Diagenetic changes are difficult to distinguish from variations in sources of organic matter to sediments. Organic geochemical comparisons of samples of wood, bark, and needles from a white spruce (Picea glauea) living today and one buried for 10,000 years in lake sediments have been used to identify the effects of diagenesis on vascular plant matter. Important biogeochemical changes are eviden...

Slow-slip megathrust events in the Hikurangi forearc region may be related to seamount subduction. IODP Expedition 375 drilled flank of Tūranganui Knoll, a Cretaceous east subduction zone containing units analogous intervals associated with subducted seamounts. Detailed investigations volcaniclastic Unit V at Site U1520, based on scanned core images, petrographic observations, point-counting, a...

Gale Crater, the Mars Science Laboratory (MSL) landing site, contains a central mound, named Aeolis Mons (informally Mount Sharp) that preserves 5 km of sedimentary stratigraphy. Formation scenarios include (1) complete filling of Gale Crater followed by partial sediment removal or (2) building of a central deposit with morphology controlled by slope winds and only incomplete sedimentary fill. ...

We have applied correlative microscopy to identify the key constituents of a dorsal rib fossil from Koreanosaurus boseongensis and its hosting mudstone discovered at the rich fossil site in Boseong, South Korea, to investigate the factors that likely contributed to diagenesis and the preservation of fossil bone. Calcite and illite were the commonly occurring phases in the rib bone, hosting muds...

Other than halite diagenesis and organic matter degradation, Cl and Br are considered to be conservative in marine pore fluids. Consequently, Br/Cl ratios should remain constant during most diagenetic reactions. Nonetheless, Br/Cl molar ratios decrease to 1.27 3 10 ('18% less than seawater value) in pore fluids from Site 833 in the Aoba Basin of the New Hebrides convergent margin despite the la...

Using diffusion-based models for concretion growth, we calculate growth times of hematitic concretions that have been found in the Burns formation at Meridiani Planum, Mars, by NASA's Opportunity Mars Exploration Rover. Growth times of ~350–1900 terrestrial years are obtained for the observed size range of the concretions over a range of parameters representing likely diagenetic conditions and ...

Abstract In-situ δ 18 O measured in the quartz overgrowths help identify temperature and fluid origin variations responsible for cementation of pore network (matrix fracture) Buntsandstein Gp. sandstone reservoirs within Upper Rhine Graben. The record two types evolution O: 1) a monotonous decrease overgrowth interpreted as linked to an increasing burial 2) random fluctuations, pointing out inj...

Two simple algorithms are suggested here to correct for the effect of diffusion and diagenetic sulfate reduction on radiocarbon age determination of marine porewater. The correction algorithms were developed from mass balances of sulfate, dissolved inorganic carbon (DIC), and 14C of the DIC (CDIC) in vertical concentrations profiles in porewater starting from the sediment water interface. The a...