The Ethno Geology of Shiprock, Navajo Volcano Fields, New Mexico

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The ethno geology of Shiprock, Navajo Volcano Fields, New Mexico

A Senior Capstone Project

Presented to the Faculty of the

Southwest Studies Department

The Colorado College

Fransiska Kate Dannemann

May 2012

Introduction

The Navajo Nation of the Four Corners Region, United States, is currently the largest

Native American tribe. Their traditional lands are filled with astounding geologic phenomena, which are often considered sacred, and thus inaccessible to non-Natives. These sacred lands are marked by legends and myths describing their cultural significance. Within the Navajo culture, myths exist to develop and maintain a sense of place as a form of establishing personal and societal identity (Semken 2005). In general, myths focus on expressing the limits and workings of the world as well as a cultural group’s place in nature with strong religious and ritual overtones. Due to these religious and or ritual overtones, myths are often transmitted orally within a ceremonial setting. Geologic phenomena and events are likely central aspects of cultural myths and legends due to two factors: a culture’s need to process and warn future generations of natural disasters, as well as the compelling desire to establish a sense of place

(Masse et. al 2007, Cajete 2000).

Strong connections between ancient myths and geologic phenomena are seen across the globe. Examples include the Delphic Oracle in Greece, where myths suggest that priestesses inhaled vapors rising from a chasm in the earth beneath her. Recent geologic investigation has revealed fault traces beneath the oracle, from which gasses could leak during seismic rupture events. The myth of the destruction of Atlantis is supported by dating and imaging of the 1625

BC super volcano Thera. In the Pacific Islands, stories abound regarding battles between the fire diety Pele and other gods, the historical dating of these battles corresponds to radiocarbon dating of scorched vegetation beneath lava sheets (Krajick, 2005). Currently, attention is being drawn to the Pacific Northwest, where aboriginal stories relate seismic events to battles between a great whale and a thunderbird.

Despite both the involved geologic history of the American Southwest, and the presence of several distinct Native American tribes living in this area, little attention has been given to potential connections between Native folklore and geologic formations. One possible explanation for this lack of geomythological research focusing in the American Southwest is the overwhelming amount of legends and tales about the area. In the words of Peter Nabokov, “one strategy that the Navajo employed to claim the Southwest as their motherland was to smother it with stories.” Because the Navajo peoples allege that they “emerged from the bowels of the earth in the Four Corners area of the Southwest to find their sacred landscape ready and waiting and already protected by their four sacred mountains,” it became necessary to weave a complex fabric of cultural tales and legends to support this creation story. These stories are of great importance to the Navajo people, who place great value upon establishing and understanding a sense of place. Gregory Cajete describes the cultural importance of both myth and land as he states, “In the same fashion as myth, land becomes an extension of the Native mind, for it is the place that holds memory.”

Examining aboriginal myths from an ethno geologic perspective places emphasis upon the sense of place and cultural value associated with creation stories while geomythological analysis places emphasis upon the validity of these myths. Within the context of the American

Southwest, several questions arise regarding the purpose of cultural stories regarding sacred places: Do Navajo creation myths serve to accurately describe historical geologic phenomenal?

Or are geologic features used as a backdrop for communicating overarching cultural themes and ideas? This paper focuses on the mythology and colloquial stories regarding Shiprock, a diatreme with radiating dikes located in the Four Corners region, to better understand the Navajo connections between geologic formations and cultural associations.

Geology of the Shiprock Region

Location

The Navajo Volcanic Field of the Four Corners Region contains 50 to 80 volcanic necks, plugs and associated dikes (Semken, 2003). The field extends north to south from Gallup, NM to Mesa Verde, CO and east to west from the Monument upwarp to the San Juan Basin (Figure

1). These igneous features were emplaced within the 40-45 km thick crust of the Colorado

Plateau, where sedimentary strata are underlain by Precambrian crystalline basement rock.

Figure 1: Location of Navajo Volcanic Field (Williams, 1936)

Sedimentary Environment

Six craton-wide unconformities mark the post-Precambrian stratigraphic record of North

America (Sloss et. al, 1963). Each unconformity represents a stratigraphic sequence of a major seaway transgression and regression within the North American interior. The first of these sequences is the Sauk Sequence, which ranges in age from latest Precambrian to Early

Ordovician. Sauk seas across the continental platform of western Laurentia deposited limestone and dolostones; however, erosion associated with seaway regression, removed most depositional evidence. This Precambrian to Early Ordovician unconformity is clearly seen in the Four

Corners Region Stratigraphic Column (Figure Two). The Tippecanoe Sequence ranges in age from Middle Ordovician to Early Devonian, representing a shallow sea environment covering present-day Arizona, New Mexico, West Texas and northern Mexico. The Kaslaskia Sequence ranges in age from Early Devonian to Mississippian, representing a major marine transgression.

Deposition throughout this sequence includes limestone and dolostone deposits (Leadville

Limestone, Ouray Limestone). The interfingered calcareous shale and earthy limestone deposits of the Elbert Formation, and the glauconitic shales, dolomites, coals, evaporates and limestone of the Aneth formation, indicate several marine transgressions and regressions throughout the

Kaskaskia (Turner, 1958; Baldridge, 2004).

The Absaroka Sequence, ranging in age from Mississippian to Early Jurassic, deposited the first significant sandstones and shales in the Four Corners. This transgression, occurring simultaneously with Laurentian-Gondwana collision driven uplift, produced a diverse range in depositional environments. Red soil beds, created through iron oxidation, characterize the lithology of the Southwest during the Absaroka Sequence. Sandstones dominate formations throughout the Permian, represented in the Halgaito (red siltstone and mudstones), Cedar Mesa

Sandstone, Organ Rock (red mudstones), and the DeChelly Sandstone. These formations suggest paleoenvironments marked by an arid seacoast with mud and sand dune deserts, and

Ancestral Rocky Mountain alluvial plains. Three Triassic formations: Moenkopi red mud and sandstones, Chinle mudstones, sandstones and limestones with petrified wood deposits and

Wingate eolian erg sandstones, represent Absaroka sea regression and the development of alluvial plains and a transcontinental river drainage system. Wingate eolian sandstones represent the movement of the North American section of Pangea into the tradewind belt of the northern hemisphere, forming dune sands.

The Zuni Sequence ranges in age from Middle Jurassic to middle Paleocene. A change in the Farallon Plate subduction angle produced an inland foreland basin, which flooded throughout the Cretaceous. The Western Interior Seaway extended from Utah and Arizona to Iowa and

Missouri. The first major formation associated with the Western Interior Seaway is the Dakota

Sandstone, which reflects a fluvial or deltaic depositional environment and associated tidal flats.

Deposition of Mancos Shale implies a deepening of seawaters. The Point Lookout Sandstone, representing a deltaic depositional environment, reflects the recession of this seaway. A second transgression of the Western Interior Seaway, creating the Lewis Sea, is marked in the Cliff

House Sandstone, Lewis Shale, and Pictured Cliffs Sandstone Formations, implying a similar deepening of seawaters over time. The Fruitland and Kirtland Formations, composed of mudstones, sandstones and coal, represent alluvial plain and coastal marsh depositional environments (Baldridge, 2004). The recession of the Lewis Sea marks the final time oceans covered the North American continent. Post-regression, sandstone, conglomerate and mudstone sediment (San Jose Formation, Nacimiento Formation, Ojo Alamo Sandstone) represent continental alluvial fans, plains, streams and swamps.

Figure 2: Stratigraphic column for Four Corners Area (Anderson & Lucas, 1997) Structural Setting

The Colorado Plateau is bordered on the west by the Basin and Range province and on the east by the Rocky Mountains. Despite the active tectonic development of these two areas throughout the Cretaceous and Tertiary periods, the Plateau was not subjected to significant tectonic activity. Subduction of the Kula and Farallon plates beneath the western margin of the

North American plate drove most, if not all, tectonic activity throughout the Jurassic and

Cenozoic Eras in the American Southwest (Figure Three). Two main orogenies, the Jurassic to

50 Ma Sevier Orogeny and the 80-50 Ma Laramide orogeny, are responsible for most deformation across the region. Compressional deformation associated with the Sevier Orogeny affected sedimentary units across the Four Corners region to British Columbia and formed both the Sierra Nevada and Southern California batholiths. Low-angle thrust faults throughout sedimentary units within the Colorado Plateau provide evidence for this deformation event.

The Laramide orogeny represents a continuation of the Sevier orogeny throughout the change in Farallon plate subduction angle. This decrease in subduction angle moved deformation 1,000 to 1,500 km inland from the subducting plate and changed deformation from low angle thrust faults to high angle reverse faults that uplifted Precambrian basement rocks.

Although deformation migrated towards the interior of the North American continent, the

Colorado Plateau was relatively unaffected by deformation. Dominant structural features of the

Plateau include north to northeast-trending Laramide age monoclines (Laughlin et. al, 1985).

Figure 3: Plate Subduction Underneath the Western United States 80 Ma to 40 Ma (Bird, 1988)

The Laramide orogeny ended around 28 Ma with a change in plate boundaries along the western border of the North American plate. As the Farallon plate disappeared beneath North

America, it split into the Cocos and Juan de Fuca plates. Additionally, right-lateral shear contact between the North American and Pacific plates initiated along the western North American boundary at this time (Baldridge, 2004). The Basin and Range province in Utah and Nevada developed around 20 Ma from extensional high-angle normal faulting that formed fault block mountains and deep sedimentary basins. Again, the Colorado Plateau remained relatively unaffected by tectonic deformation events.

Overall, the Colorado Plateau is composed of horizontal Precambrian to Paleocene sedimentary units associated with seaway regression and transgression sequences. The Plateau has been subjected to varying degrees of uplift yet shows little evidence of large deformational events. North to northeast-trending monoclines associated with the Laramide orogeny are the major structural features of the area.

Magmatism

Shiprock is part of the broader Navajo Volcanic Field, a 30,000 km2 area comprised of

50-80 exposed volcanic necks emplaced into the Mancos shale and Dakota sandstone of the

Colorado Plateau. Estimated eruption time ranges from 28-19 Ma, which coincides with termination of the Laramide orogeny and onset of Basin and Range extension throughout the

Western United States. The NVF experienced two main types of volcanism; explosive, emplacing minette diatremes and passive, emplacing potassic to ultrapostassic dikes and flows

(Semken, 2003). K-Ar dating suggests that minette volcanism occurred at 25 m.y., potentially commencing at 30 m.y. Dating of dike and sill emplacement suggests ages of 28 m.y. to 19 m.y.

Petrography

Minette is a potassic lamprophye that contains phlogopite, diopside and olivine phenocrysts within an aphanitic groundmass of phlogopite, diopside, apatite, sanidine, magnetite and analcime (Semken, 2003). Both felsic and mafic minettes occur in close proximity throughout the NVF, characterized by their differences in SiO2 weight percentages, 48-52% and

60% respectively, suggesting that felsic minettes formed from crystal fractionization of mafic minettes in the upper mantle (Roden, 1981). Volcanic neck breccias are composed of shale and sandstone fragments in a groundmass of minette (Delaney & Pollard, 1981).

Condie et al, 1999 completed a petrographic analysis of over 250 granitoid xenoliths from the NVF area. This study found considerable variability in major minerals, with K-feldspar dominating most samples (average 32%). Quartz, plagioclase and biotite are also abundant, with average compositions of 30%, 21% and 20% respectively. Quartz crystals range in size from 5 mm to very small; large crystals show wavy extinction while smaller crystals show recrystallization patches. K-feldspar and plagioclase show alteration to sericite and epidote.

Alteration and deformation of almost all samples suggest that xenoliths come from pre or syntectonic plutons within the upper crust and mantle. The presence of olivine phenocrysts combined with granitoid xenoliths suggests that magma originated through partial melting of the mantle and was altered by assimilation of continental crust (Roden, 1981).

Geochemistry

Great variations in chemical and mineralogical variations typically characterize alkali- rich igneous rocks, especially lamprophyres. (Laughlin et. al, 1986). The variability in chemical compositions results from differences in parent material, magma genesis depth and degree of

10 partial melting and potential crustal assimilation while the variability in mineralogy results from mineral reaction equilibrium and cooling rates. NVF minettes have high MgO concentrations

(4.3 to 13.3 wt %), and high Cr and Ni concentrations (Roden et. al, 1991). Despite the potassic

2+ nature of the minette, the K2O/Na2O ratio is independent of MgO content. Mg/Mg+Fe ratios suggest that partial melting of a metasomatized garnet peridotite crust, which reached olivine equilibration. The high abundance of K, Ti, Ba, Se, REE, and F suggests an infiltration of the overlying mantle into partial melts from the subducted (Farallon Plate) slab containing sediments and altered oceanic crust (Jonest et. al, 1983). This melt reacted with the peridotite to produce the phlogopite-rich minettes.

Elemental analysis of granitoid xenoliths shows a broad calc-alkaline trend (Condie et. al,

1999). Silica content ranges from 57 to 76%, and shows negative correlation with other major elements. Within the granitoid xenoliths at Shiprock, two main classifications of geochemical populations exist. One population (A) has high Al, K and low Ca, Mg, Fe and Ti elemental concentrations when compared to the other. This population is also enriched in Nb, Ta, Th, Zr and Rb, suggesting that the xenoliths originated from a late fractionation phase occurring in a single pluton.

Connection Between Magmatism and Colorado Plateau Tectonics

The random orientation of the Navajo dikes suggests that during the mid-Tertiary, an isotropic stress field existed on the Colorado Plateau. Along the east of the Plateau, extensional stress fields were oriented in the E-W direction while along the southeast and southwest, extensional stress fields were oriented in the NE-SW direction (Laughlin et. al, 1985). This suggests that by 28 m.y., the Colorado Plateau began decoupling from the Rio Grande rift and

11 the Basin and Range, becoming an independent structural block unaffected by the mid-Tertiary extension of the southwestern United States.

Lloyd and Bailey hypothesize that mantle phlogopite formation beneath the NVF resulted from the interaction between upward migrating K-rich fluids and mantle peridotites. NVF volcanism and Colorado Plateau uplift both occurred around 28 m.y., suggesting that the positive volume change associated with phlogopite formation may have driven Colorado Plateau uplift.

Specifically, a changing subduction angle of the Farralon plate beneath the Western

United States could inject volatiles released from the slab at greater depths. Metasomatism would begin as these volatiles migrated up through the mantle, resulting in positive volume changes, uplift and partial melting of the mantle further inland due to the shallower nature of the slab. The geochemical signature of the NVF minettes suggests that an alteration of subduction- related magma sources is necessary to produce the ultrapotassic rocks seen within the area. The most likely source of this contamination is assimilation of crustal materials.

Diatreme and Dike Formation

The volcanic necks seen intruding shales and sandstones throughout the NVF are maar- diatremes, which extend into dikes at depth (Lorenz, 1986). The presumption is that phreatomagmatic eruptions formed these diatremes through interactions of magma with the underlying water table. The interaction of magma and water produces steam, which increases the pressure of the magma chamber, resulting in highly explosive eruptions. These eruptions migrate downward, depleting the local aquifer and leaving behind a pipe composed of beccia and host rock. (Figure Four). In 1981, Delaney and Pollard observed that all diatremes within the

NVF, with the exception of The Thumb, are associated with dikes.

Figure 4: Maar-Diatreme Formation (Lorenz, 1986) Shiprock itself, like many other diatremes throughout the area, is composed of tuff breccia, representing the diatreme pipe that has been excavated to the surface through Colorado

Plateau uplift and erosion of the surrounding Mancos Shale. Shiprock currently rises 600 m above the San Juan Valley Floor. Correlation with the local stratigraphic section suggests that the maar surface of Shiprock was approximately 1,000 m above the present-day valley floor

(Rotzien, 2007). There are six exposed minette dikes surrounding Shiprock of 9, 4 and 3 km, with widths of 1-8 m that trend S12E, N80W and N55E (Delaney & Pollar, 1981). These dikes appear to merge along the west side of Shiprock.

There are two competing hypotheses for the emplacement of these minette dikes throughout the NVF. The first, classic hypothesis is in concordance with introductory geology

13 textbooks. The diatremes are described as relict volcano plugs with underlying magma chambers, implying that the dikes formed post-diatreme emplacement (Rotzein, 2007). The entire San Juan volcanic field of Southern Colorado is an example of such a system. Here, massive magma chambers underlay continental volcanoes. These volcanoes erupted explosively, fracturing the host rock. Sheets of magma infill these fractures, producing the observed dikes radiating from the volcanic center.

The minette dikes of Shiprock do not radiate outwards from the diatreme itself, but instead follow linear trends. This suggests preferential emplacement of ascending magma along a single dike composed of en echelon segments as the formation mechanism for Shiprock, and the NVF as a whole (Figure. As magma propagated along this dike, dike walls fractured and eroded, leading to the formation of beccias. Continued erosion of dike walls allowed for pooling of magma in these “buds”, which grew into the visible plugs or volcanic necks as magma cooled

(Delaney & Pollard, 1981). The alignment of dike segments around Shiprock in particular represents segmentation of the dike at depth. Segmentation of dikes at depth typically suggests that magma preferentially fills joints and preexisting fractures within the host rock; however, the

Colorado Plateau lacks a regional joint pattern of a similar orientation. This presents they hypothesis that the observed joints formed because of changing thermal stresses due to the cooling and contraction of magma. Contrary to previous ideas attributing dike formation to magma infill of explosion-generated fractures, here dike formation is prior to diatreme formation. Additionally, a magma chamber at depth need not be present.

Figure 5: Dike Propagation (Delaney & Pollard, 1983) Gravity and Magnetic Imaging

Preliminary geophysical investigations of Shiprock began in 2003 with the purpose of imaging the buried Shiprock structure (Gruen, et. al, 2003). Collected data and corresponding models suggest that gravitational methods cannot accurately image smaller subsurface dikes

15 while magnetic imaging methods can. Additionally, models show a high-density, deep body near the Shiprock diatreme itself.

Continuation of this research occurred during the summer of 2006 through a Keck

Geology Symposium Project advised by Jeff Noblett, Charles Bank, Glenn Kroeger and Steven

Semken. Undergraduate students embarked on a gravity and magnetic survey of Shiprock and its associated dikes. Gravity imaging techniques were used with the goal of imaging subsurface bodies and locations within the volcanic field, as well as the root contacts of dikes, diatremes and magma chambers at depth (Yospin et. al, 2007). With this technique, high gravity anomalies would indicate high-density material beneath the detection instrument. Because minette is much denser than the surrounding shale, high gravity anomalies are expected beneath Shiprock.

Gravitational results showed two main anomalies at Shiprock: a steep high and a slight low. Interpretation of the gravity low suggests imaging of the effects of Shiprock’s aboveground mass on gravity signature. Interpretation of the gravity high suggests a contrast between the minette of Shiprock and the surrounding Mancos shale, or a buried dense body. Modeling of this density contrast suggests three possibilities: (1) a broad, dense body emplaced where Mancos shale meets the basement material (600 km), (2) a small, buried magma chamber with a 950 m radius, buried at 2000 m, or (3) an up-warping of dense basement rock, located at a shallower depth. These interpretations are significant when considering the dike and diatreme emplacement mechanisms because a buried magma chamber could support the dike formation hypothesis over the explosive volcanic neck hypothesis.

The use of magnetic surveying techniques investigated whether dikes connect and merge in the subsurface and whether the plugs near the diatreme relate to these subsurface dikes (Beiki,

16 et. al 2007). Because igneous rocks of Shiprock have high magnetic susceptibility when compared to Mancos Shale, large contrasts in magnetism should be seen within the area.

Additionally, under the influence of a geomagnetic field, rocks acquire a stronger induced magnetization; therefore, dikes and intrusions should cause large magnetic anomalies.

Interpretation of observed anomalies shows that the western dike propagates underground past field exposure for 1 km, while the northeast dike propagates underground for 0.55 km and the southern dike terminates at site of last exposure. Imaging also shows that the western and southern dikes have bottoms 30 m beneath the surface while the bottom of the northeastern dike is at 18 m. These results also support mechanisms of dike flow and plug formation within the

NVF as opposed to explosive volcanism.

Microgravity and micromagnetic surveys constrained subsurface features underneath the en echelon dike structures (Tewksbury et. al, 2007). Four models help to constrain the subsurface structure of these dikes, suggesting (1) the dike segments are not connected, (2) the dike segments are connected in the deep surface, (3) the dike segments are connected in the shallow subsurface, (4) the dike segments are rotated with respect to the main dike (Figure Four).

A combination of models 3 and 4 would provide support for Delaney and Pollards argument of vertical dike propagation because if the segments are joined just beneath the surface, they behaved as a single segment during propagation and if dike segments are rotated, the en echelon pattern corresponds to a rotation of the principal horizontal stress during propagation. Delaney and Pollard suggest that en echelon segments are formed through magma rising and rotating from a single dike located at depth.

Figure 6: Dike Segement Hypotheses a) The dike segments are not connected, b) The dike segments are connected in the deep subsurface, c) The dike segments are connected in the shallow subsurface, d) The dike segments are rotated with respect to the main dike (Tewksberry, 2007). External estimations of magma flow direction were made using field indicators such as stretched vesicles, phenocrysts and flows while internal estimations of magma flow directions was made using anisotropy of magnetic susceptibility (Hardman et. al, 2007). Anisotropic magnetic susceptibility measures the susceptibility and alignments of crystallized magnetic minerals within phenocrysts of the host rocks. AMS data shows a trend in horizontal flow from the central stock. These potential results indicate initial vertical magma migration through the central stock, which upon eruption spread out horizontally during initial dike propagation. This suggests that magma transport initiated in a centralized magma chamber from the subsurface as opposed to a more expansive magma chamber that would produce complex flow patterns and

18 vertical magma flows, contradicting the other Keck studies in support of Delaney and Pollards’ hypotheses.

Despite the findings of the 2006 Keck Consortium projects, the formation of the NVF diatremes is still highly contested. The ultrapotassic nature of minettes throughout the field suggests magmatic interaction between mantle melt and the continental crust. The relationship between this interaction and the plate tectonics of the Western United States is still questionable.

The highly erosive nature of surrounding Mancos shale has extensively exhumed dikes and diatremes throughout the area, allowing for magnetic and gravitational analysis of formation processes. Additional information is necessary for distinguishing between dike propagation as sheets into the sedimentary units or explosive volcanoes at the water table.

Navajo Mythology

The idea of opposing forces is omnipresent within Navajo culture. Texts describe two main oppositional pairs: male vs. female and Nohosdzáán (Earth) vs. Yadi¬hil (Sky) (Semken,

2003). The Navajo conceptualize these pairs as “two halves of a whole”, where each half is necessary for completeness (Griffen-Pierce, 1992). These oppositional pairs balance each other throughout Navajo religious and mythologic texts, especially throughout the Navajo creation story. Although texts personify nearly all natural phenomena, a balance between the two is ideal.

Within this context, male phenomena (Naayee) are characterized as mobile, energetic, dominant and violent while female phenomena (Hozho) are characterized as gentle, enduring, passive and compliant. Despite this discrepancy, within Navajo culture neither gender is preferable or morally superior to each other, again illustrating the importance of balance. Other sources

19 suggest that female forces dominate when the Navajo universe is in order while male forces dominate when there is chaos in the world (Navajo Language and Culture).

The Diné origin legend explains how the Navajo gods created the lands that the people now occupy. It is divided into four chapters: The Story of Emergence, Early Events in the Fifth

World, The War Gods, The Growth of the Navajo Nation (Matthews, 1994). The 1984 translation of the legend titles the four chapters: The Emergence, The Fifth World, Slaying the

Monsters and Gathering of the Clans (Zolbrod, 1984). In these chapters, the fifth world refers to the American Southwest where the Navajo people currently reside. A summary of the second chapter is as follows,

“Shortly after First Man and First Woman climbed onto the surface of this “glittering” earthly plane, they used direct earth brought up from the underworlds to “plant” the four sacred directional mountains. Each peak had its mantle – white shell for the East, turquoise for the South, abalone for the West, obsidian for the North. Each peak also had its own inner life. Within the protective dominion of these greater-than-human mountain beings, the host of spirits whom the Navajo know as Holy People (Haashch’eeh Dine’e) then created the sky, the seasons and death.”

Peter Nabokov “Where Lightning Strikes: The Lives of American Indian Sacred Places”

These four directional mountains are known as Tsǐsnadzǐ’ni (eastern mountain, Mt.

Blanca), Tsótsǐl (southern mountain, Mt. Taylor), Dokoslíd, (western mountain, San Francisco

Peaks) and Depĕ’ntsa (northern mountain, Mt. Hesperus) (Matthews, 1994). Legend tells that a male and female god was put into each mountain to dwell, illustrating both the importance of male and female within the culture, as well as the idea that “Navajo mountains are gods”

(Nabokov, 2007). These four directional mountains represent the strong associations to place

20 within the Navajo culture. Stories and names are given to formations, large and small, throughout the region, as a way of identifying and preserving the culture.

Specifically, Shiprock, known to the Navajo as Tsé’bǐtaǐ, (Winged Rock), is mentioned in three separate cultural tales. The first mention occurs in the third chapter of the Origin Legend, the second in Navajo Blessing chants and the third is a colloquial tale regarding the rescue of the

Navajo people from their enemies.

The third chapter of the Origin Legend describes the conception, birth and adventures of

“the monster slayers”,

“When First Man and First Woman discovered a girl baby on top of Huerfano Mesa, the Holy People raised her. Named Changing Woman, she gave birth to the Sun’s twins, Monster Slayer and Child Born of Water. They slew the cannibals and performed legendary deeds, and the land remembered them” Peter Novak

The twins sought their father, and after proving their identity, asked his help in slaying the anáye, or monsters, who destroyed their people. These monsters were said to symbolize the transgressions of the women in the fourth world, when they were separated from the men

(Matthews, 1994). The Sun gave them clothing of pes (iron), and four arrows composed of chain-lightning, sheet lightning, a sunbeam and a rainbow. With these arrows, they decapitated the monster Yéitso. His head rolled to the east of Tsótsǐl and his blood flowed across the valleyi.

The twins then parted ways as Nayénĕzgani, the elder son, left to slay the Tse’nă’hale, the monsters who dwelled at Tsé’bǐtaǐ (Winged Rock)ii. Tales tell that Winged Rock was originally a bird (Correspondence at Shiprock). The son was swept onto Winged Rock in the Tse’nă’hale’s talons, and dropped upon a ledge. This fall did not kill the son, for he was carrying a life-feather.

Instead, he hid along the ledge and awaited the Tse’nă’hale’s returniii. When the monsters

21 returned, the son slay them with his lightning arrows, and then transformed the young

Tse’nă’hales into eagles and owls. Different variations of this story describe Shiprock transforming from a giant bird itself. The radial dikes are described as wings of the bird or blood of the slayed monsters (Carl Slater, oral correspondence).

Figure 7: Depiction of the Monster Slayer (Browne, 1993) Mentions of Shiprock also occur in the Navajo Blessing chants. In these chants, the

Chuska Mountain range comprises the body of Yo’díDzil (Goods of Value Mountain). Chuska

Peak is the head of this figure, while the Carrizos are his lower extremities and Beautiful

Mountain is his feet. Shiprock is the medicine pouch or bow that he carries (Lindford, 2000).

This figure is the male counterpart to Pollen Mountain, comprised of Navajo Mountain, Black

Mesa and other features. Aside from this mention in Navajo Places: History, Legend,

Landscape, little is known about the significance of Shiprock and other mountain formations in the Navajo Blessing Chants.

Another mention of Shiprock potentially relates to the uplift of the Colorado Plateau,

“A long time ago they tell that the Navajo were hard pressed by the enemy. One night their medicine men prayed for the deliverance of their tribe. Their prayers were heard by the Gods. The earth rose, lifting the Navajos and it rose like a great wave into the east. It settled where Shiprock now stands. This is the way they escaped from their enemies”

--Laurence D. Lindford,

Lindford also mentions that “…the earliest treatments of Navajo ceremonialism do not mention the peak (Shiprock) or its myths; thus any ceremonial significance may be recent origin rather than based in antiquity”. This observation supports ideas regarding the strong sense of place in Navajo culture. It is possible that stories regarding Shiprock were modern explanations of this landform to provide cultural context to tribe members settling in the Shiprock area of

Navajo Nation.

Navajo Understanding of Geologic Processes

On a larger scale, Navajo concepts of balancing pairs can be related to geologic processes like magmatism, orogeny and weathering (Semken, 1993). Endogenic, solid-Earth processes like magmatism and mountain building occur on the Earth (Nohosdzáán) and are often energetic, male-like processes. Exogenic, fluid-Earth processes such as fluctuations in the water cycle and weathering are related to the Sky (Yadi¬hil). These processes are typically passive and female- like.

Semken, 1998 describes the origin and evolution of the Navajo volcanic field as a whole in a combination of female and male-like processes.

“Violent (male-like) interaction between magma (Earth) and meteoric water (Sky) formed the diatremes, and subsequent interaction between Colorado Plateau uplift (Earth-driven; female-like) and weathering and erosion (Sky-driven; male-like) exposed and sculpted the diatremes and dikes into their present shapes.”

This understanding of the duality in earth-systems processes gives rise to a smaller scale question; did the Navajo understand the processes of volcanic formation and more importantly, did the people explain these formations in their mythology when establishing a sense of place?

The erosional characteristics of the mesas of the Colorado Plateau and the Shiprock diatreme suggest that the ancient people may have strived to explain the striking differences in the sedimentary canyons and igneous intrusions.

The mention of Shiprock specifically in several Navajo tales suggests that the people did realize this formation was different from the surrounding mesa. Although myths lack information about explosive events or eruptions, the creation story does acknowledge that the land existed prior to the Diné arrival to the fifth world, removing the necessity to explain processes of formation in-depth. Stories relating Shiprock to a giant bird, with radiating dikes as wings, support ideas of lateral dike emplacement, as the entire structure formed at the same time.

Stories relating the dikes to the blood of slayed birds support ideas of dike formation post- eruption. Alternatively, stories of the Navajo escaping from their enemies as Shiprock “rose like a great wave into the east” (Lindford, 1997). This specific mention of Shiprock rising suggests that the Navajo people understood that diatremes formed due to magma releasing from the

Earth’s crust.

Although these myths do not directly explain volcanism or dike emplacement, the Navajo seem to have an inherent understanding of Earth processes, specifically realizing that the diatremes within the NVF were extremely different from the surrounding mesa. The lack of strong explanations for the formation of geologic phenomena suggests that the Navajo people had a rudimentary understanding of geologic processes. The people chose to focus on associating formations within the Navajo Nation to cultural values and ideals, in an attempt to establish a sense of place within the greater United States.

i Descriptions of the monster’s head and blood correspond to a dark volcanic hill 40 miles northeast of Mt. San Mateo called The Great Head. Additionally, there are great plains of lava to the south and west of the San Mateo Mountain Range. (Matthews, 1994) ii This is the first mention of what is inferred to be present day Shiprock. A translation of the legend states “…he came close to Tsé’bǐtaǐ, which is a great black rock that looks like a bird. (Matthews, 1994 p. 119) iii Here the text makes reference to female Tse’nă’hale returning to Shiprock with she-rains, and male Tse’nă’hale’s returning to Shiprock with male rains.

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