X-ray diffraction analysis reveals that aragonite persists as a volumetrically important mineral constituent (38% to 56%) and as an important driver of continued diagenesis in rocks that constitute the uppermost Lucayan depositional succession. The existing porosity (average = 15.5%), which is a combination of cement-reduced primary interparticle, secondary laminamoldic, and secondary pelmoldic porosity is more evenly distributed throughout the stratigraphic succession than was precursor depositional porosity. Dissolution and cementation resulted in a net depositional porosity loss of approximately 50%. Three distinctive zones of porosity were present upon deposition: a lower zone of relatively high interparticle porosity (21.3% to 33.2%) in the medial part of P1, a low-porosity zone (< 10%) in muddy peloidal sediments in the upper part of P1, and a zone of high interparticle porosity (19 to 43%) in grain-dominated radar packages P2 through P6. Core data demonstrate a relationship between stratigraphically controlled sedimentological attributes, diagenesis, and pore distribution. The uppermost radar package is a thin (0.15 to 0.55 m), partially calichified carbonate sand sheet that mantles the entire survey site and that reflects late highstand and fall of sea level.Įxposure of the studied interval to meteoric vadose diagenesis over the past 100,000+ years has resulted in partial stabilization of the largely aragonitic precursor sediment through selective partial dissolution of aragonitic grains (mainly ooid cortical layers, peloids, and mollusk shells) accompanied by precipitation of patchily distributed low-magnesium calcite cement. Constructional accommodation on the front of the prograding subaqueous dune in the northwest part of the survey area and erosional accommodation created by downcutting of a shallow tidal channel into the upper part of the subaqueous dune depositional unit in the northeast part of the study area were filled with peloid- and ooid-dominated carbonate sands as sea level stabilized. The stratigraphic succession indicates development of a burrowed backshoal lagoon during early flooding of the bank top followed by deposition of flood-tide-driven, low-angle sheet sands and sigmoidal subaqueous dune deposits as the shelf-margin sand shoal moved bankward as a function of continued sea-level rise. Six radar packages (P1–P6) bounded by radar surfaces (S1–S6) have been identified in the two 3D radar volumes. Two complementary 3D (200 MHz and 400 MHz) ground-penetrating-radar surveys and three shallow cores reveal that the uppermost part of the upper Pleistocene (Marine Isotope Stage 5e) Lucayan Formation at Red Bays, Andros Island, Great Bahama Bank, comprises a single, 6-m-thick upward-shallowing parasequence. An understanding of how these parameters, especially porosity, are preserved or modified in the eogenetic environment is essential in bridging the gap between modern and ancient analogs. And in the darkness between the stars, an old enemy lurks, fearless, perhaps waiting for order to collapse entirely.Linkages among surface sediments, depositional processes, geomorphic forms, stratigraphic architecture, and pore distribution in Bahamian sand bodies and oolite-capped depositional successions have been characterized in recent studies. The mercenaries they hire for a few credits a kill are too few, too unreliable to do so either. The Cooperative's police force, concentrated near a few influential planets, can no longer maintain order. The trade ships that once safely travelled between planets now have to be well armed and escorted to fend off pirate attacks, from small-time criminals desperate for their next meal, to powerful robber barons extracting tithes from everyone who passes through their space. Ooids are spheroidal grains with a nucleus and mineral cortex accreted around it which increases in sphericity with distance from the nucleus. Most oolites are limestones ooids are made of calcium carbonate (minerals aragonite or calcite ). The two thousand star systems of the Cooperative once enjoyed a golden age of peace and prosperity, and perhaps the wealthiest of them can still pretend to. Oolite is a sedimentary rock made up of ooids (ooliths) that are cemented together. Perhaps one day, everyone might know your name. You've got a ship, some weapons, and enough spare cash to get started - and one day, you might get the fame, wealth or glory you want. Among the seven trillion people who are - at least officially - Cooperative citizens, you are nobody.
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