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A basalt of Sister Rocks dike (a subsurface magmatic structure) cutting across a scoria deposit from a previous eruption of Sister Rocks. Being in a scoria deposit can indicate that you are near a volcanic vent, as scoria is not ejected very far from its source. This feature can be accessed just off the trail to the summit of Sister Rocks.
A basalt of Sister Rocks dike (a subsurface magmatic structure) cutting across a scoria deposit from a previous eruption of Sister Rocks. Being in a scoria deposit can indicate that you are near a volcanic vent, as scoria is not ejected very far from its source. This feature can be accessed just off the trail to the summit of Sister Rocks.
SP Crater (right foreground), like many volcanoes in Arizona’s San Francisco volcanic field, erupted mafic lava that lacks sanidine crystals.
SP Crater (right foreground), like many volcanoes in Arizona’s San Francisco volcanic field, erupted mafic lava that lacks sanidine crystals.
A USGS scientists uses a hammer and chisel to collect a sample from the surface of a basalt boulder in the San Francisco Volcanic Field of northern Arizona. The age of the sample will be determined using a technique called cosmogenic surface exposure dating, which determines how long the rock has been exposed to cosmic rays at the surface of the Earth.
A USGS scientists uses a hammer and chisel to collect a sample from the surface of a basalt boulder in the San Francisco Volcanic Field of northern Arizona. The age of the sample will be determined using a technique called cosmogenic surface exposure dating, which determines how long the rock has been exposed to cosmic rays at the surface of the Earth.
A basalt of Sister Rocks dike (a subsurface magmatic structure) cutting across a scoria deposit from a previous eruption of Sister Rocks. Being in a scoria deposit can indicate that you are near a volcanic vent, as scoria is not ejected very far from its source. This feature can be accessed just off the trail to the summit of Sister Rocks.
A basalt of Sister Rocks dike (a subsurface magmatic structure) cutting across a scoria deposit from a previous eruption of Sister Rocks. Being in a scoria deposit can indicate that you are near a volcanic vent, as scoria is not ejected very far from its source. This feature can be accessed just off the trail to the summit of Sister Rocks.
SP Crater (right foreground), like many volcanoes in Arizona’s San Francisco volcanic field, erupted mafic lava that lacks sanidine crystals.
SP Crater (right foreground), like many volcanoes in Arizona’s San Francisco volcanic field, erupted mafic lava that lacks sanidine crystals.
A USGS scientists uses a hammer and chisel to collect a sample from the surface of a basalt boulder in the San Francisco Volcanic Field of northern Arizona. The age of the sample will be determined using a technique called cosmogenic surface exposure dating, which determines how long the rock has been exposed to cosmic rays at the surface of the Earth.
A USGS scientists uses a hammer and chisel to collect a sample from the surface of a basalt boulder in the San Francisco Volcanic Field of northern Arizona. The age of the sample will be determined using a technique called cosmogenic surface exposure dating, which determines how long the rock has been exposed to cosmic rays at the surface of the Earth.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government