Middle and Late Jurassic climatic, oceanographic and environmental trends along the Viking Corridor

<p><strong>Keywords: Late Jurassic; palaeoclimate; Greenland; carbon cycling; Viking Corridor; belemnite stable isotopes</strong></p><p>The “polar amplification” effect, whereby the poles experience greater changes in temperature compared to the low latitudes for a given global average temperature change, makes high-latitude isotope records ideally suited to investigate fluctuations in palaeoclimate. The present study investigates palaeoclimatic and oceanographic changes along the Viking Corridor – the narrow seaway that connected the Tethys to the Arctic Boreal Realm during the Middle and Late Jurassic.</p><p>Stable-isotope data obtained from belemnites from East Greenland, originating from along the western margin of the Viking Corridor, show a M. Bathonian warming trend, which may indicate the reopening of the corridor after North Sea doming. We also discuss various controls on the carbon-isotope record that may dampen or amplify global signals. Changes in local depositional settings caused partial overprinting of the δ<sup>13</sup>C record during the Late Jurassic VOICE event.</p>

UJI DENSITAS DAN POROSITAS SERTA KARAKTERISASI MENGGUNAKAN XRD DAERAH MATA AIR PANAS SEMURUP SUNGAI MEDANG KABUPATEN KERINCI PROVINSI JAMBI

Test Density and Porosity of rock have been done to see the relation to temperature influence 100 ᵒC, 200 ᵒC and 300 ᵒC. Rocks that will be tested first heated temperature with furnace tool then weighed with a digital balance. Density and Porosity measurement data were analyzed using Matlab Software with ASTMC373 equation. The result of Matlab in the form of graph shows average temperature change to Semurup rock density of 0.03 g / cm3 and the effect of temperature on Semurup rock porosity at 300 ᵒC is 30.29%. The average temperature change to Medang River rock density is 0.003 g / cm3 and the effect of temperature on Medang River rock porosity at 300 ᵒC is 0,55%. Looking at the rock crystal structure used XRD. Data from Characterization using XRD was analyzed with High Score Plus software. The result of rock characterization using XRD, from semurup showed that component of CaCO3 is 94%, crystal structure not yet fully formed and still in amorphous form, meanwhile rock from medang river show that component of CaCO3 is with 98%, crystalline structure have formed crystal.