Page 20 - i1052-5173-32-11

PENROSE CONFERENCE ANNOUNCEMENT
The Role of Outburst Floods in

Earth and Planetary Evolution

5–9 June 2023 | Grand Coulee, Washington, USA
www.geosociety.org/penrose

CONVENERS of settings, processes, and hazards results in a wide range of back-
Tim Goudge, University of Texas at Austin, Dept. of Geological grounds, disciplines, and geographies represented by outburst flood
Sciences, Austin, Texas, USA, tgoudge@jsg.utexas.edu researchers, including engineers, geomechanicists, glaciologists,
Isaac Larsen, University of Massachusetts, Dept. of Geosciences, volcanologists, geologists, geographers, hydrologists, and planetary
Amherst, Massachusetts, USA, ilarsen@umass.edu scientists. This thematic session aims to search for commonalities
Jim O’Connor, U.S. Geological Survey, Geology, Minerals, Energy, and distinctions among outburst flood generation mechanisms and
and Geophysics Science Center, Portland, Oregon, USA, oconnor@ geomorphic consequences (across landscapes and planets), thereby
usgs.gov enriching the perspective for the outburst flood research community.
Greta Wells, University of Iceland, Institute of Earth Sciences,
Reykjavík, Iceland, ghwells@hi.is 3. Mechanistic Understanding of Outburst Flood Processes—
Flow, Erosion, and Deposition
SPONSORS Outburst floods produce spectacular features—huge cataract
The Geological Society of America complexes, eroded rock basins, streamlined landforms, and immense
National Science Foundation stratified deposits. Given the lack of in situ observations of ice-age
and planetary megaflood processes, various methods have been used
DESCRIPTION AND OBJECTIVES to address historical questions regarding flood magnitude, the num-
The century following the start of the “Spokane Flood” debate has ber of floods, or the shear stresses generated by flooding, including
seen tremendous growth in the understanding of the significant role empirical, stratigraphic, mechanistic, modeling, and physical experi-
outburst floods have played in shaping the surfaces of Earth and mentation. The development, refinement, and testing of mechanistic
Mars. Study of the geomorphology and hydrology of outburst floods models have been key to advancing the overall understanding of how
has, in turn, generated hypotheses regarding the role such floods play outburst floods drive the evolution of planetary surfaces. The objec-
in driving climate change and a greater recognition of the geohazards tive of this thematic session is to generate discussion that charts a path
associated with outburst flooding. The objective of this Penrose for novel approaches for mechanistic understanding of the energetic
Conference is to bring together a diverse community of scholars to and dynamic flows that produce outburst flood landforms.
discuss the current state of knowledge and chart the future of outburst
flood science. The timing of the proposed conference in 2023 is also 4. Broader Implications of Outburst Floods—Cultural
historically significant, as it marks the centennial anniversary of Consequences and Hazards, Ocean Circulation and Climatic
J Harlen Bretz’s first publication on the Channeled Scabland. Systems, Ecosystems, and Landscape Evolution
The hazards and impacts from outburst floods are immense,
PRELIMINARY OUTLINE OF THEMATIC SESSIONS global, and diverse, begging several overarching questions. Are there
1. The Channeled Scabland and the Missoula Floods specific geologic and climatologic settings that can condition such
The Missoula Floods and the Channeled Scabland are a
“Megaflood testing ground” for studies applicable throughout the
solar system. It is here where Bretz’s controversial and outrageous
hypothesis for a flood origin of the Channeled Scabland brought huge
ice-age outburst floods into the realm of modern Earth science. The
Channeled Scabland continues to inspire geological analysis and
modeling approaches, and this spectacular geographic area has long
attracted attention, culturally and scientifically. This thematic session
will explore the state of knowledge of the Channeled Scabland land-
scape and the Missoula floods, as well as the scientific controversies
that have persisted for the past century and continue today.

2. Outburst Floods—A Universal Process
A wide range of geological processes lead to impoundment of
water bodies that can then rapidly drain to cause large floods, ranging
from tectonics to meteor impacts. Floods from ice-dammed, moraine-
dammed, and landslide-dammed lakes can cause human catastro- Aerial view downstream (south) of Dry Falls cataract complex, Grand Cou-
lee, Washington, USA. The pair of giant cataracts at the head of lower Grand
phes. Floods from constructed dams have also profoundly affected Coulee are 120 m deep and span 2 km in width. They formed via headward
landscapes and people. Spectacular flood-carved landscapes on other erosion during several Missoula floods. The planned conference venue,
Camp Delany, sits at the foot of the left (eastern) amphitheater. Photograph
planets, particularly Mars, owe to huge outburst floods. The diversity by Bruce Bjornstad.

20 GSA TODAY | November 2022