Earth Sciences Commons^™

Grain Size Variability Spanning The Paleocene-Eocene Thermal Maximum In Laramide Basins: Reconstructing Paleoslopes And Overbank Erodibility, Delaney Todd

WWU Graduate School Collection

The Paleocene-Eocene Thermal Maximum (PETM) is an extensively studied global warming event occurring approximately 56 Ma and lasting around 200 kyr. Marked by a negative ¹³C excursion from a massive influx of CO₂ to the atmosphere, the PETM caused environmental alterations including increases in global temperature, changes in hydrology and ocean chemistry, and floral and faunal overturns. Evidence of these alterations during the PETM is found within both marine and continental basins. During the early Paleogene, the Laramide Orogeny formed a series of nonmarine basins within the Western Interior of the United States. Three of these basins, the …

Evaluating Thresholds In Fluvial Response To The Eocene Thermal Maximum 2 In The Bighorn Basin (Wyoming, U.S.A), Grace Marie Sutherland

WWU Graduate School Collection

Earth's climate experienced a set of hyperthermal events during the greenhouse climate state of the early Paleogene. The Paleocene-Eocene Thermal Maximum (PETM) was the largest of these abrupt global warming events, occurring at ~56 Ma and lasting for ~200,000 years. The PETM is identifiable by a large negative carbon isotope excursion and associated with significant changes in global temperature, hydrology, ocean chemistry, and biology. Subsequent smaller hyperthermal events appear to have commensurately smaller effects on marine environments, but the scaling of the complementary nonmarine environmental responses is unclear.

The Bighorn Basin of northwest Wyoming contains the most detailed nonmarine record …

Auto-Stratigraphic Evolution Of Experimental Crater-Fill Basins: Implications For Interpreting Mars Sequence Stratigraphy And Paleoclimate, Lexie Stodden

WWU Graduate School Collection

Preserved fluvial and deltaic sedimentary deposits found within martian crater-fill basins are important evidence documenting past warmer, wetter climatic periods on Mars. The morphologic and stratigraphic patterns of these sedimentary deposits are commonly interpreted to record variably complex transgression and regression histories of crater-lake levels, driven by fluctuations in the prevailing hydroclimatic conditions. Yet this tendency for direct inversion of sedimentary characteristics to formative boundary conditions largely neglects large-scale autogenic processes operating in crater-fill basins. The goal of this research is to illustrate an idiosyncratic feature of these basin types, wherein attributes of the sediment source play an outsized role …

Validation Of Predicted Tsunami Inundation For The Inland Coast Of The Salish Sea Associated With Cascadia Subduction Zone Earthquakes, Paige Morkner

WWU Graduate School Collection

The Cascadia subduction zone is understood to produce large, Mw 9.0, earthquakes every 300-1000 years. As a result of large ruptures along the fault, Washington, Oregon and Northern California, are susceptible large tsunamis along the coast. Hazard modeling and mapping along the Cascadia subduction zone has concluded that large tsunamis are able to travel through the Strait of Juan de Fuca and inundate coastal regions of the Salish Sea and Puget Sound. However, to improve modeling efforts, field validation of models is required. Tsunamis can move material from the near shore and beach and deposit in low-laying coastal marshes and …

Geology Of The Park Butte-Loomis Mountain Area, Washington (Eastern Margin Of The Twin Sisters Dunite), David L. (David Lewis) Blackwell

WWU Graduate School Collection

Mappable units in the Park Butte-Loomis Mountain area of northwestern Washington are distinguished on the basis of age, lithologic association, structural position, and metamorphic recrystallization. There are four volcanic/volcaniclastic units: the Chilliwack Group, the Cultus Formation, the Elbow Lake-Haystack Mountain unit, and the Nooksack Group: and at least three allocthonous crystalline units: ultramafic rock (including the Twin Sisters and Goat Mountain dunite bodies), the Yellow Aster Complex, and the Vedder Complex. All units occur as tectonic fragments (fault bounded blocks) which are juxtaposed along anastomosing, horizontal to low angle, west dipping faults.

The upper Paleozoic Chilliwack Group is represented by …

Stratigraphy And Petrology Of The Nooksack Group In The Glacier Creek-Skyline Divide Area, North Cascades, Washington, Jon Niels Sondergaard

WWU Graduate School Collection

The 6-7 kilometer thick Upper Jurassic-Lower Cretaceous Nooksack Group is divided informally into four units on the basis of lithology. The basal unit consists of tuffaceous sandstone and keratophyric tuff with minor intercalations of argillite and intermediate crystalline volcanic rocks. The lower unit is composed of interbedded black argillite and volcaniclastic sandstone. The middle unit consists of thick-bedded volcaniclastic sandstone and coarse, sedimentary breccia with minor argillite. The upper unit is comprised of interbedded black argillite and volcaniclastic sandstone.

Lithologies and sedimentary structures within these units suggest: (1) the lower and upper units represent depositional lobe deposits of a middle …

The Geology Of Southwestern Fidalgo Island, Daryl Gusey

WWU Graduate School Collection

Detailed geologic mapping of rocks in the upper stratigraphic levels of the Fidalgo ophiolite Indicates that keratophyres and spilites are interbedded with tuffaceous sediments, sedimentary breccias, and graywacke. Sedimentary breccias containing plutonlc rock fragments as well as volcanic rock fragments are common. The graywackes were derived from a volcanic source area. Radiolaria In the tuffaceous sediments indicate a depositional age of Lower Kimmeridgian to Upper Valanginian.

Compared to the stratigraphy and petrology of other ophiolites and present-day tectonic environments, the Fidalgo Complex most closely resembles that of ancient and modern island-arc sequences.