Wyoming Geology

In this article, chipped stone raw materials from the Garrett Allen site are discussed, with emphasis on the stone tools. As indicated by Eckles (2013), who discussed the history of investigations and chronology, this is one of several articles to be presented on various aspects of the site’s artifacts. One of the remarkable aspects of the site is the variety of chipped stone raw materials. There are varieties of flint, chert, agate, jasper, chalcedony, petrified wood, orthoquartzite, metaquartzite, quartz, silicified shale, clinker, non-volcanic glass, obsidian, and basalt from many parts of Wyoming and surrounding states. The diversity of raw material types is present throughout the cultural deposits. There is no knappable tool stone on site; the only rocks are small fragments of drab, buff-gray sandstone. All culturally manipulated lithic materials were therefore brought into the site, many from considerable distances. The site is located on private land in southeastern Carbon County, Wyoming at the northern end of the Medicine Bow Mountains and southern edge of the Hanna-Carbon Basin. It is within a homoclinal valley near the perennial Quealy Spring. Deposits are primarily alluvial, derived from the surrounding geological formations (Hayter 1981:31).

An EMAP ( Electro-Magnetic Aray Profiiing ) survey was run over
the southern Wind River Overthrust in southwestern Wyoming. EMAP is an electromagnetic geophysical method based on magnetotellurics. Array processing keyed to apparent depth of penetration is used to attenuate the effects of near surface inhomogeneities to produce a more accurate conductivity versus depth cross section.

The results from the EMAP survey are integrated with local geologic information, well data, and other geophysical data to produce a final interpreted geologic cross-section. The results of the EMAP survey indicate that the hanging wall of the southern Wind River Thrust is a juxtaposition of two different rock types; a faulted synclinorium of metamorphic rocks surrounded by gneissic and granitic rocks. The conductivity contrast
between these rocks is well defined on the section.

The existence of mechanicaliy weaker metamolphic rocks in the midst of the gneissis and granitic rocks has had a profound influence on the structural history of the southern Wind River Thrust. It is likely that the metamorphic rocks influenced the location and existence of the Continental Fault, a normal fault downthrown towards the mountains which cuts the Wind River Thrust. It is also probable that the metamorphic rocks are partly
responsible for the flattening of the thrust observed on seismic sections in the shallow parts of the thrust.

Laterally extensive intervals containing sedimentary deformation features are identified in outcrops of lacustrine deposits of the Eocene (∼ 52–51 Ma) Green River Formation in Fossil Basin, southwestern Wyoming. Fossil Basin is the smallest of the paleo-lakes in the Green River system and is located in the Sevier Fold and Thrust Belt, which was tectonically active during deposition. Deformation structures include convolute lamination, load structures, hybrid brittle–ductile features, sedimentary dikes, microfaults, fluid-escape features such as cusps and pipes, oil-shale breccias, and mass-transport deposits. In most cases these structures are hosted by finely laminated, variably organic-rich carbonate mudstones that accumulated in a low-energy profundal lacustrine environment. Deformed intervals range from a few centimeters to 5 m in thickness and are bound above and below by undeformed strata of the same facies, which demonstrates the early post-depositional timing of deformation. The distribution of these features indicates a primary control exerted by sediment rheology, resulting from variation in grain size, clay and organic content, and degree of lithification, which in turn were governed by the depositional environment and early diagenesis.

Based on their morphological attributes, lateral extent, and recurrence at different stratigraphic levels, along with their sedimentary environment and the tectonic setting of the basin, the deformation structures are interpreted to be “seismites,” i.e., the result of stresses induced by syndepositional earthquakes, and other potential trigger agents are rejected. Moreover, stratigraphic relationships indicate that these small-scale deformation features as well as the mass-transport deposits, formed on a virtually flat lake floor, ruling out instability caused by the gravitational regime. Syndepositional deformation in Fossil Basin points to tectonic activity along the nearby Absaroka and/or Hogsback thrusts and related fault systems. Seismites point to possible tectonic forcing as a mechanism for changes in bathymetry and sedimentation in the Green River Formation and, consequently, demonstrate their potential for elucidating the tectonic history of other lacustrine and marine basins.

Detailed topographic map evidence is used to test the ability of two fundamentally different regional geomorphology paradigms to explain Bighorn-Wind River drainage divide evidence in the Copper and Lysite Mountain areas between Wind River Canyon and the Bighorn Mountains. Identified divide crossings were interpreted to be places where water had once flowed across what is now a major drainage divide. More than 20 such divide crossings were identified and ranged in elevation from 1924 to 2485 meters and could all be linked to north-oriented Bighorn River tributaries and also to south-oriented streams flowing to west-oriented Badwater Creek (a Wind River tributary). Lowest elevation divide crossings were located to the north of both Copper Mountain and Lysite Mountain. An attempt was first made to explain each identified divide crossing or group of divide crossings from the accepted paradigm's perspective, which requires drainage routes to have originated on the surface of a hypothesized Oligocene and Miocene sediment cover that buried the drainage divide area with the drainage routes eroding down through the sediment cover as the drainage divide was exhumed. Next the same evidence was interpreted from a recently proposed paradigm's perspective, which requires massive south-and southeast-oriented floods to have flowed across the Missouri River drainage basin as mountain ranges and plateau areas were being uplifted. The accepted paradigm could not easily explain the large number of observed divide crossings, many divide crossing details, and why geologic maps show few or no hypothesized sediment cover remnants. The new paradigm explained the large number of observed divide crossing and most observed divide crossing details and did not require an Oligocene and Miocene sedimentary cover.

Between 11 am and 1 pm on September 25, 17,524 BP (15,574 BC; 14,380 C14 BP), a 2300-meter tide slammed into the Pacific Coast from Alaska to Mexico, drawn by gravity from Nibiru. It flooded British Columbia, Washington, Oregon, California, Mexico, Idaho, Nevada, Utah, Arizona, Montana, Wyoming, Colorado and New Mexico. Its antipode in the Indian Ocean struck Antarctica, Australia, Africa and India.
It left scars still visible on Google Earth: brown mud, scoured hillsides, less-fertile land underlain by hard-pan, and salt playas. In the Central Valley of California, a brick-hard red clay beneath a layer of silt requires a previous close encounter to fire the clay before it was later covered by the sea. The flood eroded enough ice to raise sea level 4 meters. Evaporation of mountain glaciers and sea-water caused a deep snowfall in Greenland that skewed layer-counting by twenty years.
At insanely high speed, the tide swept around the Sierra Nevada and over the Cascade Range of Oregon and Washington. It scoured soil from the land, poisoned the remaining soil with salt, and created numerous lakes, some temporary, some permanent. The outflow cut the Grand Canyon deeper.
Its force eroded 1.6 million cubic kilometers of ice along the west coast of Canada, the northwest border of the US, the mountains of the Sierra Nevada, and the coast of Antarctica facing the Indian Ocean.

Premise of research. Although largely neglected by the paleobotanical literature, the Early Devonian genus Sphondylophyton Schultes and Dorf is on record as the oldest sphenophyte. Given current understanding of the fossil record, a revised interpretation of the depositional environment at the fossil locality, and the discovery of new specimens, reconsideration of the taxonomic affinities of Sphondylophyton is necessary.
Methodology. All known Sphondylophyton specimens were examined for morphological comparison with plant and algal lineages exhibiting a similar whorled architecture.
Pivotal results. Sphondylophyton is characterized by sparsely branched, flexuous axes bearing whorled, simple, terete appendages with dimorphic apical morphology. Sphenophyte affinities are ruled out, as whorled taxis does not appear in vascular plants until the Late Devonian. Evidence for marine influences in the depositional environment of Sphondylophyton warrants consideration of algal affinities. Although dasycladalean and charophycean green algae share superficial morphological similarities with Sphondylophyton, they can be excluded upon detailed comparison (e.g., branching, lateral appendage dimensions and complexity).
The combination of characters of Sphondylophyton falls within the morphospace of the Rhodophyta. Among these, Sphondylophyton is most similar to rhodomelacean taxa in overall habit, appendage morphology, and thallus durability. Generic and specific emended amplified diagnoses are provided.
Conclusions. Sphondylophyton is not a sphenophyte as previously suggested; dasycladalean and charophycean
affinities are not supported. We demonstrate that Sphondylophyton is a red alga most comparable to Rhodomelaceae, although no taxonomic placement below the phylum rank is proposed; as such, it contributes to the limited fossil record of the Rhodophyta.

Topographic map evidence from the Wyoming Wind River-Sweetwater River drainage divide area is used to test a recently proposed regional geomorphol-ogy paradigm defined by massive south-and southeast-oriented continental ice sheet melt water floods that flowed across the entire Missouri River drainage basin. The new paradigm forces recognition of an ice sheet created and occupied deep "hole" and is fundamentally different from the commonly accepted paradigm in which a pre-glacial north-and northeast-oriented slope would have prevented continental ice sheet melt water from reaching or crossing the Wind River-Sweetwater River drainage divide. Divide crossings (or low points) are identified as places where water once flowed across the drainage divide. Map evidence is interpreted first from the accepted paradigm perspective and second from the new paradigm perspective to determine the simplest explanation. Both paradigm perspectives suggest south-oriented water crossed the drainage divide, although accepted paradigm interpretations do not satisfactorily explain the large number of observed divide crossings and are complicated by the need to bury the Owl Creek and Bridger Mountains to explain why the Wind River now flows in a north direction through Wind River Canyon. New paradigm interpretations explain the large number of divide crossings as diverging and converging channel evidence (as in flood-formed anastomosing channel complexes), Owl Creek and Bridger Mountain uplift to have occurred as south-oriented floodwaters carved Wind River Canyon, and a major flood flow reversal (caused by ice sheet related crustal warping and the opening up of deep "hole" space by ice sheet melting)

Plant fossils in the Early Devonian Beartooth Butte Formation (Wyoming, USA) are colonized by microconchid encrusters which are found on several plant taxa, at two fossil localities in the formation, and whose tube coil diameters range from 230 to 1170 um. Colonization is densest on broad Drepanophycus devonicus stems where microconchid individuals encompassing broad size ranges co-occur in close vicinity. This indicates exposure to microconchid colonization and, therefore, submergence of the plant material for relatively extended periods of time prior to burial. For in situ preserved Drepanophycus, this suggests that the plants grew partially submerged and their submerged parts were colonized by microconchids while still alive. In turn, this indicates that by the Early Devonian microconchids were colonizing freshwater environments. The Beartooth Butte Formation provides the first record of plant colonization by microconchids in North
America and, along with only one other Early Devonian record from Germany, the oldest evidence for microconchids colonizing plant substrates.

Curated paleontological field experiences can be understood as a kind of time travel. As travel across landscapes offers opportunities to engage with and become accustomed to a variety of terrains and diverse human perspectives, travel through time offers opportunities to practice engagement with the archaic lives and ecosystems that yielded our worlds, and which continue to exist within them. The stories I relate here call attention to how paleontological fieldwork and its extinct companion species invite us to imagine life under other conditions, and to recognize the material continuities between worlds apparently separated by time.

Divide crossings (or low points or gaps) notched into the North American east-west continental divide segments completely encircling Wyoming"s Great Divide Basin interior drainage region (as observed on detailed topographic maps) are used to compare the commonly accepted regional geomorphology paradigm with a fundamentally different and new regional geomorphology paradigm. Paradigms are sets of rules governing how a scientific discipline conducts its research and are judged on their ability to explain observed evidence. Published literature is used to contrast an accepted paradigm interpretation that east-oriented drainage previously flowed across what is now the Great Divide Basin with the new paradigm basic requirement that mountain range and continental divide uplift occurred while immense south-oriented floods flowed across them. Numerous divide crossings are notched into the continental divide segments now completely encircling the relatively flat-floored Great Divide Basin interior drainage area and divide crossings observed along each of the Great Divide Basin"s north, east, south, and west margins are described and interpreted first from the accepted paradigm perspective (using published literature interpretations to the extent possible) and second from the new paradigm perspective. The published literature does not mention most of the described divide crossings, much less provide explanations for their origins, perhaps because the accepted paradigm cannot satisfactorily explain those origins. In contrast the new paradigm successfully explains most if not all of the described (and observed, but undescribed) divide crossings, although the new paradigm requires a completely different middle and late Cenozoic regional geologic history than what most published regional geology literature describes.