how was the basement rock formed?
Between two and three million years ago, during the Pliocene, the Sierra Nevada was uplifted and tilted westward. A series of volcanic mudflows (lahars) from three major source areas contributed debris that covered almost to form the oldest distinctive geologic formation in the High Cascades. The resulting Tuscan Formation is not exposed anywhere in the national park but it is just below the surface in many places within it. The oldest pyroclastic material in the formation is 3 or 4 million years old. The youngest part of the formation consists of interbedded conglomerates and volcanic breccias that are 2 million years old.
Geology of the Lassen volcanic area
Between two and three million years ago, during the Pliocene, the Sierra Nevada was uplifted and tilted westward. A series of volcanic mudflows (lahars) from three major source areas contributed debris that covered almost to form the oldest distinctive geologic formation in the High Cascades. The resulting Tuscan Formation is not exposed anywhere in the national park but it is just below the surface in many places within it. The oldest pyroclastic material in the formation is 3 or 4 million years old. The youngest part of the formation consists of interbedded conglomerates and volcanic breccias that are 2 million years old.
what does geology of the lassen volcanic area refers to? It refers to a record of sedimentation and volcanic activity in the area in and around Lassen Volcanic National Park in Northern California, U.S. The park is located in the southernmost part of the Cascade Mountain Range in the Pacific Northwest region of the United States.
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Geology of the Lassen volcanic area [SEP] Formation of basement rocks
Between two and three million years ago, during the Pliocene, the Sierra Nevada was uplifted and tilted westward. A series of volcanic mudflows (lahars) from three major source areas contributed debris that covered almost to form the oldest distinctive geologic formation in the High Cascades. The resulting Tuscan Formation is not exposed anywhere in the national park but it is just below the surface in many places within it. The oldest pyroclastic material in the formation is 3 or 4 million years old. The youngest part of the formation consists of interbedded conglomerates and volcanic breccias that are 2 million years old.