New Senator Caldera
Encyclopedia
Archean
The Archean , also spelled Archeozoic or Archæozoic) is a geologic eon before the Paleoproterozoic Era of the Proterozoic Eon, before 2.5 Ga ago. Instead of being based on stratigraphy, this date is defined chronometrically...
caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
complex within the heart of the Blake River Megacaldera Complex
Blake River Megacaldera Complex
The Blake River Megacaldera Complex, also called the Blake River Group, is a giant subaqueous caldera cluster or a nested caldera system that spans across the Ontario-Quebec border in Canada....
, Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. It has a diameter of 15-30 kilometers and is made of thick massive mafic
Mafic
Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron; the term is a portmanteau of the words "magnesium" and "ferric". Most mafic minerals are dark in color and the relative density is greater than 3. Common rock-forming mafic minerals include olivine,...
sequences. The caldera complex has inferred to be a subaqueous lava lake
Lava lake
Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified...
during the early stages of the caldera's development. Gabbro
Gabbro
Gabbro refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
sill
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. The term sill is synonymous with concordant intrusive sheet...
s represent lava lake
Lava lake
Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified...
s, which are common in mafic summit calderas. These subaqueous lava lakes are large units with a change in grain size from coarse to fine grained and a hyaloclastite
Hyaloclastite
Hyaloclastite is a hydrated tuff-like breccia rich in black volcanic glass, formed during volcanic eruptions under water, under ice or where subaerial flows reach the sea or other bodies of water. It has the appearance of angular flat fragments sized between a millimeter to few centimeters...
top. The Kiwanis (Norands) intrusion, a high-level synvolcanic magma chamber
Magma chamber
A magma chamber is a large underground pool of molten rock found beneath the surface of the Earth. The molten rock in such a chamber is under great pressure, and given enough time, that pressure can gradually fracture the rock around it creating outlets for the magma...
, intrudes felsic rocks, and is in turn cross-cut by basaltic dikes and sills.
The Glenwood fault forms the eastern margin of the New Senator Caldera.
See also
- Noranda CalderaNoranda CalderaThe Noranda Caldera is a well-known large subaqueous Archean caldera complex within the Blake River Megacaldera Complex, Quebec, Canada. The caldera contains a 7-to-9-km-thick succession of bimodal mafic-felsic tholeiitic to calc-alkaline volcanic rocks which were erupted during five major series...
- Misema CalderaMisema CalderaThe Misema Caldera is a striking 2,704-2,707 million year old caldera in Ontario and Quebec, Canada.- Geographic extent :It is the caldera that forms the Blake River Megacaldera Complex and has a diameter of 40-80 kilometers.- Composition :...
- Volcanism of Canada
- Volcanism of Eastern CanadaVolcanism of Eastern CanadaVolcanism of Eastern Canada has led to the formation of hundreds of volcanic areas and extensive lava formations, indicating volcanism played a major role in shaping its surface. The region's different volcano and lava types originate from different tectonic settings and types of volcanic...
- List of volcanoes in Canada