is the study of the possible origins and development of the cosmos or
universe. Cosmologists, whose chief tools are observational
astronomy and particle physics, consider The Big Bang theory of
origin as most likely at this time. Google "cosmic by bang" and you
will get numerous images illustrating that very brief instant which
heralded the beginnings of space, time and all of that.
The Smithsonian Institution's illustration has a sense of drama in showing its' version of the creation of sub-atomic parttiles. It is thought that the "cosmic soup" of which the earliest universe consisted, was superheated to 5.5-billion C. If there had been a human observer back then this might have seemed a non event. NASA says that this mix of fundamental particles such as protons, electrons and neutrons had no capacity to transmit light.
The quote comes from novelist Douglas Adams. As the relatively small universe which developed 13.8 billion years ago expanded, the interactions between those particles caused the universe to act like a cooling thermonuclear reactor. While as NASA says, "...free electrons would have caused light (photons) to scatter the way sunlight scatters from the water droplets in clouds, science reporter Elizabeth Howells notes that " free electrons met up with nuclei and created neutral atoms.' This created afterglow (Rod's illustration) about 380,000 years after the Big Bang. "Afterglow" is more properly identified as "Cosmic Microwave Background."
This NASA illustration shows the singularity of creation at extreme left. It lasted a fraction of a second. This was followed by Afterglow and another spell of seeming nothingness, during which nuclei and atoms developed. Drawn to one another by gravity these aggregated forming the first stars and later star systems, galaxies, planets and the rest. NASA's Wilkinson Microwave Anisotropy Probe (WMAP) did not actually fly the limits of time and space to photograph the oldest light in the universe. This and other probes have mapped background radiation left over from the Big Bang and used this information to help astronomers determine the age of the universe.
The plant earth is roughly spherical, no matter what flat-earther's say. However, galaxies and planetary systems trend in the direction of a planar spinning disk. The planet called Earth has grown in size over time because of collisions with planetoids, asteroids comets and moons.
Geology was originally the science that deals with the earth's physical structure and substance, its history, and the processes that act on it. Geology also deals with the study of the history of all life that's ever lived on or is living on the earth now. The definition has recently been extended to include the solid features of any planetary body.
Geology is divided into two categories: physical geology and historical geology. Physical geologists study of the physical features of the earth and the processes acting on them. Historical geologists focus on what's happened to Earth since its formation. They also study the changes in life throughout time.
You think you've had a rough year? On Earth, and probably on other planets, the heavier iron atoms sank down and became the core, while lighter atoms like silica and hydrogen rose to the surface. Most of the gases generated: hydrogen, carbon dioxide, methane, ammonia, and nitrogen, floated away into space.
About 45 million years after plants began to form a wandering planetoid, the size of Mars, crashed into the proto-planet Earth. Sometimes called Theia, it splashed a huge chunk of matter into space. Some of this hot rock assumed an orbit around the earth and accreated and cooled to form the Moon. According to NASA, "When the young Earth and this rogue body collided, the energy involved was 100 million times larger than the much later event believed to have wiped out the dinosaurs."
The prevailing theory supported by the scientific community, this kind of event might explain why the moon is made up of lighter elements, making it less dense than Earth. This would be because the material that formed it came from the crust, leaving the planet's iron deep rocks and iron core untouched. The Moon was then closer in its elliptic path than is now the case.
A sizable quantity of water would have been in the material that formed Earth but it is thought that the impact which created the moon probably dissipated the earliest atmosphere.Gradual leakage of water stored in hydrate minerals of Earth's rocks could have formed a portion of its present oceans. Water may also have come from volcanism: water vapor in the atmosphere that originated in volcanic eruptions may have condensed to form rain, slowly filling Earth's oceanic basins.
As the Earth cooled , starting around 4.3 billion years ago, the steam in the atmosphere also moderated in temperature and fell as rain on the Earth. That made the oceans. By 4.2 billion years ago, Earth had some land and oceans just as it does today. That's not to say that the Hadean influence was past. It is usually said to have ended 4 billion years past. The atmosphere of Earth way have contained a high rock vapour content following that massive collision. This would have created a green-house gas effect with carbon-dioxide mixing with water vapour and hydrogen.
There was still a hot time in the old town, but even with a surface temperature as high as 230 °C, the atmospheric pressure of the heavy CO2 atmosphere allowed water to remain on the surface. The amounts there oscillated wildly as new interactions took place between the unstable crust and the mantle and water of one kind or another. Comets, trans-Neptunian objects or water-rich meteoroids (protoplanets) from the outer reaches of the asteroid belt colliding with Earth may also have brought water to the world's oceans.
The study and dating of Hadean zircons has found that liquid water must have existed as long ago very soon after the formation of Earth as it is essential in their formation. . Australian Hadean rock has been found to hold minerals that point to the existence of plate tectonics as early as 4 billion years ago. The action of plate tectonics entraps vast amounts of carbon dioxide, thereby eliminating greenhouse effects, and leading to a much cooler surface temperature, and possibly the formation of more solid rock than was formerly thought possible. In that case, the Hadean may have been more compatible for life than previously thought.
This is Earth as visualized 4-billion years ago. If your visual imagination is not great you may not recognize the main solid mass as present-day Canada. What is now Hudson Bay is the largest impact crater seen on this mass of continental crust. The current Province of Quebec is far right, centre. "In 2017, fossilized microorganisms, or microfossils, were announced to have been discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada that may be as old as 4.28 billion years old. These are not, of course, complex organisms. The Maritime Provinces and much of New England was geographically remote at this time.
What was actually found was tiny filaments and tubes deposited by bacteria that lived on iron found encased in quartz layers in the "Nuvvuagittuq Supracrustal Belt". The "NSB" contains some of the oldest sedimentary rocks known on Earth and likely once formed part of an iron-rich deep-sea hydrothermal vent where such creatures are still known to live. Remains were first dated tentatively at 3,770 million years of age. By contrast, the oldest human fossil dates at 195,000 years.
Here is a partial new report.It seems possible that single-celled organisms may have been around in the Hadean, possibly within a billion years of Earth's formation. The first multicellular animals did not evolve until about 600 million years ago, and 99 percent of antique species are now extinct either through accident or design.
The Earth did not return to Hadean conditions but has on the whole been warmer in the past than it is now. There have also been many ice ages, most of them long before humans made an appearance on the planet. The most antique was the Snowball Earth Situation also referred to as the Huronian Glaciation, was the longest and most severe.
Illustration simplified. It is usually blamed on a greenhouse effect created by the Great Oxygenation Event, a time when increased atmospheric oxygen supplanted atmospheric methane. The oxygen combined with the methane to form carbon dioxide and water, which does not retain heat as well as methane in the cold atmosphere which lasted from 2.4 billion years past until 2.1 billion years ago.
It was caused by cyanobacteria which evolved as photosynthetic organisms. It took about three billion years ago for the process to become complete at which time the estimated oxygen levels were about four times previous levels. Prior to the deep freeze microscopic multicellular species developed but those anerobic microbes which were at the surface of the planet and not photosynthetic were largely "bleached" out of existence.
Some encysted bacteria survived the "Oxygen Holocaust." The few (Eukaryotes) which persisted evolved adaptations to counter this toxic gas, we are descended from them.
Others (Archaea) escaped underground and continue to live in obscure places like volcanic acid lakes and underground.
Astrobiogogist Roger Buick noted, "That kind of ice coverage (averaging one-half mile in depth) chokes off photosynthesis, so there's no food for anything." Nevertheless, his research in southern Ontario showed that these micro organisms survived to have relatives, like those cyanobacteria seen today.
During the more recent part of earth history air and water temperatures have yo-yoed between a cold-house and hot-house situations. Some scientists say that the Snowball Earth situation came again roughly 650 million years ago. Others think that was more of a Slushball Earth with open areas of water at the equator. There was a similar frigid situation 500 million years back. In most of the last 850 million years, the mean temperature has favoured higher values than at present. Aside from the Huronian Extinction, the only glaciation tied to a major massive loss of life occurred about 450 million years ago during the Ordovician Period.
The Ordovician Period lasted almost 45 million years, beginning 488.3 million years ago and ending 443.7 million years ago. During this period, the area north of the tropics was almost entirely ocean. The major part of the world's land existed as the southern super continent Gondwana. Throughout the Ordovician, Gondwana moved towards the South Pole (SP) and much of it was submerged underwater. Quebec was sub-tropically situated in Laurentia and there was no polar ice.
Antarctic view: Sometime in in the early Ordivician, the ocean seen above commenced to close and land masses began to come together. Partial arrows indicate slippage along a fault. Lines with diamonds indicate faults along which new oceanic crust is upwelling pushing the earlier crust away in both directions. The numbered terranes or micro-continents are those which eventually collided with Laurentia and became sutured to it. The last to arrive was the Meguma Terrane (3), part of which now comprises southwestern Nova Scotia.
Lines with triangles indicate areas where the crust is being destroyed and subducted downward toward the interior of the planet.Terranes that later accreated to Laurentia were very, very slowly following the currents imposed by continental drift: 1. The Tetagouche Terrane destined to become a part of New Brunswick, PEI and Cape Breton; 2. The Avalon Terrane, later associated with Nova Scotia and PEI, and 3; The Meguma Terrane which originated in offshore waters somewhere off Gondwana in the Antarctic. These two terranes "docked" in Late Ordivician or Early Silurian time, some say individually, others as a pre-extant unit.
This equatorial view in Ordovician time shows Laurentia just left of centre with all the land masses on a grand collision course. Even before the land areas made actual contact, sediments along the North American edge of the continental shelf were crushed and upraised into a mountain range stretching in a 2,5000 mile arc from western Newfoundland into New York State. In our area, the last remains of that of the defunct ocean took the form of troughs or basins in New Brunswick and Newfoundland.
The Silurian Period, which followed the Ordivician, saw little additional mountain building in the North American Appalachian Mountain Chain. However, the continental plates were moving rapidly and vulcanism occurred creating lava flows and atmospheric ash. Iron deposits occur in relation to volcanic deposits and five thousand metres of these deposits are found in the Yarmouth area. Folded bands of similar remnants of Silurian age are found in the Cobequids, Pictou and Antigonish counties.
The Ordovician–Silurian extinction events, taken together, are the second-largest of the five major extinction events in Earth's "recent" history in terms of percentage of genera that became extinct. Almost all major taxonomic groups were affected. Extinction was global during this period, eliminating 49-60% of marine genera and nearly 85% of marine species. A combination of lowering of sea level and glacially driven cooling were likely driving agents for the losses. which might have been exaberated by toxic ocean conditions.
Here's the lay of the land in Maritime Canada after all the terranes came into intimate contact and were sutured to one another, for good or ill. The old Supercontinent of Laurentia to which all became attached is seen in red. The areas in blue were those involved in the so-called Taconic Orogeny, named after the Taconic Mountains, upthrust when a northern part of what is now Britain affected that area early on during the Ordovician. Suture lines for terranes are now defined as fault zones or fault systems.
Here is the current situation with respect to mountain building in much of southwestern Nova Scotia. The hills and valley are parallel to the coast and at right angles to the forces which distorted an older flat landscape. Of course, these are mere stubs of once majestic mountains. The final climatic collision of plates which produces the Acadian Mountains took place in the following Devonian Period. The Taconic are was not much disturbed but but older regions between the Avalon Peninsula in Newfoundland through Cape Breton and southern New Brunswick, were unceremoniously crushed and distorted. The greywackes slates and granites mentioned above were moved about and crumpled against the thicker continental crust to the northwest.
Part of the oceanic crust was wedged down beneath the thicker continental crust, where it was affected by the high temperatures and pressure created by those once massive mountains. Granites were formed within the mountains and now they outcrop in a broad arc known as the South Mountain Batholith. At the time Nova Scotia was at a position 40ºN of the equator. Since then it has rotated with respect to the African coat and moved further north. The Meguma Terrane has to be remembered as from sediments laid down by cold turbidity currents an entire ocean away. These were left compressed against, and left attached to the North American continent.
While some areas along the coast were thrust upward, other regions were bent downward creating basins. The Maritimes Basin was one of many along the coast to the south and west created during this time. F = Fault. "The Maritimes Basin is a Mid-Devonian to Early Permian sedimentary basin that underlies parts of the northeastern United States and Atlantic Canada. "This is the largest basin in the Appalachian System and later acquired Carboniferous strata overlapping parts of the suture between the Avalon and Meguma terranes. In the past, there was earth movement along that southernmost fault ending in Early Jurrasic time. Today 70% of the area of this former deep depositional basin is beneath waters of the Gulf of St. Lawrence.
The Devonian Period spanned 60 million years from the end of the Silurian, 419.2 million years ago to the beginning of the Carboniferous, 358.9 past. In the the earliest part, micro and macro-continents were still zeroed in on the much altered Laurentia. When Baltica became an adherent it was renamed Euramerica . That continent stood poised between Siberia in the north and Gondwana in the south. The first significant evolution of life on dry land occurred during the Devonian. Fish reached such diversity that the period was sometimes described at the "Age of Fishes." During the Early Devonian, arid conditions were prevalent through much of the world including Siberia, Australia, North America, and China, but land masses which became Africa and South America had a warm temperate climate. At the equator. it was not only arid but very hot, following the development of a zone now known as the Tropic of Capricorn.
Middle Devonian:Euramerica rotated in alignment with the equator, where topical air masses created a hot arid situation. In these near-deserts, "Old Red Sandstone" sedimentary beds formed where water was available. The soil was mad red by the oxidization of iron particles in it, a characteristic of drought conditions. Moss forests and bacterial and algal mats of the Silurian were now joined by primitive rooted plants that created the first stable soils and harbored arthropods like mites, scorpions, trigonotarbids and myriapods. Arthropods appeared on land in the Early Devonian.
In the Late Devonian, the tree-like ancestral Progymnosperm which had conifer-like wood and fern-like foliage appeared, the oldest known trees of the world's first forests. By the end of the Devonian, the first seed-forming plants had also evolved. This rapid appearance of so many new species gave rise to the expression, "Devonian Explosion". That happening may have led to a further extinction when accumulated carbon dioxide gas cooled the climate. Sea levels in the Devonian were generally high. Above, Dunkleosteus, one of the largest armoured fish known.
As the Devonian came to an end Euramerica, which some prefer to call Laurussia or even Laurasia, was starting to meet tectonic pressure from Gondwana, which further raised the Northern Appalachians and created the Caledonian Mountains in Britain and Scandinavia. Aside from the all encompassing Panthalassic Ocean, earlier oceans were shallow remnants. Much of the land of former times lay under shallow seas, where tropical reef organisms lived.
These were the some of the mountains as seen after that meeting of continents. The Taconic Appalachians (blue) were thrust up earlier on. The Acadian Orogeny was the most violent disturbance in our part of the world. All Atlantic Provinces were affected in some part, In the east folds produced by the Taconic Orogeny were tightened and refolded creating metamorphic rock created by gneissesm slates and shists from sediments,The Acadian Mountains involved folded compressed areas southwest in Nova Scotia and on the now submerged Scotian coastal shelf.
The Carboniferous is a geologic period and system which spans 60 million years from the end of the Devonian Period at 358.9 million years ago to the beginning of the Permian Period, 298.9 ago. A global drop in sea level at the end of the Devonian reversed early in the Carboniferous and this recreated many inland seas. Gondwana collided with Laurasia and was heavily glaciated during this time, possibly a hold-over situation from the Devonian. The Alleghenian Orogeny in North America extended the newly uplifted Appalachians southwestward. Average global temperatures in the Early Carboniferous were high: approximately 20 °C. However, cooling during the Middle Carboniferous reduced average global temperatures to about 12 °C.
This diagram minimizes the the number of basins found as an accessories to the Appalachian System. Most were located inland and gained what water they could from thee local runoff of fresh water. The Maritimes Basin, sometimes referred to as the inland Windsor Sea, was numbered as one of a few which might be in connection with saline Mid Euramerican Sea ( which you can be located about the centre of the coloured planetary illustration above). As this basin was in a tropical arid to semi-arid situation one geologist thinks it has to have been in a "punctual " relationship with The Salt in spite of "weak marine incursions."
Today Carboniferous strata account for more than half the surficial rock seen on the northeast of Nova Scotia and this map explains why. The inset map shows possible past connections with salt water. In addition to massive amounts of red sandstone and shale, parts of this basin collected "hypersaline Windsor salts" apparently derived from that Euramerican Sea which persisted between what is now America and Europe through the entire Carboniferous. Deposits are found chiefly in the "Study Area." Rocks of the Windsor Group are a part of the Mahone Bay Harbour surround. In the 1940s, a maverick geologist suggested that the inlet might be in that region.
By the end of the Carboniferous Period The continents were close to forming a single unit, and that is what happened in the early Mesozoic Era. Everything came together like a jigsaw puzzle 335 million years ago. Nova Scotia (on the central land mass) was still near water, and all land masses were stitched together with a bit of shallow water here and there between them. In those days most of the land mass was south of the equator enclosed by an all-embracing Panthallesic Ocean.The Triassic is the first period of the Mesozoic Era and it ended 251.9 million years ago.
That date is a few million off the mark but this illustration does help to define Nova Scotia as things stood in the Triassic. The land was at this time more or less continuous from the Canadian Shield through Nova Scotia to the edge of the continental shelf and Africa was not far away. There was an undulating landscape covered with deep fine red sand and gravels, a virtual desert except for some of those lowland areas. Those lofty mountains had been eroded and weathered, but there might have been more relief if the basins were not filled under the influence of wind. The Fundy Basin sagged its way into existence when the forces driving tectonic movements backtracked in this area. Wavy black lines are drainage rivers and streams. A graben is a depressed area in the early surface bordered by parallel faults.
Carboniferous Rocks are found all over the world, but those contain g fossils are often in inaccessible locations. The bad news all that soft rock is being dumped into the sea. For geologists that is good news. Harvard University paleontologist Stephanie Pierce visited Nova Scotia last summer and noticed that, "It has got lots of beaches and lots of cliffs - a lot of that Carboniferous rock is actually outcropping there and a lot of those fossils are actually falling out of those cliffs." Her group stumbled upon a new fossil bed near Sydney Mines in Cape Breton. Most fossils which draw ecotourists to the area are Triassic in age.
The Pierce team found and took four hours to transport the encased remains of a tetrapod. Four-legged creatures are not uncommon today but those from the Early Carboniferous, 350 million years ago remain rare. "They're definitely large tetrapods. They could be early amphibians, they could be early mammals," Pierce said. "It's definitely something new for Nova Scotia paleontology." The fossils are to be prepared, studied and returned to Nova Scotia for display.
All fossils found in Nova Scotia belong to the province and the Nova Scotia Museum is the official caretaker of these specimens.
By the way there is an underfunded "Cape Breton Fossil Centre," located in Sydney Mines. It has been described by visiting practicing paleontologist Victor J. Tollerson Jr. as having the best collection of period plant fossils found anywhere in the world. "The degree of preservation of the plant fossils is superb and is superior to the plant fossils from Joggins, St. Claire, Penn., the Mazon Creek region of Illinois and the various coal fields of England. I highly recommend the Fossil Centre to people interested in the natural history of Nova Scotia. It is a shame that the Nova Scotia government does not seem to appreciate its immense scientific, historical and cultural value.” According to the curator their input of funds is $0.00.
"The Fundy Geological Museum is a geological museum in Parrsboro, Nova Scotia, Canada. It first opened in 1993. It has averaged more than 21,000 visitors per year since then.
It is open from June 1 to October 15. It includes a research centre at its location on Minas Basin.
Situated on Chebucto Bay, Joggins is arural community located in western Cumberland County. On July 7, 2008 a 15-km length of the coast constituting the Joggins Fossil Cliffs was officially inscribed on the World Heritage List. In 2009, palaeontologist Melissa Grey was hired as the first scientific curator for the Joggins Fossil Institute. The Joggins Fossil Institute continues to conduct and foster research at the site and hosts international paleontologists and geologists and conference field-trips.
In 2017, a great deal of attention was directed at crumbling Carboniferous cliffs, and media headlines reflected this interest. Google: "Dog Stumbles on 300 million-year-old fossil in N.S.; Dinosaur egg potential excites Digby student; N.S. fishermen's catch older than dinosaurs...etc." Dr. Tim Fedak the current curator at Joggins says that the nearby Parrsboro cliffs suggested that scientists had stumbled upon a mass extinction of dinosaurs following finds in 1997 and 1978. "That mass accumulation of bones is very rare... "These," he said "are Canada's oldest dinosaurs. They basically start the dawn of dinosaurs."
Prosauropods were large semi-quadrupedal, herbivorous dinosaurs of the Triassic and Early Jurassic. The same implies a lineage pro+ sauropod. Latin. "before the sauropods". Unlike other contemporary animals some survived an extinction event that resulted in the demise of some 76 percent of all marine and terrestrial species.
It is thought that the Triassic extinction, which started at the end of that period was the game-changer that allowed the dinosaurs to become the dominant land animals on Earth.
The fact that the Fundy Basin is gone suggests that tensions were renewed during the Jurrasic Period when some of the continental blocks were starting to act in a wayward fashion. The Jurrasic spanned 56 million years from the end of the Triassic, 201.3 million years ago until the commencement of the Cretaceous 154 million years before present time. The super continent Pangaea started to pull itself apart at the end of the Triassic, Laurasia drifting to the north, and Gondwana to the south. This created more coastlines and shifted the continental climate from dry to humid Many of the arid deserts of the Triassic were replaced by lush rain forests. The presence of limestone says that marine life was present in numbers allowing their shells to be ground up and compacted into limestone.
CAMP has nothing to do with camping. In the Triassic being mapped as part of the Central Atlantic Magmatic Province at the end of the Triassic meant you should have been considering moving to a new homeland, but the dinosaurs were not listening. Magma is hot fluid or semi fluid material below or within the earth's crust from which lava and other igneous rock is formed by cooling. Black basalt fields persist to this day after much erosion and weathering. Mafic or Magmatic Dykes are created as a sudden intrusion when magma fills a crack in pre-existing rock. They usually come to the surface in a near vertical position and can be very narrow or several metres in width.
An example of an intrusive dyke in sandstone. Faults and wider rift valleys have been identified and dated to this period on both sides of the Atlantic. Swarms of smaller dykes are not uncommon in Nova Scotia which was in CAMPing country. In Yarmouth County one of these is 60 to 150 metres in width and extends from the west for 110 kilometres to the La Have Islands, in Lunenburg County. Dated, it is of the same age as North Mountain basalt on the south shore of the Bay of Fundy. In point of fact the bay is a rift valley.
A rift valley is a linear-shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. In the case of the Bay of Fundy, the main fault was along the southern margin. This lengthy crack ran along the entire northern coast from Blomidon to Brier Island. It allowed magma to come to the surface 201 million years ago, well over the top of the opening and slide down hill toward New Brunswick. Two main intrusions took place in the Digby to Brier Island neighbourhood, but to the northeast there were as 17 episodes piling up basalt to a height of as much as 15 metres.
This geologist worked out the coverage in what is generally known as the Palisades Disturbance. A basaltic flow of the same age disturbed the New York City area at this same time. Eroded dykes give form to the Palisades along the Hudson River. Today ECMA is an acronym for East Coast Music Awards! It has been suggested that increased vulcanism and sea floor-spreading activity during the Jurassic released large amounts of carbon dioxide—a greenhouse gas—and led to higher global temperatures.
The Shelburne Dyke terminates at the mouth of the only river charted on the South Shore. Mahone Bay (orange circle) is next door. The Exposed Basin Basalt mentioned above created North Mountain. There is decreasing elevation from Digby Gut westward to Brier Island. That Triassic Basin is believed to have developed first in the western end where the Bay of Fundy now becomes the Gulf of Maine. The largest drainage rivers were ancestral to the Saint Croix and St John rivers on the north face. On the south face there were smaller streams originating on South Mountain which penetrated the basalt of North Mountain and entered the basin at the Gut and Sandy Cove. The Upper The area sagged downward as it became loaded with Traiassic and Jurrasic sandstone and related sediments.
Basalt may seem like a very impervious rock, but the layering and jointed nature of this variety has made it very susceptible to easy weathering and erosion, and in spring the cliffs there rain rock, sometimes of considerable size. Mahone Bay in the south has a sampling of north coast rocks but no basalt in the vicinity of Mahone Bay Harbour.
This view of Boot Island at a Horton's Landing look off features Blomidon Cape in the middle ground and the Parrsboro shore in the far distance. The vulnerability and colour of those Triassic red sandstones, laid down in horizontal layers is seen in the obvious loss of land and the accumulation of loose sediments at the base of cliffs. The Annapolis Valley Triassic lowlands which shares these colours were tilted off the horizontal by forces in action when that basalt intruded. The basalt which intruded upon the sandstone strata is seen furtherest out on Blomodin and is purplish-grey in this photo.
Triassic animals fleeing vulcanism. If not too close to the creation of a magmatic dyke they may have survived. The cause of the end-Triassic extinction is a matter of debate. Many scientists contend that this event was caused by climate change and rising sea levels resulting from the sudden release of large amounts of carbon dioxide. Locally, that CAMP event has had to have had a part in the demise of a lot of plants and animals.
Presumably animals and plants were resident in the Fundy Basin when North Mountain was created. Then animal seen above is not an herb-eating suarapod but a carnivorous relative, named the Allosaurus. The species dates from the Middle Jurassic. Sauropods (including the huge, huge Apatosaurus) appeared in the Early Jurassic and reached the peak of their diversity, abundance, and body size in the Late Jurassic. Sauropods were generally long-necked and probably adapted to browsing on the leaves of tall trees. Their decline in the latest Jurassic appears to have corresponded to a a loss of this type of vegetation. The gas clouds which swept downhill in incidents like this were often sulphurous and lethal, but even ordinary ash could lead to respiratory death.
Tim Fedak, the curator of the Fundy Geological Museum in Parrsboro is among those that think that global warming due to magma release led to extinction of many species. However that massive bone pile he has been uncovering at the shores of Parrsboro date later that that event and he characterizes those dinosaurs as "survivors." The opening of the Atlantic did not cease after that happening. The area in the vicinity of the Bay of Fundy sank as tectonic plates moved. There was plenty of sand in the area, more than at any other point in geologic time. When the earth moved and air moved and sand moved, dinosaurs were entrapped. He thinks that is probably how they ended up as fossils embedded in 100 metre high cliffs. There is a lot of red sandstone remaining to release more bones of the past.
At 170 million years the world was still in mid-Jurrasic time. Conditions in Atlantic Canada during the first 50 million years after the continents rifted is uncertain since most Jurrasic rock was destroyed or malformed by tectonic and volcanic activity. From situations elsewhere at other times, we can guess that the remnants of vulcanism we now see may have been small potatoes compared with the actual size of intrusions. When the oceanic cracks between worlds opened, the upwelling of magma could have climbed to 1,500 metres.
The new undersea kingdom created would have spread outward and sloped inland on both sides of the rift (red lines) for several hundred kilometres. As the Atlantic, and other oceans, widened, continental shorelines moved away from the spreading centre. The margains at first under run by heated basalt subsided as it cooler. Half of this slumping took place within 10 million years, the rest in the next fifty. Not a stable situation and more dangerous than any disaster movie.
Mahone Bay is seem as a white dot on these globes.
Conditions in the Early Jurrasic when there was all that initial jostling about created a terrane which was probably mountainous but with a climate which was very hot. All that faulting, slumping, humping, bumping and sliding about, called the Pallisades Disturbance, probably took place at this time. Initially the new ocean was narrow and contained warm waters, but widening it resembled the Mediterranean Sea of today.
The Cretaceous Period arrived 145 million years ago and terminated 66 million years past. It was a period of erosion and weathering of mountainous regions worldwide as mountain building was not pronounced. The cooling trend of last epoch of the Jurassic continued into the Cretaceous. Following a brief minor ice age which only afflicted high mountainous regions, temperatures increased, and the climate was almost constant until the end of the period. Tropical sea surface temperatures may have briefly been as warm as 42 °C warmer than at present, and that they averaged around 37 °C. Deep ocean temperatures were as much as 15 to 20 °C, warmer than at present.
With things calmed down on the tectonic front, there was not great "disturbance" to life as th Triassic merged into the Cretaceous Period. Under the weight of Jurassic/Triassic sediments which collected off the continental edge it began sinking downward into the ocean creating a shallow water areas now called the continental shelf. After a hundred million years of sand and water erosion and weathering the surface of Nova Scotia was worn down to an almost flat surface. With that downward push at the seaside, the so called peneplain began to slope downhill from the interior to the margin. The present surface of exposed granite, greywackes and slates in southwestern Nova Scotia is partly a result of this process.
The Lower Cretaceous sediments were laid down in valleys which lie below todays upland surface in the south west. These buried valleys are now only 60 to 120 metres deep and only seen as outliers (black dots). When the peneplain was first formed these valleys would have been deeper and the surface far above present levels. By the end of the Cretaceous the Atlantic had opened to two-thirds of its present width and had drifted far north of its earlier positions. That made the climate temperate, more like the modern Carolinas that the arid southwestern United States.
In the Early Cretaceous when this meat-eater was active that flat plane was reminiscent of the Prairie Provinces. It is possible that areas of the erosion surface was at times invaded by salt water and that unconsolidated matter here was carried off into the Atlantic. Tim Fadack says that a small portion of the snout of an animal like this has been found in Nova Scotia.
A collection of later Cretaceous reptiles and their more lush surround. Large herds of herbivorous ornithischians also thrived during the Cretaceous and some of them were able to ward off all but the most vicious dinosaurs. Notice that extraterrestrial intruder?
Watterson did a great job popularizing dinosaurs for an earlier generation of kids. His illustrations were close enough to be fearsome.
Deinonychus carnivorous nightmare with one described species, Deinonychus antirrhopus. This species, which could grow up to 3.4 metres. The oceans and Paleontologist John Ostrom's study of Deinonychus in the late 1960s revolutionized fuelled a debate over whether dinosaurs were warm-blooded or cold blooded. Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants. This beast had the small sleek, horizontal posture, and body, and had very large claws. These features suggested an active, agile predator.
This beast was so overexposed in the Jurrasic Park motion picture he need not be named. However his prey will be less well known, especially among adults. Top to bottom, left to right: a small Sauropod; a flock of Pteranodons; Olorotian; and a pair of Tricepteraropians.
This seeming herbivore seems to have been one of the Deinonychus is spite of his (or her) seemingly toothless state.
That was not the usual outcome when Tyrannosaurus rex confronted another species. Sometimes Wattersons blurbs were quite didactic but never boring.
Allosaurus was at the top of the food chain, probably preying on contemporaneous large herbivorous dinosaurs, and perhaps even other predators. Potential prey included ornithopods, stegosaurids, and sauropods. "Big Al" was not as big as Brontosaurus, or "thunder lizard", was a gigantic quadruped sauropod. The largest sauropod recovered as a fossil. The family includes some of the longest and largest creatures ever to walk the earth; one misstep and...
Ultrasaurus belongs in the same family as Brachiosaurus, and its body shape resembles that of the brachiosaurs more than other sauropods. The tall front legs of Ultrasaurus reached a height at the shoulder of perhaps 25 feet, and the long, massive neck could have reached nearly 60 feet above the ground.
That is another species of flying reptile.
With eyes in the sides of their heads these creatures has a much wider angle of view than those with mere frontal vision.
Chasmosaurus was a medium-size animal, 4.3–4.8 metres and weighing abut 1.5 tonnes. It was a herbivore and the defensive capability of those horns has been described as "problematic." They did have to fear an airborne menace but it was not Tyrannosaurs in jet planes.
The seas were also populated with now-extinct marine reptiles, ammonites and rudists. The latter were
a group of box-, tube-, or ring-shaped bivalves that arose during the Late Jurassic and became astonishingly diverse during the Cretaceous. When they died their shells created the chalk beds for which this period is noted. However, one will recall that Calvin was diverted from schoolwork by another animal in the Cretaceous sea.
Here is another undersea creature which was a meat-eater, and has relatives living in the world to this day. All-in-all the world was not less diverse or dangerous for water animals than land creatures.
While this looks cool and placid these large marine monsters include an moasaur (top). Mosasaurs evolved from an extinct group of aquatic lizards in the Early Cretaceous and were the dominant predators. Also seen are three Xiphactinus, massive fresh-eating fish that stalked the inland sea connecting the Arctic Ocean with the Gulf of Mexico.
While dinosaurs continued to dominate on land, new groups of mammals and birds, as well as flowering plants, evolved.
All of these earth-bound critters were unknowingly at risk.
And we have impact. Rising sea levels cause by that mid-Atlantic activity was bad news for may species of plant and animal. However it is now guessed that the impact of a large mass of material from outer space was the nail in the coffin for three-quarters of all plant and animal species at the end of the Cretaceous.Species which depended on photosynthesis declined or became extinct as atmospheric particles blocked solar energy.Herbivorous animals, which depended on plants and plankton as their food, died out as their food sources became scarce. The top predators such as Tyrannosaurus rex also perished from alack of herbivores to eat.
The strike was centred partly offshore in Central America, so their would have been tsunamis and renewed tectonic activity. At that, only three major groups of four-footed animals disappeared completely; the non-avian dinosaurs, the plesiosaurs and the pterosaurs. The other Cretaceous group that did not survive into the Cenozoic era, were the marine ichthyosaurs. Omnivores, insectivores and carrion-eaters survived the extinction event for obvious reasons. Mammals and birds which survived the extinction fed on insects, larvae, worms and snails, which in turn fed on dead plant and animal matter.
Animals who could not consume or digest detritus were in big trouble. The ancestors of humans must have shared this taste with modern crocodiles who also survived the Cretaceous-end extinction event. The survivors, overall few in number, were a long time making a comeback in spite of the abundance of available new niches. When I studied geology the next period was referred to as the the Tertiary, and the extinction even as the K-T (Tertiary) Boundary Extinction. Today it is called the K-Pg (Paleogene)Event.
The Paleogene; informally Lower Tertiary, is a geologic period that spans 43 million years from the end of the Cretaceous, 66 million years ago to the beginning of the Neogene Period, 23.03 million years past. The cliffs facing the present abyssal plain of the Atlantic Ocean were then dry land. This period consists of the Paleocene, Eocene, and Oligocene epochs. Earlier on, it is theorized that this erosion plain could have been submerged. Oligocene deposits at the margin of the continental shelf appear to have been deposited in very deep water. If the ocean did cover most of this map area, it is said to have rebounded soon after the period began. Northeastern then tilted down to the Atlantic in the southwest and stood 200 to 300 metres above present elevations. One supposed river of that period had its origin offshore from present Lunenburg County.
Eocene biota. In this period, Europe separated completely from North America. As the climate significantly cooled and dried, sea levels continued to drop from late Cretaceous levels, draining most interior seaways. The cooling and drying trend began in earnest following a sudden temperature spike about 55 million years ago. As the climate cooled and dried again following the warming, forests gave way to open woodlands and grasslands in the northern hemisphere and started to support thundering herds of grazing mammals.
From cool to hot to cold: At the Paleocene-Eocene Thermal Maximum, CO2 again accumulated in concentrations which were 2 to 3 times normal. Air temperatures on land rose by 5-7°C and that is when many of those primitive animals from the last period finally bit the dust. With acidification of the oceans 35-50 % of benthic species went extinct.
While the oncoming hot spell took less than 10,000 years to develop, onset of cold took about 10 times as long to become full blown. Scientists say this effect was generated by the break up of Antarctica from Australia. This created a closed circumpolar current and water near the bottom became very cold leading to the first Antarctic glaciers. That glacier ultimately covered all of Antarctica and spread over southern Australia. There was a resultant change from wet forests to dry woodlands in North America and Europe.
The Neogene is a geologic period that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago, to the beginning of the present Quaternary Period 2.58 million years ago. Some geologists insist that the Quaternary is a part of the Neogene.The global climate continued on an overall drying and cooling trend. Ice caps became features of both poles. Geologically, the most important event of this time was the connection of North and South America by a land bridge now called the Panama Isthmus. This prevented the warm ocean currents from the Pacific from flowing into the Atlantic Ocean. The Gulf Stream was left alone in transferring heat to the Arctic Ocean. As a result, global climate cooled throughout the Neogene, giving rise to a series of continental glaciations in the Quaternary Period that followed.
Because sea levels dropped, land bridges opened up. The Panama passage has been mentioned. Africa became directly connected with Europe by the Mediterranean basin which was largely dry land. Eastern Asia made contact with North America by way of a Siberian land bridge. Tectonically, the Indian continent made contact with Asia and began the slow process of creating the Himalayas.
Mammals and birds continued to evolve into roughly modern forms, while other groups of life remained unchanged. Early hominids, the ancestors of humans, appeared in Africa near the end of the period. With cooler seasons, tropical plant species gave way to deciduous ones and grasslands replaced many forests. In the grasslands, herbivorous mammals were the breeding stock which produced today's horses, antelope, and bison, gazelles, antelopes, goats and sheep and cows. Meat eating animals began to develop to take advantage of this resource. What could possibly cloud this sunlit scene?
NEXT: The Quaternary Period, in which we are all temporarily stranded; till death us do part.