![]() But LIDAR shows terraces in stream sediments along Bear Creek near the base of this lobe, suggesting that for some period after the lava cooled, the Middle Fork was backed up, forming a lake. Molten lava on this scale would have instantly vaporized the Middle Fork as it flowed down valley. Here, a lobe of lava pushed laterally (left) and uphill into the side canyon of Bear Creek, permanently diverting the Middle Fork Hood River in the process. The oversteepened slopes along the west margin of the stream (shown as a distinct shadow) are the result of the Middle Fork continuing to cut away at the base of Blue Ridge, some 7,000 years after the lava flow formed.Īnother view of the mid-section of the Parkdale flow (Map C, below) shows fascinating features along the west margin of the formation. The view in Map B, above, also shows how the Parkdale flow pushed the Middle Fork Hood River against the foot of Blue Ridge, to the west. This view also shows the first lateral lobes, splitting off the main flow as the molten lava reached the open floor of the Upper Hood River Valley, and where the volume of lava overtopped or burst through the levees along the main channel. This main channel also has well defined levees of solidified lava along its margins, a common feature on the more liquid Pahoehoe (pronounced pa-HOI-hoi) form of lava, but less so with the viscous A’a’ lava that makes up the Parkdale formation. Moving south to the middle of the Parkdale flow (Map B, below), the LIDAR image shows a powerful, quarter-mile wide stream of lava pushing down a channel at the center of the flow. Below the flow, the flood area averages about one-third mile in width, but where the channel along the west side of the lava flow, it measures only a out one-tenth of a mile in width. In this lowest extent of the flow, it’s also clear that the lava covered most of the Middle Fork flood plain. The gentle slope of the open valley floor was responsible for the broad toe of the lava flow, which spread out in the shape of a hand (or paw?) once it emerged from the confining canyon walls of the Middle Fork canyon. Though the flow was generally heading downhill (the underlying valley floor drops about 250 feet per mile in this area), LIDAR shows it was spreading out, too, as evidenced in the many secondary lobes that formed at the terminus of the flow. Starting on the north end, at the toe of the Parkdale flow (Map A, below), the LIDAR imagery reveals the flow lines in the once-molten rock in great detail, when compared to traditional maps and air photos. The LIDAR imagery beautifully illustrates these characteristics of an A’a’ flow, including the tall, steep edges of the flow that result from this dense, slow-moving form of lava. This floating skin of jagged, solidified rocks echoes the movement of the underlying flow, thus creating the flow lines. The Parkdale lava is of the A’a’ variety (pronounced “ah-ah”), characterized by a thick, pasty molten core carrying hardened chunks of cooled lava on its surface like a crusty skin. (for a larger LIDAR view of the entire flow, click here) This article focuses on the Parkdale Lava Flow, one of the formations where LIDAR offers an especially striking new look at the geologic story.įour sections of the Parkdale flow (shown on the index map, below) are the focus of the article. Macphun are also excited to offer a 3-month 500px membership for free as a bonus to Tonality.The new LIDAR data viewer created by Oregon’s Department of Geology and Mineral Industries (DOGAMI) offers a fascinating new look at familiar features in the Mount Hood region. ![]() Macphun have teamed up with 500px to allow users to easily export images directly from Tonality to the global online photography community. Current favorite preset packs include Portrait, Architecture, and Dramatic.ĥ00px Support plus 3-month FREE membership ![]() Statistics show that since August 2014 (when the software was launched) Tonality users have processed over 7 million images, and applied over 50 million presets to their photos. Macphun have enlisted the expertise of professional photographers, including Serge Ramelli, John Batdorff, Dan Hughes, Andy Krucezk and others to create exciting new preset packs exclusive to Tonality, which can be found at /tonalitypresets. To access the library, users simply need to click “Get more presets” from inside the software. Tonality users will now have access to a free preset library, created by professional photographers from around the world. Preset Packs from World-Famous Photographers
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