Skip to main content

MESOZOIC ERA


MESOZOIC ERA

This is subdivided into three periods viz:
         
Cretaceous            (about 144  -  66.4  mya) - The youngest period in the Mesozoic era

         
          Jurassic                 (about 208  -  144  mya)

Triassic                 (about 245  -  208  mya) – The oldest period in the Mesozoic era


ACTIVITIES IN THE TRIASSIC PERIOD
Appearance of Primitive Mammals
Emergence of the Continents

Terrestrial deposition starts

Marine Invertebrates reduced in population (mass extinction)

Archosaurs occured on land as dinosaurs, Pterosaurs in the air while Ichthyosaurs, Nothosaurs  in  oceans

Formation of red beds

Global climate and ocean circulation was altered

Formation of Gypsum and Salt

Climate was arid

Lizards, modern conifers, first turtles, dinosaurs, cycadeoids, and mammals appeared

Appearance of first mammals and crocodiles

Orogenic activities still continued in some parts

Ceratitic ammonoids were in abundance

Pangaea was still in existence (intact)



ACTIVITIES IN THE JURASSIC PERIOD
Pangaea broke up into Gondwanaland and Laurasia

Dinosaurs that eat green plants existed

Gymnosperms abounded

Palm-like cycads and Ferns abounded

There was a hyper increase in the Atmospheric CO2

First frogs appeared, also flying reptiles, birds, salamanders, crocodiles, were present

Sponges, starfish, crinoids were abundant   


Various types of Dinosaurs were in dominant

Sea  urchins  were  ubiquitous



THE CRETACEOUS PERIOD

ACTIVITIES IN THE CRETACEOUS PERIOD
Belemnites, Marine Pelecypods, sponges and bivalves were common

Appearance of first primates

Chalk deposits were present

New types of insects evolved

Flying reptiles and toothed birds (Primitive birds) were present

Angiosperms were present

Formation of Rocky Mountains

Various types of dinosaurs were on the land

Various types of crocodiles were on the land

Modern flowering plants were present new types of insects.

Gondwanaland broke up

Echinoids, Ammonites were all over


Comments

Post a Comment

COMMENT

Popular posts from this blog

THE AGE OF THE EARTH - THE OLDEST MAN ON EARTH IS THE EARTH

THE AGE OF THE EARTH Hey … Just as we celebrate our birthdays to commemorate the day we were born, has it ever occurred to you to ponder on the age of the earth? Don’t you think that there was a day (way back) when the earth was formed? Don’t get it twisted!!! This is no myth. It is a reality. It is REAL!!! The Earth is approximately 4.6 billion years old!!! Sounds absurd??? Well, this figure did not come as a result of fiction or imagination – but by radiometric dating in the early 20 th century. Lead in uranium-rich minerals when dated by early scientists,  were able to discover that they were billions of years old. Another pointer to this is that small crystals of Zircon obtained from Jack Hills, Western Australia when dated, was around 4.4 billion years old. One may ask: “How is this possible”? Rocks are aggregate of minerals. Some of these minerals have radioactive elements like Uranium and Thorium. In the process of their decay (radioactive
11 comments
Read more

Lead in Drinking / Groundwater

Possible sources of lead in groundwater Places well known for lead-zinc (Pb-zn) deposits are in danger of having their groundwater contaminated with Lead. Lead is a known silent killer especially in infants and children as it has high affinity for Hemoglobin. Another reason it is a silent killer is because it accumulates (bioaccumulation) in the body gradually stealthily. The fatality of lead is that it gets stored in the bones (as Calcium is stored) and becomes part of the body. From there, it gets released directly into the body. Pregnant and nursing women are the most hit because the Calcium which their bodies require for the growth of the fetus and for breast milk production may be mixed with Lead. The detrimental effects of lead are enormous and felt among infants / children, pregnant women and adults. Among the children , these (but not limited to the following) are pronounced: Ø   Anemia Ø   Slowed / stunted growth Ø   Poor body development Ø   Poor i
10 comments
Read more

Vasquez Rocks

Have you heard of Vasquez Rock? Credit: The above picture will be alien except to those within the vicinity of Aqua Dulce, California or perhaps, those that have visited here at one time or the other. Just watch the arcs and the angles formed by this deposit!! In case you do not know, the image you are seeing is Vasquez Rocks. Am fascinated about the arcs and the acute angles formed by this deposit.. Your groundwater may be polluted!!! Nature is indeed wonderful!!!! For emphasis sake, this is in Aqua Dulce, California, north of Los Angeles. Research has it that the ‘arcs’ formed (i.e. tilting was as a result of the North American Plate collision with the Pacific Plate) along the San Andreas fault. We can see that the collision resulted in the uplift.
2 comments
Read more