Period (geology)

Creationist Geologic Time Scale: Should the scientific community continue to fight rear-guard skirmishes with creationists, or insist that “young-earthers” defend their model in toto? Introduction This manuscript proposes a new approach for science’s battle against the rising influence in America of pseudo-science and the Creationist movement. The framework of Creationist Bible-based earth history, focusing on Genesis and the Noachian flood, can be assembled into a single geologic time scale Figure 1 , enlarged by addition of many geologic facts, difficult for Creationists to explain. Figure 1 is an abbreviated version of the time scale outlined in the following paragraph which was redrawn and published by the American Scientist. Some of the items are so absurd that all but the most dedicated fundamentalists will see the overall picture as scientific nonsense, even bordering on humor, a most rare commodity in Creationist literature. Science, rather than using its traditional defensive approach of item-by-item rebuttal of Creationist attacks, needs to take the offensive by challenging Creationists to defend their “scientific” view of earth history as represented by this time scale. Note that the numbered items in this Time Scale are further expanded in subsequent numbered sections which are keyed to these same numbers.

Australian Museum

When an igneous melt crystallizes, parent and daughter elements are chemically separated into different crystals. Further radioactive decay keeps the parent and daughter elements in the same crystal. Individual crystals of the same mineral are dated to give the age of crystallization or cooling. Examples include zircon, muscovite, and biotite.

Note that whole rock analysis would not give the age of cooling.

Stratigraphy is a branch of geology concerned with the study of rock layers and layering (stratification).It is primarily used in the study of sedimentary and layered volcanic graphy has two related subfields: lithostratigraphy (lithologic stratigraphy) and biostratigraphy (biologic stratigraphy).

All aspects of Paleozoic Palynology and their applications will be covered, such as: Taxonomy and systematics; Development of optical methods for kerogen classification and organic maturity assessment; Applications to basin modelling; Applications to conventional and unconventional hydrocarbon exploration Keywords: These studies build on the traditional strengths and foundations of classical Palaeozoic palynology such as taxonomy, classification, palynostratigraphy, palaeogeography, and palaeoenvironmental analyses.

The topics mentioned above are included in this session, but the emphasis is on the future directions of Palaeozoic palynology research. This special session will be inclusive in terms of both current and future research trends, as well as speculative presentations on the future of Palaeozoic palynology. This session focuses on all aspects of Upper Palaeozoic and Mesozoic palaeobotanical biostratigraphy, including the use of palynology and macrofloras.

In particular, it will focus on the use of special tools, applications, and common or individually customized methods to produce improved and conclusive stratigraphical results. Examples of the themes to be covered include: This session is meant to highlight the importance of combining these approaches on the same fossil pollen grain for a more accurate botanical affiliation to pollen of extant plants.

All contributions on taxonomy, palaeovegetation, palaeoenvironments and palaeophytogeography are welcomed. Questions related to vegetation-climate interactions and human versus climate impacts on terrestrial vegetation and plant diversity past, present and future are especially in need of such information from the past. Given the increasing number of such studies, it would be most valuable to gather together scientists working with these model approaches and applying them to test specific research questions.

Hypothesis testing to understand processes involved in climate-vegetation-human interactions in the past and formulate lessons from the past for present and future environmental challenges will be of particular interest. This new capability has arisen as a response to new chemical, physical and statistical methods of data treatment and to a better understanding of the functioning of the global environmental system.


Definitions and Procedures A. Layer of rock characterized by particular lithologic properties and attributes that distinguish it from adjacent layers. The systematic organization of the Earth’s rock bodies, as they are found in their original relationships, into units based on any of the properties or attributes that may be useful in stratigraphic work. A body of rock established as a distinct entity in the classification of the Earth’s rocks, based on any of the properties or attributes or combinations thereof that rocks possess.

Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. Usually the aim is correlation, demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at some other section. The fossils are useful because sediments of the.

The boundary surface between two formations is a type of geologic contact. Fault surfaces and the boundary between an igneous intrusion and its wall-rock are also types of contacts. The stratigraphic formations and stratigraphic column for the Grand Canyon in Arizona. The walls of the canyon look striped, because they expose a variety of rock types that differ in color and in resistance to erosion. Some formations include a single rock type, whereas others include interlayered beds of two or more rock types.

Not all formations have the same thickness, and the thickness of a single formation can vary with location. Note that in the formal name of a formation, all words are capitalized. Several adjacent formations in a succession may be lumped together as a stratigraphic group. Where did the concept of a stratigraphic formation come from? While excavating canals in England, William Smith discovered that formations cropping out at one locality resembled formations cropping out at another, in that their beds looked similar and contained similar fossil assemblages.

Sequence Stratigraphy of the Middle and Upper Ordovician of the Eastern United States

Lund As part of an extensive regional study of the Gulf of Suez synrift stratigraphy, a paleomagnetic analysis of early to middle Miocene sediments was undertaken to establish the suitability of the stratigraphic sequence for magnetostratigraphic correlation. During an initial field program, multiple hand-oriented samples were collected at key stratigraphic localities along the western Sinai Peninsula within the onshore rift sequence. All important clastic lithofacies were sampled for test analysis, although finer-grained lithologies were preferentially collected due to their usually lower susceptibility to remagnetization.

Initial rock magnetic studies indicate that although they are weakly magnetized, the samples do preserve a primary paleomagnetic signature. Thermal and alternating-field demagnetization studies suggest that detrital titano-magnetite is the likely primary magnetic carrier.

Other articles where Stratigraphic correlation is discussed: geology: Paleontology: and on different continents, involves stratigraphic correlation from place to place. Although correlation of strata over modest distances often can be accomplished by tracing particular beds from place to place, correlation over long distances and over the oceans almost invariably involves comparison of fossils.

Correlation Principles and techniques Correlation is, as mentioned earlier, the technique of piecing together the informational content of separated outcrops. When information derived from two outcrops is integrated , the time interval they represent is probably greater than that of each alone. This optimistic hope, however, must be tempered by the realization that much of the Precambrian record—older than million years—is missing.

Correlating two separated outcrops means establishing that they share certain characteristics indicative of contemporary formation. The most useful indication of time equivalence is similar fossil content, provided of course that such remains are present. The basis for assuming that like fossils indicate contemporary formation is faunal succession. However, as previously noted, times of volcanism and metamorphism, which are both critical parts of global processes, cannot be correlated by fossil content.

Furthermore, useful fossils are either rare or totally absent in rocks from Precambrian time , which constitutes more than 87 percent of Earth history. Precambrian rocks must therefore be correlated by means of precise isotopic dating.

Archaeology 101: Reading Stratigraphy

Several erroneous notions have been attached to the geologic column. The following are the ten most common misconceptions. 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 by catastrophists who were creationists.

These men stood for careful empirical science and were not compelled to believe evolutionary speculation or side with uniformitarian theory.

stratigraphic correlation Geologic study concerned with establishing geochronological relationships between different areas, based on geologic investigations of many local successions. Pick a style below, and copy the text for your bibliography. gives you the ability to cite.

February 16, Archaeology Layers of a lasagna are like stratigraphic layers. The easiest way to think about stratigraphy is as if you were making lasagna: There is no way for you to put the bottom layer of pasta on before you put the sauce on, and still maintain the same sequence or location of these different layers. This works the same way for archaeology, and can be used to determine a sequence of events. Where one layer overlies another, the lower layer was deposited first.

When an archaeological unit is done being excavated, the walls of the unit reveal the different layers of stratigraphy. Archaeologists are then able to tell which of these layers happened before or after layers. Labeled archaeological stratigraphy Sometimes, these strata can be confusing: For archaeologists, however, these intrusions are important, because they are often the product of human behavior.


A thriving culture of Paleo-Americans, known as the Clovis people, vanished seemingly overnight. Gone, too, were most of the largest animals: In just the last few years, there has arisen a controversial scientific hypothesis to explain this chain of events, and it involves an extraterrestrial calamity: Now the proponents of this apocalyptic scenario say they have found a new line of evidence: They say they have found these tiny structures across North America in sediments from 12, years ago, and they argue that the diamonds had to have been formed by a high-temperature, high-pressure event, such as a cometary impact.

The advantages of the present methods for both absolute dating and chronostratigraphic correlation were evident when the age estimates derived from pollen data .

The Radiometric Dating Game Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive elements such as uranium, strontium, and potassium. On the surface, radiometric dating methods appear to give powerful support to the statement that life has existed on the earth for hundreds of millions, even billions, of years.

We are told that these methods are accurate to a few percent, and that there are many different methods. We are told that of all the radiometric dates that are measured, only a few percent are anomalous. This gives us the impression that all but a small percentage of the dates computed by radiometric methods agree with the assumed ages of the rocks in which they are found, and that all of these various methods almost always give ages that agree with each other to within a few percentage points.

Since there doesn’t seem to be any systematic error that could cause so many methods to agree with each other so often, it seems that there is no other rational conclusion than to accept these dates as accurate. However, this causes a problem for those who believe based on the Bible that life has only existed on the earth for a few thousand years, since fossils are found in rocks that are dated to be over million years old by radiometric methods, and some fossils are found in rocks that are dated to be billions of years old.

If these dates are correct, this calls the Biblical account of a recent creation of life into question. After study and discussion of this question, I now believe that the claimed accuracy of radiometric dating methods is a result of a great misunderstanding of the data, and that the various methods hardly ever agree with each other, and often do not agree with the assumed ages of the rocks in which they are found. I believe that there is a great need for this information to be made known, so I am making this article available in the hopes that it will enlighten others who are considering these questions.

Even the creationist accounts that I have read do not adequately treat these issues. At the start, let me clarify that my main concern is not the age of the earth, the moon, or the solar system, but rather the age of life, that is, how long has life existed on earth. Many dating methods seem to give about the same ages on meteorites.

Digitised records 1960s

Mahmoud Zizi, in Regional Geology and Tectonics: This simplified stratigraphic summary is based on several publications on the Canadian margin e. Similarities include the stratigraphic architecture of the syn-rift sequence dominated by continental clastics and salt e. The frequent basalt intercalations within the syn-rift strata with an age clustering around Ma have been studied by many e.

Geologic Time and Stratigraphic Correlation Geology Geology for Environmental ScientistsGeology for Environmental Scientists. Radiometric Dating: the source of the dates on the Geologicof the dates on the Geologic Time Scale. Radiometric Dating • Actually a simple technique.

Glossary Terms Introduction Stratigraphy is the study of rock layers and reconstruction of the original sequence in which they were deposited. The stratigraphy of an area provides the basis for putting together the geologic history of an area. The details of a region’s stratigraphic story are revealed by: What exactly is in each stratum layer — the types of rocks and minerals, the sedimentary structure , and the fossils.

This reveals what was happening at the time the layer of sediment was being deposited in terms of geological activity, water, climate, and living things The sequence of strata — which layer is on top of which. This allows the story to be told sequentially as a series of changes, some gradual, some abrupt.

Stratigraphy – PowerPoint PPT Presentation

There are lots of ways to guesstimate ages, and geologists knew the earth was old a long time ago and I might add that they were mostly Christian creationist geologists. But they didn’t know how old. Radiometric dating actually allows the measurement of absolute ages, and so it is deadly to the argument that the earth cannot be more than 10, years old. Radiometric methods measure the time elapsed since the particular radiometric clock was reset.

Radiocarbon dating, which is probably best known in the general public, works only on things that were once alive and are now dead.

Physical Anthropology Quiz 3. STUDY. PLAY. phylogeny. The evolutionary relationships of a group of organisms. stratigraphic correlation. The radiometric dating method in which the ratio of 14C to 12C is measured to provide an absolute date for a material younger than 50, years.

Lithostratigraphy Chalk layers in Cyprus , showing sedimentary layering Variation in rock units, most obviously displayed as visible layering, is due to physical contrasts in rock type lithology. This variation can occur vertically as layering bedding , or laterally, and reflects changes in environments of deposition known as facies change.

These variations provide a lithostratigraphy or lithologic stratigraphy of the rock unit. Key concepts in stratigraphy involve understanding how certain geometric relationships between rock layers arise and what these geometries imply about their original depositional environment. The basic concept in stratigraphy, called the law of superposition , states: Chemostratigraphy studies the changes in the relative proportions of trace elements and isotopes within and between lithologic units.


The results of these studies are summarized in a correlation chart, available as a pdf. This chart represents a work in progress, and should be viewed as a hypothesis to be tested. The original correlation charts were published in Holland and Patzkowsky , with the Nashville Dome correlations added in Holland and Patzkowsky , If you have any comments or questions on these charts, send them to Steven Holland at stratum uga. Sequence numbering We have numbered the third-order sequences sequentially, and prefix the numbers by the series in which the sequence starts.

So, sequences that begin in the Whiterockian start with W, those that begin in the Mowhawkian begin with M, and those that begin in the Cincinnatian start with C.

Thus we do not know the numeric age of any given layer. The civilizations that deposited the trash had a culture and industrial capabilities that evolved through time. The oldest inhabitants used primitive stone tools, later inhabitants used cups made of ceramics, even later inhabitants eventually used tin cans and then changed to Aluminum cans, and then they developed a technology that used computers.

This shows that society has evolved over the years. Similar cultures must have existed in both areas and lived at the same time. Thus we can make correlations between the layers found at the different sites by reasoning that layers containing similar distinctive discarded items artifacts were deposited during the same time period. Because the Ceramic Cups layer is found at the Tulane site, but not at the Zoo site, the civilization that produced the Ceramic cups probably did not live in the Zoo area.

Thus, we can recognize a break in the depositional sequence at the Zoo site. The surface marking the break in deposition would be called an unconformity in geologic terms, and represents time missing from the depositional record. The trash pits contain some clues to numeric age: The Tulane trash pit has an old license plate in the Tin Cans layer.

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