How might the Charmouth area have looked million years ago? Introduction Charmouth was one of the first locations added to Discovering Fossils, and has since been the destination for several organised fossil trips. The famous coastline between Lyme Regis in the west , and Seatown in the east , has yielded a range of spectacular fossils, including: Parking and refreshments are available alongside the mouth of the river Char. The area is well suited to amateur and experienced fossil hunters alike; throughout the year visitors flock in their masses to scour the beach for fossils washed out of the cliffs and foreshore. The rocks at Charmouth date predominantly from the early part of the Jurassic period around million years ago , during which time this area lay beneath a warm, shallow sea, closer to the equator, approximately where North Africa resides today. A family explore the foreshore for loose fossils among the rock pools. A young fossil hunter inquisitively hammers a foreshore boulder. Charmouth is well equipped for visiting fossil hunters:
Are Fossils the Result of Noah’s Flood?
How Old Is The Earth? How old is the Earth? Scientists think that the Earth is 4. Coincidentally, this is the same age as the rest of the planets in the Solar System, as well as the Sun. In the early Solar System, all of the planets formed in the solar nebula; the remnants left over from the formation of the Sun. Small particles of dust collected together into larger and larger objects — pebbles, rocks, boulders, etc — until there were many planetoids in the Solar System.
But are dates from mica always accepted, and do they always agree with the age of their geologic period?
It is a trick question. You cannot do it. There is no convincing someone who has his mind made up already. But sometimes, it is even worse. Sometimes, when you point out a fossil that falls into the middle of a gap and is a superb morphological and chronological intermediate, you are met with the response: You are losing ground! Duane Gish of the Institute for Creation Research ICR regularly trots out the “bossie-to-blowhole” transition to ridicule the idea that whales could have evolved from terrestrial, hooved ancestors.
There simply are no transitional forms in the fossil record between the marine mammals and their supposed land mammal ancestors. It is quite entertaining, starting with cows, pigs, or buffaloes, to attempt to visualize what the intermediates may have looked life.
Leibnitz reworked Descartes’s cosmogony. Protogea was published much later in An essay toward a Natural History of the Earth. Woodward came down fairly strongly for the view that the flood was an act of God that could not be accounted for by normal physical processes. He also postulated hydrological sorting to account for the ordering of fossils. Whiston added comets to Burnet’s cosmogony as the source of the waters of the flood.
Although many varied forms of life evolved and were preserved extensively as fossil remains in Cambrian sedimentary rocks, detailed mapping and examination of Precambrian rocks on most continents have revealed that additional primitive life-forms existed as early as about 3.
A sedimentary rock is just what it sounds like: Sedimentary rocks can consist of sand, clay, chalk and fossils and as a marine geologist I find sedimentary rocks very fascinating! Some may think that sedimentary rocks is a bit dull since sedimentary rocks isn’t created by violent and exciting volcano eruptions from the Earths mantle like the igneous rocks. No, sedimentary rocks have another type of fascinating origin and every single rock tells a story if you just know how to “read” the rock!
That is one of the fascinating thing with sedimentary rocks! The other exciting part with sedimentary rocks is that they tell us about Earths history! I will tell you a little about how to do read the rocks and I hope it will help you to see sedimentary rocks in nature in a new way! Every single particle in a sedimentary rock initially comes from a rock or as soil on land. By time, the rock is broken down into small particles by weathering and the small particles are transported away.
Sometimes the transportation distance is long and sometimes shorter. And most sedimentary rocks consists of small particles that have a long and fascinating story to tell from their long journey behind them.
Natural History Museum of Los Angeles County
Anabaena The Three Domains of Life As previously noted, stromatolites are most often described as biogenically-produced structures formed by colonies of photosynthesizing cyanobacteria. However, this is an enormous oversimplification given that the weight of scientific evidence suggests that all three domains of life the Archaeans, Eubacteria, and Eukaryotes appeared in the Archaean Era, and thus the so-called microbial mats would have contained representatives among all three domains.
Just how and when the base of the tree of life split into the three main branches remains one of the most important questions in all of biology and science, and is the source of constant scientific dispute. Which of the prokaryotes came first, the Archaeans or the Eubacteria remains unresolved, and a consensus has emerged that these primitive microorganisms laterally exchanged genes further confounding attempts to validate what begat what during to course of early evolution on earth.
Most amino acids have at least one chiral carbon, hence, they have a left-handed L form and right-handed D form.
See Article History Alternative Title: The Precambrian represents more than 80 percent of the total geologic record. International Commission on Stratigraphy ICS All life-forms were long assumed to have originated in the Cambrian, and therefore all earlier rocks were grouped together into the Precambrian. Although many varied forms of life evolved and were preserved extensively as fossil remains in Cambrian sedimentary rocks, detailed mapping and examination of Precambrian rocks on most continents have revealed that additional primitive life-forms existed as early as about 3.
Nevertheless, the original terminology to distinguish Precambrian rocks from all younger rocks is still used for subdividing geologic time. The earliest evidence for the advent of life includes Precambrian microfossils that resemble algae , cysts of flagellates , tubes interpreted to be the remains of filamentous organisms, and stromatolites sheetlike mats precipitated by communities of microorganisms.
In the late Precambrian, the first multicellular organisms evolved, and sexual division developed. By the end of the Precambrian, conditions were set for the explosion of life that took place at the start of the Phanerozoic Eon. The Precambrian environment Several rock types yield information on the range of environments that may have existed during Precambrian time. Evolution of the atmosphere is recorded by banded-iron formations BIFs , paleosols buried soil horizons , and red beds, whereas tillites sedimentary rocks formed by the lithification of glacial till provide clues to the climatic patterns that occurred during Precambrian glaciations.
Paleogeography One of the most important factors controlling the nature of sediments deposited today is continental drift.
Changing Views of the History of the Earth
Mineralogy As a discipline, mineralogy has had close historical ties with geology. Minerals as basic constituents of rocks and ore deposits are obviously an integral aspect of geology. The problems and techniques of mineralogy, however, are distinct in many respects from those of the rest of geology, with the result that mineralogy has grown to be a large, complex discipline in itself. Nepheline greasy light gray , sodalite blue , cancrinite yellow , feldspar white , and ferromagnesian minerals black in an alkalic syenite from Litchfield, Maine, U.
About 3, distinct mineral species are recognized, but relatively few are important in the kinds of rocks that are abundant in the outer part of the Earth. Thus a few minerals such as the feldspars, quartz, and mica are the essential ingredients in granite and its near relatives.
When it came to hearing, Pakicetus was more terrestrial than aquatic, but the shape of its skull was definitely cetacean, and its teeth were between the ancestral and modern states.
Konstantin Mereschkowski proposed a symbiotic origin for cells with nuclei. In and , the Russian biologist Konstantin Mereschkowski — argued three things about the origin of nucleated cells. Firstly, plastids were reduced cyanobacteria in a symbiosis with a non- photosynthetic heterotrophic host. Secondly, the host had earlier in evolution formed by symbiosis between an amoeba-like host and a bacteria-like “micrococcal” cell that formed the nucleus. Thirdly, plants inherited photosynthesis from cyanobacteria.
The terms prokaryote and eukaryote were more definitively reintroduced by the Canadian microbiologist Roger Stanier and the Dutch-American microbiologist C. In his work Titres et Travaux Scientifiques, Chatton had proposed the two terms, calling the bacteria prokaryotes and organisms with nuclei in their cells eukaryotes. However he mentioned this in only one paragraph, and the idea was effectively ignored until Chatton’s statement was rediscovered by Stanier and van Niel.
This helped to uncover the origin of the eukaryotes and the symbiogenesis of two important eukaryote organelles , mitochondria and chloroplasts. Wheeler renamed this the Archaea.
At the time that Darwin’s On the Origin of Species was published, the earth was “scientifically” determined to be million years old. By , it was found to be 1. In , science firmly established that the earth was 3. Finally in , it was discovered that the earth is “really” 4.
And the whole thing gets mixed up.
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.
Sedimentary Rocks Formation and Fossils!
Evidence for Creation Years ago, National Geographic published a remarkable photograph of a polystrate fossil, a fossilized tree that extended stratigraphically upward through several layers of rock in Tennessee. Its roots were in a coal seam, and the overlying deposits included bedded shale and thin carbon-rich layers.
An advocate of any form of uniformitarianism would believe that it took many, many years to deposit this sequence of layers much longer than it takes for a tree to grow and eventually die and decay , yet one vertical fossil extends through them all. This one fossilized tree offered a direct contradiction to the evolutionary mantra that “the present is the key to the past.
I am not trying to say that they are falsifying their data.
Important We believe any unbiased reader will realize that we were fair with our treatment of the two models in the table above. Yet, although the theory of evolution matches the facts in some cases, evolution is still an unproven theory. By now, you may believe it should be your first choice also. Unlike many others that preceded us, we attempted to find a clear defense of evolution for two reasons: To keep from being accused of bias.
To keep from making claims that someone could refute later.
Problems with the U-Pb Radioisotope Dating Methods—1. Common Pb
These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus slowing decomposition. Stromatolites Lower Proterozoic Stromatolites from Bolivia , South America Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms , especially cyanobacteria.
While older, Archean fossil remains are presumed to be colonies of cyanobacteria , younger that is, Proterozoic fossils may be primordial forms of the eukaryote chlorophytes that is, green algae. One genus of stromatolite very common in the geologic record is Collenia. The earliest stromatolite of confirmed microbial origin dates to 2. The most widely supported explanation is that stromatolite builders fell victims to grazing creatures the Cambrian substrate revolution , implying that sufficiently complex organisms were common over 1 billion years ago.
Outlook Other Abstract U-Pb radioisotope dating is now the absolute dating method of first choice among geochronologists, especially using the mineral zircon. A variety of analytical instruments have also now been developed using different micro-sampling techniques coupled with mass spectrometers, thus enabling wide usage of U-Pb radioisotope dating.
However, problems remain in the interpretation of the measured Pb isotopic ratios to transform them into ages. Among them is the presence of non-radiogenic Pb of unknown composition, often referred to as common or initial Pb. There is also primordial Pb that the earth acquired when it formed, its isotopic composition determined as that of troilite in the Canyon Diablo iron meteorite.
Subsequently new crustal rocks formed via partial melts from the mantle. So the Pb isotope ratios measured in these rocks today must be interpreted before their U-Pb ages can be calculated. Various methods have been devised to determine this initial or common Pb, but all involve making unprovable assumptions. Zircon does incorporate initial Pb when it crystallizes. The amount of Pb cannot be measured independently and accurately. It cannot be demonstrated that the initial Pb only consisted of Pb atoms.