ROCKY MOUNTAIN SECfION .. S.E.P.M. CENOZOIC PALEOGEOGRAPHY OF WEST-CENTRAL UNITED STATES R.M . FLORES AND SOS. KAPLAN. EDITORS DENVER. COLORADO 1985 CENOZOIC PALEOGEOGRAPHY OF ARIZONA
Dale Nations Jan C. Wilt Richard H. Hevly Geology Department Consulting Geologist Biology Department tlorthern Ari zona Un i vers ity 3035 S. Shiela Northern Arizona University Flagstaff, AZ 86011 Tucson, AZ 85746 Flagstaff, AZ 86011
ABSTRACT In southern and western Arizona, Paleocene volcanic rocks are common, but no sediments of The Cenozoic paleogeography of Arizona is in Paleocene or Eo~ene age are known. Eocene volcanic terpreted from the seQimentary and volcanic strata rocks are rare in Arizona. Oligocene sediments and throughout the state. Paleogeographic features such volcanics occur in uplifted fault blocks of as mountains, plateaus, depositional basins, and present-day mountain ranges and in the subsurface of drainage systems are interpreted within the several sedimentary basins. These sedimentary rocks constraints of known structural features of laramide include coarse-grained, angular, poorly-sorted age, and in some places, the depth of erosion into redbeds that were deposited as fanglomerates the pre-Cenozoi c basement rocks. The absence of adjacent to local highs that were formed by laramide Paleocene sediments and the pronounced unconformity and middle Tertiary orogenesis. Fine-grained beneath Cenozoic rocks attests to an epeirogenic clastic, carbonate, a~d evaporite sediments are uplift of the region during the laramide orogeny. intercalated with those basin margin fanglomerates This uplift was most pronounced in central and in some areas, suggesting deposition in the center western Ari zona. The resultant eros i on produced a of closed basins. late Oligocene-Early Miocene beveled surface that cut deeply into Precambrian strata include fanglomerates and fine-grained roc ks of centra 1 Ari zona and removed much of the fluvial and lacustrine sediments with clasts and Mesozoic cover of the future Colorado Plateau. flows of silicic tc intermediate volcanic rocks Paleocene drainage systems transported the sediments reflecting the onset of extensive volcanism and of that age northward to the Uinta basin of Utah and structural warping of the mid-Tertiary orogeny. eastward to the San Juan basin of New Mexico, along Middle Miocene sediments and volcanics were affected the downwarped Coconino and Baca-Eager basins that by low-angle normal faulting, subsequent folding, were formed as a syn~lina' trend adjacent to the and unroofing of metamorphic core complexes. Mogollon Highlands. The northward regional drainage was controlled by the Sevier foreland basin in Utah. late Miocene-Pleistocene sedimentary and vol canic rocks are generally confined to basins that During the Paleocene and Eocene, compressional coincide with modern valleys throughout the state. rJeformati on of the Larami de orogeny upl i fted the late Miocene to Holocene strata in the Basin and Rocky Mountains, which interrupted eastward Range Province were deposited in normal-fault drainages and converted the Colorado Plateau to a bounded extensional basins initiated by the Basin very large internally drained basin during the and Range disturbance. In southern Arizona b~sin Eocene. It was bounded on the west by the Sevi er deposits typically exhibit gradation from marglnal thrust belt, on the north by the Uinta uplift, on fanglomerates to fine-grained clastic, carbonate, the south by the Mogollon Highlands and by the Rocky and evaporite sediments in the centers of closed Mountains to the east. That same deformation basins. By late Miocene time, the integrated created numerous north-trending anticlinal and drainage system of the Gila, Salt, Verde and otr.u synclinal folds, thereby converting the Colorado tributaries to the lower Colorado River had Plateau into a syncl inorium. These interior folds developed, and dissection of the higher basins controlled the development of drainage patterns (e.g., Chino Valley, Verde, Tonto, and Safford throughout the remainder of the Tertiary. bas i ns) had begun in response to the lowered base level established by the opening of the Gulf of Eocene strata on the southern Colorado Plateau California in the late Miocene. The are typically coarse-grained, we1l-sorted Pl i ocene-Pl ei stocene paleogeography of Ari zona was conglomerates, with cl asts of Precambri an ·i gneous similar to present topography. except fo~ a !ew and metamorphic rock whose provenance was the Holocene volcanic mountains and lncreased dlssectlon Mogollon Highlands of central and southern Arizona. of eroded stream valleys. These strata were deposited in elongate synclinal and erosional valleys north of the Mogollon I NTRODUCTl ON Highlands by streams that fiowed northward into the early Tertiary Coconino and Baca-Eager basins on the Nature of the Stratigraphic Record southern margin of the Colorado Plateau. The coarse clastics were deposited at the southern margins, and locations of sedimentary basins, drainage fine-grained clastic and carbonate sediments systems, and source areas shown on the maps (Figs. accumulated in the more distal, northern parts of 2- 7) in thi s paper have been i n~erpreted !rom the basins. Drainage patterns were controlled by scattered occurrences of Tertlarv ma 1'1 ne, laramide anticlinal uplifts and synclines. lacustrine, and fluvial sediments and their
335 D. NATIONS, J.e. WILT, AND R.H. HEVLY
relationships to Laramid~ and subsequent structural differently to Larar;]ide and Tertic.ry tectonism, and topographic features. The record varies from presumably dup to differences in thickness and sparse occurrences of Eocene and Oligocene comp-osition of the crust, which, resulted in sedimentary rocks to common and l'le ll-preserved different types of Laramide structural features and Miocene and Pliocen~ deposits. Chronological Cenozoic sedimentary basins, control is also quite variable and is based on isotopic dating of int.ercalated volcanics and The Lnra~ide structurE'S on the relatively paleontological correlations (Fig. 1). stable Colorado PlatEau were tormed by subtle structural warping or monocline grol'lth, which The areal extent of Paleogene basins and controlled the development of drainage systeTl's and drainage systems is highly interpretiv~ because the subsequent erosion. Laramide uplifts disrupted the depos i ts have been subsequertly deformed by mi ddl e pre-Laramide reqional dY'ainage patterns that flowed Miocene tectonic events and by younger Basin and eastward from the Sevier thrust belt in Nevada and Range extens i ona 1 tectoni cs. They also have been northward from the Mogollon Highlands of central largely removed by erosion or covered by younger Ari z('na (Cool ey and Davi dson, 1963), into the depos its. The Paleogene depos its of southern and coastal plain and the Cretaceous \·,t!$t~rn Interior western Arizona are found only in I:xposed fault Seaway that occupi ed northern Ari"' Jna. Structural blocks of present-day mountain ranges or in deeper features in the Transition Zone arc nasin and Range portions of wells drilled beneath the Neogene Province of southern and westerI' Arizona were formed sedimentary and volcanic fill of modern basins. by more i ntpnse structura 1 deformati on. There, Some Paleogene units are precisely dated by isotopic Cenozoic deformation began with Laramide regional ages on interbedded volcanics or by mammal fossils. uplift, plutonism, volcanism and thrusting; The ages of other Paleogene rocks are loosely continued with mid-Tertiary folding, faulting and constrained by the unconformable relationships with volcanism; and culminated with late-Tertiary older rocks and by degree of structural deformation. extensional tectonics. As a result of these differences in structural deformation, only a few Source areas for Paleogene strata are poorly Cenozoic sedimentary basins were formed on the known because outcrops are limited and because very Colorado Plateau, while numerous Cenozoic basins few detailed measured sections, facies analyses, or were formed in the Transition Zone and southern and paleogE'ographic analyses have been done. The western Arizona. coarse-grained fluvial strata were probably derived from adjacent highlands that are not clearly The locations of Cenozoic sedimentary deposits defi nab 1e because they were subsequently di srupted (some with intercalated volcanics) arE' shown on a by middle and late Tertiary t.ectonic events. Many series of paleogeographic maps (Figs. 2-7) that of the Tertiary units, particularly those of depict successive time intervals. The precise ages Paleogene age, consist of texturally immature of many of these units are not known, and many of alluvial fan deposits that accumulated adjacent to them span more than one Tertiary epoch. The active fault scarps or near elevated areas that were sedimentary basins were formed and defined by formed by volcanism, plutonism, or tectonism. episodes of crustal deformation and erosion, Fine-grained clastic and chemical deposits are also including the Laramide orogeny (Late Cretaceous to present, although facies relationships are difficult late Eocene); mid-Tertiary orogeny (late Eocene to to analyze because of the smell lateral extent of middle Miocene); and the Basin and Ranqe disturbance preserved outcrops. (middle Miocene the present).
Source areas for Neogene strata are more The stratigraphic units that were depOSited in obvious because the facies relationships are hasins formed by these tectonic events tend to span consistent with present topography. Fine-grained the times ot deformation, and are not limited to the clastic, biogenic, and/or chemical strata typically epochs of the standard Cenozcic time scale. For occur in the central parts of the basins and grade this reason, the mapped intervals used herein laterally to fanglomerates at the basin margins. reflect the times of basin formation, i.e., Paleo Most of the fine-grained materials of the cene-mi ddl e Eocene (Fi g. 3) ,late Eocene-mi ddl e basin-center facies are typically buried beneath 01 i gocene (Fi g. 4), 1 ate 01 i gocene-mi ddl e Mi ocene younger basin fill sediments and are not commonly (Fig. 5), late Miocene to early Pliocene (Fig. 6) exposed. Some basins have bE'pn dissected by and late Pliocene-Recent (Fig. 7) rather than epoch Quaternary erosion, thus exposing the earlier boundaries. Volcanic rocks from many stratigraphic basin-center facies. A few closed basins remain un units have been dated and thei rage is used to dissected. relate the stratigraphic units to epoch subdivisions of the standard Cenozoic time scale of Palmer Regional Setting (1983) (Fig. 1).
Arizona is dividE'd into two distinct Age of Sedimentary Rocks structural-physiographic provinces--the Colorado Plateau Province to the north and the Basin and IsotopiC dating of intercalated volcanic rocks Ranqe Province to the south, with a narrow is the most useful techl"ique for dating Cenozoic Transition Zone in between. While the whole state sedimentary rocks. Numerous dates published during was affected by epeirogenic uplift in late tt> .. past fevi yrars, have provided the chronologic Cretaceous time, these two regions responded contro 1 neceSSet"y for our i nterprptat i on of the
336 CENOZOIC PALEOGEOGRAPHY, ARIZONA
CHRONOLOGY OF TERTIARY SEDI MENTARY UNITS COLORADO ITRANSITION BASIN ' AND RANGE MY PLATEAU ZONE NORTHWEST SOUTHWEST SOUTHEAST
'0 :r < w '0 :IJ w » 0 w -< ;>; r :IJ :r '0 r 0 :IJ ..... :r z en ~ 0 s: !!? z ::r - I» :D s: :r 0 c: ~ c'i n' g .. ow w : :; .0' .. ~ ~ 0' ii ~ c: ~ to ~ ~ ~ ~ .g ~ :; c: c. £ _' 7C C. = .. 3 CD 7i' :r 0 c: '0 i ~ ~ ~ '0 ~ a ~ ii' 3 .. CD o ~ ~ 3 CD a C. r en = CD .. :IJ lS :IJ iD c. .. CD :; 41 '< .. CD .. ~ en :r 3 '< g '< :; a 0 7i' i iii ~ !!. a ~ < ~ .. gg' 1.6 I b PL IOCENE , * I I I 53 • ! * , *' *' f I t I ' l 10 ? I 111 i I •I ! + I . I ? . I MIOCENE .j. I I + + I I I . I . I I I I I I I I I ? ? ? I I 20 I I I I I I I I I I I I ? I ? % . I ? I I l' I . I I . I ? I I l' 1 I I •I 1 OLIGOCENE 30 I ~ I *I I I ? I I I I I I I .... I ? I I 40 I • + + t I I EOCENE I I r I 150 I *' I I '. . I I PALEOCENE rs O Figure 1: Correlation of selected Tertiary stratigraphic units and basin-fill sequences in Arizona. The shifting of depocenters through the Tertiary is illustrated by Eocene deposition in the Colorado Plateau area, Oligocene deposition in southern Arizona and late Miocene-Pliocene deposition across the state (modified from Nations and others, 1982). o - isotopic date; * - paleontological age; + - lithologic correlation. EXPLANATION OF SYMBOLS ON ~lAPS 2 - 6 #}-ToPOgraPhiC and structural Outcrop areas Uplift axis ~ highs 4 • ~ Topographic and structural • Metamorphic core complexes Syncl ine axis L/"" lows ' ~ Faults; bar & ball on ~ down th rown side o r·10noc 1i ne .y o o Erosional limits of o Paleozoic strata ~ Inferred drainages o 0 Thrust fault Uplifts: D=Defiance;M=Monument; K=Kaibab; CC=Circle Cliffs; Z=Zuni; S=Sedona arch; CM=Chuska Mts. 337 D. NATIONS, J.C. WILT, AND R.H. HEVLY \ \ \ \ ,, .... -.... ----,, .' , '\ 1110 , .... _-- ..... ",\"'" (;'O/"I \. ______------:-:-;;: <"Oll; " •• ,------,.,.' , '...... ------_/ \y;~\\\\ 1 o1e HIGHLcWDS : ",,' ...... Figure 2: Late Cretaceous to Eocene tectonic features of the Colorado Plateau synclinorium. The peripheral up lifts (Sevier thrust belt, Mogollon Highlands, Rocky Mountains and tne Uinta uplift), were formed by thrusting and/or vertical upl ift by compression from the west and south. Foreland downwarping occurred in a concentric pattern, inside the uplifted periphery. The northeasterly compression warped the interior of the area into several large northwest-southeast anticlines and synclines, tnat constrained the development of drainage patterns throughout the Cenozoic. Eocene depositional basins are indicated by the shaded pattern and are restricted to the peripheral downwarps. Oligocene sediments are absent fro~ the synclinorium, probably indicating uplift at that time with drainage tOl-lards the Oligocene depositional area east of the Rocky i~tns. in Colorado, ~Jyoming and r~ebraska. 338 CENOZOIC PALEOGEOGRAPHY, ARIZONA 115" 114" 110· 109· I I I I 37° - 35" - BASIN---- 32" - o 50 100 mi , , , 1 , , I Figure 3: Paleocene to Middle Eocene Paleogeography of Arizona. The• dominant physiogra~hic features at tnis time are the Mogollon Highlands and the Sevier thrust belt. These areas were broadly uplifted and being eroded during tne Paleocene. The Colorado Plateau area was raised slightly above sea level, tilted to ,the northeast and eroded to a beveled pediment surface by streams flowing into the Sevier foreland basin and the St. Johns Sag to the Uinta basin and the San Juan basin. By Eocene time, continued warping of the crust created interruptions of the regional drainage and additional ponding of drainage in the Coconino and Baca-~agar basins, and deposition of coarse materials ("Rim gravels") on the pediment surface nearer the rising Mogollon Highlands. The absence of Paleocene or ~ocene sediments from southern and central Arizona indicates that those areas were high enough to cause erosion and no deposition. Other features shmm include the "Rim gravels," Laramide monoclines and uplifts, and various drainages inferred in northwestern Arizona. 339 D. NATIONS, J.e. WILT, AND R.H. HEVLY 115' 114' 113' 112' 110' 109' I I I I I I 37' - 36" - 35' - 0 GO t.. ~t.. 0 34" - Iy/ . COCHISE LOW o 50 100 mi I ! I , • I Figure 4: Late Eocene to middle Oligocene Paleogeography. By late Eocene, continued uplift had raised the Colorado Plateau synclinorium enough to initiate drainage and erosion of the Coconino basin and cause the depocenter of the Uinta basin to shift northward. The Baca-Eager basin was not drained because it was contained by the Sedona arch, Kaibab uplift, Sierra uplift and the cuesta of r~esozoic strata to the north. During this time the whole Colorado Plateau was upl ifted to approximately 1000 m (3000 feet) and eroded, with sediments transported predominantly northward. In southern Arizona, sediments of this age began to accumulate in northwest-trending depocenters in broad downwarped basins that were separated by elongate upwarps. 340 CENOZOIC PALEOGEOGRAPHY, ARIZONA 115° 114" 113" 0 111 110· I I I 109" I I 37" - 0 36 - 35° - 34" - 32° - COCHISE 9 50 100 mi ~~~~'~I~'~~~'~I Fi gure 5: Late 01 i gocene to Mi ddl e t~i ocene Paleogeography, Conti nued up 1i ft and eros i on of the Colorado Pl ateau occurred with drainage centered in the Kaiparowits-Black Mesa downwarp and the Sevier foreland basin, and northeastward through the Uinta-Green River basins. Eocene sediments were eroded from the Coconino and Baca-Eager basins. The ancestral Little Colorado River erodes the ancestral Bidahochi basin by down-dip retreat of escarpment around the Black t4esa downwarp, The ancestral Mogollon Rim is forr.led by scarp retreat, down-dip from the Mogollon Highlands, with reworked "Rim gravels" and other coarse sediments accumulating along its base. Depocenters in southern Arizona expanding due to continued warping, with accumulation of coarse sediments derived from Mogollon Highlands and unroofing of rising metamorphic core complexes. 341 D. NATIONS, J.C. WILT, AND R.H. HEVL Y 115· 114" 113" 0 112' III" 109 I I I I I I 37' - 32· - o 50 100 mi ( •••• I •••• I Figure 6: Late Miocene to Middle Pliocene Paleogeography. Drainage reversals on the Colorado Plateau were caused by south\~ard tilting, with depocenters shifting to the Bidahochi and the t·luddy Creek basins. The northeastward drainage from the Kaibab uplift and the Paria Plateau and other, previously north ~/ard flowing streams, were deflected southward along the KaiparO\~its-Black Mesa downwarp, into the Uidahochi basin. The previously northward flowing stream west of the Kaibab uplift was reversed and flowed southwestward into the Huddy Creek basin that was formed by down-to-the-west normal faults. By middle Pl iocene the lo\~er Colorado River erodf'd its channel across the Kaibab upl ift, captured the Bidahochi basin drainages and completed the modern integrated Colorado River drainage system. The onset of Basin and Range faulting at 13-12 Ma, created numerous graben-type basins throughout the Basin and Range Province of Arizona. Drainage systems were disrupted and created many restricted basins where fluvial, volcanic, and lacustrine sediments were deposited. tiy late t~iocene the marine Gulf of Cal ifornia embayment extended northward, to or near the I·iuddy Creek basin. 342 CENOZOIC PALEOGEOGRAPHY, ARIZONA Figure 7: L-a te Pl i ocene to Recent. Phys i ographi c di agram with recent topographi c features, major drainages and major citi es (from Smil ey and others. 1984). 343 D. NATIONS, J.e. WILT, AND R.H. HEVLY Cenozoic paleogeography of Arizona. Because (1 atest Eocene), througr the 01 i gOl-er!e, to about 13 Cenozoi c vol cani sm and tectoni sm is di scussed by Ma (middle Miocene) in southern and western Arizona. several other authors cited in this paper, the During the mid-Tertiary oroge.ny crustal heat '. " obviously important volcanic stratigraphy is not metamorphism. melting, and tectonism resulted in the summari zed here. Many of the dates on these formation of granitic plutons, associated volcanic rocks were published and/or summarized by intermediate to silicic volcanic rocks, and uplift Keith (1977); Eberly and Stanley (1978); Marvin and of metamorphic core complexes. The resulting others (1978); Peirce and others (1979); Shafiqullah crusta 1 di sturbances created 1oca 1 el eva ted areas and others (1978, 1980); Wilt and Scarborough and adJacent bas i ns in southern Ari zona that were (1981); and Otton (1982). Paleontologic and filled with predominantly coarse continental wagnetic-reversal chronologies have been used to sediments. The sizes and shapes of thesE basins supplement isotopic dates (Lindsay and Tessman, hove been obscured by later events, but their 1974; Lindsay. 1978: Lindsay and others, 1984; distribution and the presence of intercalated Nations and Landye, 1984) (Fig. 1). fine-grained sediments suggests that there were interconnected areas of internal-drainage (Wilt and TECTONIC SETTING Scarborough, 1981; Pei rce, 1984b). Chaoti c breccias, fang10merates and low-angle detachment The Tertiary history of Arizona was dominated faults are common in areas adjacent to the by three major tectonic events: the Laramide metamorphic core complexes, suggesting a process of orogeny, mid-Tertiary orogeny and Basin and Range unroofing by erosion and gravity gliding into disturbance. General age ranges of Late Cretaceous adjacent low areas. The absence of Oligocene - middle Eocene (Laramide orogeny), late Eocene - sediments and retreat northward of middle and late middle Miocene (mid-Tertiary orogeny), and middle Eocene deposits in the Uinta basin suggests that the Miocene-present (Basin and Range disturbance) are Plateau was also uplifted enough during the commonly used. However, the exact beginning and 01 i gocene to create externa 1 dra i nage through the ending age dates vary from place to place because Uinta-Green River and Washakie basins, through the these orogenies were time-transgressive. In Rocky Mountains to the Denver basin and Great Plains general, the time interval for the Laramide orogeny where extensive deposits of Oligocene sediments are was earlier in the west and later in the east (Coney found (Fig. 2). ~nd Reynolds, 1977). The time interval for the mid-Tertiary orogeny was earlier in the southeast The third event, the Basin and Range . and 1ater in the northwest (Wi lt and Scarborough, disturbance of Scarborough and Peirce (1978) lasted 1981). Therefore, the age ranges used in this paper from 13 Ma (middle Miocene) to the present, although are general ranges rather than ebsolute ages. active tectonism was probably confined to the first few million years of that period in southern Arizona The Laramide orogeny of Coney (1972) lasted (Menges and McFadden, 1981). Thi s event was from about 85 Ma (middle Late Cretaceous) to about characterized by crustal extension, basaltic 43 Ma (late middle Eocene) and resulted in a broad volcanism, and high-angle normal faulting, that epeirogenic upl ift of the entire state. The resulted in the formation of numerous grabens with southern and central parts of the state were internal drainage. For a more detailed discussion subjected to compressional stresses, resulting in and documentation of Tertiary tectonic events, see extensive thrust faulting, silicic plutonism and Eberly and Stanley (1978); Shafiqullah and others, volcanism, and upl ift. The Colorado Plateau area 1980; Damon and others (1984). was raised to a lesser degree as part of the epeirogenic uplift and became an eroded pediment surface, gently sloping northward toward the early PALEOBIOGEOGRAPHY Tertiary lake basins of Utah, New ~exico, and Colorado (Shafiqullah and others, 1980; Epis and The Tertiary basins of Arizona and adjoining Chapin, 1975). The Plateau was bounded by highlands areas contain a variety of plant and animal fossils. around its periphery, including the Sevier thrust Comparison of these fossils to their nearest living belt to the west, the Mogollon Highlands to the . equivalents in modern communities permits south, the Rocky Mountains to the east, and the uniformitarian reconstruction of Tertiary Uinta uplift to the north which converted it into a paleoenvironments, including inferences of climate, broad interiorly-drained basin. The Coconino and elevation, and drainage patterns. The Paleogene Bace-Eager bas ins were formed by downwarpi ng and portion of this reconstruction must be based on data eros i on along the southern rna rg i n of the i ntpri or from adjacent areas since there is very little basin and adjacent to the Mogollon Highlands. These fossil data from rocks of that age in Arizona. The basins were filled with fluvial and lacustrine Neogene fossil record is qui te good. with numerous sediments during the Eocene, most of which were occurrences of fossil plants, invertebrates and later removed by erosion during the Oligocene. The vertebrates known across the state (Nations and interior of the Plateau was warped into several Landye, 1984). dominantly north-trending anticl ines and syncl ines that influenced the subsequent development of Paleobotany and Paleogeography drainage patterns within the Plateau (Fig. 2). The fossil record of Cenozoic plants indicates The second event, the mi d-Terti ary orogeny of that many modern families and genera of angiosperms Eberl.v and Stanley (1978) lasted from about 38 Ma and gymnosperms have stratigraphic ranges that 344 CENOZOIC PALEOGEOGRAPHY, ARIZONA extend back to the early Cenozoic, permitting Tertiary sediments accumulated. An additional basin interpretations of paleoenvironments. There is herein named the Coconino basin is defined as the increasing similarity of these floras to modern downwarped portion of the Coconino Plateau in which communities, from early Cenozoic to the present. Early Eocene fl uvi a 1 and 1acustri ne sediments were deposited (Young, 1982; Young and Hartman, 1984). Modern plant communities are limited to narrow They were formed adjacent to the large scale or climatic ranges that are largely controlled by regional uplifts (Sevier, r~ogollon, San Juan, elevation above sea level. The composition of plant Sierra, etc.) that bounded the Colorado Plateau communities of the past are known from fossil synclinorium (Fig. 2). Other downwarps were formed records of pollen or other plant rell'a i ns, and the in the central part of the future Plateau, e.g., climatic conditions that existed at the time and Kaiparowits, Black Mesa, and Henry basins. These location of their deposition C1:1'1 be inferred. The subordinate basins were adjacent to upl ifts such as variation of fossil plant communities that are the Kaibab, Echo Cliffs, Monument and Defiance preserved in rocks of the same age in adjoining uplifts (Hunt, 1956; Kelley, 1959; Chapin and locations, can be interpreted as indicating , Cather, 1981) (Fi g. 1). No sedimentary units of differences in paleocl imates and/or elevations of Paleocene age have been definitely identified in the depositional sites. Based on the interpret northern Arizona. The absence of Paleocene ation of uniform Neogene climate (Wolfe, 1978), the sediments on the Colorado Plateau of northern occurrence of plant communities with different Arizona suggests that the area was being eroded with temperature tolerances in sediments of different the derived sediments being transported into the ages in the same area, are believed to indicate Paleocene basins of Lake Flagstaff in southwestern changing elevations of the depositional basin Utah and the San Juan bas in of northwestern New (Axelrod and Bailey, 1976). This makes the fossil Mexico (Hunt, 1956). It is probable that the plant record a valuable tool for interpreting removal of all f4esozoic strata from the Coconino paleoclimates and related elevation changes through Plateau, where early Eocene sediments were the Cenozoic. deposited, (Young, 198?) and the erosion of post-Triassic sediments from the Eocene-Oligocene LARAMIDE (85-43 Ma) PALEOGEOGRAPHY Baca basin area (Chapin and Cather, 1981), was accomplished by this Paleocene erosion. The Paleocene (66 .4-57.8 Ma) drainage courses probably followed the synclinal axes or strike valleys that were developed parallel The shallow Cretaceous seas which had to the uplifted Sevier thrust belt to the west and previously occupied the northeastern and the Mogollon Highlands to the south (Figs. ? and 3). southeastern portions of Arizona and adjacent areas (Enos, 1983; Molenaar, 1983) had receded by early Paleocene Paleobiogeography Tertiary time as a result of the epeirogenic uplift of the region during the Laramide orogeny At the beginning of the Laramide orogeny in (Dickinson, 1981; Haxel and others, 1984). The ' late Cretaceous time, much of Arizona was near or tectonically stable Mogollon Highlands of central below sea level (Enos, 1983; Molenaar, 1983). As and northwestern Arizona was broadly upl ifted and the area was elevated above sea level, it was the Paleozoic and Mesozoic strata of northern colonized by humid, warm-temperate to subtropical Arizona were tilted gently to the north. The mesophytic forests. Palynological studies of the previously established northward flowing streams Paleocene Ojo Alamo and Nacimiento formations of the beveled the strata to a gently sloping pediment and San Juan basin by Anderson (1960) documented a began transporting debris from the exposed diverse assemblage of spores and pollen of taxa Precambrian and Paleozoic rocks across the beveled whose modern phytogeography permits i nterpretati ons surface. The southern edge of the mountainous of the adjacent Paleocene topography. Fossil pollen reg; on south of the Mogo 11 on Hi ghl ands formed as a of the gymnosperms Podocarpus and Taxodium in those result of compressive deformation, plutonism and formations, indicate significant topographic relief volcanism, in a thrust-faulted terrain called the in the source areas of those sediments. Podocarpus Maricopa thrust belt. In the southeastern portion , lives today in upland areas of southern Mexico and of the state, silicic plutonic and volcanic rocks of Central America, while Taxodium is typically found Paleocene age include the Gringo Gulch volcanics in wet, coastal lowlands of Mexico and the (60.4 Ma), Beehive Peak rhyolite (60.5 Ma), Ruby southeastern United States. Angiosperm pollen Star granodiorite (67-53 Ma) and Patagonia reported by Anderson (1960) includes subtropical granodiorite (64-58 Ma) (Keith, 1977). No Paleocene taxa such as the Bombacaceae and Sapindaceae, which age sedimentary rocks are known in southern Arizona, probably grew in low-lying areas near th~ basin which also suggests that the area was elevated and margin; but also includes more temperate taxa such undergoing erosion, with no low areas in which as maple (Acer), alder (Alnus), willow (Salix), oak deposition could occur-. ( uercus) erm-(Ulmus), tupelo (Nyssa) ana-basswood ( i i a , that must have grown in the adj acent San In the northern portion of the state and Juan-- Mountains, and other structurally ~nd adjacent parts of the Plateau, faulting and folding topographically high areas such as the Monument, of the Laramide orogeny produced broad downwarps Defiance and Zuni uplifts where more temperate such as the Sevier foreland basin, Uinta basin, San climates existed (Fig. 2). Juan basin (Hamilton, 1978), and the Baca-Eager basin (Chapin and Cather, 1981), ~ n which early 345 D. NATIONS, J.e. WILT, AND R.H. HEVLY . The similarity of the raleocene flora in the The E(J eene Eagar Formation crops out in the ' ~an Juan basin to that in the Paleocene Silverado Springerville area (Fig. 4). It includes basal Formation of ! luthwestern California (Axelrod, 1979; gravels and fine-grained sediments equivalent to the Gaponoff, 1984) sU9gests that the former was also Eocene Datil Formation of southwestern New ~'Exico. depos ited very near sea 1eve 1 and that the Pl ateau These sediments were depos itpd in the Baca bas i n area was not very hi gh above sea 1eve 1 duri ng the which was localized in a downwarped area the St. Pal~ncene. The forests of gymnosperms and both Johns Sag of Kelley (1955) and eroded down to ever ~ reen and deciduous angiosperms persisted Triassic strata during the late Cretaceous and throJgh the Paleocene into the Eocene (Axelrod and Paleocene by an eastward flowing stream system. The BailEY, 1976; Leopold and MacGinitie, 1972). initiation of sedimentation in the Saca Basin was caused by structural damming of the easterly Eocene (57.8-36.6 Ma) paleodrainage by the Sierra uplift (Chapin and Cather, 1901). They appear to be the fine-grained Northern Arizona equivalent of the "Rim gravels" of the Show Low area (Lucas and Ingersoll, 1981). Tne Coconino and Eocene "Rim gravels" of Peirce and others Baca-Eager basins appear to have been separated in (1979) crop out at several places along the Mogollon central Arizona, possibly by renewed uplif~ of the Pim and on the Coconino and Shivwits plateaus (Fig. Sedona arch of Blakey (1980). 3.7). These gravels are ~/ell-rounded, well-sorted, fluvial deposits that were transported from a Southern Arizona s ou~herl y source and depos ited on Cretaceous. Tri ;; SSlC or f'erl.lian rocks that were exposed on the No records of Eocene age sediments have been Paleocene pediment, downslope from the Mogollon described for southern Arizona. Highlands. They are now preserved at high elevations along the southern edge of the Plateau Eocene Paleobiogeography bnd are interpreted as remnants of a well-developed stream system that was flowing across the Paleocene No Eocene pollen records are known in Arizona, pediment from central and northwestern Arizona but the Eocene Green River and associated formations northward toward the Eocene Coconino and Baca-Eager of Utah and Co lorado i ncl ude sediments transported basins on the present southern edge of the Colorado by streams flowing northward from Arizona. These Plateau (Fig. 3). They consist of clasts of formations contain pollen of plant taxa which 1 ive Precambrian sedimentary. metamorphic and plutonic today in envi ronments rangi ng from cool temperate rocks and lower Paleozoic limestones and cherts that uplands to subtropical lowlands (Newman, 1983). were derived from Precambrian and Paleozoic terranes Eocene pollen indicative of warm temperate to in the Mogollon Highlands of central Arizona. The subtropical lowland environments includes presence of the" Rim gravels" on the high plateaus Cycadaceae, Taxodiaceae, Palmae, Rutaceae, irdicates that the streams that carried these Malvaceae, Euphorbiaceae, Bombacaceae, Sapindaceae sediments predated the development of the Mogollon and juglandaceous taxa such as Engelhardtia. Fossil I 11" that subsequently separated the drainages of the pollen indicative of cooler, drier, temperate ( 0 lorado Pl a teau and the Trans it i on Zone . The age forests includes Podocarpus, Ulmus-Zelkovia, Acer, 0: the "Rim gravels" has been brackf'ted in the Carpinus, Corylus, Salix, Populus, Castinopsis, ~Jhlteriver area between 54.6 Ma and 28 Ma by Peirce Pinus and such juglandaceous elemf'nts as C~rya and and others (1979) with the maximum age determined by Pterocarya. Joint occurrence of these taxa 1n those clasts in the gravels and the minimum age by the formations is indicative of a source area with an overlying volcanics (Figs. 3 and 4). The occurrence environmental gradient ranging from warm, moist of widespread early Eocene fluvial and lacustrine lowlands to cooler, drier ·uplands. Modern analogs u'diments on the Coconi no Pl ateau suggests an for such assemblages are found in the broadleaved f'xtensive drainage system flowed from west-central evergreen forests of southern China and eastern n.ri zona across the eros i ona 1 surface that was cut Mexico (Axelrod and Bailey, 1976). These pollen duwn to the Kaibab Limestone during the late records indicate that such environments existed in ~Retaceous and Paleocene when it lay at a lower elevated regions around the Green River and Uinta ~ levation (Young, 1979, 1982). These strata include basins, possibly including the Kaibab and Monument ?- Im gravel-type sediments of Precambrian clasts uplifts, and the Mogollon Highlands of northern and derived from the south, and overlying lacustrine centra 1 Ari zona (Fi g. 2). Eocene po 11 en and 1 ' mestones dated as early Eocene by fossil snail s macroscopic plant remains suggest that similar plant (Young and Hartman, 1984). Young noted that the communities ranged over a wide area from Wyoming, strata on the Coconino Plateau occur in a structural California and New Mexico (Axelrod, 1966; Cushman, downwarp on top of the Kaibab Limestone (here called 1983; Leopold, 1983; Leopold and MacGintie, 1972). Coconino basin) and appear to have been deposited in The only Eocene fossils reported from Arizona are a dra i nage system that was bounded on the north by viviparid gastropods snails in the limestone of the Laramide age Supai Monocline (Young, 1982) Coconi no bas i n (Young and Hartman, 1984) and (Fi gs. 2 & ~). Si mil u gr" '/el s are present on the charophytes (Lasky and Weber, 1949), and hydrobioid Triassic MOf' nkUJii F(mnatioll, hrnrath Miocene (6-3 snails (Nations and Landye, 1984) from the Artillery Ma) basalt flows or. the Shivwits rlateau (Lucchitta, Formation south of the aill Willi~ms River. 1975), which cr uld have been deposited in the margin of Cocon in o ba :; ill "". that Silme t i ml (Fig. 3). 346 CENOZOIC PALEOGEOGRAPHY, ARIZONA MID-TERTIARY (40-13 Ma) PALEOGEOGRAPHY Early (lligocene units in southeastern Arizona include the Locomotive fanqlomerate, Hr:'imet Oligocene (36.6-23.7 Ma) fanglomerate, Whitetail Conglomerate, Mineta Formation, and Pantano Formation (Shafiqullah and Northern Arizona others, ]978, 1980; Wilt anti Scarborough, 198]; Pei rce, 1984b; Damon and others, 1984). They range No 01 igocene sediments are known on the widely in thickness anti in lithology, but are ' Co10rado Plateau except the eolian Chuska Sandstone typically coarse-grained and poorly sorted. They that crops out high on the eastern side of the generally consist of reddish-brown conglomerate, either as a 11 uvi a l-fan accumul ati ons rangi ng from D~fiance uplift (Damon and Shafiqullah, 1981) (Fig. 2000 to 10,000 ft thick, or as relatively thin, 5, . basal conglomeratic units underlying iQnimbritic The absence of fluvial or lacustrine sediments volcanics of early to middle Oligocene' age-(Wilt and on the Colorado Plateau is int~rpreted as indicating Scarborough, 19G1). Because of this relationship to th~t the Plateau was uplifted enough during the 011 gocene to cause eros i on of the regi on by 01 i gocene ignimbrites, Wi lt and Scarborouoh (1981) northward flowing drainage systems. These streams designated these as "pre-ignimbrite sediments". are believed to have followed the relatively low They occasionally contain fine-grained members Uinta-Green River downwarps northeastward, between consisting of light-colored to greenish mudstone, upl ifts of the Wyomi ng Rocki es, to the 01 i gocene calcareous shale and limestone with some gypsifercus depositional basins and Great Plains of northeastern beds that are of probable lacustrine origin. The Colorado, Wyoming, Montana and Nebraska (Fig. 1). limestones are commonly fetid, indicating a high organ~c carbon content, and deposition in l~custrine By late Oligocene the Mogollon Rim with up to environments. The presence of red fanglomerate and 600 m relief was formed by scarp retreat caused by monolitho10gic megabreccia overlying or underlying down-dip erosion of the northward dipping Mesozoic fine-grained strata indicates that nearby areas had and Paleozoic strata. This minimum age of the Rim high relief (~iilt and Scarborough, 1981). TheSE is defined by the presence of pre- 22 Ma gravels of observations suggest that southern Arizona during probable Oligocene age which wer~ deposited at the the Oligocene was a mountainous region with local base of the eroded escarpment by strealfls flowing internal drainage systems in which lakes and playas along its strike valley (Peirce and others, 1979). were formed periodical.ly fFig. 5). The 01 igocene These gravels and other sediments south of the Mi ocene cong 1omera te and redbeds of the Yuma a rea Mogollon Rim in the White River, Cibeque and Alpine (Olmstead and others, 1973) anti several other fine areas, including the 25 Ma eolian sandstone of 'to coarse-grained depos its such as the Sil Murk, Escudil1a Mountain (Damon and Shafiqullah, 1981), rlanton Hills, and Gila Bend limestones and the are believed to be the result of the reworking of Locomotive fanglomerate, indicate conditions in "Rim gravel sOl and transport of fresh gravel s by southwestern Arizona were similar to those in eastward flowing streams from the Mogollon so~theastern Arizona (Wilt and Scarborough, 1981). Highlands, after the Mogollon Rim was formed (Fig. Ollgocene and/or early Miocene isotopic dates of 5). intercalated volcanics in cores from deep well s in the Paradise, Higley, Picacho and Red Rock basins Southern Arizona (Fig. 1), indicate that the south Central Arizona (the Gil a Low of Pei rce, 1976) subs i ded duri ng the Stratigraphic units of Oligocene age are common mid-Tertiary orogeny, and has remained low ever in the southern part of Ari zona, where they since. accumulated as predominantly coarse clastic Volcanism was not common until middle Oligocene sediments in local basins formed by crustal (30 Ma) when silicic volcanism t~rmed the deformation during the mid-Oligocene figs. 4,S~ The "ignimbrite flareup" by Coney (1976) began. Oligo shape and size of these basins are interpreted in a cene sediments intercalated with thick sections of very generalized way, but are based on the observed volcanics in the "ignimbrite package" of Wilt and distribution of Cenozoic sediments in elongate Scarborough (1981) include the Nipper Formation, patterns, which suggest that the southern Arizona Faraway Ranch Formation, Cloudburst Formation crust was broadly warped. Drainage systems wer~ Artillery Formation, upper Sil Murk Formation: probab ly 1oca 1i zed by the conti nued development of Kinter Formation, and many others figs. 4.5). Many of broad scale folding (Fig. 5). The (11 igocene strata these formations include relatively thin (compared occur as isolated exposures in uplifted fault blocks to the volcanics) sections of mudstone. fetid and , of present-day mountain ranges and in the lower cherty limestone, and tuffaceous shale indicating portions of deep grabens that resulted from the probable deposition in lacustrine environments. disruption of Oligocene basins during subsequent These sections also co~on1y contain thick units of Basin and Range faulting. The area of apparent monolithologic breccia, indicating high basin-margin concentration of early to middle Oligocene sediMents relief and deposition of landslide debris. in southeastern Arizona is believed to have been a local downwarped "sump" to which the Mogollon Sediments deposited after the bulk of ignimbrite volcanics were extruded were included in es~arpment drainage flowed (Figs. 4, 5). Early Ollgocene strata are dominantly fine-grained but the the "post-ignimbrite package" by Wilt and middle and late Oligocene strata are coarse-grained, S~arborough (1981). These sediments are generally reflecting the nnset of the Mid-Tertiary orogeny. llght-colored and contain thin, reworked tuffaceous . material or proximal tuff deposits. One example is 347 D. NATIONS, J.C. WILT, AND R.H. HEVLY the 1oca lly-deri ved 01 i gocene-Mi ocene "Chalk Canyon Southern Arizona . formation" of the Cave Creek area which is dated by a 23.3 Ma andesite flow and a middle Oligocene Several lower and middle Miocene (pre - !~ Ma) oreodont (Gomez and Elston, 1978; Shafiqullah and stratigraphic units in central ard southern Arizona others, 1980). Some coarse-grained fang10merates were structurally deformed and isolated from are included in these sections. Although these subsequent depositional basins by the Basin and post-ignimbrite sediments range in age from late Range disturbance. These strata were called the 01 i gocene to early 11i ocene, they are di scussed in "post-ignimbri te package" by Wi lt and Scarborough more detail in the section on Miocene rocks. They (1981). They include the Nogales Formation, Big are mapped, along with the "ignimbrite sediments" of Dome Formation, Rillito III beds, Chapin I~ash Wilt and Scarborough, in Figure 5. Formation, San Manuel Formation, Milk Creek beds, "Chalk Canyon Formation" (%Rock Springs beds). older Oligocene Paleobiogeography sediments of the Big Sandy basin, and sediments of Bloody basin and the Horseshoe Reservoir areas (Fig. The Oligocene floras 'of western North America 5) • exhibit a marked change in composition toward a more modern aspect. This modernization is reflected in a Several Oligocene-Miocene sedimentary rock reduced diversity of evergreen angiosperms and units, such as the Copper Bas i nand Chapi n Wash incrE.'ased diversity of savanna, woodland and formations, were at least partly eroded or detached chaparral elements (Axelrod and Bailey, 1976; from the metamorphic core complexes of the Buckskin Leopold and MacGinitie, 1972). Fossil pollen and and Rawhide Mountains in western Arizona (Davis and plant rema ins in 01 i gocene sedi ments of Colorado, others, 1979; Rehrig and Reynolds, 1980). ~Jyomi ng and Montana are suggesti ve of temperatE.' vegetation closely allied to that living in the The Artillery Formation, which was reported to highlands of northeastern Mexico today (Leopold and be Eocene (?) age by Lasky and Webber (1949), has MacGinitie, 1972). The composition and proportion been determined to be Miocene age north of the Bill of taxa of Oligocene plants suggest a 1000 m (3000 Williams River, based on isotopic dates of foot) elevation of the depositional basins, which is interbedded lavas and on fossil pollen collected supportive of our interpretation of a broad uplift near the base of the formation (Lucchitta, 1980). of the Plateau beginning in the Oligocene. Analysis However, Otton (1982) has reported an Eocene a~e, of the margins of fossil leaves from western North based on a 43.3 Ma basalt flow in the lower Chapin Ameri ca also i ndi cates that duri ng the 01 i gocene, Wash Formation in the Date Creek basin south of the climates became cooler, drier and more variable than Bill Williams River. Further work is needed to duri ng the Eocene. Except for mi nor osci 11 ati ons, better define the stratigraphic relations of the these cool, dry climates continued through the Tertiary rocks in that area. Neogene in western North America (Wolfe, 1978). BASIN AND RANGE (13-0 Ma) PALEOGEOGRAPHY Anima 1 foss il s reported from the 01 i gocene of Arizona include an oreodont (Lindsay and Lundin, ,Late Miocene (13-5.3 Ma) 1972), the rhinoceros Diceratherium (Lindsay arid Tessman, 1974), and mesogastropods from the Southern Arizona Nipper Formation (Nations and Landye, 1984). The onset of Basin and Range faulting at 13-12 Early and Middle Miocene (23.7-11.2 Ma) Ma, created numerous graben-type bas ins throughout the Basin and Range Province (Eberly and Stanley, The onset of the Basin and Range disturbance in 1978; Oppenheimer and Sumner, 1981) and the middle Miocene at 13-12 Ma deformed early Miocene Transition Zone (Nations and others, 1982), and was and older sedimentary and volcanic rocks and created accompanied by basaltic volcanism (Shafiqullah and a different tectonic setting for late Miocene and others, 1980; Wilt and Scarborough, 1981). The Pliocene sedimentation (Peirce, 1976; Eberly and normal faulting associated with that disturbance Stanley, 1978; Scarborough and Peirce, 1978; Wilt disrupted drainage systems and created many and Scarborough, 1981; Peirce, 1984b). For this 'restricted basins in which thick sequences of reason, early and middle Miocene stratigraphic units fluvial, volcanic, and lacustrine sediments were are discussed and mapped separately from late Miocene ~eposited (Fig. 6). In contrast with the older units. Tertiary deposits, these basin-fill sediments are intact relative to their hasin margins, which makes Northern Arizona it possible to observe facies relationships. Many of these bas ins contain hundreds to thousands of No early or middle Miocene sedimentary rocks meters of evaporites which indicate deposition in have been reported on the Colorado Plateau. We closed basins and a lack of through-flowing drainag p inter:pret their absence as indicating that it was systems at that time (Peirce, 1976, 1984b; Eberly being uplifted and eroded as in the Oligocene, with and Stanley, 1978). cOJltinued drainage northward. The lower to middle . Miocene strata of the Uinta Mourtains, and the Great Plains east of t~e Ro~kv ~0untains may have been derived frolil the northward sloping Plateau. (fig.' 2). 348 CENOZOIC PALEOGEOGRAPHY, ARIZONA Bas i n-fi 11 depos its are typi ca lly undeformed, The ~arine sediments beneath the BOUSE rest unconformably on tilted or folded older Formation in the Yuma area began to accumulate in' Tertiary sedimentary or volcanic rocks, and the proto-Gulf of Cal ifornia by late Miocene time .. unconformably underlie thin Pleistocene deposits The gulf was formed by the eastward migration of the (Wilt and Scarborough, 19B1). The deposition of active Pacific and North American Plate bounda!'Y basin-fill sediments began about 13 Ma and continued after 17 / 349 D. NATIONS, J.e. WILT, AND R.H. HEVLY adequately. The areal extent of Bidahochi Formation basin drainage (Figs. 3,4,5) u"til the drainage outcrops has been mapped by Akers (1964), which reversal in late Miocene time. With the southward provides a minimum area of the fluvial and tilting, this river changed its course southwestward lacustrine Bidahochi basin. Cooley (1962) suggested 3nd flowed into the Muddy Creek bas i n (Fi g. 6). By that calcnrpou~ sand and silt, that crops out 5.5 Ma the Gulf of California had opened and the between basalt and the Chinle Formation at Sunset lower Colorado River segment was erodin~ its channel Buttes, 30 km southwest of Winslow is similar to the northward toward the Muddy Creek basin (Fig. 6). It upper Bi dahochi Formati on. Several other outcrops cut its channel down into the 5.9 Ma Fortification of Tertiary sediments along the Mogollon Slope and Hill basalt of the Muddy Creek Formation and in the Little Colorado River valley (Ulrich and completed the lower Colorado River drainage, between others, 1984) appear to be genet i ca lly related to 5.9 and 3.B Ma (Shafiqullah and others, 1980). The the upper Bidahochi and are interpreted here as lowered base level resulting from the opening of the such. If those deposits were continuous with the Gulf of California increased headward erosion by the Bidahochi Formation, then the fluvial sands of the river, thereby capturing both the Marble Canyon Bidahochi basin probably extended as far west as the segment of the Colorado River and the Little Kaibab Uplift (Figure 6). Lucchitta (1984) Colorado River completing the integration of the postulates a ·through-flowing, ancestral (pre-Basin upper Colorado River system with the lower Colorado anc Range faulting) Little Colorado River River to the Gulf of California (Figs. 6 and 7). approximately along its present course and in the Sedimentation continued in the ancestral Little same direction. This is logical because a long Colorado River Valley until the Kaibab Up1 ift erosional" event by a well established drainage barrier was breached by headward erosion of the system was necesssary to erode the topographic basin lower Colorado River at its present confluence with in which the Bidahochi Formation was deposited. We the Little Colorado River sometime after the middle propose that this stream course wa"s established in member of the Bidahochi Formation was deposited 6.7 the strike valley of the Chinle FDrmation on the Ma (Scarborough and others, 1974). This breaching Mogollon Slope after headward erosion by a of the Kaibab Uplift and drail"ing of the Bidahochi southeastward-flowing stream in the Baca-Eager basin bas i n probably occurred primarily by headward intersected the northward-flowing regional drainage erosion and stream capture by a short tributary to down the Kaiparowits-Black Mesa downwarp. The the lower Colorado River during the I-'Ilocene. resulting stream capture created the Since then the mouth of the Little Colorado River northward-flowing ancestral Little Colorado River, has been lowered to 900 m (2700 ft) above sea level, and continued to erode the Little Colorado River well below the 1970 m (5900 ft) lowest elevation of valley between the Kaibab Uplift to the west and the the base of the Bidahochi Formation. This lowering Black Mesa plateau to the east (Figs. 4 and 5). of local base level resulted in the removal of much of the Bidahochi Formation from a large portion of Bidahochi sedimentation may have begun in that the ancestral Little Colorado River Valley (Fig. 6). erosional valley as early as 10-15 Ma (Lance, 1954). At that time, southward til ti ng of the Pl ateau, Incised meanders on the Doney Cliffs Monocline probably effected by subsidence in the adjoining (Breed, 1969), easterly flowing drainage channels on Aasin and Range Province, caused the revers"al of Gray Mountain (Barnes, 1985, pers. comm.), and drainage of the long established northward drainage barbed drainages of the Littl e Colorado Ri ver were system (Figs. 5 and 6). By that time, headward probably developed during the deposition of the eros i on by the ancestral Littl e Colorado and San Bidahochi Formation, prior to its dissection by the Juan rivers had dissected the Cretaceous integrated Colorado River system. cliff-forming sandstones enough to allow the reversed drai nage to abandon the previ ouS regi ona 1 Pliocene (5.3-1.6 Ma) drainage in the Kaiparowits-Black Mesa downwarp, and to flow into the ancestral Little Colorado River Valley possibly along the course of Moenkopi Wash Basins that continued to accumulate sediments (Fig. 6). That dissection effectively separated the through upper Miocene and into the Pliocene include Kaiparowits and Black Mesa plateaus. Sedimentologi the Gulf of California embayment (Bouse Fm.), ~1uddy cal evidence of the early development of this Creek basin, Bidahochi basin, Verde basin, Safford drainage reversal may be found in the gravels Basin(?), Big Sandy basin, San Pedro basin, containing lithologic clasts from the San Juan Perkinsville basin, San Raphael basin, Duncan basin, Mountains that are now located on White Mesa (Hunt, and the Safford basin. They all are partially or 1956). It is likely that the Marble Canyon portion entirely Pliocene in age, but appear to have been of the Colorado River and the Paria River were drained at different times during the Pliocene as entrenched during that drainage reversal int.o the headward erosion of the developing integrated stream Bidahochi basin (Fig. 6). The other streams of the system reached them and breache~ their margins. upper Colorado River system were integrated into the reversed drainage system into the Bidahochi basin at Miocene-Pliocene Paleobiogeography that time, including the San Juan River which established its course across the ~onument uplift by Neogene plant and animal fossils are relatively late Miocene time (Hunt, 1956; Huber, 19&1). common in Arizona. The locations and taxonomic The segment of the Colorado River which composition of the Cenozoic fossil localities of Presently flows west of the R~ibab uplift, was Arizona were summarized by Nations al"d Landye (1984) flowing nort.hward as part of the Sevier foreland and Lindsay (1984). 350 CENOZOIC PALEOGEOGRAPHY, ARIZONA Aquatic plants, ilwertebrates and vertebrates extinction of many Plio-Pleistocene vertebrates. have been used to interpret intrabasin environments Thi s subject has been thoroughly di scussed ina of deposition in the Bouse Formation (Smith, 1970), recent symposium volume (Martin and Klein, 1984). Muddy Creek basin (Blair and others, 1979; Cornell, 1979), Verde basin (Nations and others, ]981) and in ACKNOWLEDGEMENTS the Bidahochi I:>asin (Taylor, 1957; Baskin, 1975). Former drainage patterns have bpen inferred from the We are indebted to numerous cuthors who have distribution of fossil and modern fish faunas (Uyeno published lithologic descriptions, paleontologic and and Miller, 1965; Smith, 1966; and Miller, 1981). isotopic dates, and correlations of the Tertiary stratigraphic units of Arizona. We have relied Terrestrial palynomorphs and macrofossils in heavily on several recent publications in which Neogene sediments have been ci ted as evi dence of numerous isotopic dates were used to interpret the elevation above sea level for several Miocene chronology of stratigraphic units and tectonic depos iti ona 1 basins. The occurrence of pi ne and history of various parts of the state. Foremost other high altitude genera in the Nogales Formation among these authors are: P. E. Damon, I. Lucchitta, (Damon and Miller, 1963), the Bidahochi basin H. W. Peirce, R. Scarborough, N. Shafiqullah, R. A. (Anderson, 1962), and the Verde basin (Nations and Young, and many others who havp contributed to the others, 1982), indicates elevations above 1300 m data base necessary for this synthesis. Helpful (4000 ft). The absence of higher elevation (+2200 suggesti ons for improvement of the manuscri pt were m) taxa such as Abies, Picea and Pseudotsuga in made by H. W. Peirce, and T. N. V. Karlstrom, R. B. Miocene or older sedi~ents-or-Arizona suggests that Scarborough, and S. A. Keith. there was no topography of that elevation until the The interpretations expressed in this paper are Pliocene, at which time those genera appear in the our own and will most cert~inly find disagreement in Safford basin (~artin and Gray. 1962). They become parts with any particular workers. We offer them as common in the Sul phur Spri ngs Va 11 ey and in the an attempt to pull together the diverse data lacustrine sediments of the Colorado Plateau during relative to Cenozoic history and evolution of the the Pleistocene (Nations and Landye. 1984). state of Ari zona. and as a cha 11 enge to thosp who wi 11 add more data and/or improve upon our The occurrence of fan palm (Washin~tonia) in interpretations. the Miocene Big Sandy basin (Axelrod. 195 ; Worley. Technical and financial support was provided by 1979) indicate warm climates ana elevationsless than the Geology Department, Department of Biological 1200 m (3500 ft). A similar interpretation is Sciences and the Organized Research Committee of indicated for the Pliocene of the Yuma basin. based Northern Arizona University, Flagstaff, Arizona. on the occurrence of paloverde (Cercidium or Final drafting of the maps and correlation table was Parkinsonia) (Lee and Zavada, 1977). done by Teresa Mueller and Randy Hintz; word processing was done by Lisa Barr. Preliminary analysis of the distribution of mammal taxa in Tertiary deposits. suggests that they REFERENCES CITED may also be useful indicators of paleoclimates and paleogeography during the Tertiary, including the Anderson, R.Y., 1960, Cretaceous-Tertiary development of physiographic barriers to dispersal. palynology, eastern side of the San ,Juan Basin, New Mexico: State Bureau of Mines and Mineral Pleistocene (1.6 Ma - Present) Resources, New Mexico Institute of Mines and Technology Memoir #6, 60 pp. Other basins, generally in the low-lying areas Akers, J.P., 1964, Geology and ground water in the of the Basin and Range (the Gila Low of Peirce. central part of Apache County, Arizona: U.S. 1976), or areas not yet in the modern integrated Geological Survey Water-Supply Paper 1771, 107 drai nage system, conti nued to accumul ate sediments p. through the Pleistocene and Holocene. They include Arizona Geological Society, 1967, Arizona Hignway Red Lake, Luke, Paradise, Higley, Picacho, Red Rock Geologjcal Map, 1 :1,000,000. and Tucson Basins (Figs. 1. 6, 7). .l\s previously stated, these basins commonly contain sediments Axelrod, D. I .•. 1950. The evolution of desert ranging from Oligocene to Recent because they are vegetation in Western North America. Carnegie located in areas that have remained low sincp the Institute of Washington Pub. 590:215-306. end of Laramide time, and have remained near or Axel rod. D. I., 1979, Age and ori gi n of Sonoran below base level during the Tertiary tectonic Desert vegetation: Occasional Papers of the events. California Academy of Science, v. 132, p. 1-74. Axelrod, D. I., 1966. The Eocene Copper Basin flora Pleistocene Paleobiogeography of northeastern Nevada: University of California Publications in Geological Sciences. Significant climatic change occurred during the v. 59, p. 1-83. Pleistocene resulting in drastically altered Axelrod, D. I.. and Bailey, H. P.• 1976, Tertiary distributions of both plants and animals. The vegetation. climate, and altitude of the Rio present distribution of taxa and the resulting Grande depression, . New Mexico-Colorado: composition of biotic communities has emerged only Paleobiology, v. 2, p. 235-254: within the past 11,000 years (Axelrod, 1979). Baskin, J. A., 1975, Small v~rtebrates of the Associated with this development has been the Bidahochi Formation, White Cone, non:,I-;· "~~I'!'I 351 D. NATIONS, J.e. WILT, AND R.H. HEVLY Arizona: Unpublished M. S. Thesis, University Landscapes of Arizona: The Geologic Story, of Arizona, Tucson, 105 p. University Press of America, 505 p. Best, M. G., and Hamblin, W. K., 1978, Origin of the Damon, P. E., and Miller, H. W., Jr., 1963, A lava northern Basin and Range Province: covered Terti ary forest in southern Ad zona: Imp1 ications from the geology of its eastern Journal of. the Arizona Academy of Science, v. boundary: Geological Society of America Memoir 2, p. 117-119. 152, p. 313-340. Damon, P. E., and Shafiqullah, M., 1981, Evidence Blair, W. N., Bradbury, J. P., and Oscarson, R. L., for 01 i gocene deserts in Ari zona (abs): . 1979, Upper Mi ocene Hua 1apa i 1imestone member Ari zona-Nevada Academy of Sci ence, 25th AnnlJa 1 from the proto-Gulf of California at Lake r~ead, Meeting. Arizona: in Newman, G. W., and Goode, H. D., Davis, G. A., Anderson, J. L., Frost, E. G., and eds., Basin-and Range symposium and Great Basin Shackelford, P. J., 1979, Regional Miocene field conference: Rocky Mountain Association of detachment faulting and early Tertiary (?) Geologists, p. ?85-292. mylonitization, Whipp1e-Buckskin-Rawhide Blakey, R. C., 1980, Pennsylvanian and Early Permian mountains, southeastern Califorhia and western pa 1eogeography, southern Colorado P1 ateau and Arizona: in Abbott, P. L., ed., ~eological vicinity: in: Fouch, T. D., and Magathan, E. Excursions 10 the Southern California ftrea: San R., eds., Paleozoic Paleogeography of Diego, San Diego State University, p. 75-108. west-central United States, Paleogeography Dickinson, W. R., 1981, Plate tectonic evolution of Symposium I, Rocky Mountain Section S.E.P.M., the southern Cordillera, p. 113-136, in p. 239-257. Dickinson, W. R., and Payne, W. D., eds~ Breed, W. J., 1969, A Pliocene river channel in Relations of tectonics to ore deposits in the Wupatki National Monument, Arizona: Journal of southern Cordillera: Arizona Geological Society Ari zona Academy of Sci ence, v. 5, no. 3, p. Digest, v. 14, 288 p. 177-181. Eberly, L. D., and Stanley, R. B., 1978, Cenozoic Chapin, C. E., and Cather, S. M., 1981, Eocene stratigraphy and geologic history of tectonics and sedimentation in the Colorado southwestern Arizona: Geological Society of Plateau-Rocky Mountain area: Arizona America Bulletin, v. 89, p. 921-940. Geological Society Digest, v. 14, p. 173-198. Coney, P. J., 1972, Cordilleran tectonics and North Enos, P., 1983, Late Mesozoic paleogeography of American plate motions: American Journal of Mexico, in Reynolds, M. W., and E. D. Dolly, Science, v. 272, p. 603-628. eds., Mesozoic Paleogeography of the Coney, P. J., 1976, Plate tectonics and the Laramide West-Centra 1 United States, Rocky Mountain orogeny: in Woodward, L.A., and Northrup, Paleogeography Symposium 2: Society of S.A., eds., Tectonics and mineral resources of Economi c Pal eonto 1ogi sts and Mineral ogi sts, southwestern North America: New Mexico Rocky Mountain Section, p. 133-157. Geological Society, Special Publications No.6, Epis, R. C.~ and C. E. Chapin, 1975, Geomorphic and p. 5-10. tectonic implications of the post-Laramide, Coney, P. J., and Reynolds, S. J., 1977, Cordilleran Late Eocene eros i on surface in the Southern Benioff Zones: Nature, v. 270, p. 403-406. Rocky Mountains: in Curtis, B. F., ed., Cooley, M. E., 1962, Late Pleistocene and Recent Cenozoic History of the Southern Rocky erosion and a1luvi~tion in parts of the Mountains, Geological Society of America Colorado River system, Arizona and Utah: U.S. Memoir 144, p. 45-74. Geological Survey Professional Paper 450-B, p. Gaponoff, S. L., 1984, Palynology of the Silverado 48-50. Formation (Late Paleocene), Riverside and Cooley, M. E., and Davidson, E. S., 1963, The Orange Counties, California: Palynology, v. 8, Mogollon Highlands-their influence on Mesozoic p. 76-106. and Cenozoic erosion and sedimentation: Gomez, Ernest, and Elston, D. P., 1978, 01 igocene Arizona Geological Society Digest, v. 6, p. and Miocene development of the mountain-desert 7-35. region boundary, Cave Creek, Arizona (abs.): Cornell, W. C., 1972, Gulf of California in Lake Geological Society of America Abstracts with Mead area of Arizona and Nevada during late Programs, v. 10, p. 107. Miocene time: Discussion: American Hamilton, Warren, 1978, Mesozoic tectonics of the Association of P~tro1eum Geologists Bulletin, western United States: in: Howell, D. G., and v. 63, p. 11 ~ ~-1140. McDowell, K. A. (eds.), Mesozoic Paleogeography Cushman, R.A., Jr., 1983, Palynology and of the western United .States, Pacific Coast Pa1eoeco109Y of the Fossil Butte Member of the Symposium I, Pacific Section S.E.P.M., p. Eocene Green River Formation in Fossil Basin 33-70. Lincoln County, Wyoming: American Association Haxe1, G. B., Tosdal, R. M., May, O. J., Wright, J. of Stratigraphic' Pa1yno10gists-Palynology of E., 1984, Latest Cretaceous and early Tertiary Tertiary Floras of Western North America orogenesiS in south-central Arizona: thrust Symposium abstracts, p. 7. faulting, regional 'metamorphism and granitic Damon, P. E., Lynch, D. J., and Shafiqullah, M., plutonism: Geological Society of America 1984, Cenozoic landscape development in the Bulletin, v. 95, p. 631-653. Basin and Range Province of Arizona, p. Heindl, L. A., 1963, Cenozoic geology in the mammoth 175-206: in Smiley, T. L., Nations, j. D., area, Pinal County, Arizona: U.S. Geo1('1ciull Pewe, T. L. , and Schafer, J. P. , eds. , Survev Bulletin 1141-E. 41 D. - 352 CENOZOIC PALEOGEOGRAPHY, ARIZONA Huber, G. C., 19B1, The canyon of the San Juan v. 46, p. 115-119. River; in: Baars, D. L. (ed.), Geology of the Lindsay, E. H., Opdyke, N. D., and Johnson, N. D., Canyons of the San Juan Ri ver, Four Corners 1984, Bl ancan-Herr~h ill ian 1 and mammal ages and Geological Society, Seventh Field Conference, late Cenozoic mammal dispersal events: Annual San Juan River Expediticn, 1973. Review Earth and Planetary Sciences, v. 12, p. Hunt, C. B., 1956, Cenozoic geology of the Colorado 445-5B8. Plateau: U.S. Geological Survey Professional Lindsay, E. H., and Tessman, N. R., 1974, Cenozoic Paper 279, 99 p. vertebrate localities and faunas in Arizona: Karlstrom, T. N. V., Billingsley, G. H., and Journa 1 of the Ari zcna Academy of Sci ence, v. McColley, R., 19B3, Mineral resource potential 9, p. 3-24. and geology of the Rattlesnake roadless area, Longwell, C. R., 1963, Reconnaissance geology Coconino and Yavapai Counties, Arizona: U.S. between Lake Mead and Davis Dam, Geological Survey, Miscellaneous Field Studies Arizona-Nevada: U.S. Geological Survey Map, MF-1567-A. Professional Paper 374-E, 51 p. Keith, S.B., 1977, Compilation of radiometric age Lucas, S. G., and Ingersoll, R. V., 1981, Cenozoic dates for Arizona: Arizona Bureau of Geology continental deposits of New Mexico: an and Mineral Technology, Open File P.eport 187 p. overview: Geological Society of America Kei th , S. B., 19B4, Map of outcrops of La rami de Bulletin, v. 92, p. 917-932. (Cretaceous-Tertiary) rocks in Arizona and Lucchitta, Iva, 1975, The Shivwits Plateau: in adjacent regions, 1:1,000,000: Arizona Bureau Applications of ERTS Images and Image of Geology and t-'ineral Technology, Geological Processing to Pegional Geologic Problems and Survey Branch. Geologic mapping in Northern Arizona, NASA Kelly, V. C., 1955, Regional tectonics of the Technical Report 32 - 1597, p. 41-72. Colorado Plateau and rplationship to the origin Lucchitta, Iva, 1979, Late Cenozoic uplift of the and distribution of uranium: University of New southwestprn Colorado Plateau and adjacent Mexico Publications in Geology, no. 5, 120 p. Lower River region: Tectonophysics, v. 61, p. Kelly, V. C., 1959, Tectonics of the Black Mesa 63-95. basin region of Arizona: in Anderson, R. Y., Lucchitta, Iva, 1980, The Miocene Artillery and and Harshbarger, J. W., eds~ Guidebook of the Chapin Wash formations of west-central Arizona: Black Mesa Basin, northeastern Arizona: Ninth identification and significance (abs.) : Field Conference, New Mexico Geological Geol ogi ca 1 Soci ety of Ameri ca Abstracts with Society, p. 146-150. Program, v. 12, p. 279. Lance, J. F., 1954, Age of the Bidahochi Formation, Lucchitta, Iva, 19B4, Dpvelopment of landscape in Arizona (abs.): Geological Society of America northwestern Arizona: the country of plateaus Bulletin, v. 65, p. 1276. and canyons, in Smiley, T. L., Nations, J. D., Lasky, S. G., and Webber, B. N., 1949, Manganese Pewe, T. L.--;- and Schafer, J. P., eds., resources of the Artillery Mountain region, Landscapes of Arizona: The Geologic Story: Mohave County, Arizona: U.S. Geological Survey University Press of America, p. 269-302. Bulletin 961, B6 p. Martin, P. S., and Gray, J., 1962, Pollen analysis Lee, M. R., and Zavada, M., 1977, Report of a late and the Cenozoic: Science, v. 137, no. 3524, Tertiary Petrified wood from Yuma County, p. 103-111. Arizona: Arizona-Nevada Academy of Science 12, Martin, P. S. and Klein, R. G., 1984, Ouaternary p. 21-22. Extinctions. University of Arizona Press, 841 Leopold, f. B., 1983, Pollen identifications from p. the Eocene, Chalk Buttes Flora, California: in Marvin, R. F., Naeser, C. ~l., and Mehnert, H. H., American Association of Stratigraphic 1978, Tabulation of radiometric ages including Palynologists: Palynology of Tertiary floras unpublished K-Ar and fission-track ages for of Western North America, Symposium abstracts, rocks in southeastern Arizona and southwestern p. 8. New Mexico: in Callendar, J . F., Wilt, J. C., Leopold, E. B., and MacGinitie, H. D., 1972, and Clemons, ~ E., eds., Land of Cochise; New Development and affinities of Tertiary floras Mexico Geological Society Guidebook, 29th Field in the Rocky Mountains: in Graham, A., ed., Conference, p. 243-252. Floristics and Paleofloristics of Asia and Menges, C. M., and tt,cFadden, L. D., 1981, Evidence Eastern North America: Elsevier Publishing for a latest Miocene to Pl iocene transition Company, Amsterdam, p. 147-200. from Basin-Range tectonic to post-tectcnic Lindsay, E. H., 1978, Late Cenozoic vertebrate landscape evolution in southeeastern Arizona: faunas, southeastern Arizona, in Callencar, J. in Stone C. and Jenney, J. P., eds; ' Ari zona F., Wilt, J. C., and Clemons, R-:-E., eds., Land Geologic Society Digest, vol. 13, p. 151-160. of Cochise: New Hexico Geological Society Miller, R.R., 1981(?), Coevolution of deserts and Guidebook, 29th Field Conference, p. 269-275. pup-fi shes (Genus Cypri nodon) in the Ameri can Lindsay, E. H., 1984, Windows to the past: Fossils southwest: in Naiman, R. J. and Soltz, D. L., of the San Pedro Valley: Arizona Bureau of eds., Fi shes in North Ameri can Deserts: John Geology and Mineral Techno'ogy, Fieldnotes, v. Hiley and Sons, p. 39-94. 14, no. 4, p. 1-9. Molenaar, C. M., 1983, Major depositional cycles and Lindsay, E. H., and Lundin, R. F., 1972, An regi ana 1 correl ati ons of upper Cretaceous Oligocene oreodont (Mammalia: Artiodactyla) rocks, southern Colorado Pl ateau and adj acent from central Arizona: Journal of Paleontology, areas: in Reynolds, 1-1. W., and E. D. Dolly, 353 D. NATIONS, J.e. WILT, AND R.H. HEVLY eds., Mesozoic Paleogeography of the west-central United States, Rocky Mountain Twenter, F. R., 1962, U. S. t~i ocene and P1 i ocene rcleogeography symposium 2, Society of Economic history of central Arizona: Geolooical Survey Paleontologists and Mineralogists, Rocky Profnssional Paper 424-C, p. 153-156. Mountain Section p. 201-224. Ulrich, G. E., Billingsley, G. H., Hereford, R., Nations, J. D., Hevly, R. H., Blinn, D. W., and Wolfe, E. W., Nealey, L. D., and Sutton, R. L., Landye, J. J., 1981, Paleontology, 1984, Map showing geology, structure, and p~ 1eoeco 1o~y , and depos it i ona 1 his tory of the uranium deposits of the Flagstaff 1° x ?~ M10cene-Pl10cene Verde Formation, Yavapai Quadrangle, Arizona: U.S. Geological Survey, County, Arizona: Arizona Geological Society Miscellaneous Invstigation Series, Map 1-1446. Digest, v. 13, p. 133-149. Uyeno, T., and Miller, R. R., 1965, Middle Pliocene Nations, J. D., Landye, ,1. J., and Hevly, R. H., cyprinid fishes from the Bidahochi Formation, 1982, Location and chronology of Tertiary Arizona: Copeia, v. 1965, p. 28-41. sedimentary deposits in Arizona: A review: in Van Horn, W. L., 1962, Late Cenozoic alluvial Ingersoll, R. V. and Woodburne, M. 0., eds:: depos its of the upper Safford Va 11 ey, Graham Cenozoi c nonmari ne deposits of Cali forni a and County, Arizona: Arizona Geological Society Arizona: Pacific Section, Society of Economic Digest, number 5, p. 89-96 . . Paleontologists and Mineralogists, p. 107-122. Wilt, J. C., and Scarborough, R. ~., 1981, Cenozoic Nat1 ons, J. D., and Landye, J. J., 1984, Cenozoi c sediments, volcanics, and related uranium in plant and animal fossils of Arizona: in the Basin and Range Province of Arizona: in Smiley, T. L., Nations, J. D., Pewe, T. L., arid Goodell, P. C. and Waters, A. C., eds., liranium Schafer, J. P. eds., Landscapes of Ari zona: in volcanic and volcaniclastic rocks: American The Geologic Story, University Press of Association Petroleum Geologists Studies in America, p. 7-36, appendices p. 428-479. Geology Number 13, p. 123-143. ~ewman, K. R., 1983, Palynomorphs of the Green River Wol fe, J. A., 1978, A pal eobotani ca 1 i nterpretati on formation (Eocene) Colorado and Utah: Some of Tertiary climates in the northern observations and interpretations: in American hemisphere: Amprican Scientist, v. 66, p. Association of Stratigraphic PalYnologist: 294-703. Palynology of Tertiary Floras of Western North Worley, P. L. H., 1979, Sedimentology and America, Symposium abstracts, p. 6. stratigraphy of the Tule Wash area, Mohave Olmstead, F. H., Loeltz, O. J., and Irelan, B., County, Arizona: Unpublished M.S. thesis, 1973, Geohydrology of the Yuma area, Ari zona Arizonn State University, 99 p. and California: U.S. Geological Survey Young, R. A., 1979, Laramide deformation, erosion Pr?fessional Paper 486-H, 227 p. and plutonism along the southwestern margin of Oppenhe1me~, J. M., and Sumner, J. S., 1981, Gravity the Colorado Pl ateau: Tectonophys i cs, v. 61, model1ng of the basins in the Basin and Range p. 25-47. Province, Arizona: in Stone, Claudia, and Young, R. A. . , 1982, Paleogeomorphic evidence for the Jenney, J. P., eds., ArIzona Geological Digest, structural evolution of the Basin and v. 13, p. 111-115. Range-Colorado Plateau boundary in western Otton, J. K., 1982, Tertiary extensional tectonics Arizona: in Frost, E. G., and Martin, D. L., and associated volcanism in west-central eds., Mesozoic-Cenozoic tectonic Evolution of Arizona: in Frost, E. G., and D. L. Martin the Colorado River Region, California, Arizona eds., Mesozoi c-Cenozoi c Tectoni c Evo 1uti on of and Nevada: Cordilleran Publishers, San Diego the Colorado River Region, California, Arizona, California, p. 29-40. ' and Nevada, p. 143-157. Young, R. A., and Hartman, J. H., 1984, Early Eocene Palmer, A. R., 1983, The Decade of North American fl~violacust~ine sediments near Grand Canyon, Geology 1983 geologic time scale: Geology, v. Ar1zona: eV1dence for Laramide drainage across l1, p. 503-504. northern Arizona into southern Utah: Pederson, E. P., and Royse, C. F., 1970, Late Geological Society of America Program with Cenozoic geology of the Pavson Basin Gila Abstracts, v. 16, no. 6, p. 703. County, Ari zona: Journa 1 . of the Ari zona Rehrig, W. A., and Reynolds, S. J., i980, Geologic Academy of Science, v. 6, p. 168-179. and geochronologic reconnaissance of a Peirce, H. W., 1976, Tectonic Significance of Basin northwest-trending zones of metamorphic core and Range thi ck evaporite depos i ts: Ari zona complexes in southern and western Ariozna: Geological Society Digest, v. 10, p. 325-339. Geo 1ogi ca 1 Soc i ety of Ameri ca, Memoi r 153 p. Peirce, H. W., 1984a, The Mogollon Escarpment: 131-157. ' Fieldnotes of the Arizona Bureau of Geology and . Scarborough, R. B., Damon, P. E., and Shafiqullah, . Mineral Technology, v. 14, no. 2, p. 8-11. Mo:-" .3mmad, 1974, K/Ar age for a basalt hom the Pe1rce, H. W., 1984b, Some late Cenozoic basins and volcanic member (unit 5) of the Bidahochi basin deposits of. southern and western Arizona Formation (abs.): Geological SociPty of in Smiley, T. L., Nations, J. D., Pewe, T. L.: Ameri ca Ahstracts with Programs. v. 6. no. 5, p. 472. an~ Schafer, J. P. , eds. , Landscapes of Ar1zona: The Geological Story: University Scarborough, R. B., and Peirce, H. W., 1978, Late Press of America, p. 207-228. Cenoz?ic basins of Arizona, in Callendar, J. Peirce, H. W., Damon, P. E., and Shafiqullah, M., F., W1lt, J. C., and Clemons, R: E.• eds., Land 1979, An Oligocene Colorado Plateau edge in of Cochise: New Mexico Geological SOCiety Arizona: Tectonophysics, v. 61, P. 1-14. r,lIir!phnnlt. ?qt.h Field Conference. D. 253-259. 354 CENOZOIC PALEOGEOGRAPHY, ARIZONA ~hafiqullah, M., Damon, P. E., Lynch. D. J., and Kuck, P. H., 1978, Mid-Tertiary magmatism in southeastern Arizona: in Callendar, J. F., Wilt, J. C., and Clemons~ R. E., eds., Land of Cochise; New Mexico Geological Society Guidebook, 29th Field Conference, p. 231-241. Shafiqullah, M., Damon, P. E., Lynch, D. J., Reynolds, S. ,1., Rehrig, W. A., and Raymond, R. H., 1980, K-Ar geochronology and geologic hi story of southwes tern Ari zona and adjacent areas: Arizona Geological Society Digest, v. 12, p. 201-260. Smith, G. R., 1966, Distribution and evolution of the North American catostomid fishes of the subgenus Pantosteus, Genus Catostomus: Museum of Zoology, University of Michigan Miscellaneous Publication 631, 34 p. Smith, M. L., 1981, Late Cenozoic fishes in the warm deserts of North America: a reinterpretation of dE'sert adaptations: in Naiman, R. J. and Soltz, D. L., eds., Fishes in North American Deserts; John Wiley and Sons, p. 11-38. Smith, P. B., 1970, New evidence for Pliocene marine embayment along the lower Colorado area California and Arizona: Geological Society of America Bulletin, v. 81, p. 1411-1420. Taylor, D. W., 1957, Pl iocene fresh-water mollusks from Navajo County, Ari zona: Journa 1 of Paleontology, v. 31, p. 654-661. 355 CENOZOIC PALEOGEOGRAPHY OF WEST -CENTRAL UNITED STATES 356