Concretion Formation In Volcaniclastic Host Rocks: Evaluating the Role of Organics, Mineralogy, and Geochemistry On Early Diagenesis

2014 ◽  
Vol 84 (10) ◽  
pp. 875-892 ◽  
Author(s):  
S. L. Potter-McIntyre ◽  
M. A. Chan ◽  
B. J. McPherson
Keyword(s):  
Early Diagenesis ◽  
Host Rocks

Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination

2000 ◽  
Vol 37 (4) ◽  
pp. 535-547 ◽  
Author(s):  
David I Schofield ◽  
Richard S D'Lemos
Keyword(s):  
Magma Mixing ◽  
Mobile Belt ◽  
Multiple Sources ◽  
Potential Source ◽  
Iapetus Ocean ◽  
Granite Magmatism ◽  
Host Rocks ◽  
Binary Mixing ◽  
Lower Crustal

Silurian to Devonian granites within the Gander Zone of the Appalachian Central Mobile Belt in northeastern Newfoundland formed adjacent to the former Gondwanan continental margin following terminal closure of the Iapetus Ocean. Comparison of geochemical and isotopic characteristics of the granites with their host migmatites and metasediments, amphibolite, and orthogneiss constrain their potential source. Nd and Sr isotopic compositions indicate that no single source or binary mixing product could have produced the granites. Instead, we show that they result from multicomponent mixing involving a contribution from unexposed crystalline basement, mantle or underplate, and variable contamination by supracrustal host rocks. The timing and composition of granite magmatism do not exhibit collisional orogenic, subduction-related, or continental rifting characteristics. Hence, we relate magmatism to lithospheric melting following delamination of an orogenic keel. This process provides the influx of mantle-derived magma into fertile crust and hence promotes lower crustal melting and primary magma mixing.

scholarly journals The role of early diagenesis in the sedimentary steroids around Penguin Island, Antarctica

2010 ◽  
pp. 155-161
Author(s):  
Liziane M. M. Ceschim ◽  
Rosalinda C. Montone ◽  
César C. Martins
Keyword(s):  
Early Diagenesis

ORGANOCHLORINE PESTICIDES IN THE COASTAL SEDIMENT OF CITARUM ESTUARY, JAKARTA BAY: THE IMP ORTANT ROLE OF FINE FRACTION OF THE SEDIMENT AS THEIR AGENT TRANSPORT AND PROCESSES OF THEIR EARLY DIAGENESIS

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
T. Pratono ◽  
H. Razak ◽  
I. Gunawan
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Fine Fraction ◽  
Aerobic Condition ◽  
Early Diagenesis ◽  
Chemical Processes ◽  
Coastal Sediment ◽  
Sediment Samples ◽  
Transport Agent

DDT (1,1,1-Tricholor-2,2-bis(chlorophenil)ethane) and its two derivatives, DDD (1,1-Dicholor-2,2-bis(chlorophenil)ethane) and DDE (1,1-Tricholor-2,2-bis(chlorophenil)-ethylene) were identified in the coastal sediment of Citarum Estuary, Jakarta Bay.Eight stations of the sediment sampling were designed in order to obtain the changing of their concentration sadjacent to the estuary as possible input. Sediment samples were collected in the surface layer within a less than 5 cm depth. In addition to pesticides, texture of sediment and total organic carbon were analyzed. Generally, fine fractions (silt and clay) were predominant grain-size of the sediment ranging 21–35,8 % and 17,6–65,6 %, respectively, while total organic carbon (TOC) ranged from 0,30–1,49 %. Concentrations of p’,p’-DDT varied from 0,621–1,187ppb, concentrations of p’,p’-DDD ranged from 0,176–2,153 ppb and concentrations of p’,p’-DDE were from 0.181–2,254 ppb. The occurrence of total DDT (ΣDDT+DDD+DDE) tended to correlated positively to the fine fraction indicating as transport agent. DDD and DDE as DDT metabolites were formed by biological and chemical processes within predominantly aerobic condition. Keywords: pesticide, DDT, DDD, DDE, sediment, transport agent, Citarum, Jakarta Bay  

ROLE OF ORE MAGMAS IN THE FORMATION OF DEPOSITS

2021 ◽  
pp. 84-91
Author(s):  
S. S. Dolgushin ◽  
◽  
A. P. Dolgushin ◽  
◽  
Keyword(s):  
Hydrothermal Solutions ◽  
Hydrothermal Deposits ◽  
Decisive Importance ◽  
Host Rocks

Notions are substantiated that for a certain group of so-called hydrothermal deposits, not regular lowconcentration hydrothermal solutions, including their more concentrated derivatives, colloids, are not of decisive importance in their formation, but highly concentrated magmatic systems – ore magmas forming deposits by intrusive way, at a time when hydrothermal (including gas-hydrothermal) solutions coexisting with them, being more mobile and chemically active, produce only metasomatic changes in the host rocks and wallrock dissemination, masking the magmatic nature of deposits.

scholarly journals Mineral composition of host sediments influences the fossilization of soft tissues

2018 ◽  
Vol 55 (11) ◽  
pp. 1271-1283 ◽  
Author(s):  
Elena Naimark ◽  
Maria Kalinina ◽  
Alexander Shokurov ◽  
Alexander Markov ◽  
Liubov Zaytseva ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Mineralogical Composition ◽  
Artemia Salina ◽  
New Mineral ◽  
X Ray ◽  
Mineral Phases ◽  
Long Term Experiments ◽  
Host Rocks

Cambrian Lagerstätten host rocks are frequently composed of kaolinite and chlorite in varying amounts; accordingly, our goal was to study the preservation potential of crustaceans in these two clays. We conducted long-term experiments (12–18 months, the longest duration of actualistic taphonomy experiments from published literature) on the decay of Artemia salina in these clay sediments. The degree of preservation, transformed mineralogical composition of the sediments, and the elemental composition of the nauplial remains were examined. We demonstrate that the kaolinite and chlorite sediment enhanced the preservation (in the kaolinite the effect was considerably higher than in the chlorite) compared with the sediment-free control. pH inside the sediments dropped to 6.5–7.1 and was even lower (<4) around the buried carcasses, facilitating the dissolution of clays. This phenomenon was confirmed by mineralogical analyses of the experimental sediments, which showed mineralogical signatures of such dissolution and new mineral phases. According to the variations in the dissolved minerals in the sediments, different cations entered the buried remains as was shown by the multiple energy dispersive X-ray analyses. An increased level of Mg was detected in the carcasses buried in chlorite, whereas Al and Si concentrations were higher in the kaolinite; in both cases, Ca rapidly entered the decaying tissues from marine water. Bacteria underwent similar mineralization as the macroremains and apparently had no direct effect on the mineralization. The results confirmed an important role of dissolved Al ions in preservation of soft-bodied organisms in clay-dominated sediments and explained wide variation in chemical composition of their fossils.

scholarly journals Early diagenesis of sulfur in Bornholm Basin sediments: The role of upward diffusion of isotopically “heavy” sulfide

2021 ◽  
Author(s):  
Jiarui Liu ◽  
André Pellerin ◽  
Gilad Antler ◽  
Gareth Izon ◽  
Alyssa J. Findlay ◽  
...  
Keyword(s):  
Early Diagenesis ◽  
Bornholm Basin

Tsumoite (BiTe) and associated Ni-PGE mineralization from Gondpipri mafic-ultramafic complex, Bastar Craton, Central India: mineralogy and genetic significance

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
M. Dora ◽  
H. Singh ◽  
A. Kundu ◽  
M. Shareef ◽  
K. Randive ◽  
...  
Keyword(s):  
Total Concentration ◽  
Central India ◽  
Olivine Gabbro ◽  
Pge Mineralization ◽  
Ultramafic Complex ◽  
Mineral Assemblages ◽  
Hydrothermal Remobilization ◽  
Two Stages ◽  
Host Rocks

AbstractThis paper reports the occurrence of Tsumoite (a bismuth telluride) in the Heti Cu-Ni-PGM prospect, Gondpipri mafic-ultramafic complex, Central India. The Gondpipri complex consists of several tectonically dismembered gabbronorite-gabbro-anorthositic gabbro — olivine gabbro -websterite disposed in ∼10 km long tonalite-trondhjemitegranodiorite (TTG) and charnockite-enderbite suite of rocks. The mineralization occurs in the sulphide zone hosted by gabbro variants. The host rocks have been deformed and metamorphosed to granulite grade and subjected to various degrees of hydrothermal alteration. The mineralization comprises chalcopyrite, pentlandite, pyrrhotite, cubanite, millerite, and pyrite. In addition to these, occur (1) tsumoite (2) PGM in the form of moncheite, merenskyite, Pd-mellonite, and Pt-Pd-Te-Bi-Fe-S alloy.The present study indicates that the mineralization occurs in two stages related to: (i) magmatic and (ii) hydrothermal remobilization and transport of Cu-rich sulphides, tsumoite and PGM, and their re-deposition in hydrosilicate alteration zones. It is possible that the mineralization at Heti formed at different stages of bismuth activity under variable fS2, T, and fTe2 conditions due to change in total concentration of Te and S and /or cooling. Since the role of S is limited, Te and cooling are important factor influencing mineralogy and composition of tsumoite and associated mineralization. Mineralization occurs in two different modes of occurrences. The early mineralisation occur as blebs, specks and dissemination of sulphides, viz. pyrrhotite, chalcopyrite, pentlandite and minor pyrite ± PGM, whereas later mineralisation occur as stringers, minor veins of sulphides viz. pyrite, millerite, cubanite, sijenite, tsumoite and ± PGM.Mineral assemblages and textural relationships at Heti has indicated precipitation of tsumoite and associated PGM along fractures and secondary silicates, which confirms their hydrothermal origin.

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