Landscape Evolution at an Active Plate Margin - Biological Science ...

More documents

Recommendations

Info

in 1922 the companies were merged. Production continued until 1972 when a lawsuit pursued by the BLM found the original claims to be invalid. 45.3 (0.4) Continue past the right (north) turnoff to Last Chance Canyon. Once the main access into the El Paso Mountains, this road now requires 4WD since flash floods have re-engineered the road. 47.7 (2.4) The site of Gypsite (south), operated by Charles Koehn in 1909, produced gypsite (gypsum and clay) used for plaster and agricultural soil amendments (Hensher, 1998). 49.1 (1.4) Cross the channel of Red Rock Canyon Wash. 49.6 (0.5) View of Honda test facility (see below). 49.9 (0.3) Continue past Cantil Road to the left. 50.7 (0.8) Cross a drainage. 53.0 (2.3) Neuralia Road is on the left just before we turn off on CA 14. Stop at the intersection with CA 14. Look to the south to see a curving line of vegetation. This marks the edge of a 3-mile-wide oval (clearly seen in Goggle Earth imagery) test facility owned by Honda Motor Corporation. The facility is well guarded and off limits to travelers. At night, car headlights can often be seen as they circle the track. This has fueled conspiracy theories that the test track is the locus of “alien” activity from the nearby “vortex” in the El Paso Mountains. TURN RIGHT (north) toward Red Rock Canyon State Park. 55.4 (2.4) A trace of the El Paso fault is visible ahead to the left and right. The tan sediments to the west contain a fossil fauna that is significantly younger (late Hemphillian) than faunas in the Dove Spring formation. The sediments are bounded by the El Paso fault (north), the Sierra front fault (west) and the Garlock fault (southeast) and higher degree of clockwise rotation (35 degrees) than the Dove Spring Formation (15 degrees; Whistler, 1991, p. 111). This suggests that the block has a history independent from the Dove Spring Formation, and may have been left-laterally translated from the Bedrock Spring Formation in the Lava Mountains (east of Hwy 395); a distance of approximately 30 miles in the last 7–5 Ma. 56.1 (0.7) Cross the trace of the El Paso fault, which here juxtaposes Mesozoic (Jurassic?) rocks and undifferentiated Ricardo Miocene Group on its down- D. R. Jessey and R. E. Reynolds thrown side (Whistler, 2005). Although motion along this fault has been characterized as predominantly dip-slip, its proximity to the Garlock fault suggests it may have a left-slip component. Despite paleoseismic studies on the nearby Garlock fault (McGill, 1992), little is known about slip rates for the El Paso fault. The SCEDC website suggests last movement in the Late Quaternary, but this presents a structural conundrum. The Garlock fault near this location has moved within the past 500 years, suggesting it is quite active. As such, its close proximity to the south-dipping El Paso fault should result in the Garlock fault buttressing dip slip movement along the El Paso fault. Perhaps Quaternary movement along the El Paso fault has been largely left-slip? 56.8 (0.7) Basement rocks (largely granite) are unconformably overlain by the Miocene Ricardo Group. This is best seen driving south on CA 14; when driving north, look back at the unconformity after passing a ridge of Mesozoic basement rock. 57.4 (0.6) Move to left lane and prepare for a left turn. Watch for oncoming traffic. 57.6 (0.2) TURN LEFT (west) on Abbott Road to the Ricardo Campground and Red Rock Park headquarters. 58.5 (0.9) Note the basalt outcrop on the left side of the road. 58.8 (0.3) Red Rock Canyon visitors center (El: 2175 ft.). PARK on pavement before kiosk. STOP 1-2 (N 35°22’23.3”; W 117°59’18.3”). This outcrop (Fig. 1-5) lies within the west-dipping Dove Spring Formation of the Miocene Ricardo Group. Loomis (1984) divided the Dove Spring Formation Figure 1-5. Stop 2: outcrop of Miocene Dove Spring basalt exposed along Abbott Road. [D. R. Jessey photo] 12 2009 Desert Symposium
into six units which range in age from 7 to 13 Ma. The Dove Spring Formation lies unconformably on the Cudahy Camp Formation. The Cudahy Camp is thought to have been deposited from 15-19 Ma (Loomis and Burbank, 1988). The base of the Dove Spring is marked by conglomerate grading upward into arkose. Overlying layers are comprised of a variety of differing lithologies including lacustrine and fluvial sandstones, siltstones and conglomerates, felsic tuffs and basalt flows. The uppermost unit (Unit 6 of Loomis, 1984) is a nearly flat-lying sedimentary sequence that lies disconformably on the units 1-5 of the Dove Spring. Recent ages published by Frankel, et al., (2008) indicate the three lowermost basalts were extruded between 11.7 and 10.5 Ma. No age is available for the uppermost basalt flow, but Whistler (1987) quotes an age of 8.1 Ma for a rhyolite tuff above the basalt. This brackets basalt extrusion between about 8-12 Ma. Loomis and Burbank (1988) examined the evolution of the El Paso basin and concluded that extrusion of the basalts was coincident with the onset of left-slip motion along the Garlock fault and the east-west extension characteristic of Basin and Range topography. The subsequent emergence of the Sierra Nevada Mountains began at 8 Ma. Frankel (Frankel et al. 2008) argues that the Summit Mountains south of the Garlock fault are correlative with the Dove Spring Formation, but paradoxically they contain no basalt flows. This suggests a very local source for the basalts. Unfortunately, evidence for nearby faults of the proper age to provide a conduit for the basalt flows is absent. (Fig. 1-6) 2009 Desert Symposium Landscape evolutuion at an active plate margin: field trip Anderson (2004) sampled four basalt flows within the Dove Spring Formation (Tba 1 –Tba 3 of Loomis (1984) and a fourth undifferentiated flow within unit 4 of Loomis). Figure 1-6ais a total alkalis vs. silica diagram for the basalts of the Dove Spring Formation. Basalts from the Coso volcanic field (Stop 3) are shown for comparison. Note that Dove Spring (DS) basalts average approximately 53% total SiO 2 and 3% total alkalis. This is 3-5% more silica than basalts from other Owens Valley and Mojave basalt fields and 1-3% more alkalis. Figure 1-6b is a basalt tetrahedron, again comparing the DS and Coso basalts. DS basalts are generally tholeiites while those from Coso are predominantly alkali basalts. The latter are far more characteristic of southern California basalt fields. While some fields; i.e., Big Pine and Darwin, span the entire range of basalt compositions, most like Coso, Cima, Pisgah and Amboy are distinctly alkaline. Tholeiitic basalts are uncommon. Anderson (2004) also noted the presence of iddingsite in many DS basalts. Iddingsite, a cryptocrystalline mixture of hydrated iron oxides and Mg-clays rims, veins and in many cases totally replaces olivine. In other cases, olivine has altered to a calcium-rich siderite. Unaltered olivine is extremely rare, as the CIPW norm depicted in Figure 1-6b would suggest. Iddingsite is a controversial mineral/alteration product originally thought to form by weathering of olivine. However, Edwards (1938) suggested that iddingsite was more likely a deuteric alteration product formed during magma mixing. Baker and Haggerty (1967) concluded the formation of iddingsite required only an increased oxygen fugacity and could be achieved simply by allowing a basaltic magma to incorporate circulating meteoric water. Furgal and McMillan (2001) reached a similar conclusion, but cautioned the alteration required elevated temperatures, not typical of circulating groundwater. Figure 1-6. (a) Total alkalis vs. silica (TAS) diagram for the Coso and Ricardo (Dove Spring) volcanic fields; (b) basalt tetrahedron for the two fields [modified from Anderson, 2004]. 13
Page 1 and 2: Landscape Evolution at an Active Pl
Page 3 and 4: Table of contents Landscape evoluti
Page 5 and 6: Evaluation of minor and trace eleme
Page 7 and 8: Landscape evolution at an active pl
Page 9 and 10: 25.3 (0.2) Continue past Osdick Rd.
Page 11: and Wesnousky, 1994). Reported rate
Page 15 and 16: Nevada & California railroad were u
Page 17 and 18: een built to meet the growing deman
Page 19 and 20: Figure 1-10. Offset drainages of Lo
Page 21 and 22: tary and metavolcanic units are lar
Page 23 and 24: Landscape evolutuion at an active p
Page 25 and 26: the Independence fault is dip-slip,
Page 27 and 28: Figure 1-18. Upper—view to the no
Page 29 and 30: 2009 Desert Symposium Landscape evo
Page 31 and 32: eruption of the Long Valley caldera
Page 33 and 34: Figure 2-2. Collapsed aqueduct pipe
Page 35 and 36: 63.7 (0.4) PARK at turnout. STOP 2-
Page 37 and 38: Sierra Nevada fault system has offs
Page 39 and 40: Landscape evolutuion at an active p
Page 41 and 42: (Cleveland, 1962). The rhyolite has
Page 43 and 44: ahead on the left. 95.6 (1.2) Stop
Page 45 and 46: ay. The big 40m dish is now used by
Page 47 and 48: cupied in 1865, and finally abandon
Page 49 and 50: Figure 3-6. Independence dikes. [S.
Page 51 and 52: which has significant concentration
Page 53 and 54: The Pliocene (Blancan NALMA) Coso F
Page 55 and 56: Current Research in the Pleistocene
Page 57 and 58: Quaternary data and references: A c
Page 59 and 60: and volume, p. 26-35. Smith, G. I.,
Page 61 and 62: Stolzite and jixianite from Darwin,
Page 63 and 64:
(112) (Palache, et al., 1951). The
Page 65 and 66:
ing gold and silver deposits. From
Page 67 and 68:
the United States. Several small de
Page 69 and 70:
at the base of the Lost Burro were
Page 71 and 72:
silver-lead ore and is the one exce
Page 73 and 74:
Significance of the Independence Di
Page 75 and 76:
Independence Dike Swarm Figure 2: C
Page 77 and 78:
40 km of displacement was too low.
Page 79 and 80:
dominant northwest strike. Dikes wi
Page 81 and 82:
Moore, J.G., 1963, Geology of the M
Page 83 and 84:
summarizes the formations you will
Page 85 and 86:
The Perdido Formation conformably r
Page 87 and 88:
note the spheroidal weathering patt
Page 89 and 90:
Lower Cambrian-Precambrian stratigr
Page 91 and 92:
lus. Six to ten species of echinode
Page 93 and 94:
The Olancha Dunes, Owens Valley, Ca
Page 95 and 96:
Triassic ammonoids from Union Wash,
Page 97 and 98:
Archaeocyathids from Westgard Pass,
Page 99 and 100:
Basaltic volcanism in the southern
Page 101 and 102:
Basaltic volcanism in the southern
Page 103 and 104:
oxene, whereas Pleistocene basalt i
Page 105 and 106:
in much slower rates of displacemen
Page 107 and 108:
Vegetation of the Owens Valley and
Page 109 and 110:
cone and limber pine woodlands and
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Figure 21. The alpine zone of the W
Page 117 and 118:
The rush from the Kern River mines
Page 119 and 120:
The rush from the Kern River mnes i
Page 121 and 122:
2009 Desert Symposium The rush from
Page 123 and 124:
mining company; and A. K. Warner an
Page 125 and 126:
chinery and the castings for a smel
Page 127 and 128:
Advertisement for the Hobard and Re
Page 129 and 130:
November 1864, a series of lines be
Page 131 and 132:
When the geologist W. A. Goodyear v
Page 133 and 134:
Montgomery City Alan Hensher, 593 C
Page 135 and 136:
The Blue Chert Mine: an epithermal
Page 137 and 138:
2009 Desert Symposium The Blue Cher
Page 139 and 140:
2009 Desert Symposium The Blue Cher
Page 141 and 142:
Tectonic implications of basaltic v
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
The Goler Club Figure 2. Outcrop ma
Page 151 and 152:
closest relatives were early Paleoc
Page 153 and 154:
The Goler Club Figure 8. Goler Club
Page 155 and 156:
prospecting, Baum wandered over to
Page 157 and 158:
ejonian age (Thewissen 1990; Lofgre
Page 159 and 160:
Fish Creek rhythmites and aperiodic
Page 161 and 162:
We analyzed each of the three rhyth
Page 163 and 164:
Figure 10. Threshold rhythmite prod
Page 165 and 166:
Holocene slip rate and tectonic rol
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Figure 2. Camelops sp. (camel) meta
Page 175 and 176:
moist, brush- and grass-covered, fr
Page 177 and 178:
Recent records of fossil fish from
Page 179 and 180:
geal arches are similar to S. b. sn
Page 181 and 182:
elatives seen in Pliocene and early
Page 183 and 184:
Jennings, C.W. 1958, Geologic map o
Page 185 and 186:
Competing mesquite and creosote dun
Page 187 and 188:
Figure 9. Sheetwash area near the w
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
The Oak Crrek mudflow of July 12, 2
Page 195 and 196:
Photo 8. Deeply incised channel of
Page 197 and 198:
than the north fork because of the
Page 199 and 200:
mass contents of Gram negatives (sa
Page 201 and 202:
to different uses. I do not suggest
Page 203 and 204:
Geochronology and paleoenvironment
Page 205 and 206:
Reproductive ecology of female Sono
Page 207 and 208:
Garbage production is the other sid
Page 209 and 210:
ties and preparation for use of som
show all

Landscape Evolution at an Active Plate Margin - Biological Science ...

Create successful ePaper yourself

Delete template?

Save as template?