Petrologic evolution of boninite lavas from the IBM Fore-arc, IODP Expedition 352: Evidence for open-system processes during early subduction zone magmatism
Petrologic evolution of boninite lavas from the IBM Fore-arc, IODP Expedition 352: Evidence for open-system processes during early subduction zone magmatism
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IBM Fore-arc, IODP Expedition 352 的桠泥岩熔岩的岩石学演化：早期俯冲带岩浆作用期间开放系统过程的证据
DOI：
10.2138/am-2021-7733
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发表时间：
2022
影响因子：
3.1
通讯作者：
Bradford Mack
中科院分区：
文献类型：
--
作者：
J. Scholpp;J. Ryan;J. Shervais;C. Stremtan;M. Rittner;A. Luna;Stephen Hill;Z. Atlas;Bradford Mack
摘要在IODP探险352期间，在U1439C孔内的几个区段中发现的玻安石样品显示出高度可变的矿物化学成分，暗示着复杂的结晶历史。细小的辉石颗粒表现出振荡分带，其核心和带的范围从白云母到辉石不等。晚期结晶辉石的Al_2O_3含量(1.9-13.7wt%)和Ca-Tschermak组分含量(3-13mol%)变化很大，反映了不平衡条件。大的、整面体、低钙辉石(即顽辉石/斜辉石)晶体表现出复杂的扇形和振荡分带模式。橄榄石和低钙辉石中均含有富铬尖晶石包裹体。早期结晶橄榄石斑晶对边缘有包裹体和反应，一些早期结晶橄榄石表现出分带性。一些橄榄树有多个区域，正常区域和反向区域都在Fo86-92之间。橄榄石捕虏晶也有包裹体和反应边缘；然而，捕虏晶没有化学分带模式，具有一致的FO88成分。辉石边缘结晶的不平衡反映了喷发过程中的快速冷却。低钙辉石中的扇形分带是在混合事件之间的适度过冷期结晶的结果。橄榄石和辉石中的振荡、正常和反向分带似乎是对多阶段岩浆混合或混合过程的响应，这些过程将额外的Ca、Fe、Ti和Al引入母质玻尼质熔体中。橄榄石包裹体和斜方辉石的存在表明在2-4kbar处是平衡的(Whattam等人。(2020)表明玻安岩岩浆混合事件可能发生在含有富含橄榄石的堆积堆的浅层岩浆房中。较大的混合事件可能破坏了岩浆室的稳定，导致去挥发和喷发。相比之下，较小的混合事件缺乏破坏矿房稳定的能量，导致受多个小混合事件影响的矿物中的成分反复振荡。
Abstract Boninite samples from several intervals within Hole U1439C, recovered during IODP Expedition 352, show highly variable mineral chemistries that imply complex crystallization histories. Small pyroxene grains show oscillatory zoning with cores and zones ranging from pigeonite to augite. Late crystallizing augite has highly variable Al2O3 contents (1.9–13.7 wt%) and Ca-Tschermak component contents (3–13 mol%), which reflect disequilibrium conditions. Large, euhedral, low-Ca pyroxene (i.e., enstatite/clinoenstatite) crystals exhibit complex sector and oscillatory zoning patterns. Cr-rich spinel is found as inclusions both in olivine and low-Ca pyroxene. Early crystallized olivine phenocrysts have embayed and reacted margins, and some early crystallized olivines exhibit zoning. A few olivines have multiple zones, with both normal and reverse zoning between Fo86–92. Olivine xenocrysts also have embayed and reacted margins; however, xenocrysts do not exhibit chemical zoning patterns and have consistent Fo88 compositions. Disequilibrium crystallization of pyroxene rims reflects rapid cooling during an eruption. Sector zoning in low-Ca pyroxenes is the result of crystallization during periods of moderate undercooling between mixing events. Oscillatory, normal, and reverse zoning in olivine and pyroxene appears to have formed in response to multi-stage magma mingling or mixing processes, which introduced additional Ca, Fe, Ti, and Al into parental boninitic melts. The presence of olivine xenocrysts and orthopyroxene indicate equilibrium at 2–4 kbar (Whattam et al. 2020) indicates that boninite magma mixing events likely occurred within shallow magma chambers containing olivine-rich cumulate piles. Large mixing events probably destabilized the magma chamber, resulting in devolatilization and eruption. In contrast, small mixing events lacked the energy to destabilize the chamber, resulting in repeated compositional oscillations in minerals affected by multiple small mixing events.
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影响因子：
2.6
作者：
M. Reagan;J. Pearce;K. Petronotis;R. Almeev;Aaron Avery;C. Carvallo;T. Chapman;G. Christeson
通讯作者：
M. Reagan;J. Pearce;K. Petronotis;R. Almeev;Aaron Avery;C. Carvallo;T. Chapman;G. Christeson
影响因子：
5.3
作者：
Hongyang Li;R. Taylor;J. Prytulak;M. Kirchenbaur;J. Shervais;J. Ryan;M. Godard;M. Reagan;
通讯作者：
Hongyang Li;R. Taylor;J. Prytulak;M. Kirchenbaur;J. Shervais;J. Ryan;M. Godard;M. Reagan;
影响因子：
3.1
作者：
T. Shea;F. Costa;D. Krimer;J. Hammer
通讯作者：
T. Shea;F. Costa;D. Krimer;J. Hammer
影响因子：
3.7
作者：
J. Shervais;M. Reagan;M. Godard;J. Prytulak;J. Ryan;J. Pearce;R. Almeev;Hongyang Li;E. Haugen;T. Chapman;W. Kurz;W. Nelson;D. Heaton;M. Kirchenbaur;K. Shimizu;T. Sakuyama;S. Vetter;Yibing Li;S. Whattam
通讯作者：
J. Shervais;M. Reagan;M. Godard;J. Prytulak;J. Ryan;J. Pearce;R. Almeev;Hongyang Li;E. Haugen;T. Chapman;W. Kurz;W. Nelson;D. Heaton;M. Kirchenbaur;K. Shimizu;T. Sakuyama;S. Vetter;Yibing Li;S. Whattam
橄榄石中磷和铝的分区：两种名义上不相容的微量元素的对比行为
影响因子：
3.5
作者：
Shea, Thomas;Hammer, Julia E.;Hellebrand, Eric;Mourey, Adrien J.;Costa, Fidel;First, Emily C.;Lynn, Kendra J.;Melnik, Oleg
通讯作者：
Melnik, Oleg