ALBERT

Description: Four new latest Pleistocene slip rates from two sites along the northwestern half of the San Bernardino strand of the San Andreas fault suggest the slip rate decreases southeastward as slip transfers from the Mojave section of the San Andreas fault onto the northern San Jacinto fault zone. At Badger Canyon, offsets coupled with radiocarbon and optically stimulated luminescence (OSL) ages provide three independent slip rates (with 95% confidence intervals): (1) the apex of the oldest dated alluvial fan (ca. 30–28 ka) is right-laterally offset ~300–400 m yielding a slip rate of 13.5 +2.2/−2.5 mm/yr; (2) a terrace riser incised into the northwestern side of this alluvial fan is offset ~280–290 m and was abandoned ca. 23 ka, yielding a slip rate of 11.9 +0.9/−1.2 mm/yr; and (3) a younger alluvial fan (13–15 ka) has been offset 120–200 m from the same source canyon, yielding a slip rate of 11.8 +4.2/−3.5 mm/yr. These rates are all consistent and result in a preferred, time-averaged rate for the past ~28 k.y. of 12.8 +5.3/−4.7 mm/yr (95% confidence interval), with an 84% confidence interval of 10–16 mm/yr. At Matthews Ranch, in Pitman Canyon, ~13 km northwest of Badger Canyon, a landslide offset ~650 m with a 10Be age of ca. 47 ka yields a slip rate of 14.5 +9.9/−6.2 mm/yr (95% confidence interval). All of these slip rates for the San Bernardino strand are significantly slower than a previously published rate of 24.5 ± 3.5 mm/yr at the southern end of the Mojave section of the San Andreas fault (Weldon and Sieh, 1985), suggesting that ~12 mm/yr of slip transfers from the Mojave section of the San Andreas fault to the northern San Jacinto fault zone (and other faults) between Lone Pine Canyon and Badger Canyon, with most (if not all) of this slip transfer happening near Cajon Creek. This has been a consistent behavior of the fault for at least the past ~47 k.y.

Description: Continuous or discontinued manure applications to agricultural soils may impact soil organic carbon (SOC) and water balances because of manure carbon inputs and the potential for manure-induced soil hydrophobicity (SH) and soil water repellency (SWR). A laboratory study was conducted using a long-term (44 yr) field experiment on a clay loam soil to determine the effect of application rate of feedlot manure under dryland (0, 30, 60, and 120 Mg ha-1 wet wt.) and irrigation (0, 60, 120, 180 Mg ha-1) on SOC, SH and SWR. In addition, we compared the effect of 44 yr of continuous annual manure applications (C44) to legacy treatments which had discontinued applications for 14 yr (D14) or 30 yr (D30). Laboratory measurements were conducted on air-dried and sieved ( 1.95) SWR. Manure application rate had a significant (P ≤ 0.05) and positive effect on SOC and SH, and both followed an exponential model. In contrast, RI had a negative response to application rate under dryland and had no response under irrigation. Overall, positive responses of SOC and SH to application rate supported our hypothesis, but it was not supported for RI. The hypothesis of greater SOC, SH, and RI for continuous versus discontinued treatments was also supported for SOC and SH, but not for RI.

Description: For four decades fairbankite was reported to have the formula Pb2+(Te4+O3), but repeated attempts to isolate fairbankite crystals for structural determination found only the visually similar cerussite and, more rarely, anglesite. The crystal-structure determination of fairbankite using single-crystal X-ray diffraction, supported by electron microprobe analysis and X-ray powder diffraction on the type specimen, has shown that fairbankite contains essential S, along with Pb, Te, and O. The chemical formula of fairbankite has been revised to Pb122+(Te4+O3)11(SO4). This change has been accepted by the IMA–CNMNC, Proposal 19-I. The crystal structure of fairbankite [space group P1 (no. 1); revised cell: a = 7.0205(3) Å, b = 10.6828(6) Å, c = 14.4916(8) Å, a = 75.161(5)°, b = 81.571(4)°, g = 83.744(4)°, V = 1036.35(9) Å3, and Z = 1] is the first atomic arrangement known to contain a Te34+O96− non-cyclic, finite building unit. Fairbankite has an average structure, formed from a 3D framework of Pb2+On polyhedra, Te4+On polyhedra, and SO4 tetrahedra in a 12:11:1 ratio. The stereoactive lone pairs of the Pb2+ and Te4+ cations are oriented into void space within the structure. Fairbankite contains two mixed sites statistically occupied by Te4+ and S6+ in approximately 4:1 and 1:4 ratios. These two sites possess Te4+ in trigonal-pyramidal environment and S6+ in tetrahedral environment (with an additional O site to create tetrahedral SO4 shape for the S-dominant site). Six of the 10 fully occupied Te4+ sites have Te4+ in trigonal-pyramidal environment, while four have Te4+ at the center of highly distorted Te4+O4 disphenoids. The disphenoids allow for the creation of two dimeric Te24+O64− units in addition to the Te34+O96− trimeric unit, which contains two disphenoids. All linkage between disphenoids and trigonal pyramids is via corner-linking. Secondary connectivity is via long Te–O and Pb–O bonds.

Description: Geomorphic mapping, landform and sediment analysis, and cosmogenic 10Be and 36Cl ages from erratics, moraine boulders, and glacially polished bedrock help define the timing of the Wisconsinan glaciations in the Chugach Mountains of south-central Alaska. The maximum extent of glaciation in the Chugach Mountains during the last glacial period (marine isotope stages [MIS] 5d through 2) occurred at ~50 ka during MIS 3. In the Williwaw Lakes valley and Thompson Pass areas of the Chugach Mountains, moraines date to ~26.7 ± 2.4, 25.4 ± 2.4, 18.8 ± 1.6, 19.3 ± 1.7, and 17.3 ± 1.5 ka, representing times of glacial retreat. These data suggest that glaciers retreated later in the Chugach Mountain than in other regions of Alaska. Reconstructed equilibrium-line altitude depressions range from 400 to 430 m for late Wisconsinan glacial advances in the Chugach Mountains, representing a possible temperature depression of 2.1–2.3°C. These reconstructed temperature depressions suggest that climate was warmer in this part of Alaska than in many other regions throughout Alaska and elsewhere in the world during the global last glacial maximum.

Description: Quantifying sedimentary deposits is crucial to fully test generic trends cited within facies models. To date, few studies have quantified downstream trends alongside vertical and lateral variations within distributive fluvial systems (DFS), with most studies reporting qualitative trends. This study reports on the generation of a quantitative dataset on the Huesca DFS, Ebro Basin, Spain, in which downstream, vertical and lateral trends in channel characteristics are analyzed using a fusion of field data and virtual outcrop model derived data (VOM). Vertical trend analysis reveals that the exposed portion of the Huesca DFS does not show any systematic changes through time, which suggests autogenic-driven local variability. Proximal-to-distal trends from field data display a downstream decrease in average channel body thicknesses (13.1–0.7 m), channel deposit percentage (70–4%), and average storey thicknesses (5.2–0.7 m) and confirm trends observed on other DFS. The VOM dataset shows a similar downstream trend in all characteristics. The range in values are, however, larger due to the increase in amount of data that can be collected, and trends are thus less clear. This study therefore highlights that standard field techniques do not capture the variability that can be present in outcrops. Channel percentage was found to be most variable (37% variation) in the medial setting, whereas channel body thickness is most variable (∼15 m range) in the proximal setting. Storey thickness varied in both the proximal and medial settings (range of 9 and 11 m for field and VOM data respectively) becoming more consistent downstream. Downstream shifts in architecture are also noted from massive, highly amalgamated channel-body sandstones in proximal regions to isolated or offset-stacked channel-bodies dominating the distal region. Trends are explained by spatial variability in DFS processes and preservation potential. The overlap present indicates that no single value is representative of position within a DFS, which has important implications for interpreting the location that a data point sits within a DFS when using limited (i.e., single log) datasets. These comparative results contribute to improving the accuracy of system-scale downstream predictions for channel characteristic variability within subsurface deposits.

Description: The Çukurova Delta Complex, formed by the Seyhan, Ceyhan, and Berdan rivers, is the second-largest delta system in the Mediterranean. The delta complex is a major depocenter that contains sediments transported from the Taurus Mountain belt since the Miocene. Studies on the Quaternary landscape evolution of the Çukurova Delta Complex are scarce, and in particular, the Holocene evolution of the Seyhan Delta section of the Çukurova Delta Complex has been poorly understood. Sedimentological analysis, high-resolution digital elevation models derived using structure from motion, and optically stimulated luminescence dating of the foredune ridges in the Seyhan Delta help define the lesser-known nature of Late-Holocene paleoenvironmental and landscape evolution of the Seyhan section of the Çukurova Delta Complex. The foredune ridges provide evidence that the Akyatan Lagoon, one of Turkey’s largest lagoon, formed at the beginning of the last millennium. The ridges bordering the north and south of Tuzla Lagoon show that the lagoon completed its formation between the 11th and 14th centuries when the ancient delta was to the east. The Seyhan River flowed 10 km east from its current course until at least the 16th Century, and its ancient delta was active until that time. After the 16th Century, the Seyhan River shifted to its current course in the west and began to build the modern delta and the youngest foredune ridges were formed by a combination of aeolian and littoral processes. The contemporary delta continued to prograde until the construction of the Seyhan Dam in AD 1956. Since the construction of the Seyhan Dam, the delta shoreline at the river mouth retreated drastically and foredune formation stopped. In the past few decades, most of the foredune ridges have been eroded away by coastal processes and agricultural activities.

Description: The Wabash Valley seismic zone (WVSZ) is a region of diffuse, modern intraplate seismicity in the central United States with a history of strong, late Quaternary and Holocene seismicity as determined through paleoliquefaction studies. Yet, there are no specific faults linked to these strong WVSZ paleoearthquakes, some of which were as large as Mw 7.2–7.5. A multidisciplinary investigation of a linear, 5-kilometer-long and ∼3-meter-high scarp on the Ohio River floodplain in the southernmost WVSZ in western Kentucky evaluated whether the scarp is a fluvial landform or a tectonic feature. Geomorphic mapping and optically stimulated luminescence geochronology show that the age and orientation of the scarp are inconsistent with surrounding fluvial landforms. Trenching, core drilling, seismic reflection, electrical resistivity profiling, and cross sections of petroleum well logs all indicate a blind fault directly underlies the scarp. The scarp is interpreted to be the fold axis of a down-to-the-west monocline formed in alluvium by slip on the underlying blind fault, herein named the Uniontown fault. The Uniontown fault connects the Hovey Lake fault, striking N20°E and having   ∼0.5  km of documented strike-slip offset, with an unnamed fault complex to the south that strikes N40°E, suggesting the Uniontown fault is part of a larger, Paleozoic structure that has been reactivated with strike-slip deformation. Geomorphic mapping utilizing luminescence and radiocarbon geochronology indicates that folding and faulting occurred ∼3.5  ka. Paleoliquefaction was suppressed by a thick clay cap in the main Ohio Valley, but paleoliquefaction features are widespread on Ohio River tributaries. Gravel dikes at one site had a maximum age of 3.4±0.4  ka, confirming the region has experienced strong, late Holocene shaking. Estimates using vertical displacement and rupture length indicate that slip on the Uniontown scarp could produce an Mw 6.2–7.7 earthquake, which is comparable to other large paleoearthquakes in the WVSZ paleoseismic record.

Description: Around 4000 cal yr BP, Scots pine ( Pinus sylvestris) suffered a widespread demise across the British Isles. This paper presents new information about P. sylvestris populations found in the Welsh Marches (western central Britain), for which the long-term history and origins are poorly known. Two new pollen records were produced from the Lin Can Moss ombrotrophic bog (LM18) and the Breidden Hill pond (BH18). The LM18 peat core is supported by loss-on-ignition, humification analysis and radiocarbon dating. Lead concentrations were used to provide an estimated timeframe for the recent BH18 record. In contrast to many other Holocene pollen records from the British Isles, analysis of LM18 reveals that Scots pine grains were deposited continuously between c. 6900–300 cal yr BP, at frequencies of 0.3–5.4%. It is possible that individual Scots pine trees persisted through the wider demise on thin soils of steep drought-prone crags of hills or the fringes of lowland bogs in the Welsh Marches. At BH18, the record indicates a transition from broadleaved to mixed woodland, including conifer species introduced around AD 1850 including Picea and Pinus. The insights from BH18 suggest that the current populations may largely be the result of planting. Comparison of the LM18 findings with other regional pollen records highlights consistent patterns, including a Mid-Holocene maximum (ca. 7000 cal yr BP), long-term persistence at low pollen percentages and a Late-Holocene minimum (ca. 3000 cal yr BP). These distinctive trends encourage further studies on refugial areas for Scots pine in this region and elsewhere.