Basin Analysis of Tertiary Strata in Golden Bay, Nelson

10.26686/wgtn.16999198.v1 ◽

2021 ◽

Author(s):

◽

William Leslie Leask

Keyword(s):

Iron Ore ◽

Tectonic Activity ◽

New Members ◽

Shallow Marine ◽

Marine Deposits ◽

Facies Associations ◽

Iron Ore Deposit ◽

Sand And Gravel ◽

Coal Measures ◽

River Catchments

<p>Eocene to Miocene strata comprise the Brunner Coal Measures (Ak-Ld), Takaka Limestone (Ld-Po), Tarakohe Mudstone (P1-S1) and Waitui Sandstone (Sc-Sl), and form a transgressive-regressive sequence on an essentially stable structural platform. Brunner Coal Measures in the Takaka valley (up to 350m thick) consist of cross-bedded sand and gravel, interlaminated sand and silt, bioturbated muddy sandstone, carbonaceous mudstone and coal. Five facies associations are recognized and interpreted as river/floodbasin, estuarine and shallow marine deposits. In the Aorere and Parapara River catchments, two new members are recognized: the Quartz Wash Member, comprising quartzose sand and conglomerate, and the Washbourn Limonite Member, a sedimentary iron-ore deposit. The Takaka Limestone (up to 100m thick), consists of bryozoan, bivalve or sandy grainstone or packstone, deposited on a tidal current-swept shallow-middle shelf with minimal terrigenous influx. Diagenesis was controlled by pressure-solution during deep burial, and resulted in a rightly cemented rock with dolomite and neomorphic features. The Tarakohe Mudstone (up to 900m thick) is dominated in its lower half by massive mudstone of hemipelagic and turbiditic origin, and in its upper half by shallow shelf-estuarine sandstones and mudstones. The Waitui Sandstone (160m thick) comprises shallow marine sandstone. Deposition of the Brunner Coal Measures took place in localized fault-angle depressions. The Takaka Limestone was deposited during a period of regional subsidence and minimal tectonic activity. The Tarakohe Mudstone and Waitui Sandstone were deposited in synclinal basins which were later modified by rising monoclinal boundaries.</p>

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Petrology and genesis of the Bhainskati iron ore deposit of Palpa District, western Nepal

Bulletin of the Department of Geology ◽

10.3126/bdg.v15i0.7418 ◽

2013 ◽

Vol 15 ◽

pp. 63-68

Author(s):

Sujan Devkota ◽

Lalu Prasad Paudel

Keyword(s):

Marine Environment ◽

Mineral Assemblage ◽

Iron Ore ◽

Ore Deposit ◽

Shallow Marine ◽

Shallow Marine Environment ◽

Long Time ◽

Iron Ore Deposit ◽

Petrographic Study ◽

Oolitic Ironstone

The Bhainskati Formation of the Tansen Group in the Palpa area is known for hematite iron ore deposit for long time. A prominent band of hematite of about 1-2 m thickness and extending >5 km was identified in the upper part of the Bhainskati Formation in the present study. The band is repeated three times in the area by folding and faulting. Petrographic study shows that it is oolitic ironstone of sedimentary origin. Main minerals in the band are hematite, goethite, quartz, calcite, siderite and albite. Hematite content varies considerably among samples and occurs mainly as oolite and cement. The Bhainskati ironstone with its ferrous mineral assemblage and well-rounded texture of the ooids suggests shallow marine environment (prodeltaic to estuarine) with reduced clastic input. DOI: http://dx.doi.org/10.3126/bdg.v15i0.7418 Bulletin of the Department of Geology, Vol. 15, 2012, pp. 63-68

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Petrology and Genesis of the Bhainskati Iron Ore Deposit of Palpa District, Western Nepal

Tribhuvan University Journal ◽

10.3126/tuj.v28i1-2.26237 ◽

2013 ◽

Vol 28 (1-2) ◽

pp. 153-160

Author(s):

Lalu Poudel ◽

Sujan Devkota

Keyword(s):

Marine Environment ◽

Mineral Assemblage ◽

Iron Ore ◽

Ore Deposit ◽

Marine Origin ◽

Shallow Marine ◽

Long Time ◽

Iron Ore Deposit ◽

Petrographic Study ◽

Oolitic Ironstone

The Bhainskati Formation of the Tansen Group in Palpa area is known for hematite iron ore deposit for long time. A prominent band of hematite of about 1-2 km thickness extending >5 km was identified in the upper part of the Bhainskati Formation in the present study and the band is repeated three times in the area by folding and faulting. Petrographic study shows that it is oolitic ironstone of sedimentary shallow marine origin. Main minerals in the band are hematite, goethite, quartz, calcite, siderite and albite. Hematite content varies considerably among samples and occurs mainly as oolite and cement. The Bhainskati ironstone with its ferrous mineral assemblage and well-rounded texture of the ooids suggests prodeltaicto estuarine with shallow marine environment reduced clastic input.

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Sedimentology and stratigraphic architecture of a fluvial to shallow-marine succession: The Jurassic Dhruma Formation, Saudi Arabia

Journal of Sedimentary Research ◽

10.2110/jsr.2020.077 ◽

2021 ◽

Vol 91 (7) ◽

pp. 773-794

Author(s):

Bassam Alshammari ◽

Nigel P. Mountney ◽

Luca Colombera ◽

Mohammed A. Al-Masrahy

Keyword(s):

Saudi Arabia ◽

Gamma Ray ◽

Quantitative Information ◽

Delta Front ◽

Thin Sections ◽

Shallow Marine ◽

Marine Deposits ◽

Wide Range ◽

Facies Associations ◽

Depositional Models

ABSTRACT The interaction of fluvial, tidal, and wave processes in coastal and paralic environments gives rise to sedimentary successions with highly varied styles of facies architecture; these are determined by the morphology and evolutionary behavior of the range of coastal sub-environments, which may be difficult to diagnose in subsurface sedimentary successions with limited well control. This study presents depositional models to account for stratigraphic complexity in a subsurface fluvial to shallow-marine succession, the Middle Jurassic Dhruma Formation, Saudi Arabia. The study achieves the following: i) it examines and demonstrates sedimentary relationships between various fluvial, nearshore, and shallow-marine deposits, ii) it develops depositional models to account for the stratigraphic complexity inherent in fluvial to shallow-marine successions, and iii) it documents the sedimentology and the stratigraphic evolutionary patterns of the lower Dhruma Formation in the studied area of Saudi Arabia. The dataset comprises facies descriptions of 570 m of core from 14 wells, 77 representative core thin sections, 14 gamma-ray logs, and FMI image logs from 4 wells. These data are integrated with quantitative information from > 50 analogous systems from a wide range of modern and ancient settings, stored in a relational database. Stratigraphic correlations reveal the internal anatomy of the succession. Facies associations are representative of fluvial channels, intertidal flats, pedogenically modified supratidal flats or floodplains, river-influenced tidal bars, weakly storm-affected shoreface and offshore-transition zones, storm-dominated delta-front and prodelta settings, and an open-marine carbonate-dominated shelf. These sub-environments interacted in a complex way through space and time. The vertical succession of the studied interval records an overall transition from coastal-plain deposits at the base to marine deposits at the top. As such, the succession records a long-term transgressive, deepening-upward trend. However, this general trend is punctuated by repeated progradational events whereby coastal sand bodies of fluvial, wave, and tidal origin prograded basinward during stillstands to fill bays along a coastline. The nature of juxtaposition of neighboring sub-environments has resulted in a sedimentary record that is highly complex compared to that generated by morphologically simple shoreface systems that accumulate more regularly ordered stratal packages.

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