Hydrothermal fields in the Mid-Atlantic Ridge: Setting and prospects for further discoveries

Mazarovich, A. O.; Sokolov, S. Yu.

doi:10.2205/2002es000104

Cited by 9 publications

(5 citation statements)

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“…High levels of the SPM concentration were also noted above the MAR. The axial region of the MAR including the rift zone experiences high seismicity and bears a big number of earthquake epicenters as well as the sulfide mineralization zones of various origins and bedrock zones showing strong hydrothermal imprints (Mazarovich and Sokolov, 2002); in particular in the Sierra Leone fracture zone, i.e. immediately below the Ioffe-2000 transect (see Fig.…”

Section: Deep Oceanmentioning

confidence: 99%

Distribution of suspended particulate matter at the equatorial transect in the Atlantic Ocean

Sivkov

Bubnova

2021

Preprint

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Abstract. Studied oceanographic transect across the Equatorial Atlantic is considered as a “screenshot” of suspended particulate matter distribution against a hydrographical background. The area of abnormal high suspended matter volume concentrations was found above the Sierra Leone Rise from top to bottom (eastern part of the transect). The suggested explanation for the anomaly is based on the ballast hypothesis whereby solid particles are incorporated as ballast into suspended biogenic aggregates, leading to increased velocities of sinking. This process is located within the Northwest African upwelling area since the plankton exposed to the Saharan dust abundance form a significant number of aggregates lately transported equatorward via Canary Current. The intermediate nepheloid layer associated with the Deep Western Boundary Current was recorded from the American Slope at the 3200–3700 m to the depth of 4300 m above the Para Abyssal Plain. Antarctic Bottom Water enriched in the suspended matter was found mostly in the troughs at 40–41° W. It was detached from the bottom, coinciding with the core of the flow due to the bottom rise (“dam”) located up-stream. The grain size of particles was in accordance with polymodal distribution – the 2–4 μm and the 8–13 μm modes. The registered rise in the percentage of the 7–21 μm-sized particles suggests the presence of the well-known coarse mode (20–60 μm) formed by aggregation of transparent exopolymer particles (mucus).

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Section: Deep Oceanmentioning

confidence: 99%

Distribution of suspended particulate matter at the equatorial transect in the Atlantic Ocean

Sivkov

Bubnova

2021

Preprint

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“…According to Lavelle (2012), both these currents may be accelerated along the flanks of the ridge and represent a significant stirring mechanism for abyssal flow and cause the SPM concentration rise. Moreover, the axial region of the Mid-Atlantic Ridge including the rift zone experiences high seismicity and bears a large number of earthquake epicentres as well as the sulfide mineralization zones of various origins and bedrock zones showing strong hydrothermal imprints (Mazarovich and Sokolov, 2002), in particular in the Sierra Leone fracture zone, i.e. immediately below the Ioffe-2000 transect (see Fig.…”

Section: Deep Oceanmentioning

confidence: 99%

Distribution of suspended particulate matter at the equatorial transect in the Atlantic Ocean

Sivkov

Bubnova

2021

Ocean Sci.

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Abstract. A suspended particulate matter distribution against a hydrographical background was studied at the oceanographic transect across the equatorial Atlantic in the year 2000. An area of abnormally high suspended matter volume concentrations was found above the Sierra Leone Rise in the entire water column (eastern part of the transect). The suggested explanation for the anomaly is based on the ballast hypothesis whereby solid particles are incorporated as ballast into suspended biogenic aggregates, leading to increased velocities of sinking. This occurs within the Northwest African upwelling area, where the plankton exposed to the Saharan dust abundance form a significant number of aggregates, which are later transported equatorward via the Canary Current. An intermediate nepheloid layer associated with the Deep Western Boundary Current was recorded from the South American Slope at depths of 3200–3700 to 4300 m above the Para Abyssal Plain. Antarctic Bottom Water enriched in suspended matter was found mostly in the troughs at 40–41∘ W. It was detached from the bottom, coinciding with the core of the flow due to the bottom rise “dam” located up-stream. The grain size of particles along the entire transect has a polymodal distribution with 2–4 and 8–13 µm modes. The registered rise in percentage in some parts of the transect of the 7–21 µm sized particles suggests the presence of the well-known coarse mode (20–60 µm) formed by aggregation of transparent exopolymer particles (mucus).

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“…Исключения составляют области пересечения СА Х трансформными разломами большой длины, вдоль которых активность связана со сдвиговыми смещениями. Отображение сейсмичности без временного фактора (Мазарович, Соколов, 1998;Mazarovich, Sokolov, 2002) показывает чередование областей с повышенным и пониженным уровнем сейсмичности, но не дает настолько наглядной картины, какую можно получить в пространстве с временной координатой. По данным (Schlindwein, 2012) сейсмичность может быть представлена в виде комбинации одиночных событий, вертикальных полос (в оригинале -sequence) и кластеров (в оригинале -swarm).…”

Section: подходы к пространственно-временному анализуunclassified

“…гетерогенное плотностное распределение и изостатический фон, который влияет на характер сейсмичности, связанной с магматическими процессами. Неравномерное распределение сейсмичности вдоль всего САХ является давно установленной (Болдырев, 1998) и обсуждалась в работах (Мазарович, Соколов, 1998;Mazarovich, Sokolov, 2002) в связи с распределением вдоль САХ гидротермальных систем. Интерпретация фактов неравномерности приобретает дополнительные и необходимые аргументы при ее рассмотрении совместно с изостатическими ано-малиями и другими геофизическими данными, имеющими геодинамический смысл -вариации скоростей в мантии, горизонтальный градиент изостатических аномалий.…”

Section: Introductionunclassified

Spatial-Temporal Comparison of Distribution of Seismic Activity and Isostatic Anomalies Along the Mid-Atlantic Ridge

Sokolov¹,

Zarayskaya²

2019

BKRAESC. Earth Sciences

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Пространственно-временная структура сейсмичности вдоль Срединно-Атлантического хребта (САХ) по телесейсмическим данным выражена чередованием зон повышенной сейсмичности, которые на пространственно-временных графиках отображаются полосами концентрации сейсмических событий, и неактивных зон, отмеченных на графиках пустотами. Полосы сейсмичности в сочетании с минимумами изостазии интерпретируются наличием дискретных зон прогретой мантии, в которых подъем вещества формирует аномальное гравитационное поле и устойчивый тремор. Полосы проявлены в сегментах САХ, где превалирует низкотемпературный и малоглубинный магматизм «спредингового» типа. Пустоты сейсмичности проявлены в областях высокопродуктивного магматизма «плюмового» типа, при котором мантия обладает пониженной вязкостью и не происходит накопления больших напряжений. Широкие полосы интенсивной сейсмичности соответствуют разломным зонам с событиями сдвигового типа, по которым имеет место большое латеральное смещение оси САХ. Сочетания полос с локальными максимумами изостазии указывает на сдвиговую природу сейсмичности по небольшим трансформным разломам, либо на проявления тремора в областях высокопродуктивного плюмового магматизма, при котором подъем вещества с глубины перешел в формирование вулканических построек, выраженных в рельефе и формирующих избыток масс.

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Hydrothermal fields in the Mid-Atlantic Ridge: Setting and prospects for further discoveries

Abstract: Abstract. Analyzed is the setting of active and inactive hydrothermal fields and sulfide occurrences on the Mid-Atlantic Ridge between 65• N and 65• S. Multifaceted interpretation of data has enabled a prediction of how sulfide mineralization is distributed in the Atlantic Ocean.

Cited by 9 publications

References 9 publications

Distribution of suspended particulate matter at the equatorial transect in the Atlantic Ocean

Distribution of suspended particulate matter at the equatorial transect in the Atlantic Ocean

Distribution of suspended particulate matter at the equatorial transect in the Atlantic Ocean

Spatial-Temporal Comparison of Distribution of Seismic Activity and Isostatic Anomalies Along the Mid-Atlantic Ridge

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