U.S. DEPARTMENT OF THE INTERIOR Prepared in cooperation with the GEOLOGIC INVESTIGATIONS SERIES I–2771 U.S. GEOLOGICAL SURVEY NATIONAL PARK SERVICE Pamphlet accompanies map 111°36´00˝ 111°35´30˝ 111°35´00˝ 111°37´30˝ 111°37´00˝ 111°36´30˝ 36°54´00˝ CORRELATION OF MAP UNITS 36°54´00˝ River valley (Ulrich and others, 1983) 110 km south-southeast of the study area. Beyond ALLUVIUM COLLUVIUM EOLIAN BEDROCK this, however, the ages of the gravels are poorly known. Age and correlation ^m Alluvial S Alluvial deposits A In the eastern 100 km downstream of , a sequence of terrace-forming N deposits Gravel Debris-flow Talus Landslide Sand Sedimentary D of the 111°37´15˝ 111°35´00˝ of the deposits deposits deposits deposits dunes rocks gravels were dated by Machette and Rosholt (1991) and Lucchitta and others (1995). Although these Paria River and tributaries P A workers used different dating techniques, their results agree broadly within the analytical error of the S S ND P SA ASS methods when the same levels were dated. Lucchitta and others (1995) report ages between about TR lsc AIL 60–80 ka for deposits ranging from 17 to 30 m above the river and 100 ka for those between 44–46 977.6 m above the river. These heights correspond to levels 3–4 and level 5 of Machette and Rosholt aces

ecently (1991) that are 10–40 and 150 ka, respectively. These authors dated two substantially older terraces, mt TR A nd IL deposits osits levels 6 and 7, that are 90 and 135 m above the Colorado River whose ages are 500 and greater than ^cs ns pt 1002.4 36°53´45˝ AGE (DATE) 700 ka, respectively.

ts races a ts st (yr) Tentative ages are assigned to the gravels in the Lonely Dell/Lees Ferry area by correlation with races and Active and r ated dep ated deposits SERIES 978.7 Ter 975 SYSTEM Pleistocene terr the Machette and Rosholt (1991) dated sequence in eastern Grand Canyon. The a-level gravel (unit Ter Tributary channel Alluvial fa active channel bars and Debris fans st rel and ponded rel gva) correlates with level 7 at greater than 700 ka, b-level gravel (unit gvb) correlates with level 6 at 977 A.D. 2000 500 ka, c-level gravel (unit gvc) is equivalent to levels 4–5 at 75–150 ka, and the d-level (unit gvd) mt st 975.5 1980 pdz correlates with levels 3–4 which are 10 to 40 ka. 977.4 997 ^m ac afa dfa 1963 mt Climate and deposition of the gravels 1023.9 gvc ECHO Pleistocene gravels and related terraces are present as high-level remnants in many river valleys ea 1940 ? pda ^cs on the southern . The relation of gravels to Pleistocene climate, however, is poorly ^m 1922 ht Flood deposits pd gv ea known. Specifically, were the gravels deposited during the glacial periods with cool, moist climate yt 1900 fdy or following glaciation as the landscape adjusted to warmer, drier climate and large changes in vege- NATIONAL 1885 ? mt F CLIFFS tation type and density? Evidence from the map area supports the former explanation. The c- and d- O 1800 afs O RECREATION AREA afa 971.6 T level gravels (units gvc and gvd) are contemporaneous with large landslide and earthflow deposits 1700 T st it lsc lsd R (units and ), suggesting that they were deposited during glacial climates when large-scale gvc A

ts I 978.6 975.5 993.3 L 1600 mass wasting was enhanced. Indeed, the gravel and mass wasting deposits probably formed during pt pt ? ? ? ? the glacial climates corresponding to oxygen isotope stages 2 around 20–30 ka and stage 6 at Holocene 1400 130–150 ka as determined from sediment in deep-ocean cores. gvd 975.4 Paria 1200 ? Paria Figure 2. Upstream view of Paria Canyon. Echo Cliffs on distant skyline. Reddish-brown slope ? LATE HOLOCENE TERRACES AND RELATED DEPOSITS 974.4 1000 1028 above river valley is the Moenkopi Formation (unit ^m), which is overlain by cliff-forming pt afp dfp st afa 980 Late Holocene alluvium occupies most of the inner valley of the Paria River. The deposits C Shinarump Member (unit ^cs) of the Chinle Formation, the boundary of the map area. 973.4 anyon B.C. 1 973.2 underlie four terraces that are 2–7 m above the river. The alluvia are separated by disconformities, Flood ^m ? ? deposits ? ? erosional contacts that truncate underlying beds (fig. 3). Termed cut-and-fill, this stratigraphic rela- FERRY SWALE 7.5´ QUADRANGLE ef ht mt 976 36°52´30˝ tion results from channel cutting by deepening, widening, and realignment followed by filling or LEES FERRY 7.5´ QUADRANGLE River 5000 fdo ts aggradation of the channel and partial refilling of the alluvial valley. The fill deposit typically over- 970 ts afs ? laps the near-channel margin of the older alluvium and terrace. Arroyo cutting is the development of Gaging station ea tsfd an entrenched, rectangular channel, which is the geomorphic or surface expression of a disconform- gvd gvc B.P 10,000 ? 972 ^cs Cemetary gvd lsd ? ity. The causes of arroyo cutting are debated intensely, the subject of a large, complex body of litera- 40,000 972.4 afp lsc ture (reviewed by Graf, 1983; Webb, 1985). Lonely Dell ht/st 75,000–150,000 gvc 1043 gv Ranch mt/ht st/pt 500,000 Age and correlation mt 978.5 Lees Ferry gvb The ages of the deposits of the prehistoric (unit pt) and settlement (unit st) terraces were deter-

Pleistocene 700,000 36°53´30˝ gva mined mainly by radiocarbon assays of charcoal found in the alluvium. The dates, however, do not 36°53´30˝ mt afa Boat ramp ts Ferry fully constrain the ages of either unit. In the case of the prehistoric alluvium, the context and age of ^cp the charcoal suggest that deposition was ongoing at 1030–1200 and that deposition had ended before ^cs Road Water tower 1220–1290 (table 1, nos. RC2, RC5, RC6). Deposition of the younger settlement alluvium was NPS Ranger station R ^cs E Gaging station ongoing around 1640–1870 (table 1, no. RC4). The minimum age of the settlement terrace is IV A 971.4 R Unconformity 973.3 1840–1890, based on germination dates of cottonwood trees on the terrace.

O TRIASSIC QUATERNARY st ts D

Lees ^m An inset stratigraphic relation shows that the historic alluvium was deposited after incision of mt RA O OL the settlement alluvium, which began around 1885, as explained below. Beginning in the early C NAVAJO INDIAN 1940s and lasting until 1980, the modern alluvium was deposited on a floodplain that aggraded 971.9 RESERVATION throughout the Lonely Dell reach and Paria River basin (Hereford, 1986). 976.8 The late Holocene alluvial chronology of the map area is similar to several other streams in the Sheetwash sand of historic alluvium DESCRIPTION OF MAP UNITS COLLUVIUM 0 1 MILE Alluvium of historic terrace southern Colorado Plateau (Hereford, 2002). The stratigraphy and terrace sequence in the map area 971.2 (ht) Agricultural soil [All dates are anno Domini (A.D.) unless otherwise noted] Debris-flow deposits lsd 0 1 KILOMETER are present regionally with only minor variation, suggesting the deposits accumulated at about the Debris fans mt Agricultural soil ALLUVIUM same time under similar conditions. Regional correlation of the prehistoric alluvium indicates that dfa deposition ended around 1200 when an episode of arroyo cutting, lasting until 1400, incised chan- Contour interval 40 feet Alluvial deposits of the Paria River and tributaries Active debris-flow deposits (1940–2000)—Gravel consisting mainly of angular to sub- Table 1. Radiocarbon dates of late Holocene alluvium Supplemental contour interval 20 feet Alluvium of settlement terrace angular cobble to small and medium boulder-size sandstones of Moenkopi Forma- nels across the southern Colorado Plateau (Hereford, 2002). This disruption of channel systems in gv 1015.5 (st) Terraces and related deposits Map No. Sample No. 14C age Calibrated age1 A.D. Description afa 971.6 Figure 1. Topography of the map area, scale 1:24,000. Alluvium of historic terrace tion (unit ^m) and cobbles of siliceous sandstone from Petrified Forest Member of the late 12th and 13th centuries was a major factor leading to abandonment of large areas of the pla- mt (Lab. No.) (2σ rel. probability) (Map unit) 988 (ht) Modern terrace (1940–1980) of Hereford and others (2000)—Light-colored, very Chinle Formation (unit ^cp); clast to matrix-supported texture; thickness 1–2 m. teau by the Anasazi people, ancestors of the Hopi Indians of northern . Likewise, regional gvc fine grained sand with thin lenticular beds of gravel and continuous beds of silty Deposited on and probably interfingers with alluvium of the modern terrace (unit correlation of the settlement alluvium suggests that aggradation in the Lonely Dell area probably RC1 PRLDRC-1 150 ± 40 yr 1670–1944 Charcoal sand; thickness 2–4 m. Deposits are well exposed near Paria River gaging station mt yt ). Boulders are fresh appearing and unweathered began after 1400, when a shift to valley-fill alluviation occurred regionally. (W-2451) (1.0) (base unit ) st 1065 st Marker bed 2 where they were described and dated by Hereford (1986). Near former site of dfp Prehistoric debris-flow deposits (middle to late Holocene)—Gravel similar to unit dfa RC2 PRLDRC-2 920±40 yr 1030–1200 Charcoal Spencer cabin (Reilly, 1999; structure was removed by channel migration during HISTORIC-AGE ARROYO CUTTING, CHANNEL FILLING, AND FLOODS (W-2452) (1.0) (unit pt) above except boulders are distinctly varnished and beneath surface; undersides of 971.6 975.1 floods of September 1998), modern alluvium has inset stratigraphic relation with Near the end of the 19th century, the present settlement terrace was a floodplain of the Paria RC3 PRLDRC-3 Modern — Charcoal lsd mt Marker bed 1 boulders have incipient Stage-I carbonate morphology of thin discontinuous white ^m alluvium of historic terrace (unit ht). Unit includes active channel and floodplain of River. Beginning in 1883, the river channel in the upper Paria River basin began to incise, causing (W-2453) (unit st) ^m coatings of calcium carbonate. Two small rectangular stone structures of probable ht 971.3 Paria River. Settlement-era irrigation ditches not present on this terrace. Floods in severe problems with irrigation ditches and roads and causing abandonment of several pioneer set- RC4 PRLDRC-4 200±40 yr 1640–1870 Charcoal 970 1 meter Pueblo-II affinity (ca. 1050–1200) are present on prehistoric fan 0.5 km northwest 972.3 summer of 1997 and 1998 locally scoured surface of unit and eroded banks. Unit mt tlements (Hereford, 1986). The effects of arroyo cutting were evidently not as severe in the Lonely (W-2454) (0.82) (unit st) afa of Paria River gaging station correlates with the modern alluvium of the and other southern Colo- Dell area. Nonetheless, the channel was deepened as shown by the rebuilding of flood-damaged irri- RC5 PRLDRC-5 640±50 yr 1290–1400 Hearth top st ea rado Plateau streams (Hereford and others, 1996a; Hereford, 2002) Talus deposits gation dams and the extension of irrigation ditches progressively farther upstream (table 2). The (W-2455) (1.0) (unit pt2) 978.4 ht ts Talus, undivided (latest Pleistocene? to Holocene)—Mainly sheets of small to medium dams were relocated and the irrigation ditches were extended so the inlets to the ditches would again 972.5 B Historic terrace (1885–1940)—Light-colored, very fine grained to fine-grained sand. RC6 PRLDRC-6 750±40 yr 1220–1290 Do. boulder-size blocks of Shinarump Member of the Chinle Formation (unit ^cs) on intersect the bed of the river, which was lowered by floods. 1062 Present locally 1–2 m below settlement terrace (unit st) in abandoned meanders and (W-2456) (1.0) afp ^m gvd other protected sites at contact with settlement terrace. Settlement-era irrigation steep slopes of Moenkopi Formation (unit ) beneath cliffs of sandstone. Talus Anecdotal information concerning the Paria River, adjoining , and nearby Virgin 1 14C age calibrated to calendar years with the University of Washington, Quaternary Isotope mt afs deposits are moderately dissected and expose underlying bedrock. Sandstone blocks River (54 and 130 km west-northwest of the study area, respectively), as well as the Southwest in 967.8 ditches typically not present on this terrace, although a ditch covered by 1 m of Lab., Radiocarbon Calibration Program Rev. 4.1.2 (Stuvier and Reimer, 1993) 988.5 are distinctly varnished general, relates the initiation of historic-age arroyo cutting to several episodes of large floods (Webb, 2 st ht 966.5 gvd sheetwash gravel and alluvium is present below terrace near former site of Spencer Unlined hearths of samples RC5 and RC6 are 2 m apart in similar stratigraphic position 1998 flood-scoured surface 974 cabin and a headcut was constructed on the terrace north of Emett tunnel. Terrace tsfd Talus with interbedded flood deposits (latest Pleistocene? to Holocene)—Similar to 1985; Webb and others, 1991; Hereford and others, 1996a). This episodic flooding continued into Emett tunnel (1903) the early 20th century on the Paria River and other rivers in the region. Of the 10 largest floods since mt 965 equivalent to the older channel alluvium of Hereford (1986) unit ts above except talus contains multiple beds of very fine grained greenish-gray 965.9 1924, eight occurred by 1940 (fig. 4). mt st Settlement terrace (1400–1885)—Light-colored, very fine grained silty sand interbed- silty sand resembling Colorado River flood deposits; present at two localities 0.4 km st 966.9 Photographs of the channel in the map area taken between 1923–1940 show that it was wide, ded with reddish sand and pebble gravel of hillslope origin near margin of alluvial west-southwest of Paria River gaging station. Deposits are elevated far above any 967.8 deep, mostly flat floored, and lacked vegetation (Hereford, 1986), which is typical of most streams ts valley. Well stratified with beds 10–40 cm thick. Unit is typically 3–4 m above river known flood level of Colorado River 967.8 on the southern Colorado Plateau during arroyo cutting. The alluvium of the historic terrace is the and is disconformable with alluvium of historic and modern terraces. Well exposed Landslide deposits Table 2. Historic changes in the channel of the Paria River that relate to floods and development of only deposit from the arroyo-cutting period, and it differs from the modern and settlement alluvi- ea in fresh (as of Oct. 2000) meander scar near former site of Spencer cabin. Charcoal lsd irrigation ditches, dams, and related structures in the map area (adapted from Hereford, 1986; Topping, Landslide deposits of level d gravel (latest Pleistocene)—Poorly sorted blocks of ums. The historic alluvium is evidently not a channel-fill deposit, as it accumulated only in protected View north (upstream) into Paria Canyon showing light-colored, sparsely vegetated Alluvium of historic terrace (ht) at this locality dated 1640–1870 (table 1, no. RC4). Most settlement-era irrigation 1997; Reilly, 1999) afa brown and red sandstone and somewhat coherent, chaotically rotated segments of sites such as meander scars along the eroded margin of the settlement alluvium. These sites devel- pt late Holocene terraces (units mt, ht, and st), eolian deposits (unit ea), and abandoned Alluvium of modern terrace (mt) ditches and related structures were constructed on this terrace. Near north end of Glen Canyon Group (Mesozoic) sandstone intermixed with bentonitic clays of Petri- 967.6 ^cs oped as the eroding channel progressively widened the alluvial valley. This depositional setting dif- Date Activity 973.2 irrigation ditches. The abandoned ditches are the shallow linear depressions (circled) map area close to spot elevation 977.4 m, large, mature to senescent cottonwood fied Forest Member of the Chinle Formation (unit ^cp). Landslide originated from ^cs fers from the modern alluvium, which typically fills and overtops a preexisting channel in exposed gv trees rooted 0–75 cm below terrace date between 1840–1890 (D. Grow, written com- in the mid-ground on the left side of the river. 1 meter slope failure of bentonitic shales and subsequently slid to position of level d gravel. sites that remained fixed. It is likely that 1885–1940 was a period of net sediment transport with lit- June 1872 First dam built about 0.4 km WSW of present Paria River gaging station. Dam was 2.5 m high 36°53´00˝ mun., 2000). Settlement terrace (unit st) is equivalent to settlement terrace and Naha 36°53´00˝ 966.6 966.8 Stratigraphic relations suggest landslide and gravel are contemporaneous tle sediment storage in the channel or on the floodplain, the result of the frequent, large floods that and 36 m long; provided water to irrigate fields surrounding Lonely Dell Ranch. Presently, no alluvium of southern Colorado Plateau (Hereford and others, 1996a; Hereford, 2002) evidence of a dam at this locality; channel is 38 m wide and occupied by alluvium of the mod- st lsc Landslide deposits of level c gravel (late Pleistocene)—Similar to unit lsd above washed sediment through the channel system. pt Prehistoric terrace (late Holocene to 1200?)—Light-colored, very fine grained silty ern terrace (unit mt) ^m except that landslide slid to position of level c gravel The flood history of the Paria River (fig. 4) illustrates the link between floods, arroyo cutting, sand typically overlain and interbedded with reddish gravel of sheetwash origin. 1883 Dam built 0.8 km (0.5 mi) upstream from the 1872 dam site; provided water for new fields. 1095 and subsequent channel filling. The frequency of floods on the Paria River decreased after 1942 in Well exposed at Spencer cabin site where it is overlain disconformably by the settle- EOLIAN Presently, no evidence of a dam at this locality 981 C all frequency categories. The 10-year flood, for example, decreased from 410 m3/s (14,500 ft3/s) 1102 mt ment alluvium and an alluvial fan of settlement age (unit afs). Charcoal from near 1885 Irrigation ditches constructed in 1883 washed away Sand dunes during 1923–1941 to 200 m3/s (7,060 ft3/s) during 1942–1986, coincident with a decrease in the fre- ht base of unit within 20 cm of contact with alluvium of settlement terrace (unit st) 1890 Several dams washed out and were rebuilt or moved upstream, depending on amount of chan- gva 970.8 Figure 3. Late Holocene alluvium at the former site of Spencer cabin. A, View looking west-southwest at ea Active eolian deposits (1400?–2000)—Very fine grained to fine-grained, moderately quency of runoff-producing storms (Graf and others, 1991). Flood frequency also decreased in the ef ea dates to 1030–1200 (table 1, no. RC2). Prehistoric alluvium underlying eolian sand nel scour. Irrigation ditch to fields at Lonely Dell Ranch about 2.4 km long at this time. One of dfa meander-scar cutbank eroded in 1998 that exposed cross sections of prehistoric terrace (unit pt), settlement well sorted sand forming lightly vegetated active dune fields; thickness 1–3 m. adjoining basin (100 km north of study area; Webb and Baker, 1987). In the map (unit ea) derived from settlement alluvium (unit st) is penetrated by two unlined fire the rebuilt dams is thought to be located 0.35 km SSE (downstream) of Emett tunnel where gvb 966.7 965.6 terrace (unit st), historic terrace (unit ht), and modern terrace (unit mt) deposits. Arrows indicate subsurface Along Paria River, sand derived from reworking and deflation of adjacent alluvial area, the modern alluvium was deposited shortly after October 1939, based on photographic evi- 1101 hearths that date to 1290–1400 and 1220–1290 (table 1, nos. RC5 and RC6). Near remnants of a head gate and earthern fill resembling a dam are present on the west and east side dfp contacts between terrace deposits. B, Charcoal collected just beneath marker bed 2 dates at 1640–1870 deposits. Deposits locally cover settlement-era irrigation ditches dence from the Paria River gaging station (Hereford, 1986). Deposition, therefore, was coincident of river, respectively 963.7 Lonely Dell Ranch, archeologic remains of Pueblo-II age (ca. 1050–1200) are pres- 1039 (table 1, no. RC4). C, Modern terrace (unit mt) overlaps historic terrace (unit ht) deposits; contact is ef Falling dunes (late Pleistocene to Holocene)—Very fine grained to fine-grained, mod- with and quite probably initiated by the sustained decrease in the size of the 10-year flood. The allu- ht ent on terrace (H.C. Fairley, oral commun., 2000). Prehistoric terrace equivalent to 1903 Dams had washed out repeatedly for several years, as they had for the past two decades. To 1027 ^m displaced by burrowing. Historic terrace (unit ht) and modern terrace (unit mt) deposits are overlain by erately well sorted sand forming sand sheets that descend steep slopes of level b and vium accumulated on floodplains throughout the Paria River basin until 1980 when floods (table 2; the Tsegi alluvium, prehistoric terrace, and alluvium of Pueblo-II age of southern increase capacity of the ditches and remove them from migrating channel, the inlet was raised active alluvial fan (unit afs) deposits of settlement age. c gravel deposits. Sand derived from reworking of sand in gravel deposits fig. 4) incised the channel and floodplain, forming the modern terrace. From 1980 to 1997 a low, above floodline by excavating the Emett tunnel into Moenkopi Formation at a point about 1.8 Colorado Plateau and Colorado River in Grand Canyon (Hereford and others, 1005 965.1 lightly vegetated floodplain, which is too small to show at map scale, developed in the channel. km upstream from original dam site (1872). Remnants of a head gate are present on the historic 1996a, b) ea 963.5 BEDROCK Floods in 1997 and 1998 severely eroded this floodplain and further eroded the modern terrace. terrace (unit ht) 0.42 km north (upstream) of Emett tunnel 965.4 st Flood deposits Sedimentary rocks The effect of floods on alluvial processes in the map area since the mid-1880s suggests that the early Sept. 1909 "...a tremendous flood swept down..." (Reilly, 1999) the river with discharge estimated at 400 gvc ef fdy Younger flood deposits (1909)—Light-colored, very fine grained silty sand of Paria Chinle Formation (Upper Triassic) characteristic cut-and-fill stratigraphy (fig. 3) results from sustained increases or decreases in the m3/s (14,120 ft3/s). The river almost reached the ranch house and cemetery, suggesting flood 963.2 River origin. Unit is older than modern terrace (unit mt) and has inset relation with occurrence of large floods. An episode of large floods initiates arroyo cutting that is preserved in the overtopped the prehistoric terrace (unit pt) between gaging station and cemetery. Younger flood mt ^cp Petrified Forest Member—Bentonitic mudstone and claystone; thickness 190 m settlement age alluvial fan (unit afs), although 0.55 km northwest of gaging station stratigraphic record by erosional contacts and temporal breaks. In contrast, episodes of infrequent deposits (unit fdy) accumulated in high-level sites during flood st (Phoenix, 1963); typically forms talus-covered slopes. Not present in map area 18000 on east side of river younger flood deposits overlie prehistoric debris fan (unit dfp). large floods result in aggradation of the channel and alluvial valley by basin-wide sediment storage 1912 Junction of Paria River and Colorado River shifted SW more than 1.6 km, abandoning the for- 500 except at Lees Lookout gvb Unit probably deposited by flood of 1909, the largest post-1880 flood of the Paria on floodplains, producing a sequence of regionally correlative deposits. Climate controls flood fre- mer direct course to Colorado River across the present NPS facilities on the younger terrace afs ^cs Shinarump Member—Conglomeratic sandstone cross-stratified in lenticular beds 1012 16000 River (Topping, 1997; Reilly, 1999) quency through its influence on runoff-producing precipitation. (unit yt) Corral Estimated peak 50–150 cm thick; sharp erosional contact with underlying Moenkopi Formation; Topping (1997) Nov. 1923 U.S. Geological Survey established Paria River gaging station as result of Colorado River 966 14000 400 Tributary channel and ponded deposits thickness 0–50 m (Phoenix, 1963). Sandstone forms distinctive light-brown cliff Spencer cabin (site) REFERENCES CITED Compact ^m ac Active channel deposits (1940–2000)—Light-colored and light-red sand with pebble above inner valley of Paria Canyon; base of sandstone is outer boundary of map gvc 964.3 Oct. 5, 1925 Largest flood recorded (as of Oct. 2000) at Paria River gaging station (456 m3/s; 16,100 ft3/s) 12000 and small cobble gravel. Confined to relatively wide reaches of ephemeral channels area Andrews, E.D., 1990, The Colorado River; a perspective from Lees Ferry, Arizona, in Wolman,

^cs /s RC2-4 /s

3 M.G., and Riggs, H.C., eds., Surface water hydrology: Geological Society of America, The 3 3 3 Sept. 1939 Flood of Sept. 13, 1939 (278 m /s; 9,820 ft /s) completely washed out dam recently built 300 that flow in direct response to rainfall ^m Moenkopi Formation (Middle? and Lower Triassic)—Gypsiferous, pale-red to dark- ef 960 Geology of North America, Volume O-1, p. 304–310. upstream of Emett tunnel ef 10000 pd Ponded deposits (1871?–1940?)—Light-colored, very fine grained silty to clayey sand. brown, slope-forming mudstone, siltstone, and silty limestone; thickness 100–140 m Andrews, E.D., 1991, Sediment transport in the Colorado River basin, in Colorado River ecology Jan. 1940 Dam above Emett tunnel rebuilt after 1939 flood washed out again 962.8 gvc Present in channel of small tributary west of spot elevation 962.5 m that was (Phoenix, 1963) lsc 8000 and dam management: Washington, D.C., National Academy Press, p. 54–74. 1943 Pump driven by gasoline engine installed on bedrock near 1872 dam site. Water pumped from gvb 997 impounded by construction of settlement-era irrigation ditch 1013 mt 200 Chavez, Fray Angelico, 1976, The Dominguez-Escalante expedition: Provo, , Brigham Young Discharge, ft river to irrigation ditches to eliminate the chronic problems of earthen dams 973.7 afs gvd Discharge, m Contact ht afs 6000 Alluvial fans University Press, 203 p. June 1966 Two irrigation ponds constructed west of cemetery 987.9 afa Active alluvial fan deposits (1940–2000)—Light-red, pebble- to cobble-size gravel 960.3 Graf, J.B., Webb, R.H., and Hereford, Richard, 1991, Relation of sediment load and flood-plain for- 3 3 3 3 966.6 Spot elevation—In meters, determined photogrammetrically Sept. 1980 Floods of Sept. 1980 peaked at 241 m /s (8,510 ft /s) on Sept. 9 and 207 m /s (7,310 ft /s) on 961.5 4000 ^m gvc 100 interbedded with alluvium of Paria River origin; forms roughly fan-shaped deposits mation to climatic variability, Paria River drainage basin, Utah and Arizona: Geological Society Sept. 10 and possibly floods of Jan. 1980 realign channel eroding banks of floodplain, forming 965 RC5-6 overlying terraces of all ages Channel elevation—1-m contour elevation in channels of Paria and Colorado Rivers; mt of America Bulletin, v. 103, p. 1405–1415. modern terrace (unit ) 963 2000 afs channel elevation indicated at 5 m intervals Graf, W.L., 1983, The arroyo problem—palaeohydrology and palaeohydraulics in the short term, in Aug. 1997 and Sept. 1998 Floods of Aug. 10, 1997 (116 m3/s; 4,100 ft3/s) and Sept. 6, 1998 (191 m3/s; 6,740 ft3/s) further 983.1 1000.2 Alluvial fan deposits of settlement age (1400?–2000)—Light-red, pebble- to cobble- 968.8 size gravel in roughly fan-shaped deposits. Toes of fans are truncated by deposits of 960.3 Gregory, K.G., ed., Background to palaeohydrology: New York, John Wiley and Sons, p. realign and widen channel. Modern terrace (unit mt) locally overtopped; surface scoured and up gv ea 2 0 0 Survey control point—Elevation in meters historic and modern terraces. Fan surfaces are only slightly weathered, and active 279–302. to 10 cm of sand deposited. Spencer cabin destroyed by channel migration during flood of 1998 962.3 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 5 Photograph site—Number corresponds to photograph site number in pamphlet Hereford, Richard, 1986, Modern alluvial history of the Paria River drainage basin, southern Utah: 1 Water year channels are present locally gvc gvc 997.1 afp Alluvial fan deposits of prehistoric age (late Holocene)—Light-red, pebble- to cobble- Quaternary Research, v. 25, p. 293–311. Figure 4. Annual flood series of the Paria River (U.S. Geological Survey Station No. Ephemeral stream 973.8 size gravel in roughly fan-shaped deposits. Margin of prehistoric fans are truncated Hereford, Richard, 2002, Valley-fill alluviation (ca. A.D. 1400–1800) during the Little Ice Age, 962.5 mt 09382000), 1924–1999. Ten largest recorded floods shown in red. The younger flood Paria River basin and southern Colorado Plateau, : Geological Society of America pd by younger fans and terraces. Surface of fans are distinctly weathered with numer- Ephemeral stream ending at arrow fdy deposits (unit fdy) were probably deposited during the large flood of 1909 and the alluvium ous disintegrated clasts of sandstone and siltstone derived from Moenkopi Forma- Bulletin, v. 114, p. 1550–1563. lsc gvd 963.1 966.5 of the modern terrace (unit mt) accumulated during the relatively low floods of 1940–1980. tion Erosional scarp—Hachures at base of scarp Hereford, Richard, Burke, K.J., Thompson, K.S., 2000, Map showing Quaternary geology and geo- ea gvd 4 984.3 Although not among the 10 largest floods, those of 1997–1998 scoured portions of the 36°52´30˝ morphology of the Lees Ferry area, Arizona: U.S. Geological Survey Geologic Investigations 36°52´30˝ 111°40´ 111°35´ 111°30´ 962.9 afs gvd 983.5 dfp Alluvial deposits of the Colorado River Paria modern terrace and eroded the channel (fig. 3). Dirt road Series Map I–2663, scale 1:2,000 (with discussion). PAR Ferry Terraces and related deposits Corral 3 Hereford, Richard, Jacoby, G.C., and McCord, V.A.S., 1996a, Late Holocene alluvial geomorphol- IA 967.8 ts Graded road, dirt 36°55´ PARIA st fdy pdz Post-dam zone (1963–2000) of Hereford and others (2000)—Very fine grained, light- ogy of the Virgin River in the Zion National Park area, southwest Utah: Geological Society of River gvd fdy colored sand and gravel; deposits poorly preserved; thickness 0–2 m. Elevation America Special Paper 310, 46 p. Swale 975.1 Paved road CANYON 961 gvc ^cs ranges from 949–952 m near cableway. Mainly an erosional zone along margin of Hereford, Richard, Thompson, K.S., Burke, K.J., and Fairley, H.C., 1996b, Tributary debris fans and N O 983.4 gvc Colorado River. Sand spottily distributed on gravel; bounded by steep, erosional the late Holocene alluvial chronology of the Colorado River, eastern Grand Canyon, Arizona: Y afa Foot trail GLEN CANYON N gvc 972.1 PLATEAU A 959.3 cutbanks adjoining older terraces. Dense groves of small, relatively mature non- Geological Society of America Bulletin, v. 108, p. 3–19. NATIONAL RECREATION C 1001.3 959.6 ac native tamarisk (Tamarix, sp.) trees present locally; tree-ring counts indicate germi- Irrigation ditch—Abandoned; arrow shows direction of flow Lucchitta, Ivo, Dehler, C.M., Davis, M.E., Burke, K.J., and Basdekas, P.O., 1995, Quaternary geo- AREA nation in 1963 contemporaneous with closure of 27 km upstream logic map of the Palisades Creek-Comanche Creek area, eastern Grand Canyon, Arizona: U.S. GLEN st mt 962.0 mt Head gate of abandoned irrigation ditch Lees Ferry ht 5 of Lees Ferry Geological Survey Open-File Report 95–832, scale 1:5,000 (with discussion). 975.1 pda Pre-dam alluvium (1922–1958)—Well-bedded, very fine grained, light-colored silty Machette, M.N., and Rosholt, J.N., 1991, Quaternary geology of the Grand Canyon, Arizona, in mt ^m Irrigation-ditch tunnel dfa 7 sand with beds 10–20 cm thick; thickness 3–4 m on south side of Paria River west Morrison, R.B., ed., Quaternary nonglacial geology of the conterminous United States: Geolog- LIFFS 956.6 ht Area of gvc ical Society of America, The Geology of North America, v. K-2, p. 397–401. R afa 955 6 957.4 of National Park Service (NPS) facilities. Interbedded with lower part of alluvium Gaging station E this map IV mt Phoenix, D.A., 1963, Geology of the Lees Ferry area, Coconino , Arizona: U.S. Geological R of modern terrace of Paria River (unit ) at mouth of Paria Canyon. Elevation afa Wood or stone structure—Mapped shape is variable Survey Bulletin 1137, 86 p., 3 pls. Cat hedral 956.3 ranges from 951–953 m near cableway. Mature tamarisk trees in dense groves partly Wa s Ch O 964.4 mt Reilly, P.T., 1999, Lee's Ferry: from Mormon crossing to national park: Logan, Utah State Univer- N buried in alluvium are typical; part of unit post-dates 1935 on basis of ring counts 36°50´ O D ^m Cemetery sity Press, 542 p. ILI A from tree rooted beneath terrace on south side of river upstream of Colorado River M R NAVAJO 960.3 O tsfd ER L Irrigation dw Rusho, W.L., and Crampton, C.G., 1992, Desert river crossing: Salt Lake City, Utah, Crickett Pro- V gaging station. Driftwood deposits (unit ) on terrace contain abundant cut-and- dw Driftwood O 957.9 ductions, 168 p. C tsfd milled wood and cans and bottles dating from mid-1950s. Equivalent to pre-dam 14 terrace of Hereford and others (2000) RC1 Radiocarbon sample locality Stuvier, Minze, and Reimer, P.J., 1993, Extended C database and revised CALIB radiocarbon cali- K 89 ponds mt bration program: Radiocarbon, v. 35, p. 215–230. PAR yt Younger terrace (1884–1921) of Hereford and others (2000)—Well-bedded, very fine BADGER Disturbed Topping, D.J., 1997, Physics of flow, sediment transport, hydraulic geometry, and channel geomor- INDIAN ts ts grained, light-colored silty sand with beds 10–20 cm thick; exposed thickness 4–5 m Disturbed area of mostly covered, unmappable surficial geologic materi- ALT als—Disturbance caused by construction and presence of roads, vehicle parking phic adjustment during flash floods in an ephemeral river, the Paria River, Utah and Arizona: 89 CLIFFS at south side of Paria River north of NPS facilities. Unit interbedded with alluvium 960.4 956.1 Seattle, University of Washington, unpub. Ph.D dissertation, 405 p. CANYON of Paria River at mouth of Paria Canyon. Elevation is 953.9 m near parking area at lots, gravel pits, channel-control structures, and National Park Service facilities pt ht Turner, R.M., and Karpiscak, M.M., 1980, Recent vegetation changes along the Colorado River NATIONAL CANYON mouth of Paria River. Tamarisk locally abundant on terrace; trees are rooted on sur- 1091 between Glen Canyon Dam and , Arizona: U.S. Geological Survey Professional fill face and post-date deposition; ring counts indicate germination in early to mid- DISCUSSION Jac st Paper 1132, 125 p. ka gva ECHO 1960s. Charcoal from near base of unit dated at 1670–1944 (table 1, no. RC1). s The Lonely Dell reach of the Paria River is in the lower Paria Canyon (fig. 1), a colorful rela- s Ulrich, G.E., Billingsley, G.H., Hereford, Richard, Wolfe, E.W., Nealey, L.D., and Sutton, R.L., CANYON Younger terrace is probably equivalent to historic terrace (unit ht) of Paria River tively open valley (fig. 2) eroded into the Moenkopi Formation (Triassic). The valley lies nearly 600 C RESERVATION 1983, Geology, structure, and uranium resources of the Flagstaff 1° x 2° quadrangle: U.S. Geo- r ^cs Lees Lookout e based on similar elevations. Inset, erosional relation with intermediate terrace (unit it) m below the Echo Cliffs on the east and 900 m below the Paria Plateau on the west. Paria Canyon is e 956.9 k logical Survey Miscellaneous Investigations Series Map I–1446, scale 1:250,000. 36°45´ GRAND MARBLE Upstream west-facing view of Paria River channel from near gaging station. Light- it Intermediate terrace (1400?–1883) of Hereford and others (2000)—Well-bedded, a strike valley aligned with the Echo Cliffs monocline, a major northwest trending flexure with more gvb Webb, R.H., 1985, Late Holocene flooding on the Escalante River, south-central Utah: Tucson, Uni- 0 5 KILOMETERS very fine grained, light-colored silty sand with beds 10–20 cm thick; contains inter- than 1 km of uplift. The Paria River, a perennial stream, joins the Colorado River downstream of colored sediment on left side of channel is modern terrace (unit mt) with surface afa 1032 versity of Arizona, unpub. Ph.D dissertation, 204 p. Lonely Dell Ranch Lees Ferry, which is near the beginning of the Grand Canyon of the Colorado River. scoured by flood of August 1998. Vertical cutbank on right side of channel is portion 1023 bedded sheetwash sand and pebble gravel near tributaries; thickness 5–6 m at south Webb, R.H., and Baker, V.R., 1987, Changes in hydrologic conditions related to large floods on the 958.0 ^cp This large-scale surficial geologic map shows the age, distribution, and origin of Quaternary LOCATION OF MAP AREA, EASTERN GRAND CANYON, ARIZONA of prehistoric debris fan (unit dfp). 955.3 side of Paria River north of NPS facilities. Unit interbedded with alluvium of Paria Escalante River, south-central Utah, in Singh, V.P., ed., Regional flood frequency analysis: Bos- River at mouth of Paria Canyon. Elevation ranges from 955.2–955.9 m. Tamarisk deposits in the river valley. Information about recent geologic activity is necessary to understand the 956 mt ton, Mass., Reidel, p. 306–320. natural variability of the river system as well as the rates, magnitudes, and processes of environmen- Orchard and willow not present on terrace. A photograph of north bank of Colorado River Webb, R.H., Smith, S.S., and McCord V.A.S., 1991, Historic channel change of Kanab Creek, south- tal change. The alluvial history of the past thousand years is of particular interest as it relates to how ht 8 taken in 1873 shows intermediate terrace (Turner and Karpiscak, 1980, pls. 32A, ern Utah and northern Arizona: Grand Canyon, Arizona, Grand Canyon Natural History Associ- it 33A; photograph site 11); at that time, terrace was densely covered with rabbitbrush the climate of the Medieval Warm Period (ca. 1000–1400), the Little Ice Age (1400 to the middle- to ts ation Monograph Number 9, 91 p. and fresh-appearing driftwood. Intermediate terrace is equivalent to settlement ter- late 1800s), and recent global warming (late 1800s to present) affected the alluvial system. This his- 954.7 955.2 ^cs race (unit st) and Naha alluvium of southern Colorado Plateau (Hereford and others, tory provides clues about how the Paria River, and others like it, may respond to future climate var- 953.7 RC1 955.2 1996a; Hereford, 2002) iation brought about by increasing concentrations of greenhouse gasses. The alluvial history of the Paria River is especially important as a research topic because of the long, continuous record of 991.6 Flood deposits ^m S streamflow measurements. Beginning in 1923, this record is the longest of any stream originating on NP fdo Older flood deposits (early to middle Holocene) of Hereford and others Parking lot ties yt facili 36°52´00˝ the Colorado Plateau. The long-term streamflow patterns at the Paria and Colorado River gaging sta- 36°52´00˝ 953.5 (2000)—Very fine grained, distinctive light-greenish-gray silty sand with finely 991.3 tions reveal environmental changes of the 20th century, including arroyo cutting, droughts, and gvc interbedded silt and very fine sand couplets 1–5 mm thick that form low-angle cross 953.9 10 floods (Andrews, 1990, 1991). 955.9 it strata; exposed thickness 3–5 m. Elevation of deposit corresponds to extrapolated 974.5 The Lees Ferry/Lonely Dell area has a long and rich cultural history (Rusho and Crampton, 950 gage height (Colorado River gaging station) of 18.7–23.3 m (59.9–76.3 ft). By com- Boat ramp 952.7 1992; Reilly, 1999). The area has been an important Colorado River crossing since prehistoric times. it parison, the largest recorded flood (July 1884) has estimated gage height of only 9.6 ) (1934 yt It is the only accessible ford of the Colorado River between two virtually uncrossable canyons, Glen d m (31.5 ft), corresponding to discharge of 8,500 m3/s (300,000 ft3/s) ^m oa r r Canyon and . The first written description of the area is the Dominguez-Escalante ve ea Gravel deposits Journal (Chavez, 1976, p. 93–95), an account of an expedition through the Southwest in 1776. The W 953.7 gvc eo L 953.7 Active and recently active channel bars and Pleistocene terraces expedition camped on the banks of the Paria River below Lees Lookout from October 27 to Novem- Disturbed fdo gv ber 1, 1776, while trying unsuccessfully to cross the Colorado River. They left the area via Sand 991.6 Gravel deposits, undivided (1400?–2000)—Gravel composed mainly of sub-rounded 1 958.4 Levee 12 /2° Pass Trail and forded the Colorado River at Crossing of the Fathers, 40 km northeast of the study SCALE 1:5000 mt pda Cableway to rounded pebbles to small cobbles of local Mesozoic formations, rounded small area. As they rode north up the Paria River valley, they passed over what is now the settlement ter- TH cobbles of quartzite, pinkish pebbles of Claron Formation derived from headwaters 0 0.1 0.2 0.3 0.4 0.5 MILES ARIZONA 963.2 pdz OR of Paria River, and along Colorado River, minor well-rounded cobbles of far-travel- race (unit st). Almost a century later, the area was visited and described by John Wesley Powell dur- 952.9 952.8 led porphyritic rocks; thickness 1–4 m. At mouth of Paria River unit forms a broad ing his explorations of the Colorado River. In late 1871, the ferry and Lonely Dell Ranch were 0 0.1 0.2 0.3 0.4 0.5 KILOMETERS NPS Ranger station dw dw TRUE NORTH established by John D. Lee. Because of its regional importance as a river crossing, its spectacular AGNETIC N 11 extensively reworked fan that deflects Colorado River to south. In Paria Canyon, M MAP LOCATION Transverse mercator projection scenery, and the presence of two stream gaging stations, the area has been photographed numerous APPROXIMATE MEAN 12 unit forms gravel bars in active channel and inactive bars associated with the mod- DECLINATION, 2003 Datum WGS84 times beginning in 1872 (Turner and Karpiscak, 1980). These photographs are reproduced and inter- ea ern (unit mt), historic (unit ht), and settlement (unit st) terraces. The latter two grav- els are very lightly weathered with moderately formed to well-formed cryptobiotic preted in the accompanying pamphlet by R.H. Webb and Richard Hereford. The photographs show LE 950 gvc crusts covering matrix between clasts clearly that the channels of the Paria and Colorado Rivers have changed substantially in the inter- 953.2 vening 123 years. In modern times, the area is important for recreation including sightseeing, hiking, gvd Level d gravel deposits (latest Pleistocene)—Gravel composed mainly of sub-rounded pdz and fishing, and as a launching point for whitewater raft trips through Grand Canyon. 9 and rounded to well-rounded pebbles and small cobbles of local Mesozoic forma- 950.5 Disturbed The alluvial deposits are grouped into two principal types and ages. The older deposits are tions and well-rounded quartzite and porphyry and pinkish pebbles of Claron For- mainly gravel deposited by the Paria River and Colorado River during the middle to latest Pleisto- Map Showing Quaternary Geology and Geomorphology of the Lonely Dell Reach pda mation from headwaters of Paria River; thickness 15 m. Matrix is moderately sorted cene. These deposits occur at four distinct topographic levels ranging from about 10 to 140 m above coarse sand. Base of gravel is 8–9 m above river. Gravel on surface is distinctly var- the present river channel. The gravel deposits record the downcutting and backfilling of the river mt nished. Unit has steeply dipping concave contact with underlying Moenkopi Forma- of the Paria River, Lees Ferry, Arizona 950.3 during the past 700 ka (ka = 1,000 yrs). The younger deposits are primarily sand deposited during tion. Probably equivalent to younger gravel deposits (unit gvy) of Hereford and the late Holocene up to and including the modern era. Based on the streamflow record and contem- By ea others (2000) based on height above Paria River IA RIFF NE poraneous alluvial history, aggradation and erosion of these valley- and channel-fill deposits result 949 gvc Level c gravel deposits (late Pleistocene)—Gravel composed mainly of sub-rounded largely from changes in how often large floods occur, which in turn is relates to climate variations, Richard Hereford PAR BACKBO and rounded pebbles and small cobbles of local Mesozoic formations and well- particularly episodic increases of runoff-producing precipitation. rounded quartzite and porphyry and pinkish pebbles of Claron Formation from gv headwaters of Paria River; thickness 17–28 m and 10–33 m along Colorado and PLEISTOCENE GRAVEL DEPOSITS with accompanying pamphlet Paria Rivers, respectively. Base of gravel ranges from 14–26 m above Colorado Where well preserved, the gravel deposits are up to 33 m thick. The basal contact with bedrock LEES River and from 14–22 m above Paria River. NPS ranger station is built on terrace is concave reflecting the configuration of the underlying bedrock channel. Four distinct levels are Comparative Landscape Photographs of the Lonely Dell Area formed by this gravel. Level c gravel (unit gvc) is equivalent to older gravel (unit present: levels and with heights above the Paria River measured from the base of the gravel of 140, gvo) of Hereford and others (2000) 51–65, 14–22, and 8–9 m, respectively. Thus, Paria Canyon has been downcut 140 m through bed- and the Mouth of the Paria River gvb Level b gravel deposits (early to late Pleistocene)—Gravel composed mainly of sub- rock since deposition of the a-level gravel (unit gva). Downcutting to the present level of the river Geology compiled from aerial photographs taken August 17, rounded and rounded pebbles and small cobbles of local Mesozoic formations and was episodic occurring four times. Each downcutting, however, was followed by backfilling or By 1998. Approximate scale 1:6,000 well-rounded quartzite and porphyry and pinkish pebbles of Claron Formation from channel filling that together equaled or exceeded the 140 m of downcutting, because the cumulative Any use of trade, product, or firm names in this publication is for Digital database by Debra Block headwaters of Paria River; thickness 10–12 m. Base of gravel is 73 m above Colo- gravel thickness is at least 140 m. descriptive purposes only and does not imply endorsement by the U.S. Robert H. Webb and Richard Hereford Government. Edited by Theresa Iki; cartography by Darlene A. Ryan rado River at Lees Lookout and 51–65 m above Paria River. Gravel on surface is The surfaces of the gravels are heavily weathered. Cobbles and boulders are mainly resistant For sale by U.S. Geological Survey, Information Services, Box 25286, 2003 Manuscript approved for publication November 21, 2002 deeply varnished and heavily decomposed quartzites. Their surfaces have dark coatings of rock varnish and the undersides are rubified or have Federal Center, CO 80225, 1–888–ASK–USGS gva Level a gravel deposits (early to middle Pleistocene)—Lag gravel of well-rounded rinds of calcium carbonate up to 1 mm thick. This degree of weathering and the height of the depos- Available on World Wide Web at http://pubs.usgs.gov/imap/i2771 quartzite pebbles and small cobbles; thickness 1 m. Base of gravel is 140 m above its above the two rivers indicates they are Pleistocene. Moreover, the degree of weathering and the 36°51´30˝ height above the river are similar to gravels of known middle to late Pleistocene age in the Little 36°51´30˝ INTERIOR—GEOLOGICAL SURVEY, RESTON, VA—2003 Paria River Printed on recycled paper 111°36´00˝ 111°35´30˝ 111°35´00˝ 111°37´30˝ 111°37´00˝ 111°36´30˝