Chlorite in sandstones

Worden, Richard ORCID: 0000-0002-4686-9428, Griffiths, Josh, Wooldridge, Luke, Utley, James ORCID: 0000-0003-0397-5607, Lawan, Auwala Yola, Muhammed, Dahiru ORCID: 0000-0001-5025-5456, Simon, Naboth and Armitage, Peter (2020) Chlorite in sandstones. Earth-Science Reviews, 204. p. 103105.

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Official URL: http://dx.doi.org/10.1016/j.earscirev.2020.103105

Abstract

Chlorite, an Fe- and Mg-rich aluminosilicate clay, may be either detrital or authigenic in sandstones. Detrital chlorite includes mineral grains, components of lithic grain, matrix and detrital grain coats. Authigenic chlorite may be grain-coating, pore-filling or grain-replacing. Chlorite can be observed and quantified by a range of laboratory techniques including light optical and scanning electron microscopy and X-ray diffraction; the presence of chlorite in sandstone can be identified by the careful integration of signals from downhole logs. Grain-coating chlorite is the only type of chlorite that can help sandstone reservoir quality since it inhibits quartz cementation in deeply buried sandstones. Grain coats are up to about 10 m thick and typically isopachous on all grain surfaces; they result from rapid indiscriminate nucleation at high levels of chlorite supersaturation in the pore waters and then growth of appropriately oriented nuclei as ultra-thin, roughly equant crystals. Chlorite can have many possible origins, but it is likely that grain-coating chlorite results from closed system diagenesis at the bed scale. Chlorite sources include transformation of detrital Fe-rich berthierine, transformation of Mg-rich smectite, reaction of kaolinite with sources of Fe and breakdown of volcanic grains. The specific origin of chlorite controls its composition, with marine sandstones having a berthierine source and continental sandstones having a smectite source. Incorporation of precursor clays required for chlorite growth can be achieved by a variety of processes; these most commonly occur in marginal marine environments possibly explaining why Fe-rich chlorite coats are most commonly found in marginal marine sandstones.

Item Type:	Article
Uncontrolled Keywords:	Chlorite, Sandstone, Cement, Grain-coating, Pore-filling, Quartz-inhibition, Estuary, Delta, Reservoir quality, Wireline log, Siderite, Pyrite, Burial diagenesis, Mesodiagenesis, Eodiagenesis, Sedimentary environment, petrophysics
Depositing User:	Symplectic Admin
Date Deposited:	27 Jan 2020 08:48
Last Modified:	19 Jan 2023 00:08
DOI:	10.1016/j.earscirev.2020.103105
Open Access URL:	https://doi.org/10.1016/j.earscirev.2020.103105
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3072042