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A Pre–21St Century History of Ideas on the Origin of the Grand Canyon

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A Pre–21St Century History of Ideas on the Origin of the Grand Canyon CRevolution 2: Origin and Evolution of the Colorado River System II themed issue A pre–21st century history of ideas on the origin of the Grand Canyon Wayne Ranney* 255 E. Hutcheson Drive, Flagstaff, Arizona 86001, USA ABSTRACT INTRODUCTION from the previous one and a half centuries of study (Young and Spamer, 2001; Beard et al., From the mid-nineteenth through twen- The Grand Canyon is a world-renowned land- 2010; Karlstrom et al., 2012). tieth centuries, geologists attained a good, form that is visited each year by over 4.5 million However, modern attempts to unravel the ori- if imperfect, view of the development of the people, almost half of whom arrive from another gin of Earth’s largest erosional feature, or the Colorado River and the Grand Canyon. country. Geologists continue to debate the spe- complex history of one of our continents most Beginning in the late 1850s and continu- cifi c process or combination of processes that important rivers, are necessarily framed by the ing through the 1880s, fundamental con- have acted to form it and precisely when exca- fi ndings obtained from much earlier research cepts such as fl uvialism, antecedence, and vation commenced. The canyon’s tremendous efforts. Many seminal conclusions from the superposition were invoked to explain the size along with its striking color and texture are nineteenth and twentieth centuries serve to development of the Colorado River. Early unequaled on Earth. Results from a combina- constrain modern studies about how the Colo- proposals envisioned the Colorado River tion of fi ve independent factors have worked rado River or its ancestors helped to carve the as “old” relative to the surrounding land- together to create this unique landscape: (1) a Grand Canyon. For example, the Muddy Creek scape. Challenges to antecedence were slow thick stack of sedimentary rock; (2) variably and constraint at the foot of the Grand Wash Cliffs to emerge, and it remained the most viable vividly colored strata; (3) epeirogenic uplift that showed that the modern Colorado River could theory into the early twentieth century. At raised the rocks without signifi cant deforma- not have existed before ca. 6 Ma (Longwell, that time two distinct periods (and styles) tion; (4) deep dissection by a continental-scale 1946; Lucchitta, 1966), while other studies far- of erosion were proposed: a plateau cycle river system; and (5) location within a modern ther upstream in the state of Colorado suggested with lateral stripping of strata and a canyon arid belt where rocks are not encumbered by that the river there might be as old as ca. 20 Ma cycle of deep, vertical dissection. Beginning vegetation or extreme chemical weathering. (Hunt, 1956). Modern workers use these base- in the 1930s, newer ideas proposed that the Remove any one of these fi ve factors, and the line fi ndings to help focus their research efforts Colorado River was “young,” having been Grand Canyon, as we know it, would not exist to resolve this still intractable problem. This integrated by sequential basin spillover, the (Ranney, 2012). paper presents a summary of the evolution of timing of which was constrained by interior In spite of the intrigue, mystery, and enigmas geologic thinking on the origin of Grand Can- basin deposits lying across the mouth of the that remain, much is known about the canyon’s yon, based on work before 2000. It is hoped that Grand Canyon at the Grand Wash Cliffs (the development and formation, resulting from the perspectives from the nineteenth and twen- Muddy Creek constraint). The fi eld entered more than 150 years of scientifi c research (Karl- tieth centuries can be a valuable reference point a period of uncertainty related to the con- strom et al., 2012). Numerous workers have for future workers who will attempt to unravel fl icting evidence for an old (Paleogene) river sought to understand the origin of the Grand the mysteries that remain. upstream from the Grand Canyon versus a Canyon, and one of the basic underpinnings young (Neogene) river at Grand Wash Cliffs. of this understanding is that the canyon owes PRE-SCIENTIFIC BACKGROUND Results from a symposium convened in 1964 its existence wholly to the history and evolu- offered a solution with a poly-phase his- tion of the Colorado River (Newberry, 1861) or Native peoples of the American Southwest tory for the Colorado River. The poly-phase its ancestors. When geologists fi rst gazed into likely discovered the Grand Canyon shortly theory suggested that the river formed in a the Grand Canyon, they saw evidence for the after the continent was colonized some 13,000 complex manner by the integration of two intimate relationship between the canyon land- years ago. These natives left no written record separate drainages, although some aspects scape and the Colorado River. From this initial of their impressions but did impart oral legends became untenable. Efforts to resolve out- observation, a good, if incomplete, view of the that were the fi rst attempts by humans to com- standing dilemmas from 1964, such as the evolution of both the river and the canyon had prehend the vast scale and origin of the canyon. ages of the Colorado River and the Grand been achieved. By the end of the twentieth cen- Passed down through the millennia to today’s Canyon, have ultimately led to a modern tury, geologists were poised to move beyond the modern tribes, these legends are non-scientifi c resurgence in research. technical and theoretical limitations inherited but demonstrate nevertheless how humans in *Email: [email protected] Geosphere; April 2014; v. 10; no. 2; p. 233–242; doi:10.1130/GES00960.1; 5 fi gures. Received 12 July 2013 ♦ Revision received 4 January 2014 ♦ Accepted 5 February 2014 ♦ Published online 17 March 2014 For permission to copy, contact [email protected] 233 © 2014 Geological Society of America Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/10/2/233/3332552/233.pdf by guest on 01 October 2021 Ranney pre-scientifi c North America sought to explain ply of troops engaged in the Mormon campaign. opposite sides of the deepest chasm showed per- such an immense landform. The legends only Ives wrote confl icting statements about his fect correspondence of stratifi cation . .” (Fig. coincidentally mirror later scientifi c theo- reaction to seeing such a deeply dissected and 1). This meant to him that the Colorado River ries, but in some instances they invoke a close parched landscape, but he can be considered as was not merely following a preexisting rift or genetic association between the Colorado River one of the last persons from the pre-scientifi c fi ssure but that it was the instrumental agent and the canyon. period to view the canyon in a mostly negative that created the canyon (Newberry, 1861, Part People of European descent fi rst saw the way. He referred to the canyon as “valueless” III, p. 46). He made the seminal observation Grand Canyon in 1541 when members of the and stated that it would be “forever unvisited about Grand Canyon, still the basis of all mod- Coronado Expedition sought a way to resupply and undisturbed” (Ives, 1861, Part 1, p. 110). ern studies that “the high and perpendicular their expedition by river from the Gulf of Cali- His response to the landscape reveals how some walls belong to a vast system of erosion, and are fornia. Sparse but illuminating written accounts people, even today, can react to the southwest- wholly due to the action of water” (Newberry, show that the Spaniards were ill-prepared to ern landscape when a geologic perspective is 1861, Part III, p. 45). This concept, known as comprehend the vast excavated space or sig- lacking. The few positive comments that Ives fl uvialism, was increasingly being applied in nifi cance of the landscape laid out before them. penned about the Grand Canyon may have orig- the mid-nineteenth century to refute the anti- Descriptive passages assert that the canyon was inated from the opposing reactions expressed by quated views of diluvialism. To this day, New- larger than fi rst conceived and that some boul- his saddle-mate and geologist colleague, New- berry’s fl uvialism remains the principal datum ders within it were “bigger than the great tower berry, upon viewing the same landscape. for how the Grand Canyon was formed. The of Seville” (Winship, 1922, p. 36). In the year Newberry was trained in medicine but was central idea that the Colorado River is respon- 1541, this tower was 282 feet high, less than the also schooled in natural sciences, especially sible for the carving of the Grand Canyon has thickness of the Kaibab Limestone stratum that geology and botany. As the expedition explored never seriously been challenged, although some caps the rim of the canyon. Disinterested and Grand Canyon, Newberry came to recognize a workers have recently invoked signifi cant exca- perhaps dispirited, no Spaniard would revisit critical relationship between the canyon and the vating by ancient predecessors of the modern Grand Canyon for 235 years. Colorado River: “…examining with all possible river (Flowers et al., 2008; Wernicke, 2011). This initial encounter between Europeans care the structure of the great cañons which In 1859, Newberry was employed as geolo- and the American Southwest initiated a long we entered, I everywhere found evidence of the gist on a second exploration journey called the period in which non-geologists interacted with exclusive action of water in their formation. The San Juan Exploring Expedition, led by Captain the landscape in mostly negative ways. For 320 years, numerous conquistadors, fur trap- pers, miners, and explorers came to the Grand Canyon with the hope of fi nding precious met- als, beaver pelts, lost souls, or to attain fame.
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