Explore the eighteenth-century Indian astronomical observatories called the Jantar Mantars, massive, stunning structures built to observe and understand the heavens.
Understanding the formation of pore space, especially in low porosity shales (as source rocks and as unconventional resources), is critical to the oil and gas industry, since pores control the space ...available for hydrocarbon and participate in hydrocarbon transport. We examined 87 Ordovician and Silurian mudstone samples collected from four wells located in the Pomeranian part of the Baltic Basin (northern Poland), one of the primary Polish targets for hydrocarbon exploration. These samples represent the Pelplin, the Pasłęk, the Jantar, the Prabuty, and the Sasino Formations, which still requires more detailed porosity studies. Our study aimed to identify factors controlling porosity development, by applying bulk techniques (organic petrology and TOC analyses, quantitative mineralogy, and porosimetry) as well as nano-to microscale techniques (thin section petrography, electron microscopy). The studied samples are mainly argillaceous mudstones. The results of porosimetry measurements, combined with image analysis, indicate that the pores of all studied rocks are dominated by micropores (pores <2 nm in diameter), mesopores (2–50 nm in diameter) and small macropores. The SEM images showed three main pore types: a) voids related to clay mineral aggregates, b) pores inside organic matter particles, and c) pores between other mineral grains. In the Jantar and Sasino mudstones, the organic matter content and its thermal maturity control porosity. The occurrence of solid bitumen in the rocks from these formations reduces samples’ mesoporosity because of the pore-clogging effect. In contrast, in the Pasłęk and Prabuty Formations, there is low organic matter content and specific surface area and the volume of mesopores increase with clay minerals content. In the Pelplin mudstones, there are no prevailing factors controlling porosity. Finally, we suggest that a combination of SEM image analysis and dual liquid porosity (DLP) measurements is a powerful method to assess porosity available for petroleum flow in mudstones.
•Multi-method and multi-scale study of the porosity of mudstones from the Baltic Basin.•The domination of solid bitumen in organic matter and high TOC may cause pore-clogging.•The combination of high-resolution image analysis and the DLP method enables estimation of petroleum accessible porosity.
The transition from the Middle to Late Ordovician cold climate to the Silurian greenhouse phase was marked by major climatic and oceanographic changes. The vast epereic sea that during the early ...Paleozoic extended over the Baltic Plate for hundreds of kilometres recorded the dynamic processes that characterized this important climatic evolution. This shallow epicontinental sea experienced phases of hypoxic conditions for millions of years during the Silurian favouring the sedimentation of organic-rich deposits. A continuous core drilled in the Silurian fine-grained succession of the Baltic Basin was studied integrating sedimentological, palynological and geochemical data. The succession, deposited in a restricted environment in low-energy settings, recorded three long-term variations in bottom-water redox conditions. Our data highlight a direct control of long-term climatic changes on oceanic redox cycles. Phases of cool and dry climate with reduced runoff alternated with periods of warmer and humid conditions with higher runoff and fluvial discharge. During warmer and more humid climatic phases, the presence of a stable pycnocline hampered deep-water renewal efficiency, and together with increased nutrients led by enhanced weathering and runoff favoured the onset of anoxic bottom-water conditions. Cooler and drier intervals favoured instead a weaker and less stable pycnocline that, coupled with more oligotrophic conditions, drove the formation of oxic bottom-waters. The variation through time in water salinity and temperature influenced both the type of organic matter in the surface waters as well as its preservation along the water column. In fact, the extended residence time at the stable pycnocline during the anoxic phases led to the degradation of the organic matter and limited its accumulation at the sediment-water interface. The waning of the latest Ordovician cooling to the Silurian greenhouse climate was characterized by the progressive alternation of cool phases and warmer periods. The effect of this dynamic climatic instability on the redox state of the Baltica epicontinental sea protracted over millions of years up to the middle Silurian.
•Restricted basin hydrographic conditions caused benthic anoxia.•Long-term pycnocline and nutrient variations controlled benthic anoxia dynamics.•Hypoxia (oxia) occurred during warm-humid (cool-dry) climatic conditions.•The presence of a stable pycnocline limited organic carbon accumulation rate.•Latest Ordovician–Silurian climate change was gradual.
V članku se avtor ukvarja s problematiko dotoka jantarja na zahodni in srednji Balkan v času bronaste dobe (natanč- neje okoli 1600–900 pr. n. št.) ter njegovim kroženjem med regijami tega ...območja. Razpoložljivi podatki, povezani s to temo, so bili analizirani z uporabo različnih računskih metod. Predhodno tipološko opredeljene jantarne jagode kažejo kronološke razlike, kar omogoča delitev na dva glavna sklopa, ki ju je mogoče pripisati srednji in mlajši oz. pozni bronasti dobi. Nekatere oblike so v uporabi v obeh obdobjih. Za številne tipe je značilen omejen obseg razprostranjenosti, ki verjetno govori za lokalno proizvodnjo. Tipe jantarnih jagod avtor primerja tudi z jantarnimi izdelki s sosednjih območij z jantarjem. Izbrani predmeti, ki se pojavljajo skupaj z jantarjem, dodatno osvetljujejo notranjo dinamiko kroženja jantarja in kažejo na potencialne udeležence izmenjave.
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The hypothesis of this study was that coriander grown in the cool wet conditions of Atlantic Canada would have comparable oil composition to coriander oil marketed internationally and would have a ...potential as a cash crop for the region. Field experiments were conducted in 2001 and 2002 to evaluate the effect of seeding date (24 May and 8 June) and location (Truro and Canning, Nova Scotia) on yield and essential oil quality of coriander cultivars ‘Jantar’ and ‘Alekseevski’. Plants grew well and had normal to high seed essential oil content. However, seed and essential oil yields were low, suggesting that the crop would not compete well for a place in Atlantic Canada agriculture. In both years, the earlier seeding date (24 May) enhanced productivity. The two cultivars had dissimilar oil content, oil and seed yields. The oil composition of tested cultivars was similar to coriander oils from India and Hungary with linalool as the main component. Hence, essential oil produced in Atlantic Canada should be easily marketed as are the essential oils produced in India and Hungary. Coriander seeds produced in Atlantic Canada contained normal to high amount of linalool (64–84.6%). The other oil constituents were camphor (3.4–6.2%), α-pinene (1.2–3.2%), phellandrene (1.7–4.1%), linalyl acetate (2.4–3.3%), limonene (0.7–1.8%),
para-cymene (0.5–1.3%), and geranyl acetate (0.9–1.6). Both cultivar and seeding date affected oil composition. Further research on fall and early spring seeding dates and on the crop mineral nutrition is needed in the region to increase seed yields and essential oil productivity.
The four extant Jantar Mantar observatories at Delhi, Jaipur, Ujjain,and Varanasi have tremendous potential as teaching laboratories of positional astronomy. They could be utilised in this direction ...in their current state, but this possibility would be considerably enhanced when all the necessary restorations are undertaken, interpretation centers are in place at all the observatories, and there is a continuous presence of astronomy educators, amateur astronomers, and students undertaking observations with these intriguing and user-friendly instruments. Student usage and calibration of the instruments at the Delhi observatory in particular, where the markings are mostly absent from every instrument, has allowed a greater appreciation of the possible construction details of these gigantic instruments. Templates for restoration and also for continuous maintenance of the instruments, are emerging from these efforts.
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