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The research of the Kaizer Hill site (the Hilltop and its Terraces), recognized as a Pre Pottery Neolithic A (PPNA) quarry site, involved studies of the rock damage associated with the quarrying activities as well as of the recovered material remains, mostly chipped stone artifacts. We present here the results of our on-site explorations (excavations, surveys and surface-collections), focusing on the findings deriving from the Terraces. Diverse rock damage patterns were identified and described, portraying systematic rock mass-exploitation through quarrying fronts, natural rock joints and fissures enlargement, drilling and chiseling. There are multiple indications that the local bedrock (Bi'na Formation, Turonian) comprising flint and limestone was quarried under a systematic quality evaluation, leaving residual flint unsuitable for exploitation. Of interest to note that nearly all of the flint artifacts excavated and collected on the Terraces were made on raw material transported from the Hilltop (Mishash Formation, Campanian), knapped in-situ, on the quarried rock surfaces of the slopes. The flint tools bear witness to intensive use involving mainly boring and drilling. The dominant tool type is the flint axe for which a variety of waste products related to its production were found in-situ, enabling the reconstruction of axe reduction sequence. Similar axes and waste products were found in many PPN sites indicating that there was a common, widely-used scheme of making flint axes during the PPN. Interestingly, besides the flint waste, there were also limestone waste products typical of the last shaping and thinning stages of axe production, indicating that limestone axes were shaped technologically similar to the flint ones, contrary to what has been assumed before. Rare findings, such as obsidian pieces, originating from much further a-field indicate ties with other PPN communities, near and/or far. Overall, this study provides unique and novel insights on Levantine PPN lifeways.

The new mineral delchiaroite, Cu.sub.3 I(CH.sub.3 S).sub.2, has been discovered in La Piana quarry, Colonnata marble basin, Carrara, Apuan Alps, Tuscany, Italy. It occurs as light-yellow acicular crystals, elongated on [010], up to 0.1 mm in length and is brittle, with a light-yellow streak and a greasy luster. In reflected light, delchiaroite is light gray with abundant internal yellow reflections; anisotropism is moderate, with gray tints. Reflectance values for the four COM wavelengths are (λ (nm) Rmin/Rmax (%)) 470: 20.6/22.2; 546: 20.9/23.4; 589: 20.7/23.3; and 650: 20.1/22.4. Electron microprobe analysis resulted in the following (average of 12 spot analyses - in wt %): Cu 47.27, I 31.09, S 14.90, C.sub.calc 5.58, H.sub.calc 1.40, and total 100.24. The empirical formula of delchiaroite, calculated on the basis of Cu + I + S = 6 atoms per formula unit, is Cu.sub.3.07 I.sub.1.01 (CH.sub.3 S).sub.1.92, in accordance with the end-member formula Cu.sub.3 I(CH.sub.3 S).sub.2 . Delchiaroite is orthorhombic, space group Pmmn, with a=16.924(10), b=4.099(2), c=5.572(3) Ã, V=386.5(4) Ã.sup.3, and Z=2. The crystal structure was refined to R.sub.1 =0.0962 for 360 unique reflections, with F.sub.o 4ÏF and 27 refined parameters. It can be described as being formed by electroneutral [Cu.sub.3 I(CH.sub.3 S).sub.2 ].sup.0 100 layers stacked along a. The origin of delchiaroite is related to the supergene alteration of enargite in vugs of Liassic marbles. Chemically, this mineral belongs to the pseudo-binary system CuI-Cu(CH.sub.3 S) at a 1:2 ratio. It constitutes the first example of natural iodide-methanethiolate, illustrating the interaction between inorganic and organic chemistry. Its name honors the mineral collector Lorenzo Del Chiaro (b. 1951) for his contribution to the knowledge of the mineralogy of the vugs of the Marble Formation belonging to the Alpi Apuane metamorphic complex.

The Cambodian floodplains experience a yearly flood pulse that is essential to sustain fisheries and the agricultural calendar. Sixty years of data, from 1960–2019, are used to track the changes to the flood pulse there. We find that minimum water levels over 2010–2019 increased by up to 1.55 m at Kratie and maximum water levels decreased by up to 0.79 m at Prek Kdam when compared to 1960–1991 levels, causing a reduction of the annual flood extent. Concurrently, the duration of the flooding season has decreased by about 26 d (Kampong Cham) and 40 d (Chaktomuk), with the season starting later and ending much earlier. Along the Tonle Sap River, the average annual reverse flow from the Mekong to the Tonle Sap Lake has decreased by 56.5 %, from 48.7 km3 in 1962–1972 to 31.7 km3 in 2010–2018. As a result, wet-season water levels at Tonle Sap Lake dropped by 1.05 m in 2010–2019 compared to 1996–2009, corresponding to a 20.6 % shrinkage of the lake area. We found that upstream contributors such as current hydropower dams cannot fully account for the observed decline in flood pulse. Instead, local anthropogenic causes such as irrigation and channel incision are important drivers. We estimate that water withdrawal in the Cambodian floodplains is occurring at a rate of (2.1 ± 0.3) km3 yr−1. Sediment decline and ongoing sand-mining operations have also caused channel erosion. As the flood pulse is essential for the ecological habitats, fisheries and livelihoods of the region, its reduction will have major implications throughout the basin, from the Tonle Sap system to the Vietnamese Mekong Delta downstream.

We observed a Killdeer (Charadrius vociferus) incubating a nest containing 1 Piping Plover (Charadrius melodus) egg and 2 Killdeer eggs at a sand and gravel mine in West Point, Nebraska. Four days later, the nest contained 1 Piping Plover egg and 4 Killdeer eggs. Two days later, the Piping Plover egg was absent, and the 4 Killdeer eggs remained in the nest. Eight days later the nest was destroyed. We speculate the nest began as a Piping Plover nest and was usurped by a Killdeer pair. To our knowledge, this is the first documentation of a nest containing eggs from both species. Received 12 October 2023. Accepted 3 March 2024.

Manufactured sand concrete (MSC) has increasingly applied in engineering. However, how to enhance the thermal crack resistance of MSC has not clearly studied yet, which limits the wide applications of manufactured sand in engineering. We have adopted the method of mixing limestone powder (LP) to make MSC with four mass fractions (wt.%) of 5%, 10%, 15%, and 20% of LP content, designed the mix proportion of concrete, tested their mechanical properties, observed their microstructure by scanning electron microscopy (SEM) and investigated the effect of LP on anti-cracking performance using temperature stress testing machine (TSTM). These findings reveal that the mechanical properties and thermal crack resistance of 15% LP MSC are the best. Our results also provide a research basis for the MSC to be widely used in engineering.

The world's large rivers are facing reduced sediment loads due to anthropogenic activities such as hydropower development and sediment extraction. Globally, estimates of sand extraction from large river systems are lacking, in part due to the pervasive and distributed nature of extraction processes. For the Mekong River, the widely assumed estimate of basin-wide sand extraction is 50 Mt per year. This figure is based on 2013 estimates and is likely to be outdated. Here, we demonstrate the ability of high-resolution satellite imagery to map, monitor, and estimate volumes of sand extraction on the Lower Mekong River in Cambodia. We use monthly composite images from PlanetScope imagery (5 m resolution) to estimate sand extraction volumes over the period 2016–2020 through tracking sand barges. We show that rates of extraction have increased on a yearly basis from 24 Mt (17 to 32 Mt) in 2016 to 59 Mt (41 to 75 Mt) in 2020 at a rate of ∼8 Mt yr−1 (6 to 10 Mt yr−1), where values in parentheses relate to lower and upper error bounds, respectively. Our revised estimates for 2020 (59 Mt) are nearly 2 times greater than previous best estimates for sand extraction for Cambodia (32 Mt) and greater than current best estimates for the entire Mekong Basin (50 Mt). We show that over the 5-year period, only 2 months have seen positive (supply exceeds extraction) sand budgets under mean scenarios (5 months under the scenarios with the greatest natural sand supply). We demonstrate that this net negative sand budget is driving major reach-wide bed incision with a median rate of −0.26 m a−1 over the period 2013 to 2019. The use of satellite imagery to monitor sand mining activities provides a low-cost means to generate up-to-date, robust estimates of sand extraction in the world's large rivers that are needed to underpin sustainable management plans of the global sand commons.

The production of manufactured sand and stone processing can cause dust pollution due to the generation of a significant amount of stone powder. This dust (mainly granite powder) was collected and incorporated as a cement replacement into mass-manufactured sand concrete in order to enhance the mechanical properties and microstructures. The heat of the hydration was measured by adding the granite powder into the cementitious material system. The mechanical properties, autogenous shrinkage, and pore structures of the concrete were tested. The results showed that the mechanical strength of the concrete increased first and then decreased with the increase in granite powder content. By replacing the 5% cement with the granite powder, the 28 d compressive and flexural strength increased by 17.6% and 20.9%, respectively. The autogenous shrinkage was mitigated by the incorporation of the 10% granite powder and decreased by 19.7%. The mechanism of the granite powder in the concrete was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The porosity decreased significantly within the 10% granite powder. A microstructure analysis did not reveal a change in the type of hydration products but rather that the granite powder played a role in the microcrystalline nucleation during the hydration process.