Figure 1 - uploaded by Jordon Bright
Content may be subject to copyright.
Lake Dumont study area relative to (A.) the western United States; and (B.) to other pluvial lakes along the Amargosa and Mojave Rivers. Wavy dashed line is approximate divide between the Mojave and Amargosa River watersheds. LM – Lake Manly; LT – Lake Tecopa; LD – Lake Dumont; LMo – Lake Mojave; LMx – Lake Manix. Figure modified from Morrison (1991).
Source publication
New ostracode faunal analyses on core and numerous outcrop samples in the Salt Spring basin suggest that basing sediments previously interpreted as lacustrine are instead wetland deposits. Four wet intervals (intermittent between about 29 and 23, and again at about 18 ka) are preserved in core DU-2. The ostracode faunas found in these intervals are...
Similar publications
Faunistic associations of the Lower Pleistocene sediments, out-cropping at Cartiera Molino along the true right bank of the Ippari River (Vittoria, SE Sicily), have been investigated. This study integrates data obtained from the analysis of ostracods, foraminifers, bryozoans and serpulids found within a six metre thick sedimentary section. This mul...
Citations
... During years with above-average precipitation, the ephemeral Mojave River flows~200 km from the San Bernardino Mountains of southern California northeast across the Mojave Desert before terminating at Silver Lake basin ( Fig. 1; Enzel et al., 2003). Over the last 30,000 yr, the Mojave River terminated in each of these pluvial lakes: Harper Lake, Lake Manix (combined Afton, Coyote, and Troy sub-basins), Cronese Lake (combined East and West), Lake Mojave (combined Soda and Silver sub-basins) and Lake Manly (Death Valley) ( Fig. 1; Blackwelder, 1954;Meek, 1999;Anderson and Wells, 2003;Cox et al., 2003;Jefferson, 2003;Wells et al., 2003;Bright and Anderson, 2005;Reheis and Redwine, 2008;Reheis et al., 2012). Enzel et al. (1989Enzel et al. ( , 2003 proposed that above-average precipitation and runoff in the San Bernardino Mountains and the formation of Mojave River pluvial lakes occurred in response to a southerly shift in the North American polar jet stream (NAPJS). ...
... Anderson and Wells (2003) suggested that overflow from Lake Mojave supported downstream Lake Dumont in the Salt Spring Basin at 20 cal ka BP (recalibrated 14 C yr BP with IntCal 09 in 2013). Subsequent ostracode faunal analyses reinterpreted sediments previously identified as Mojave River-supported lake deposits to instead be groundwaterdependent wetland deposits (Bright and Anderson, 2005). ...
... Using the population and known alkalinity (ALK, typically as HCO 3 − ) to calcium ratio (ALK/Ca) in dissolved water range of various ostracode species, Bright and Anderson (2005) defined general water types for the Mojave River. Due to the generally oxic and alkaline groundwater discharging into the Mojave River (Izbicki et al., 2008), river water typically has an ALK/Ca ratio of about 1.3. ...
Accurate reconstruction of the paleo-Mojave River and pluvial lake (Harper, Manix, Cronese, and Mojave) system of southern California is critical to understanding paleoclimate and the North American polar jet stream position over the last 500 ka. Previous studies inferred a polar jet stream south of 35°N at 18 ka and at ~ 40°N at 17-14 ka. Highstand sediments of Harper Lake, the upstream-most pluvial lake along the Mojave River, have yielded uncalibrated radiocarbon ages ranging from 24,000 to > 30,000 14C yr BP. Based on geologic mapping, radiocarbon and optically stimulated luminescence dating, we infer a ~ 45-40 ka age for the Harper Lake highstand sediments. Combining the Harper Lake highstand with other Great Basin pluvial lake/spring and marine climate records, we infer that the North American polar jet stream was south of 35°N about 45-40 ka, but shifted to 40°N by ~ 35 ka. Ostracodes (Limnocythere ceriotuberosa) from Harper Lake highstand sediments are consistent with an alkaline lake environment that received seasonal inflow from the Mojave River, thus confirming the lake was fed by the Mojave River. The ~ 45-40 ka highstand at Harper Lake coincides with a shallowing interval at downstream Lake Manix.
... During years with above-average precipitation, the ephemeral Mojave River flows~200 km from the San Bernardino Mountains of southern California northeast across the Mojave Desert before terminating at Silver Lake basin ( Fig. 1; Enzel et al., 2003). Over the last 30,000 yr, the Mojave River terminated in each of these pluvial lakes: Harper Lake, Lake Manix (combined Afton, Coyote, and Troy sub-basins), Cronese Lake (combined East and West), Lake Mojave (combined Soda and Silver sub-basins) and Lake Manly (Death Valley) ( Fig. 1; Blackwelder, 1954;Meek, 1999;Anderson and Wells, 2003;Cox et al., 2003;Jefferson, 2003;Wells et al., 2003;Bright and Anderson, 2005;Reheis and Redwine, 2008;Reheis et al., 2012). Enzel et al. (1989Enzel et al. ( , 2003 proposed that above-average precipitation and runoff in the San Bernardino Mountains and the formation of Mojave River pluvial lakes occurred in response to a southerly shift in the North American polar jet stream (NAPJS). ...
... Anderson and Wells (2003) suggested that overflow from Lake Mojave supported downstream Lake Dumont in the Salt Spring Basin at 20 cal ka BP (recalibrated 14 C yr BP with IntCal 09 in 2013). Subsequent ostracode faunal analyses reinterpreted sediments previously identified as Mojave River-supported lake deposits to instead be groundwaterdependent wetland deposits (Bright and Anderson, 2005). ...
... Using the population and known alkalinity (ALK, typically as HCO 3 − ) to calcium ratio (ALK/Ca) in dissolved water range of various ostracode species, Bright and Anderson (2005) defined general water types for the Mojave River. Due to the generally oxic and alkaline groundwater discharging into the Mojave River (Izbicki et al., 2008), river water typically has an ALK/Ca ratio of about 1.3. ...
Accurate reconstruction of the paleo-Mojave River and pluvial lake (Harper, Manix, Cronese, and Mojave) system of southern California is critical to understanding paleoclimate and the North American polar jet stream position over the last 500 ka. Previous studies inferred a polar jet stream south of 35°N at 18 ka and at ~40°N at 17–14 ka. Highstand sediments of Harper Lake, the upstream-most pluvial lake along the Mojave River, have yielded uncalibrated radiocarbon ages ranging from24,000 to >30,000 14C yr BP. Based on geologic mapping, radiocarbon and optically stimulated luminescence dating, we infer a ~45–40 ka age for the Harper Lake highstand sediments. Combining the Harper Lake highstand with other Great Basin pluvial lake/spring and marine climate records, we infer that the North American polar jet stream was south of 35°N about 45–40 ka, but shifted to 40°N by ~35 ka. Ostracodes (Limnocythere ceriotuberosa) from Harper Lake highstand sediments are consistent with an alkaline lake environment that received seasonal inflow from the Mojave River, thus confirming the lake was fed by the Mojave River. The ~45–40 ka highstand at Harper Lake coincides with a shallowing interval at downstream Lake Manix.
... Lake Dumont existed before Lake Mojave and started to fill before 26 ka (radiocarbon years) radiocarbon (Anderson and Wells, 2003b). Recently, studies have suggested that some or all of the Lake Dumont deposits are wetland deposits (Reynolds et al., 2003; Bright and Anderson, 2006), rather than widespread lacustrine deposits. The Pleistocene to Holocene transition in the Silurian Valley area is marked by hydrologic responses of several kinds. ...
... Local alluvial fan channels within and east of Silurian Valley have also contributed. The modern and Holocene hydrologic system within Silurian Valley includes three low-gradient stretches: the through-flow playa of Silurian Lake, a junction with Kingston Wash near the Dumont wetland deposits of the Salt Springs area (Bright and Anderson, 2006), and at the junction with the Amargosa River. We have not dated all elements of this system, but offer several observations and dates of hydrologic events for pieces of the system. ...
The chronology of the Holocene and late Pleistocene deposits of the northeastern Mojave Desert have been largely obtained using radiocarbon ages. Our study refines and extends this framework using optically stimulated luminescence (OSL) to date deposits from Valjean Valley, Silurian Lake Playa, Red Pass, and California Valley. Of particular interest are eolian fine silts incorporated in ground-water discharge (GWD) deposits bracketed at 185–140 and 20–50 ka. Alluvial fan deposits proved amenable for OSL by dating both eolian sand lenses and reworked eolian sand in a matrix of gravel that occurs within the fan stratigraphy. Lacustrine sand in spits and bars also yielded acceptable OSL ages. These OSL ages fill gaps in the geochronology of desert deposits, which can provide data relevant to understanding the responses of several depositional systems to regional changes in climate. This study identifies the most promising deposits for future luminescence dating and suggests that for several regions of the Mojave Desert, sediments from previously undated landforms can be more accurately placed within correct geologic map units.
The western pond turtle (WPT) was formerly considered a single species ( Actinemys or Emys marmorata ) that ranged from southern British Columbia, Canada to Baja California, México. More recently it was divided into a northern and a southern species. WPTs are found primarily in streams that drain into the Pacific Ocean, although scattered populations exist in endorheic drainages of the Great Basin and Mojave deserts. Populations in the Mojave Desert were long thought to be restricted to the Mojave River, but recently another population was documented in Piute Ponds, a terminal wetland complex associated with Amargosa Creek on Edwards Air Force Base. WPT fossils in the Mojave Desert are known from the Miocene to the Pleistocene. Recently, Pleistocene fossils have been found as far into the desert as Salt Springs, just south of Death Valley. The oldest fossil records suggest that WPTs were present in wetlands and drainages of the geological feature known as the Mojave block prior to the uplift of the Sierra Nevada Range about 8 Ma and prior to the ~ 3 Ma uplift of the Transverse Ranges. Archaeological records document use of turtles by Native Americans for food and cultural purposes 1,000 or more years ago at the Cronese Lakes on the lower Mojave River and Oro Grande on the upper river. The first modern publication documenting their presence in the Mojave River was 1861. Museum specimens were collected as early as 1937. These fossil and early literature records support the indigenous status of WPTs to the Mojave River. However, mtDNA-based genetic evidence shows that Mojave River turtles share an identical haplotype with turtles on the California coast. Limited nuclear data show some minor differences. Overdraft of water from the Mojave River for municipal and agricultural uses, urban development, and saltcedar expansion are threats to the continued survival of WPTs in the Mojave River.
Considerable prior research has focused on the interconnected pluvial basins of Owens Lake and Searles Lake, resulting in a long record of paleohydrological change in the lower Owens River system. However, the published record is poorly resolved or contradictory for the period encompassing the terminal Pleistocene (22,000 to 11,600 cal BP) and early Holocene (11,600–8200 cal BP). This has resulted in conflicting interpretations about the timing of lacustrine high stands within the intermediate basin of China Lake, which harbors one of the most extensive records of early human occupation in the western Great Basin and California. Here, we report a broad range of radiocarbon-dated paleoenvironmental evidence, including lacustrine deposits and shoreline features, tufa outcrops, and mollusk, ostracode, and fish bone assemblages, as well as spring and other groundwater-related deposits (a.k.a. “black mats”) from throughout China Lake basin, its outlet, and inflow drainages. Based on 98 radiocarbon dates, we develop independent evidence for five significant lake-level oscillations between 18,000 and 13,000 cal BP, and document the persistence of groundwater-fed wetlands from the beginning of the Younger Dryas through the early Holocene (12,900–8200 cal BP); including the transition from ground-water fed lake to freshwater marsh between about 13,000 and 12,600 cal BP. Results of this study support and refine existing evidence that shows rapid, high-amplitude oscillations in the water balance of the Owens River system during the terminal Pleistocene, and suggest widespread human use of China Lake basin began during the Younger Dryas.
