Post by 1dave on Dec 21, 2015 12:47:23 GMT -5
A continuation of "Geology for Rockhounds."
Most of the "Gem Bone" shown here is from Gembone Connoisseurs - The Beauty of Gembone.
Don Wickham
Jake Crossley, Gembone Connoisseurs - The Beauty of Gembone
Dinosaurs began and ended in the Mesozoic Era (251 to 65.5 million years ago). That was the dinosaur age, and they covered all continents.
The Mesozoic is broken up into three periods. The Triassic, the Jurassic, and the Cretaceous.
250 MA - End of Permian, Beginning of Triassic, breakup of Gondwanaland: came with a bang!
A 30 mile diameter asteroid slammed into Wilks Land Antartica, formed a 300 mile (500 km) diameter crater, and broke up the Gondwana supercontinent, which pushed Australia northward,initiated the Siberian Traps in Russia (The Siberian Traps form a large region of volcanic rock, known as a Large Igneous Province (LIP), in Siberia, Russia. The massive eruptive event which formed the traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for a million years and spanned the Permian–Triassic boundary, about 251 to 250 million years ago.
Vast volumes of basaltic lava paved over a large expanse of primeval Siberia in a flood basalt event. Today the area covered is about 2 million km2—roughly equal to western Europe in land area—and estimates of the original coverage are as high as 7 million km2. The original volume of lava is estimated to range from 1 million to 4 million km3.)
These events combined caused The Permian-Triassic extinction, as it is known, which wiped out most life on land and in the oceans, and allowed dinosaurs to become the dominant land life form.
In the Triassic primitive dinosaurs came into being along with marine reptiles. Some of the first species of dinosaurs were the Plateosaurus, Eoraptor, Herrerasaurus, Pisanosaurus, Saturnalia, and Staurikosaurus.
206Ma Triassic time ends \Jurassic time begins: Breakup of Pangea
205 Ma Triassic-Jurassic Mass Extinction Event: About half of the species on Earth were wiped out. 20% of marine families and 55% of marine genera, and 70% to 75% of all species went extinct, including non-dinosaurian archosaurs (other than crocodiles). Some therapids, and most of the large amphibians and mammal-like creatures were eliminated. Around 80% of all land quadrupeds also went extinct. With most of their competition having been wiped out, the reign of the dinosaurs officially began. Non-dinosaurian archosaurs continued to dominate aquatic environments, while non-archosaurian diapsids continued to dominate marine environments.
This event happened in less than 10,000 years, just before the supercontinent Pangea began to break apart. There are several theories as to why this extinction happened, but nothing has been concretely found to determine the exact cause. The leading theories are gradual climate change, sea-level fluctuations, pulse of ocean acidity, massive volcanic eruptions (specifically from the Central Atlantic Magmatic Province, or CAMP), or asteroid impact though a telltale crater has yet to be found.
The compounding of an asteroid impact triggering the massive floods of CAMP lava and initiating the breakup of Pangea may explain the Triassic-Jurassic extinction.
In the Jurassic Period dinosaurs such as Diplodocus and Apatosaurus, and carnivores such as Allosaurus flourished. The first reptiles with primitive abilities to fly, such as Archaeopteryx appeared. The dinosaurs of this time period began to evolve much larger while many ocean dwelling reptiles were becoming extinct. In this Period the evolution of long necked Sauropods was at its peak.
144Ma Jurassic time ended \ Cretaceous time began: Breakup of Brazil and Africa
Large amounts orf lava flowed in the Pacific Ocean bed as Brazil separated from Namibia Africa.
The Paraná-Etendeka traps (or Paraná and Etendeka Plateau; or Paraná and Etendeka Province) comprise a large igneous province which includes both the main Paraná traps (in Paraná Basin, a South American Geological basin) as well as the smaller severed portions of the flood basalts at the Etendeka traps (in northwest Namibia and southwest Angola). The original basalt flows occurred 128 to 138 million years ago. The province had a post-flow surface area of 1.5 x 106 km² and an original volume projected to be in excess of 2.3 x 106 km³.[1][2] This is where the tall "Cathedral Agate Geodes" were formed.
During the Cretaceous Period the Ceratopsidae family begin to form which includes many plated dinosaurs with defense body features such as spikes like Triceratops. At the end of this Period and Era there was a large dinosaur extinction which wiped out most dinosaurs living on the earth. THEY still argue about this, but I believe a huge asteroid broke up and at least three pieces hit the earth nearly simultaneously.
Their bones must have been immediately buried to be preserved, but many have.
The earliest found were mistaken for dragon bones. ( My, what big teeth you have ! )
D-bone can be found anywhere strata of those time periods still remain, but some of the best material is found in the Morrison Formation from the Jurassic Period, deposited some 150 million years ago. The Morrison is usually seen as dark brown layers as in the photo below.
by Don Wickham
Most of the "Gem Bone" shown here is from Gembone Connoisseurs - The Beauty of Gembone.
Don Wickham
Jake Crossley, Gembone Connoisseurs - The Beauty of Gembone
Dinosaurs began and ended in the Mesozoic Era (251 to 65.5 million years ago). That was the dinosaur age, and they covered all continents.
The Mesozoic is broken up into three periods. The Triassic, the Jurassic, and the Cretaceous.
250 MA - End of Permian, Beginning of Triassic, breakup of Gondwanaland: came with a bang!
A 30 mile diameter asteroid slammed into Wilks Land Antartica, formed a 300 mile (500 km) diameter crater, and broke up the Gondwana supercontinent, which pushed Australia northward,initiated the Siberian Traps in Russia (The Siberian Traps form a large region of volcanic rock, known as a Large Igneous Province (LIP), in Siberia, Russia. The massive eruptive event which formed the traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for a million years and spanned the Permian–Triassic boundary, about 251 to 250 million years ago.
Vast volumes of basaltic lava paved over a large expanse of primeval Siberia in a flood basalt event. Today the area covered is about 2 million km2—roughly equal to western Europe in land area—and estimates of the original coverage are as high as 7 million km2. The original volume of lava is estimated to range from 1 million to 4 million km3.)
These events combined caused The Permian-Triassic extinction, as it is known, which wiped out most life on land and in the oceans, and allowed dinosaurs to become the dominant land life form.
In the Triassic primitive dinosaurs came into being along with marine reptiles. Some of the first species of dinosaurs were the Plateosaurus, Eoraptor, Herrerasaurus, Pisanosaurus, Saturnalia, and Staurikosaurus.
206Ma Triassic time ends \Jurassic time begins: Breakup of Pangea
205 Ma Triassic-Jurassic Mass Extinction Event: About half of the species on Earth were wiped out. 20% of marine families and 55% of marine genera, and 70% to 75% of all species went extinct, including non-dinosaurian archosaurs (other than crocodiles). Some therapids, and most of the large amphibians and mammal-like creatures were eliminated. Around 80% of all land quadrupeds also went extinct. With most of their competition having been wiped out, the reign of the dinosaurs officially began. Non-dinosaurian archosaurs continued to dominate aquatic environments, while non-archosaurian diapsids continued to dominate marine environments.
This event happened in less than 10,000 years, just before the supercontinent Pangea began to break apart. There are several theories as to why this extinction happened, but nothing has been concretely found to determine the exact cause. The leading theories are gradual climate change, sea-level fluctuations, pulse of ocean acidity, massive volcanic eruptions (specifically from the Central Atlantic Magmatic Province, or CAMP), or asteroid impact though a telltale crater has yet to be found.
The compounding of an asteroid impact triggering the massive floods of CAMP lava and initiating the breakup of Pangea may explain the Triassic-Jurassic extinction.
In the Jurassic Period dinosaurs such as Diplodocus and Apatosaurus, and carnivores such as Allosaurus flourished. The first reptiles with primitive abilities to fly, such as Archaeopteryx appeared. The dinosaurs of this time period began to evolve much larger while many ocean dwelling reptiles were becoming extinct. In this Period the evolution of long necked Sauropods was at its peak.
144Ma Jurassic time ended \ Cretaceous time began: Breakup of Brazil and Africa
Large amounts orf lava flowed in the Pacific Ocean bed as Brazil separated from Namibia Africa.
The Paraná-Etendeka traps (or Paraná and Etendeka Plateau; or Paraná and Etendeka Province) comprise a large igneous province which includes both the main Paraná traps (in Paraná Basin, a South American Geological basin) as well as the smaller severed portions of the flood basalts at the Etendeka traps (in northwest Namibia and southwest Angola). The original basalt flows occurred 128 to 138 million years ago. The province had a post-flow surface area of 1.5 x 106 km² and an original volume projected to be in excess of 2.3 x 106 km³.[1][2] This is where the tall "Cathedral Agate Geodes" were formed.
During the Cretaceous Period the Ceratopsidae family begin to form which includes many plated dinosaurs with defense body features such as spikes like Triceratops. At the end of this Period and Era there was a large dinosaur extinction which wiped out most dinosaurs living on the earth. THEY still argue about this, but I believe a huge asteroid broke up and at least three pieces hit the earth nearly simultaneously.
65.17 ± 0.64 Ma * Boltysh, Ukraine 24 km, N 48° 45', E 32° 10'
< 65 Ma * Eagle Butte, Alberta, Canada 10 km, N 49° 42', W 110° 30'
< 65 Ma * Vista Alegre, Brazil 9.5 km, S 25° 57', W 52° 41'
65 Ma * Shiva crater offshore of India 500 km Not officially recognized. 3 1/3 X larger than Chicxulub!
64.98 ± 0.05 Ma * Chicxulub, Yucatan, Mexico 150 km, N 21° 20', W 89° 30' 2nd largest recognized impact crater on earth!
< 65 Ma * Eagle Butte, Alberta, Canada 10 km, N 49° 42', W 110° 30'
< 65 Ma * Vista Alegre, Brazil 9.5 km, S 25° 57', W 52° 41'
65 Ma * Shiva crater offshore of India 500 km Not officially recognized. 3 1/3 X larger than Chicxulub!
64.98 ± 0.05 Ma * Chicxulub, Yucatan, Mexico 150 km, N 21° 20', W 89° 30' 2nd largest recognized impact crater on earth!
Their bones must have been immediately buried to be preserved, but many have.
The earliest found were mistaken for dragon bones. ( My, what big teeth you have ! )
D-bone can be found anywhere strata of those time periods still remain, but some of the best material is found in the Morrison Formation from the Jurassic Period, deposited some 150 million years ago. The Morrison is usually seen as dark brown layers as in the photo below.
by Don Wickham