Emplacement of submarine lava flow fields: A geomorphological model from the Niños eruption at the Galápagos Spreading Center

Abstract

In the absence of any direct observations of an active submarine eruption at a mid-ocean ridge (MOR), our understanding of volcanic processes there is based on the interpretation of eruptive products. Submarine lava flow morphology serves as a primary indicator of eruption and emplacement processes; however, there is typically a lack of visual observations and bathymetric data at a scale and extent relevant to submarine lava flows, which display meter to submeter-scale morphological variability. In this paper, we merge submersible-based visual observations with high-resolution multibeam bathymetry collected by an autonomous underwater vehicle (AUV) and examine the fine-scale geomorphology of Niños, a submarine lava flow field at the Gal apagos Spreading Center (GSC).We identify separate morphological facies (i.e., morphofacies) within the lava flow field, each having distinct patterns of lava flow morphology and volcanic structures. The spatial and stratigraphic arrangement of morphofacies suggests that they were emplaced sequentially as the eruption progressed, implying that the Niños eruption consisted of at least three eruptive phases. We estimate eruption parameters and develop a chronological model that describes the construction of the Niños lava flow field. An initial phase with high effusion rates emplaced sheet flows, then an intermediate phase emplaced a platform of lobate lavas, and then an extended final phase with low effusion rates emplaced a discontinuous row of pillow lava domes. We then compare this model to mapped lava flow fields at other MORs. Despite disparities in scale, the morphological similarities of volcanic features at MORs with different spreading rates suggest common emplacement processes that are primarily controlled by local magma supply.

Three‐Dimensional Seismic Imaging of Ancient Submarine Lava Flows: An Example From the Southern Australian Margin

“…While seismic data allow us to rapidly gather information on the distribution of a scale of tens of kilometers, it does not provide the meter‐scale vertical resolution that is required to determine lava crustal morphology and the presence of features such as lava pillars and inflation clefts (e.g., Mitchell et al, ). At best, in shallowly buried successions such as documented herein, the detection limit of the data is ≥5 m. This means that seismic‐based studies are unable to determine processes related to the temporal development of the flow such as variations in effusion rate along source fissures (White et al, ), and variations in local magma supply (McClinton & White, ). Nevertheless, our study illustrates that seismic data provide a useful method for studying ancient lava flows that are otherwise inaccessible.…”

“…The pathways are also interpreted as lava distribution systems and lava flow directions can be inferred from their branching morphologies. The trenches are interpreted as low density sections of lava distribution systems, such as portions of drained lava tubes (e.g., Figure ; McClinton & White, ). High‐amplitude regions within the plateaus, lobes, and pathways may represent high‐density sections of lava distribution systems, such as the cores of megapillows (e.g., Figure ; Goto & McPhie, ).…”

Remote sensing of river corridors: A review of current trends and future directions

“…Traditionally utilised in the marine environment, autonomous underwater vehicles (AUVs) use active sensing to guide them through missions such as maintaining survey depth for consistent resolution sea bed mapping (Brothers et al, ; Covault, Kostic, Paull, Ryan, & Fildani, ; Maier et al, ; Tubau et al, ), coral reef mapping (Armstrong & Singh, ), submarine lava identification (McClinton & White, ), and sea bed classification (Lucieer, Hill, Barrett, & Nichol, ). Terrestrial water applications are less common and require careful consideration due to the complex motion of water alongside the need for improved object detection and avoidance (Li, Xie, Luo, & Shi, ; Zhao, Lu, & Anvar, ).…”

Seamount‐Volcanic Island Transition and Evolution From Fissural to Central Activity Inferred by the Magnetic Modeling of Salina Island (Tyrrhenian Sea)

“…The availability of geophysical and marine geology data allows us to significantly advance our knowledge of submarine volcanoes and their associated genetic processes (Casalbore, , and reference therein). The style and emplacement of volcanic eruptions is, in fact, different below or above sea level interface, and it is also strongly dependent on the water depth (Bosman et al, ; McClinton & White, ; Mitchell et al, ). Morphological studies also evidence a transition from conical shapes with a subcircular base to ‘stellate’ forms (Mitchell, ) reflecting the progressive growth of seamounts and volcanic islands.…”