Basanite: A Fine-grained Mafic Volcanic Rock
Basanite is a fine-grained, dark-colored volcanic or extrusive igneous rock. Fine-grained means its grains are too small to see without a microscope. Compositionally, basanite is
Mafic
What You Shouldn’t Miss on Diabase or Dolerite Rock
Diabase, dolerite, or microgabbro is a medium-grained, dark-colored, hypabyssal, or subvolcanic rock with a composition similar to plutonic gabbro or volcanic basalt. It commonly occurs
A Guide to Basalt: A Common, Fine-grained, Dark-Colored Volcanic Rock
Basalt is a hard, fine-grained, dark-colored volcanic or extrusive rock. It has primarily calcium-rich plagioclase and augite. Also, it may have minor amounts of other
What Are Pillow Lavas? How and Where Do the Form?
Pillow lavas are mound-like tubular, nearly spherical, or pillow-shaped structures associated primarily with submarine or underwater basaltic volcanism. They usually measure 0.1-1 meter or more
What Are Sheet Flow Lavas and How Do They Form?
A sheet flow is a type of submarine lava flow. It has a broad lateral extent relative to its thickness, making it look more like
How Do Pahoehoes Compare and Contrast with Aa Lava Flows?
This post discussion will compare and contrast pahoehoes and aa subaerial lava flows, highlighting their similarities and differences. To give you a hint, some similarities
What Does an Aa Lava Flow Look Like and How Does It Form?
‘A’ā (pronounced “ah-ah”) is a Hawaiian term that describes a lava flow with jagged (sharp and rough) rubbly debris called clinkers, now a geological term accepted
How Does a Pahoehoe Lava Flow Form and Transition?
Pahoehoe or ropy lava flow is one of the subaerial lava flows, characterized by a smooth, ropy, gently undulating, or hummocky continuous chilled surface or
Gabbro: A Coarse-grained, Dark-Colored Plutonic Rock
Gabbro is a dense, coarse-grained, dark-colored, mostly plutonic rock. Its essential minerals are calcic plagioclase and pyroxene, but it may have minor amounts of amphibole,