Sedimentation in volcanic successions

Cas, Ray

doi:10.1016/0037-0738(93)90156-y

Cited by 56 publications

(105 citation statements)

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“…They may be divided into tephra fallout and pyroclastic-density-current derived Page | 9 deposits. In contrast, 'reworked volcaniclastic/tephra' deposits contain volcaniclastic material that has been eroded or remobilised after its initial deposition, and then transported and redeposited (Cas and Wright, 1987;Manville et al, 2009). 'Tephra fallout' is the rain-out of clasts through the atmosphere from a plume generated during an explosive eruption (Walker, 1971;Houghton et al, 2000).…”

Section: Volcanology Termsmentioning

confidence: 99%

Construction of volcanic records from marine sediment cores: A review and case study (Montserrat, West Indies)

Cassidy

Watt

Palmer

et al. 2014

Earth-Science Reviews

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Detailed knowledge of the past history of an active volcano is crucial for the prediction of the timing, frequency and style of future eruptions, and for the identification of potentially at-risk areas. Subaerial volcanic stratigraphies are often incomplete, due to a lack of exposure, or burial and erosion from subsequent eruptions. However, many volcanic eruptions produce widelydispersed explosive products that are frequently deposited as tephra layers in the sea. Cores of marine sediment therefore have the potential to provide more complete volcanic stratigraphies, at least for explosive eruptions. Nevertheless, problems such as bioturbation and dispersal by currents affect the preservation and subsequent detection of marine tephra deposits.Consequently, cryptotephras, in which tephra grains are not sufficiently concentrated to form layers that are visible to the naked eye, may be the only record of many explosive eruptions.Additionally, thin, reworked deposits of volcanic clasts transported by floods and landslides, or during pyroclastic density currents may be incorrectly interpreted as tephra fallout layers, leading to the construction of inaccurate records of volcanism. This work uses samples from the volcanic island of Montserrat as a case study to test different techniques for generating volcanic eruption records from marine sediment cores, with a particular relevance to cores sampled in relatively proximal settings (i.e. tens of kilometres from the volcanic source) where volcaniclastic material may form a pervasive component of the sedimentary sequence. Visible volcaniclastic deposits identified by sedimentological logging were used to test the effectiveness of potential alternative volcaniclastic-deposit detection techniques, including point counting of grain types (component analysis), glass or mineral chemistry, colour spectrophotometry, grain size measurements, XRF core scanning, magnetic susceptibility and X-radiography. This study demonstrates that a set of time-efficient, non-destructive and high-spatial-resolution analyses (e.g. XRF core-scanning and magnetic susceptibility) can be used effectively to detect potential cryptotephra horizons in marine sediment cores. Once these horizons have been sampled, microscope image analysis of volcaniclastic grains can be used successfully to discriminate between tephra fallout deposits and other volcaniclastic deposits, by using specific criteria Page | 3 related to clast morphology and sorting. Standard practice should be employed when analysing marine sediment cores to accurately identify both visible tephra and cryptotephra deposits, and to distinguish fallout deposits from other volcaniclastic deposits.

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Section: Volcanology Termsmentioning

confidence: 99%

Construction of volcanic records from marine sediment cores: A review and case study (Montserrat, West Indies)

Cassidy

Watt

Palmer

et al. 2014

Earth-Science Reviews

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“…Fisher and Schmincke, 1984, p. 107-109; and Wright, 1987;Bull and Cas, 2000). The terrestrial depositional setting of this facies is constrained by the bounding sandstone-siltstone and volcaniclastic lithofacies of fluvial origin ( Fig.…”

Section: Pyroclastic Faciesmentioning

confidence: 99%

Sedimentation history of the Palaeoproterozoic Dhanjori Formation, Singhbhum, eastern India

Mazumder

Sarkar

2004

Precambrian Research

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The Palaeoproterozoic Dhanjori Formation, eastern India is a terrestrial (dominantly fluvial) volcano-sedimentary succession. Basal conglomerate, coarse-grained sandstone, and shale rests directly on the granite basement and represents the distal fringe of an alluvial fan complex. Sieve, sheet flood, mass flow and alluvial channel and overbank deposits comprise the fan segment. The rest of the formation is entirely constituted by fining upward fluvial cycles. An event of basin tilting and volcanic eruption intervened and resulted a second phase of Dhanjori sedimentation, although the general fluvial depositional framework remained unaltered. The two members of the Dhanjori Formation display different paleocurrent trends related to fluvial response to basin tilting. In the lower member spatial variability in paleocurrent directions occurs as a consequence of fan development. Unlike the first phase, the second phase of fluvial deposition incorporates profuse volcanics and accompanying volcaniclastic deposits. These volcanic and volcaniclastic rocks might have locally blocked the river courses resulting in short-lived lacustrine deposition. Composition of the volcanics varies upward from ultramafic to mafic. The Dhanjori volcanism took place in an intracontinental rift setting as is evident from the interbedded terrestrial deposits. Interbedded volcanic and volcaniclastic rocks in different stratigraphic levels suggest episodic volcanic eruption. A semiarid paleoclimate is proposed and is consistent with development of an alluvial fan comprised of coarse clastic deposits.

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“…화쇄류암은 정치 온도와 상관없이 화산회를 포함하 는 모든 화성쇄설물의 흐름이나 사태를 말하며 대부 분 이들이 여러 차례 반복적으로 일어나 복잡하기 때 문에 여러 가지 흥미로운 연구의 대상이 되어왔다 (Sparks et al, 1973;Fisher and Schmincke, 1984;Cas and Wright, 1987;Valentine, 1987;Fisher, 1990;Druitt, 1992). 화쇄류암은 분출시의 분출상에 따라 구성원, 조성, 조직, 내부구조 등에 의해 여러 암상으로 나타난다.…”

Section: 서 언unclassified

“…3). (Cas and Wright, 1987 (Self and Rampino, 1981). 강하상 혹은 써지 상에서 화쇄류상으로의 전환은 방출률의 큰 증가를 일 으키고 (Bursik and Woods, 1996), 흔히 많은 암편을 수반할 수 있다 (Wright and Walker, 1977;Aramaki, 1984;Druitt, 1985;Druitt and Bacon, 1986;Rosi et al, 1996).…”

Section: 서 언unclassified

Eruption Styles and Processes of the Dongmakgol Tuff, Cheolwon Basin, Korea

황상구¹,

손영우²,

최장오³

et al. 2013

The Journal of the Petrological Society of Korea

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The Dongmakgol Tuff is divided into 8 lithofacies based on their grain size and depositional structures: massive tuff breccia(TBm), welded tuff and lapilli tuff(LTw), rheomorphic tuff and lapilli tuff(LTr), massive lapilli tuff(LTm), stratified lapilli tuff(LTs), gradedly bedded lapilli tuff(LTg), crudely bedded lapilli tuff(LTb) and massive fine tuff(Tm). They can be divided into 3 pyroclastic rock group based on their constituents of the lithofacies. The lower group(LI) is composed of LTm, LTw and LTr, which are interpreted to have resulted from emplacement of voluminous pyroclastic flows due to ignimbrite-form eruption to boiling-over eruption. The middle group(LT+MI) consists of LTs, LTg and LTm associated with Tm in the lower part, and of LTm, LTw and LTr in the middle and upper parts; these suggest that started with deposition of pyroclastic surges from phreatoplinian eruption by poor eternal water, passed through emplacement of pyroclastic flows from ignimbrite-form eruption and ended with deposition of voluminous pyroclastic flows from boiling-over eruption. The upper group(lUT+uUT+UI) is composed of LTs, LTg and Tm in the lowermost, TBm, LTb, LTb and Tm in the lower part, and LTm and LTw in the middle and upper part, suggesting that began with deposition of surges from phreatoplinian

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Sedimentation in volcanic successions

Cited by 56 publications

References 0 publications

Construction of volcanic records from marine sediment cores: A review and case study (Montserrat, West Indies)

Construction of volcanic records from marine sediment cores: A review and case study (Montserrat, West Indies)

Sedimentation history of the Palaeoproterozoic Dhanjori Formation, Singhbhum, eastern India

Eruption Styles and Processes of the Dongmakgol Tuff, Cheolwon Basin, Korea

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