Ocean gateways facilitate circulation between ocean basins, thereby impacting global climate. The Indonesian Gateway transports water from the Pacific to the Indian Ocean via the Indonesian Throughflow (ITF) and drives the strength and intensity of the modern Leeuwin Current, which carries warm equatorial waters along the western coast of Australia to higher latitudes. Therefore, ITF dynamics are a vital component of global thermohaline circulation. Plio‐Pleistocene changes in ITF behavior and Leeuwin Current intensity remain poorly constrained due to a lack of sedimentary records from regions under its influence. Here, organic geochemical proxies are used to reconstruct sea surface temperatures on the northwest Australian shelf at IODP Site U1463, downstream of the ITF outlet and under the influence of the Leeuwin Current. Our records, based on TEX₈₆ and the long‐chain diol index, provide insight into past ITF variability (3.5–1.5 Ma) and confirm that sea surface temperature exerted a control on Australian continental hydroclimate. A significant TEX₈₆ cooling of ~5°C occurs within the mid‐Pliocene Warm Period (3.3–3.1 Ma) suggesting that this interval was characterized by SST fluctuations at Site U1463. A major feature of both the TEX₈₆ and long‐chain diol index records is a strong cooling from ~1.7 to 1.5 Ma. We suggest that this event reflects a reduction in Leeuwin Current intensity due to a major step in ongoing ITF constriction, accompanied by a switch from South to North Pacific source waters entering the ITF inlet. Our new data suggest that an additional ITF constriction event may have occurred in the Pleistocene.

中文翻译：

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上新世印度尼西亚通流变化导致东印度洋海表温度升高

海洋通道促进了海盆之间的环流，从而影响了全球气候。印尼门户网站通过印尼流量（ITF）将水从太平洋传输到印度洋，并推动了现代的吕温海流的强度和强度，该流向澳大利亚西海岸向更高纬度输送了赤道水。因此，ITF动态是全球热盐循环的重要组成部分。由于缺乏受其影响的地区的沉积记录，ITF行为的上新世更新世和Leeuwin的电流强度仍然受到严格限制。在这里，有机地球化学代理用于重建ITF出口下游且受Leeuwin洋流影响的IODP站点U1463处澳大利亚西北陆架的海表温度。我们的记录₈₆和长链二醇指数提供了对过去ITF变异性（3.5-1.5 Ma）的洞察力，并证实了海面温度对澳大利亚大陆的水文气候有控制作用。在上新世中期（3.3-3.1 Ma）内，发生了大约5°C的TEX ₈₆显着冷却，表明该间隔的特征是站点U1463的SST波动。TEX _86的主要特点而长链二醇指数记录则从1.7 Ma降到1.5 Ma。我们建议，此事件反映出由于正在进行的ITF收缩迈出了重要一步，并且伴随着从南太平洋水源到北太平洋水源水进入ITF入口的转换，Leeuwin Current强度有所降低。我们的新数据表明，在更新世可能发生了另外的ITF收缩事件。