, the oldest dating at only 7, radiocarbon years Gill Charcoal from the same level as that containing specimen 9 yielded a radiocarbon age of 5, years.

The possibility of transport from an older source area was investigated and ruled out. Since the "Port Campbell australites include the best preserved tektites in the world Aboriginal implements have been discovered in association with the australites. A fission-track age of , years and a K-Ar age of , years for these same australites unavoidably clashes with the obvious stratigraphic and archaeological interpretation of just a few thousand years.

Commenting on the above findings by Lovering and his associates, the editors of the book, Tektites, state that, "in this paper they have built an incontrovertible case for the geologically young age of australite arrival on earth" Barnes and Barnes , p. The argument that various radiometric dating methods agree with each other isn't necessarily true.

Here we have the K-Ar and fission track dating methods agreeing with each other, but disagreeing dramatically with the radiocarbon and historical dating methods.

These findings suggest that, at least as far as tektites are concerned, the complete loss of 40 Ar and therefore the resetting of the radiometric clock may not be valid Clark et al. It has also been shown that different parts of the same tektite have significantly different K-Ar ages McDougall and Lovering, This finding suggests a real disconnect when it comes to the reliability of at least two of the most commonly used radiometric dating techniques.

In short, it seems like fission track dating is tenuous a best - even when given every benefit of the doubt. It is just too subjective and too open to pitfalls in interpretation to be used as any sort of independent measure of estimating elapsed time.

There is a methodological problem connected with the manner in which geologists infer the argon-retention abilities of different minerals. Concerning the suitability of different minerals for K-Ar dating, Faure , p. By comparing the K-Ar dates yielded by such minerals with the expected ones. Thus the correctness of the geologic time scale is assumed in deciding which minerals are suitable for dating.

For example, concerning the use of glauconies for K-Ar dating, Faure , p. Therefore, K-Ar dates of 'glauconite' have often been regarded as minimum dates that underestimate the depositional age of their host. It is also interesting that Faure , pp. However, if these "known" ages are incorrect, then fission track dating that is based on these ages is also incorrect. Thus fission track dating is not an independent test that helps to verify the accuracy of other tests.

The result is that radiometric dating in general is in danger of being based on circular reasoning. Inconsistencies and other Problems with various Radiometric Dating Techniques. Raul Esperante teamed up with Dr. This formation is approximately meters thick and consists of many layers of sedimentary rock. Yet, within essentially all of these layers are hundreds of very well preserved fossil whales. In fact, many of them are so well preserved that their baleen is still intact and attached in the usual position that baleen is attached in living whales.

Usually baleen detaches within a few days or even hours after death. Some of the fossilized whales and dolphins also have preserved remains of skin outlines around the fossilized bones. The skeletons themselves are generally well articulated and show no evidence of scavenging or significant decay. The fossil whales must have died and been completely buried by diatomaceous sediment within a very short time of death no scavenging, decay, significant disarticulation, or loss of baleen.

The layers are very smooth without significant erosion or unevenness to suggest the passage of time between layers.

There is no significant bioturbation very few tunnels or evidence of trace fossils or digging within the sedimentary layers that would be expected given long periods of time between the formation of subsequent layers. There are finely preserved shards of volcanic glass within all of the layers that have very sharp edges without the usual rounding that would be expected due to the relatively rapid ability of water to dissolve silica if long periods of time took place during the build up of these sedimentary layers.

These layers were deposited in shallow seas with evidence of flowing currents, which works against the potential counter-hypothesis that these layers were formed under anoxic conditions. Cosmogenic nuclides are isotopes that are produced by interaction of cosmic rays with the nucleus of the atom. The various isotopes produced have different half lives see table.

Cosmogenic dating using these isotopes are becoming a popular way to date the time of surface exposure of rocks and minerals to cosmic radiation. While the idea is fairly straightforward, there are just a few problems with this dating method. To illustrate this problem, consider that 3 H dating has been used to establish the theory that the driest desert on Earth, Coastal Range of the Atacama desert in northern Chile which is 20 time drier than Death Valley has been without any rain or significant moisture of any kind for around 25 million years.

The only problem with this theory is that recently investigators have discovered fairly extensive deposits of very well preserved animal droppings associated with grasses as well as human-produced artifacts like arrowheads and the like. Radiocarbon dating of these finding indicate very active life in at least semiarid conditions within the past 11, years - a far cry from 25 million years.

As it turns out, cosmogenic isotope dating has a host of problems. The production rate is a huge issue. Production rates depend upon several factors to include "latitude, altitude, surface erosion rates, sample composition, depth of sample, variations of cosmic and solar ray flux, inclusion of other radioactive elements and their contribution to target nucleotide production, variations in the geomagnetic field, muon capture reactions, various shielding effects, and, of course, the reliability of the calibration methods used.

So many variables become somewhat problematic. This problem has been highlighted by certain studies that have evaluated the published production rates of certain isotopes which have been published by different groups of scientists.

At least regarding 36 Cl in particular, there has been "no consistent pattern of variance seen between each respective research group's production rates. In short, "different analytical approaches at different localities were used to work out 36 Cl production rates, which are discordant.

So, what are the possible explanations for this "discordance"? Uncertainty in the independent chronology used to determine the age of surfaces used to calibrate a Cl production rate ex. There are 3 different latitude-altitude scaling systems in use worked out by different researchers. Whole rock analysis vs. It seems that the whole rock analysis method and the resulting optimization problem may underestimate the significance of other production pathways, i.

Fe and Ti spallation? Doesn't give one a great deal of confidence in the unbiased reliability of cosmogenic isotopic dating techniques - does it? Different Methods for Dating the Himalayan Mountains.

The Himalayan mountains are said by most modern scientists to have started their uplift or orogeny some 50 million years ago. However, recently in Yang Wang et.

Dalrymple's work early work on 26 historic lava flows showed that many of them had excess argon and were not set to zero at the eruption of the volcano. The following is the data from these tests: If the present data are representative, argon of slightly anomalous composition can be expected in approximately one out of three volcanic rocks. Dalrymple may have a point. It seems like rocks dating within one or two million years cannot be accurately dated by K-Ar techniques just because of the relatively wide ranges of error.

However, can rocks that are tens or hundreds of millions of years be more accurately dated? Perhaps, if these rocks were in fact closed systems and were not subject to contamination by external argon. Investigators also have found that excess 40 Ar is trapped in the minerals within lava flows.

The obvious conclusion most investigators have reached is that the excess 40 Ar had to be present in the molten lavas when extruded, which then did not completely degas as they cooled, the excess 40 Ar becoming trapped in constituent minerals and the rock fabrics themselves. However, from whence comes the excess 40 Ar, that is, 40 Ar which cannot be attributed to atmospheric argon or in situ radioactive decay of 40 K?

It is not simply "magmatic" argon? Funkhouser and Naughton found that the excess 40 Ar in the Hualalai flow, Hawaii, resided in fluid and gaseous inclusions in olivine, plagioclase, and pyroxene in ultramafic xenoliths in the basalt, and was sufficient to yield "ages" of 2. Many recent studies confirm the mantle source of excess 40 Ar. Hawaiian volcanism is typically cited as resulting from a mantle plume, most investigators now conceding that excess 40 Ar in the lavas, including those from the active Loihi and Kilauea volcanoes, is indicative of the mantle source area from which the magmas came.

Considerable excess 40 Ar measured in ultramafic mantle xenoliths from Kerguelen Archipelago in the southern Indian Ocean likewise is regarded as the mantle source signature of hotspot volcanism. Further confirmation comes from diamonds, which form in the mantle and are carried by explosive volcanism into the upper crust and to the surface.

When Zashu et al. The conventional K-Ar dating method was applied to the dacite flow from the new lava dome at Mount St. Porphyritic dacite which solidified on the surface of the lava dome in gives a whole rock K-Ar 'age' of 0. Mineral concentrates from the dacite which formed in give K-Ar 'ages 'from 0. These dates are, of course, preposterous. The fundamental dating assumption no radiogenic argon was present when the rock formed is brought into question.

Instead, data from the Mount St. Helens dacite argue that significant "excess" argon was present when the lava solidified in Phenocrysts of orthopyroxene, hornblende and plagioclase are interpreted to have occluded argon within their mineral structures deep in the magma chamber and to have retained this argon after emplacement and solidification of the dacite. Orthopyroxene retains the most argon, followed by hornblende, and finally, plagioclase.

The lava dome at Mount St. Helens dates very much older than its true age because phenocryst minerals inherit argon from the magma. The study of this Mount St. Helens dacite brings yet another question to mind: How accurate are K-Ar "ages" from the many other phenocryst-containing lava flows world-wide? Potassium is about 2.

Argon is about 3. We can assume then that the magma is probably about 2. Now, Lets say we are trying to date a one billion year old rock. How much of it would be 40 K? This would leave us with a 0.

This gives about 0. This is about one ten millionth of the mass of the rock, a very tiny fraction. If the rock weighed one gram, the Ar in the rock would weight one ten millionth of a gram.

And yet, with a relatively large amount of argon in the air, argon filtering up from rocks below, excess argon in lava, the fact that argon and potassium are water soluble, and the fact that argon is mobile in rock and is a gas, we are still expecting this wisp of argon gas to tell us how old the rock is?

The percentage of 40 Ar is even less for younger rocks. For example, it would be about one part in million for rocks in the vicinity of million years old. However, to get just one part in 10 million of argon in a rock in a thousand years, we would only need to get one part in 10 billion entering the rock each year. This would be less than one part in a trillion entering the rock each day, on the average.

This would suffice to give a rock an average computed potassium-argon age of over a billion years. Some geochronologists believe that a possible cause of excess argon is that argon diffuses into certain minerals progressively with time and pressure. Significant quantities of argon may be introduced into a mineral even at pressures as low as one bar.

We can also consider the average abundance of argon in the crust. This implies a radiometric age of over 4 billion years. So a rock can get a very old radiometric age just by having average amounts of potassium and argon.

It seems reasonable to me that the large radiometric ages are simply a consequence of mixing, and not related to ages at all, at least not necessarily the ages of the rocks themselves. It seems to me to be a certainty that water and gas will enter most, if not all, volcanic type rocks through tiny openings and invalidate almost all K-Ar ages. Rocks are not sealed off from the environment.

This contamination would seem to be more and more of a problem the older the rock became. Let me illustrate the circulation patterns of argon in the earth's crust. So argon is being produced throughout the earth's crust, and in the magma, all the time.

In fact, it probably rises to the top of the magma, artificially increasing its concentration there. Now, some rocks in the crust are believed not to hold their argon, so this argon will enter the spaces between the rocks. Leaching also occurs, releasing argon from rocks. Heating of rocks can also release argon. Argon is released from lava as it cools, and probably filters up into the crust from the magma below, along with helium and other radioactive decay products.

All of this argon is being produced and entering the air and water in between the rocks, and gradually filtering up to the atmosphere. So this argon that is being produced will leave some rocks and enter others. Different Dating Methods Agree. It is often said that a great many dating methods, used on a single specimen, will agree with each other, thus establishing the accuracy of the date given.

In reality, the overwhelming majority of measurements on the fossil bearing geologic column are all done using one method, the K-Ar method Recall that both potassium and argon are water soluble, and argon a gas is mobile in rock. Thus the agreement found between many dates does not necessarily reflect an agreement between different methods, but rather the agreement of the K-Ar method with itself Especially noting that Dalrymple suggested that only K-Ar dating methods were at all trust worthy.

I have seen no good double-blinded research studies that say otherwise. One would think that if this were a good science, then such studies would be done and published, but they are strangely lacking. Also, specific differences are known and have been known to exist between different dating methods.

For example, Isotopic studies of the Cardenas Basalt and associated Proterozoic diabase sills and dikes have produced a geologic mystery. Using the conventional assumptions of radioisotope dating, the Rb-Sr and K-Ar systems should give concordant "ages". However, it has been known for over 20 years that the two systems give discordant "ages", the K-Ar "age" being significantly younger than the Rb-Sr "age". The "argon reset model" was the first explanation proposed for the discordance.

A metamorphic event is supposed to have expelled significant argon from these rocks. The reset model is unable to reconcile the new data, leading to a metamorphic event which is excessively young and inconsistent with the conventional stratigraphic interpretation. The "argon leakage model" also attempts to explain why these rocks have about half the argon which seems to be required by the Rb-Sr system.

The leakage model supposes an incredible improbability. Both the old and new data imply that the rocks leaked argon in nearly exact proportion to the abundance of potassium producing a "leakage isochron", an explanation not supported by a quantity of an appropriate mineral or mesostasis phase. Strong negative correlation between K-Ar model age and K 2 O in the upper portion of the Cardenas Basalt is not easily explained in a consistent manner.

Furthermore, reset and leakage models have difficulty explaining the abundance of initial 36 Ar in the rocks, especially the abundance of 36 Ar in those rocks which supposedly leaked the most 40 Ar. Three alternatives are suggested to the two argon loss models. The "argon inheritance model" and "argon mixing model" simply propose that argon is positively correlated with potassium from its magma source or produced by a mixing process, and that the linear relationship on a plot of 40 Ar versus 40 K is an artifact of the magma, not produced by radioisotope decay within these rocks.

The inheritance of argon seems to be a better model than is the mixing model. All three explanations offered as alternatives to the argon loss models invalidate using the K-Ar system as conventional geochronology would assume. The word "isochron" basically means "same age". Isochron dating is based on the ability to draw a straight line between data points that are thought to have formed at the same time.

The slope of this line is used to calculate an age of the sample in isochron radiometric dating. The isochron method of dating is perhaps the most logically sound of all the dating methods - at first approximation.

This method seems to have internal measures to weed out those specimens that are not adequate for radiometric evaluation. Also, the various isochron dating systems seem to eliminate the problem of not knowing how much daughter element was present when the rock formed.

Isochron dating is unique in that it goes beyond measurements of parent and daughter isotopes to calculate the age of the sample based on a simple ratio of parent to daughter isotopes and a decay rate constant - plus one other key measurement.

What is needed is a measurement of a second isotope of the same element as the daughter isotope. Also, several different measurements are needed from various locations and materials within the specimen. This is different from the normal single point test used with the other "generic" methods. To make the straight line needed for isochron dating each group of measurements parent - P, daughter - D, daughter isotope - Di is plotted as a data point on a graph.

Consider the series of slowly changing forms presented at the right. Morton refers to this series as a clear example of plankton evolution in action by saying,. This gradual change is imperceptible Gradualistic evolution is documented among these tiny creatures laying bare the false claim that there are no transitional forms. What it shows is that the flood-advocates don't read anything except their own literature.

Well, after reading Morton's "literature" it seems that such variations in morphology might be easily explained by variations in environment. These forms pictures at the right might in fact be members of the same species of plankton.

After all, foraminifer are quite "plastic" indeed. The genetic information contained in one common gene pool seems quite capable of producing startling morphologic variations. Considering this ecophenotypic variation potential, how then is Morton so sure that "gradualistic evolution" is taking place here? Some point to the obvious vertical order of pollen found throughout the fossil record and suggest that such sorting can only be explained by evolutionary changes over time.

However, to say that this sorting is impossible for a large complex fluvial event or a relatively rapid series of rather complex catastrophic events to explain, seems to be a bit presumptuous. As it turns out, different pollens can be water sorted based on various characteristic differences such as size, specific gravity, density, chemical composition ie: For example, most deciduous pollen types sink in water in a few minutes while bisaccate grains pine pollen float for much longer times, sometimes years, before they sink.

Hopkins results show that there is some differential buoyancy between Pinus species. When oak pollen Quercus palustris was put through a similar process most of it sank within the first meter. Bisccate grains will only sink if the bladders are pierced either by physical, chemical or microbial processes.

They are therefore more likely to be saturated if they enter turbulent flow, or if they have been resident in a position such as the soil surface where they are open to microbial attack prior to introduction to the water.

Many pollen grains have mechanisms to prevent desiccation, but cannot prevent water uptake. Sporomorphs, many of which have no openings in the exine, have no inlet for water.

Attempts to saturate Lycopodium in the laboratory have shown that such grains are extremely resistant to water uptake. Extreme methods have been invoked, such as placing the sporomorphs in a beaker in a vacuum for up to eight hours own method or boiling in water Reynolds This means that they are likely to remain afloat in the water, in nature, for long periods of time. This is consistent with results from the Volga River where Fedorova found Lycopodium spores over km from their source. Several authors have found that water currents can sort sporomorphs.

This was first seen in the field by Muller who was looking at the palynomorph distribution in recent sediments in the Orinoco delta area. He noted that the pollen of Rhizophora, which is relatively small, was carried further out to sea than larger sporomorphs from similar source areas.

The smaller ragweed grains remain in suspension for longer periods of time, allowing them to be transported to the littoral areas of the lake by wind generated currents. Sorting was also used to explain results presented by Chen from the sediments of lake Barine in Queensland, Australia. Larger grains are deposited in the littoral areas, while smaller grains are carried to the lake center by these currents.

Clearly sorting of sporomorphs can occur in many depositional environments. The behavior of sporomorphs as sedimentary particles is, however, poorly understood. In a more recent study of alluvial sediments from a canyon stream in the chuska mountains of Arizona, Fall tested the assumption that the pollen in the alluvium was from local vegetation.

She found that pollen concentrations in general were highest in the fine-grained sediments. Non-arboreal sporomorph types however were found in higher numbers in the sandy sediments. Similar results have been reported from Glacio-lacustrine sediments in Alaska Goodwin, and braided stream deposits adjacent to the Caribou River in Yukon Catto, or they may be due to different source areas of tributaries involved. These results suggest that the deposition of fine-grained sediments, sporomophs in particular, is related both to the flow conditions of the water and the bed material over which the water flows.

This sorting is primarily due to size, but sporomorph density is also important. Although the subject of the Salt Range beds is proscribed among Indian and many western paleontologists today, the case rests precisely where it did in the early s Ghosh et al.

The fossils are modern in aspect "Eocene" according to Sahni yet the beds containing the fossils are overlain conformably by early Cambrian sediments Coates et al. In the mid- s there was a lively controversy about the age of the saline series of the Punjab salt range. On the basis of field evidence, geologists like Gee and Fox regarded it as Cambrian and Pre-Cambrian. But on the basis of the microfossils comprising Shreds of gymnospermous and angiospermous woods, cuticle of grasses, etc.

Sahni regarded it as Eocene. His contension was that angiospermous remains could not have occurred earlier than the Tertiary. To strengthen his argument he cited the absence of vascular elements in the Cambrian strata of the Salt Range which he said were unconformably lying over the Saline Series.

Ghosh and his associates checked the results obtained by Prof. Sahni and his collaborators and found the occurrence of vascular elements even in the Cambrian rocks. The controversy over the age of the saline Series could not be resolved due to the sudden demise of Prof. But it inspired Prof. Ghosh to further investigate whether vascular plants existed in Cambrian times or not. To collect sufficient evidences, he and A. From these rocks they obtained wood elements and monolete and trilete types of spores, leading to the conclusion of the fact that their findings were not in agreement with the view of the majority of investigators who did not consider vascular plants to have existed in Pre-Silurian times.

Still they had the courage to stand by their own observations, which were also supported by the works of Naumova, Reissinger and Kopeliovitch in Europe and Jacob and his associates in India. In they again published a paper on the spores of vascular plants obtained from nine samples of Cambrain rocks of North America, further reiterating the existence of vascular plants in the Cambrian. Ghosh's investigations related with the occurrence of earliest vascular plant led him to have a more critical looks to at all the organic remains reported from Pre-Cambrian deposits.

This formed the subject matter of the 43rd Acharya Jagadis Chandra Bose endowment lecture which he delivered in November under the title "Life in the Proterozoic".

The controversy received global attention and Ghosh became known as "Cambrian Ghosh" worldwide. On his retirement from ONGC in , Ghosh became an emeritus professor in the Botany Department of Calcutta University where he advised several palynology students, e. Also, in S. Leclercq published a paper in the journal Evolution entitled, "Evidence of vascular plants in the Cambrian" that included the following introduction: While the information given by palynology agrees with the flora known in the Upper and Middle Devonian, the assemblage of spores found in the Lower Devonian, Silurian and Cambrian plead in favor of a more varied and advanced type of flora than the plant impressions have so far suggested.

The recent discovery of Lycopodiaceous shoots in the Middle Cambrian of East-Siberia appears to confirm the evidence of palynology investigation. Some researchers have reported finding pollen of higher plants in strata shown by standard dating methods to be extremely old. These findings call into question the whole conventional account of the evolution of plants. In one instance, parties of scientists in Venezuela reported finding pollen of flowering plants in Precambrian rock formations judged to be 1.

This posed a serious problem, because according to current theory the flowering plants evolved fairly recently, only million years ago. The story is as follows: Late in U. Dunsterville made an expedition to collect orchids around Cerro Venamo, at the westernmost point on the frontier between Venezuela and British Guiana where this mountain is known as Wenamu Head.

Fournier, palynologist of the Mene Grande Oil Company, processed the samples and recovered well-preserved pollen and spores. Sulek, palynologists of Compa-Shell de Venezuela and Creole Petroleum Corporation, respectively, processed other pieces and recovered identical plant microfossils.

This discovery of pollen and spores in a formation of supposed Precambrian age was so remarkable that a reconnaissance expedition of qualified geologists was organized to verify the facts of the case. During April, , with the assistance of personnel and vehicles of the Ministerio de Minas e Hidrocarburos, the locality was visited by a party which included N. They confirmed the salient facts as recorded by Dunsterville.

The shale-like beds, being less competent, had eroded away below the massive Roraima sandstone, leaving an undercut extending ft. The original samples were loose, weathered fragments from the talus slope below. New samples of unweathered rock were collected from the face of the undercut. On their return to Caracas, the three palynologists made independent investigations of the new samples.

Utmost care was taken to avoid any possibility of superficial contamination. The rock cleaves along finely laminated bedding planes which are coated with limonite. Every effort was made to avoid these planes and some of the pieces processed were the central nubs left after chipping away the external parts of large blocks of the rock, which was dense enough to sound when struck with a hammer. Nevertheless, microfossils of the same type as before were recovered.

As to interpretation of the significance of the fossil pollen and spores, two sharply divided opinions have been expressed. The writers make no attempt to adjudicate, but state the two concepts impartially. One group adopts the attitude that the radiometric dating of dolerites and a hornfels within the Roraima Formation as Precambrian is beyond dispute, hence the pollen and spores must have entered as secondary contamination.

The improbability that pollen could withstand the baking process, which converted shale to hornfels, is adduced as further evidence that the pollen must be allochthonous. The absence of macroscopic plant remains in the Roraima Formation is also noted, despite its assumed continental fluviatile origin.

It is admitted that entry of the pollen into its present site defies simple explanation, though some form of washing in by meteoric waters in the geological past via joints in the overlying sandstone seems the most probable cause. The second group holds that by no conceivable physical means could the pollen and spores have entered the metamorphosed sediments from the outside.

They are dense impermeable rocks compressed by an overburden of hundreds of feet of the overlying Roraima sandstones. The undercutting at Cerro Venamo suggests that the cliff has been steadily retreating, hence the face which was sampled must have been deep within the formation until quite recent times. The Roraima sandstones are quartzitic, of low permeability, hence carriage of extraneous pollen through them by percolating water seems highly improbable.

Even if this process could occur, entry of such pollen and spores into the nonporous hornfels lacks an explanation. Furthermore, if plausibility of this process be granted, it would have been operative for a long period, and a mixed suite of spores and pollen should be expected.

In counter-argument against the first group, it is claimed that the assertion that pollen and spores cannot withstand anaerobic baking of their parent shales has never been tested experimentally.

As regards the radiometric dating, there is a disquieting overlap between stated ages of the Roraima Formation and the underlying basement rocks. The latter suffered complex deformation and vulcanism, and were then deeply peneplaned before being covered by thousands of feet of Roraima sandstones, and only after these prolonged events were the dolerites intruded, on which age-determination of the Roraima has been based.

If the radiometric technique is valid there should be a long and clear-cut time-gap between ages assigned to the basement rocks and to the Roraima beds. Such a gap does not exist in the experimental results published, but this discrepancy is glossed over in the latest summary of radiometric dating in British Guiana. As stated, we offer no solution to the paradox.

It is clear, however, that botanist Dunsterville in his hunt for rare orchids stumbled on a highly intriguing geological problem. So, to resolve the difficulty, one group of scientists decided that although the dates of the rock were correct the pollen must have been a recent intrusion, even though entry of the pollen into those layers defies simple explanation. The second group held that the pollen had been there since the rock had formed, but concluded that the dating was wrong and the rock was of recent origin.

The two groups thus contradicted each other in their interpretations of the evidence. The real significance of this treatment is that both groups felt compelled to look for ways to avoid contradicting the standard story of evolution, to which they were strongly committed. An summary of this problem is as follows: His contention was that angiosperm remains could not have occurred earlier than the Tertiary.

In they again published a paper on the spores of vascular plants obtained from nine samples of Cambrian rocks of North America, further reiterating the existence of vascular plants in the Cambrian. The presence of fragmentary vascular plant microfossils of the Vindhyans and their correlation with Salt Range could never be reconciled. Thus, Ghosh came in direct controversy with Birbal Sahni whose viewpoints contradicted Ghosh's. By at least, this problem had not been resolved.

Of great importance in the later discussions were fragments of advanced plants and insects discovered in the Salt Range Formation by researchers such as B. But geological evidence cited by others was opposed to this conclusion, supporting instead a Cambrian age for the Salt Range formation.

Modern geological opinion is unanimous that the Salt Range Formation is Cambrian. But Sahni's evidence for advanced plant and insect remains in the Salt Range Formation is not easily dismissed. It would appear that there is still a contradiction between the geological and paleontological evidence, just as there was during the time of active controversy.

During the time of active controversy, E. Gee suggested that the conflict might be resolved by positing the existence of an advanced flora and fauna in the Cambrian.

This idea was summarily dismissed at the time, but, although it challenges accepted ideas about the evolution of life on earth, it appears to provide the best fit with the different lines of evidence.

The existence of advanced plant and animal life during the Cambrian is consistent with accounts found in the Puranic literature of India. Many will argue that in different places throughout the word, there can be found layers of forests one on top of each other, with their trees, "in the position of growth" still standing up. It is also said that these forests each have their own layer of soil.

So, it is felt that each of these were forests grew over long periods of time on top of previous forests, each of which was buried by some long ago catastrophe. What is interesting about these places ie: Yellowstone National Park were up to 65 different layers can be found with trees in the vertical position 13 is that the trees are still oriented in their positions with each other.

Their soil is also found to be water sorted course to fine , and often is found half way up a tree instead of at its base. This organic material also averages only 3 cm in thickness and, for many of the "forest" layers it is missing altogether. In some areas, such as Mt.

It seems rather strange for a forest to grow into full bloom without forming an organic layer. How is this explained? Another strange finding of the organic layers is the fact that they are sorted in various ways.

Take for instance the fact that pine needles and leaves are not mixed together, but are found in separate organic layers despite the fact that there are both pine and hardwood trees "growing" from the same organic layer s. Also, the are proportionately less pine needles than there are leaves even in areas that are dominated by conifers. In a real forest, conifers drop a much higher mass of needles than deciduous trees drop leaves. And yet, in the fossil forests of Yellowstone, needles are relatively sparse even at the bases of large fossilized conifers.

This interesting fact has been recognized as far back as when Knowlton remarked about the absence of needles in the organic levels associated with the large fenced petrified tree near Roosevelt Lodge in Yellowstone National Park. However, large numbers of broad leaves and only a few pine needles are seen in the organic levels.

Sequoia needles were rare or absent. Although petrified sycamore stumps are not common, leaves of sycamore are the most abundant broad-leaf fossils. It is also interesting to note that, despite a heavy predominance of sequoia trees, fossilized sequoia cones are very rare in the fossil forests of Yellowstone National Park.

This taxonomic sorting seems quite strange indeed unless one uses a catastrophic model involving flood such as occurred during the eruption of Mt. In water, pine needles become saturated and sink before leaves sink. Pollen is another problem. Trees with wind-transported pollen, such as walnut and sycamore, should have left a pollen record in the forest floor, but little or no pollen of these two has been found.

Modern forest floors contain pollen in abundance inversely proportional to the distance from the source trees especially trees for which wind is the pollen-transporting agent. Research done on four levels of Specimen Creek Petrified Forest showed no positive correlation between fossil pollen abundance and the proximity of possible source trees.

The organic layers themselves also show no significant decay as one goes from top to bottom. In a real forest floor, organic material decays. Evidently, this does not happen in the forests of the past because the leaves at the bottom of organic layers are just as well formed as preserved as the leaves at the tops of these organic layers. Also, the material between the leaves is sorted, course to fine as one moves upward Consider the figure at the right.

There is yet another problem with the intermittent burial of forests by volcanic activity and mud-slides. If a volcanic mud slide buried only the lower parts of the trunks of the trees of a growing forest as might be suggested by the fact that some of the upright trees penetrate overlying layers , the taxonomic composition of the new forest that grew on this new surface would be similar to the composition of the forest that was buried.

The cones, seeds, nuts, and fruits would fall from the unburied branches and foliage and repopulate the new surface with a similar forest.

Such correlation between adjacent levels of the Specimen Creek Petrified Forest has not been found. The normal maturation of soil also involves the slow breakdown of feldspar and other minerals into clay. Out of 65 layers of Specimen Creek in Yellowstone National Park, only nine bands of clay were found among only seven organic layers. Horizontal sampling of two of the clay bands at 2.

Abundant unweathered feldspar is scattered throughout the Yellowstone organic levels, suggesting repeated rapid burials. The apparent absence of clay in the majority of levels implying that normal weathering of soil did not occur raises questions about the passage of long time intervals between levels.

This datum also questions the validity of the assumption that the organic levels upon which trees with hundreds of rings sit represent true soils. Furthermore, the sudden abundant appearance of clay in a few horizontal bands that included both organic levels and layers of clay in the associated breccia beds between levels suggests transport rather than in situ formation of the clay minerals.

Despite much study of the Yellowstone Petrified Forests, no animal fossils have been found. Why are animal remains absent from the plant fossil-bearing levels of Yellowstone? Because forests would be expected to harbor a wide variety of animals, some of which would be buried by the successive mud slides, the absence of animal fossils has been a mystery.

Volcanic activity could have caused larger forest animals to flee elsewhere, but flight cannot be used as an explanation for the absence of all animal remains because many animals could not or would not leave their forest habitats. Land snails, some amphibians and reptiles, many insects, arachnids, and worms would not escape burial. Immature members of many types would be unable to flee.

In addition, bones, eggs, teeth, scales, molted skins, castings, droppings, burrows, etc. None of these have been found in the fossil forest organic levels during a century of research. Considering that delicate plant parts are excellently preserved, animal remains should also have been preserved if they were present.

Only one exception is known. Remains of termites have been found in chambers within the petrified wood. If, however, the trees and the organic debris making up the soil levels were transported by water, the separation of animals from the plants before burial is much easier to explain. The volcanic ash found in the various layers is itself is quite interesting.

The chemicals that make up the ash are uniform throughout all the layers. In fact, there are only four unique chemical patterns to be found in the ash of Specimen Creek.

Spark source mass spectrometry analysis of trace elements in the bands of ash revealed pulses of ash from four source areas for the Specimen Creek Petrified Forest. The four trace element profiles interweave in an irregular manner up the sequence of 65 organic levels of Specimen Creek Petrified Forest. If these 65 ash layers organic levels were laid down over a long time span, the ash that was laid down thousands of years later near the end of the series of ash eruptions would have changed sufficiently to produce a new and different trace element profile a new "fingerprint".

This has not been the case. The rapid burial of the whole sequence seems to be required. The root systems of the upright stumps seems to be a main argument in favor of their in situ growth. Of course, some of the petrified trees have broken roots; but when were they broken? Even if a permit to collect petrified wood within the park is obtained, excavation of stumps is not permitted; furthermore, digging is difficult in the hard rock.

Consequently, to determine if the root breakage seen is pre- or post-petrification is difficult. Several examples of abrupt root terminations from Mt.

Norris, Tom Minor Basin, and Specimen Creek strongly indicate that, at least in some cases, the tree roots were broken before the trees were buried by volcanic gravels and muds. This evidence supports the view that the trees were transported.

However, small rootlets can be located at the bases of upright stumps, and this feature has been used to argue against transport. Observations in Spirit Lake near Mount St. Helens and of trees uprooted by bulldozing operations show that the small roots and rootlets are usually still intact, but the larger roots are usually broken See Figure.

The presence of small roots extending from the base of a petrified tree therefore is not evidence for an in situ interpretation unless large roots also extend unbroken.

Broken and frayed large roots could be the result of changing stream currents eroding the bases of growing trees, but such activity should leave evidences in the sediments. Furthermore, erosion must be limited; otherwise, trees would be removed or toppled.

If a forest were killed by a mud flow that buried the bases of the trees, the tops of the trees would extend above the new ground surface. They would overlap a new second forest that would commence growing on the new surface.

Imsges: are fossil dating methods accuracy

are fossil dating methods accuracy

The main elements of Figure 3 a are as follows:. We avoided charcoal and wood samples because of the possibility of inbuilt age. This taxonomic sorting seems quite strange indeed unless one uses a catastrophic model involving flood such as occurred during the eruption of Mt.

are fossil dating methods accuracy

Isochrons that are based on intra-specimen crystals can be extrapolated to date the whole specimen.

are fossil dating methods accuracy

The chamber connections are small openings between each chamber. Episodes in the History of Palaeontology. Arabe mff. Unfortunately, his misunderstanding of the radiocarbon date range has resulted in him adopting an ad hoc randomly generated number range to satisfy his hypothesis retrospectively. Are fossil dating methods accuracy, several different measurements are needed from various locations and materials within the specimen. How is this calibrated? The lava dome at Mount St.