Mapping project focuses on Basin

June 9, 2005

By LEE JUILLERAT

A state geologist compiling a map of fault lines in the Klamath Basin over the next several months will be roaming across the region collecting rock samples.

Margi Jenks, who has spent years in the Klamath Basin doing geologic mapping, will likely ask private land-owners for access to certain spots, and is open to information from local residents that will help her work.

Jenks will spend seven months mapping hundreds of square miles for the Oregon Department of Geology and Mineral Industries.

Geologic mapping in the Klamath River Basin is being done to support ongoing groundwater monitoring, said state Geologist Vicki McConnell.

Through funding from the U.S. Bureau of Reclamation, McConnell said the department plans to "compile several years of detailed geologic mapping into a single map product that can be used by our federal and state partners and the local land use decision makers alike."

Jenks, a department geologist, will lead the Klamath River Basin efforts by using detailed maps compiled over the last seven years. Jenks will map areas from the California border to the Klamath Marsh.

McConnell said the mapping will support ongoing groundwater monitoring and modeling efforts by the Oregon Water Resources Department and the U.S. Geological Survey's Water Resources Department. Mapping will center around locating the faults and layers that control the movement of groundwater within the basin.

"Our previous work has shown that the groundwater is strongly controlled by the faulting in the area," Jenks said. "To figure out the faulting and the history of the volcanic and sedimentary rocks in the Basin, I will be collecting samples of the lava flows for chemical analysis and for radiometric dating."

Jenks is interested in hearing from and working with local landowners.

"I am interested in the locations of any fossils that anyone has found in the basin, particularly fish jaws and backbone vertebra," she said.

Jenks will also be knocking on doors and telephoning to ask for permission to map on private land.

"While most of the my work will be on Forest Service and other federally owned ground, I will be asking people in specific areas for permission to view and sample the rocks on their land," she said.

"I don't go on private land if I do not have permission, so I may be pretty persistent about areas that are of particular importance to our understanding of the Basin. In the past I have often been able to tell people about interesting features on their land, like extinct volcanoes or ancient landslides."

Jenks has worked on a variety of area groundwater projects. In the summer of 2001 she help to site irrigation wells for the various Oregon irrigation districts south of Klamath Falls. She also located test well drilling sites for the Klamath and Klamath Hills drainage districts, and was "pretty successful in identifying productive well sites."

"Getting the word out that Margi is working in the area usually makes it easier for her to get permission from landowners to map on their land," said James Roddey, the department's community education coordinator.

The Oregon Department of Geology and Mineral Industries is an independent state agency that has a broad responsibility in developing a geologic understanding of natural hazards. Information is made available to communities and individuals to help reduce the risks from earthquakes, tsunamis, landslides, floods and volcanic eruptions.

For more information James Roddey, 800 NE Oregon St., Portland, OR 97232, (503) 731-4100, extension 242, or by cell phone at (503) 807-8343.

To learn more about Oregon's geology visit the department's Web site at www.oregongeology.com.