In northern Canada, much of the hard rock found is igneous rock. Igneous rock is rock formed by the hardening and crystallization of molten material that originates deep within the earth. The word igneous comes from the Greek word for fire; some people call igneous rock a fire ball rock. Rocks that have hardened from magma, the hot liquid beneath the earth's crust, are called igneous rocks. The inside of the earth is very hot - hot enough to melt rocks. The deeper you get the hotter it gets. Below the surface, the molten rock is called magma; at the earth's surface it becomes lava, nothing has changed only the name of the liquid. Igneous rock is made by fire. Small wonder the magma from which igneous rock is formed can reach temperatures close to 1200 degrees Celsius.
Posterior fossa tumors lie on the underside of the brain. These tumors can compress the cranial nerves causing facial symptoms or loss of hearing. Petroclival tumors can compress the trigeminal nerve, resulting in sharp pain in the face (trigeminal neuralgia) or spasms of the facial muscles.
There are two main types of tumors: malignant or cancerous tumors and benign tumors. Cancerous tumors can be divided into primary tumors that start within the brain, and secondary tumors that have spread from somewhere else, known as brain metastasis tumors.econdary or metastatic brain tumors are more common than primary brain tumors, with about half of metastases coming from lung cancer. Primary brain tumors occur in around 250,000 people a year globally, making up less than 2% of cancers.